Advantage Mud Manual .pdf

5/19/2018 Advantage Mud Manual .pdf

1/408

Return to Glossary

GLOSSARY

Chapter 1 Drilling Fluid Test Procedures

Chapter 2 Water Base Mud Systems

Chapter 3 Oil Base Mud Systems

Chapter 4 Drilling Fluid Contaminants

Chapter 5 Mud Related Drilling Problems

Chapter 6 Solids Control

Chapter 7 Product Data Information

Chapter 8 Hydraulics

Chapter 9 Engineering Data


2/408

Page-1

TABLE OF CONTENTS CHAPTER 1 Return to GlossaryChapter 1 Drilling Fluid Test Procedures

Return to Table of Contents

TOPICS PAGE

1.1 MUD DENSITY (Unpressurized Mud Balance) 11.2 MUD DENSITY (Tru-Wate Pressurized Mud Balance 2

1.2.1 OBTAINING TRU-WATE DENSITY WITH AN UNPRESSURIZED BALANCE 31.3 MARSH FUNNEL VISCOSITY 41.4 RHEOLOGICAL MEASUREMENTS(Viscometers) 51.5 FILTRATION TESTS 71.6 SAND CONTENT 11

1.7 LIQUID AND SOLIDS CONTENT (RETORT / SOLIDS ANALYSIS) 121.7.1 SOLIDS CALCULATIONS 13

1.8 CATION EXCHANGE CAPACITY 231.9 pH DETERMINATION 261.10 CHLORIDE DETERMINATION 261.11 FILTRATE HARDNESS (Total Hardness, Calcium & Magnesium) 27

1.12 GYPSUM (Calcium Sulfate) CONCENTRATION 291.13 MUD FILTRATE ALKALINITY 29

1.13.1 Pf / Mf Method 301.13.2 P1 / P2 Method 301.13.3 GARRET GAS TRAIN METHOD (Carbonates) 32

1.14 ALKALINITY OF THE MUD (Pm) 34

1.15 SULFATE ION CONCENTRATION 341.15.1 Sulfate Ion QUALITATIVE TEST 341.15.2 Sulfate Ion QUANTITATIVE TEST 35

1.16 AMMONIUM SULFATE TEST ( Hach Ammonia Nitrogen Test Kit (N1-8) 361.17 SULFITE ION CONCENTRATION 361.18 HYDROGEN SULFIDE CONCENTRATION 37

1.18.1 HACH H2S TEST 37

1.18.2 GARRETT GAS TRAIN (H2S 381.19 HYDROGEN SULFIDE SCAVENGING ABILITY AND ZINC CARBONATE 401.19.1 ESTIMATION of ZINC CARBONATE CONCENTRATION (Qualitative 401.19.2 H2S SCAVENGING ABILITY and ZINC CARBONATE CONCENTRATION 41

1.20 IRONITE SPONGE TEST 431.21 POTASSIUM ION CONCENTRATION 44

1.21.1 HAND CRANK CENTRIFUGE METHOD 44

1.21.2 POTASSIUM TEST STRIPS 45

1.22 POLYACRYLAMIDE (PHPA) POLYMER CONCENTRATION 461.23 DAP AND PHOSPHATE CONCENTRATION 471.24 NITRATE ION CONCENTRATION 481.25 DETERMINATION OF AMOUNT OF CORINOX IN MUD FILTRATE 491.26 LOST CIRCULATION MATERIAL CONCENTRATION 491.27 BIOCIDE CONCENTRATION 501.28 BACTERIA DIPSLIDE TEST 50

1.29 POLYGLYCOL CONCENTRATION 511.30 STABLE-K CONCENTRATION 52

1.31 SODIUM SILICATE CONCENTRATION 54


3/408

Page-2

CHAPTER 1

DRILLING FLUID TEST PROCEDURES

In order to ensure that the mud has optimum properties, certain tests are performed. Thesetests are used to make sure that the mud properties necessary for a successful drilling operationare achieved and maintained. The tests are also used as a tool to aid in diagnosing mud relatedproblems. The mud properties are routinely checked at the well site, and recorded on a dailyDrilling Mud Report.

1.1 MUD DENSITY (Unpressurized Mud Balance) Return to Table of Contents

Drilling mud density is required to calculate the hydrostatic pressure that is being exerted by acolumn of drilling mud at any given depth. Density is also used to provide an indication of thesolids content of a drilling mud.

When the test is performed using a standard mud balance, care must be taken to ensure the cupis full and free of entrapped air.

Mud Balance Calibration:

1. Remove the lid and completely fill the cup with distilled water at room temperature.2. Replace the lid carefully, and wipe the entire balance dry.3. Place the balanced arm on the base with the knife edge resting on the fulcrum.4. With the rider placed at 1000 kg/m3 (S.G. 1.0 or 8.33 lbs./gal), the bubble of the level vial

should oscillate the same distance to the left and right of the centering mark above the vial.If not, the calibration screw at the end of the balance should be adjusted until the oscillationsare equal. Some mud balances do not have an adjustment screw and required lead shot tobe removed or added through a calibration cap.

Note: A more accurate reading is obtained if the mud balance is permitted to oscillateon its knife edge, rather than allowing it to come to rest with the bubble centered overthe centering mark.

Test Procedure:

1. Remove the lid from the cup and completely fill the cup with the mud to be tested. It may benecessary to tap or vibrate the cup lightly to bring the entrapped air to the surface for highviscosity muds.

2. Replace the lid and seat it firmly on the cup in a rotating manner. Allow the excess drillingmud to be expelled through the centrally located hole in the lid.

3. Wash the mud from the outside of the cup, and dry the mud balance.4. Place the balance arm on the base with the knife edge resting on the fulcrum.

5. Adjust the rider until the bubble oscillates equally to the left and right of the centering markabove the level vial.

6. Read the mud density as shown by the indicator on the rider.7. Report the result to the nearest scale division in kg/m3.


4/408

Page-3

Calculations:

The SI density units in kg/m3 can be found from three of the four different scales on the mudbalance as follows:

kg/m3 = lb/gal X 119.82kg/m3 = lb/ft3 X 16.02kg/m3 = Relative Density (gm/cm3) X 1000

The fourth scale on the balance is a mud gradient scale with units of psi/1000 ft. The SI unit formud gradient is kPa/m.

kPa/m = 22.62 X psi/ft


1.2 MUD DENSITY (Tru-Wate Pressurized Mud Balance)

When a drilling mud contains entrapped air, or it is experiencing a foaming problem, the muddensity may be accurately determined with a pressurized mud balance. This a mud balance issimilar in operation to the instrument described in Section 1.1 the difference being that thesample is pressurized to expel air or gas.

Test Procedure:

1. Fill the sample cup with drilling mud to a level, which is approximately 10 mm below theupper edge of the cup.

2. Place the lid on the cup with the attached check valve in the down (open) position. Push thelid downward into the mouth of the cup until surface contact is made between the outer skirtof the lid and the upper edge of the cup allowing any excess mud to be expelled through theopen check valve.

3. Pull the check valve up into the closed position, rinse off the cup and threads, and the screwthe threaded cap onto the cup.

4. With the plunger in hand, push its handle into place in the inner piston to its lower mostposition. Fill the plunger by immersing its nose in the mud to be tested and pulling out thehandle until the inner piston is in its upper most position. (The plungers operation is similarto a syringe or bicycle pump).

5. Place the nose of the plunger onto the mating O-ring surface of the valve on the cap. Thesample cup is pressurized by maintaining a downward force on the cylinder in order to holdthe check valve down (open), and at the same time forcing the piston inward. Approximately220 Newtons of force is required on the plunger handle in order to pressure the cup.

6. The check valve in the lid is pressure actuated and will close (move up) under the influenceof pressure within the sample cup. Therefore the valve is closed by gradually easing up onthe plunger cylinder while maintaining pressure on the piston. When the check valve closes,disconnect the plunger from the lid, rinse the cup in water and wipe it dry.

7. Place the pressurized balance with the knife edge on the fulcrum of the balance stand.Adjust the sliding weight on the balance beam until the bubble oscillates equally to the leftand right of the centering mark above the bubble vial. Note the value of the specific gravityat this point.


5/408

Page-4

8. The pressure in the mud balance is now released by reconnecting the empty plunger to thelid an pushing to the plunger cylinder while permitting the handle to move freely. Tocomplete the procedure all components should be washed and rinsed thoroughly.

NOTE: For trouble free operation, the valve, lid and cylinder should be greased

frequently with a water proof grease such as Lubri-Plate.

Calculations:

The SI density units in kg/m3 can be found from three of the four different scales on the mudbalance as follows:

kg/m3 = lb/gal X 119.82kg/m3 = lb/ft3 X 16.02kg/m3 = Relative Density (gm/cm3) X 1000

The fourth scale on the balance is a mud gradient scale with units of psi/1000 ft. The SI unit formud gradient is kPa/m.

kPa/m = 22.62 X psi/ft


1.2.1 OBTAINING TRU-WATE DENSITY WITH AN UNPRESSURIZED BALANCE

If aeration becomes a problem in the mud system, and it is necessary to find a true mud densitywith a pressurized Tru-Wate mud balance, it may be obtained through the use of anunpressurized mud balance.

1. In a viscosity cup, add 500 ml of water.2. Slowly add the aerated mud to the water into the viscosity cup.3. Agitate the water / mud mixture to release the entrapped air.4. Continue adding mud to the mixture until the final volume of water and mud is at 1000 ml,

and all the air is released from the mixture.5. The true mud density can then be taken as follows.

Calculations:

0.5 (Water Density) + 0.5 (Unknown Mud Density ) = Mud Balance Density

Example:

Water Density = 1000 kg/m3 (500 ml)Mud Balance Density = 1060 kg/m3

Unknown Mud Density = x

0.5 (1000) + 0.5 (x) = 1060 kg/m 3

500 + 0.5 (x) = 10600.5 (x) = 1060 - 5000.5 (x) = 560x = 560

0.5x = 1120 kg/m3

The tru-wate or density of the mud is 1120 kg/m3


6/408

Page-5


1.3 MARSH FUNNEL VISCOSITY

Funnel viscosity is an indication of the overall viscosity of a drilling mud. It is affected by the

concentration, type, size, and size distribution of the solids present, and the electrochemicalnature of the drilling muds solid and liquid phase.

Consequently, funnel viscosity should only be used to provide an indication of change orconsistency of viscosity from time to time. Since Gel Strength can have a great effect on themagnitude of the funnel viscosity, the measurement should be taken as quickly as possible.

Marsh Funnel Calibration:

With the funnel in an upright position, fill it with freshwater (at 20 C) to the level of the screenwith a finger placed over the orifice. With the aid of the measuring cup (viscosity cup) the timetaken for one litre of water to pass through the funnel orifice tube should be 27.5 seconds ( 0.5sec). The Marsh Funnel viscosity can be corrected using the following formula:

27.5 sec/L XMeasured Flow = Measured FlowOf Water (sec/L) of Mud Sample

(sec/L)

X = True Marsh Funnel Viscosity

NOTE: The marsh funnel orifice is a tube, 50.8 mm in length and 4.76 mm in internaldiameter. The orifice may be cleaned by passing a 4.76 mm (3/16 inch) drill through it byhand.

Test Procedure:

1. With the funnel in an upright position, cover the orifice with a finger and rapidly pour a freshlycollected mud sample through the screen, and into the funnel until the mud just touches thebase of the screen (1500 ml).

NOTE: It is also permissible to overfill the funnel to some level above the screen, andbegin timing when the mud level reaches the screen. This is sometimes done inconjunction with not placing the finger over the orifice. In this manner, the effect ofGel Strength on funnel viscosity is minimized.

2. Immediately remove the finger from the orifice and measure the time required for the mud tofill the viscosity cup to the one (1) litre level.

3. Report the result to the nearest second as the Marsh Funnel Viscosity, at the temperature ofmeasurement in degrees Celsius.


7/408

Page-6

1.4 RHEOLOGICAL MEASUREMENTS Return to Table of Contents

In the field, the rheological characteristics of a drilling mud are determined with a concentricrotational viscometer having an industry standardized bob and sleeve. Shear stress, viscosity,

or Gel Strength is determined from the degree of rotation of the bob under the influence of theshear rate created in the mud by the action of the outer, rotating sleeve. Because most drillingmuds are non-Newtonian in behavior (pseudoplastic and thixotropic), stress, viscosity and gelstrength measurements must be performed at prescribed shear rates (rotational speeds). Theindustry standard rotational speeds are 600 and 300 rpm for any steady state of rheologicalparameter and 3 rpm for gel strength (an indication of thixotropy) measurements.

The most common field viscometers are:

Baroid Rheometer Model 280

The operation of these models is similar.

The hand crank models have three speeds which are changed by a shift lever and internallycontrolled by a slip clutch. The stirring speed is obtained by moving the shift lever counterclockwise as far as possible. The 600 rpm speed is obtained by moving the shift lever clockwisefrom the stirring speed to the first detent position. The 300 rpm rotational speed is obtained bymoving the shift lever to its next detent clockwise from the 600 rpm position. Gel strength isobtained by rotating the knurled hand wheel.

Fann Model HC34A

This hand crank model has two speeds which are changed by a shift knob (or wheel) on top ofthe instrument. The 600 rpm speed is obtained with the shift knob pushed down while thesleeve is rotating, and the 300 rpm rotational speed is obtained by moving the shift knob all theway up while the sleeve is moving. A neutral position is located by a detent half way betweenthe 600 and the 300 reading position. Gel strengths are determined by rotating the knurledwheel (located below the shift knob) by hand with the shift knob in the neutral middle position.

Fann Model 34A

This model is a 3 speed electric version of the Fann Model HC34A. The stirring speed isobtained by pressing the button on the left side of the upper body. The 600 rpm speed isobtained with the top shift knob pushed down while the sleeve is rotating, and the 300 rpmspeed is obtained by moving the top shift knob all the way up while the sleeve is rotating. Aneutral position is located by a detent half way between the 600 and 300 rpm position. Gelstrengths are determined by rotating the knurled wheel (located below the shift knob) by hand,with the shift knob in the neutral middle position.

PROCEDURES FOR RHEOLOGICAL MEASUREMENTS

In conventional field practices, the steady state rheological description of a drilling mud is givenin terms of the parameters which describe the fluid as an ideal Bingham Plastic. Theseparameters are the Plastic Viscosity and Yield Point, or Yield Stress. The time dependent natureof the drilling mud (thixotropy) is measured in terms of Gel Strength.

The temperature at which rheological measurements are taken should be constant and alwaysbe recorded.


8/408

Page-7

1. Plastic Viscosity and Yield Point

Place a recently agitated sample in a suitable container and lower the instrument head untilthe sleeve is immersed in the drilling mud sample exactly at the scribed line of the sleeve.

With the instrument set at 600 rpm, rotate the sleeve until a steady dial reading is obtained,(for highly thixotropic muds, this may take some time). Consistency of results can beachieved if the 600 rpm dial reading is taken at the point for which the change in dial readingis less than 1 degree (one dial division over a stirring time of one minute).

Rheological Measurements:

When the dial reading has reached this steady value, record this as the 600 rpm dialreading, D600.

Lower the speed to 300 rpm, and stir the sample at this speed until a steady reading isobtained using the same criteria for the steady state point. Record this value at the 300 rpmdial reading, D300.

Calculations:

Apparent Viscosity (mPa.s) = D6002

Plastic Viscosity (mPa.s) = D600 D300

Yield Point (Pa) = D300 - PV2

2. Gel Strength

Gel Strength measurements can be made as a continuation of the steady state

measurements. Measurements are taken at two rest periods; 10 seconds and 10 minutes.

a. Stir the mud sample at 600 rpm until a steady reading has been achieved. (If all timedependence has been taken out of the mud sample, this reading should be the same asthe previous 600 rpm dial reading).

b. Stop rotation of the sleeve. (For the Fann Model HC34A or 34A, the shift knob must besimultaneously brought to the neutral position).

c. Allow a rest time of 10 seconds, then slowly (at 3 rpm) and steadily rotate the GelStrength wheel (counter clockwise for the Fann instruments; clockwise for all others).

d. Record the maximum dial deflection as the initial Gel Strength dial reading, D0.e. Repeat steps (a)-(b), and in step (c), allow a rest time of 10 minutes.f. Record the maximum dial reflection as the 10 minute Gel Strength dial reading, D10.


9/408

Page-8

Calculations:

Initial Gel Strength, G0 (Pa) = D02

Ten Minute Gel Strength, G10 (Pa) = D102

Note: If the initial and the 10 minute Gel Strengths are equal, the mud has nothixotropy, i.e.: the mud has no ability to build structure while it is at rest. This type ofmud does not have any real Gel Strengths, or increased suspending power while it isat rest. For this type of mud, the gel break is not very evident, rather it will be agradual increase to a steady value. This is indicated by a lower ten minute GelStrength in comparison to a higher initial Gel Strength.

3. Instrument Care

After every usage, the instrument should be thoroughly cleaned.

a. Run the rotor immersed in water (or solvent for oil base mud) at high speed for a shortperiod of time.

b. Remove the sleeve:- hold the spindle, twist and carefully pull straight down for the Fann instruments.- hold the spindle and unscrew the sleeve for all other instruments.

c. Wipe the bob and other parts thoroughly clean with a dry, clean cloth or paper towel.

Caution: The bob is hollow and from time to time accumulated moisture inside thebob can be eliminated by removing the bob and drying it out.

Immersion of the hollow bob in extremely hot mud can result in a serious explosion.

Care should be taken not to immerse the sleeve deeper into the mud than the scribedline on the sleeve. This may result in damage to the bearings holding the bob shaft inplace. Similarly care must be taken not to splash water or solvent up into the sleevehousing when the bob and its shaft are cleaned.

1.5 FILTRATION TESTS Return to Table of Contents

The filtration and wall building characteristics of a drilling mud are important for providing arelative measure of the amount of mud filtrate invasion into a porous and permeable formation,and the amount of filter cake that will be deposited on the wall of the wellbore wherever filtrationoccurs. From a drilling view point, these properties give an indication of the amount of water (oroil) wetting that can take place in filtrate sensitive formations, and the potential for tight hole or

differential sticking problems. For productive, hydrocarbon bearing formations, these propertiesgive an indication of the amount of filtrate invasion and permeability damage that can beexpected.


10/408

Page-9

Filtration tests are conducted under two different conditions.

1. The standard API filtration test is conducted at surface (or room) temperature and 700 kPa(100 psi) pressure for 30 minutes. For this test, the fluid loss is the volume (in millimeters) of

filtrate collected in this time period, and the filter cake thickness (in millimeters) is thethickness of the cake that is deposited on the filter paper in this time period.

2. The API High Temperature High Pressure test (HT-HP test) is conducted for thirty minutesof filtration at a temperature normally at 150 degrees Celsius (300 degrees F), and adifferential pressure of 3450 kPa (500 psi). If the bottom hole temperature is known,then the filtration temperature may be run at that temperature. For this test, the filtratemud be collected under a back pressure of 700 kPa (100 psi), in order to preventvaporization of the filtrate.

For all filtration test, the filter paper characteristics are Whatman 50, or equivalent, and thefiltration area is 4560 mm2.

Many filtration tests are conducted with a half area filter press. In this event, thefilter cake thickness will be the same, but the fluid loss must be corrected to the fullsize paper by doubling the collected filtrate volume in the 30 minute time period. AllHT-HP instruments are half area presses.

Standard Filtration Test Instruments:

1. Rig Style, Standard Filter Press

This type of filter press has a test cell with a removable lid and base that is placed onto thecross beam of a frame with a screw handle at the top for holding these component partstogether during the test.

The instrument is assembled in the following order:

a. Base cap with filtrate tube, rubber gasket, screen, filter paper, rubber gasket fixed to themud cell (cylinder) using the locking dowel.

b. Pour drilling mud into the cell to within 10 mm from the top.c. Place the rubber gasket, filter paper, and lid onto the cross beam of the test cell frame.d. Then screw down the handle firmly and connect the pressure source making sure the

pressure relief valve is closed.

2. Baroid, OFI Half Area Filter Press

This type of instrument is typical of a half area cell for which the filtrate volume must bedoubled when the fluid loss is reported.

This instrument is self contained with a CO2 cartridge in a cylinder for its pressure sourcethat is adjusted using the T-handle of the built-in regulator at the top of the instrument. Themud cell is a rubber boot that is placed inside a holding cup to separate the mud for thepressure source. The lip of the boot serves as the sealing surface onto which the half areafilter paper is placed prior to securing the lid into place. The lid, in the form of a screw cap orother locking device, is either knurled on the inside to simulate a screen, or it may contain anactual, fixed screen. The relief valve (sliding bar) on the side of the cell must be open toapply pressure to the outside of the boot, and closed when the filtration test is complete, inorder to permit pressure to be relieved.


11/408

Page-10

3. Fann Model MB (Magcobar Style) Filter Press

This instrument consists of a mud cell assembly, pressure regulator and gauge mounted onthe top of the carrying case. The cell is attached to the regulator by means of a coupling

adapter by simply inserting the male cell coupling into the female filter press coupling, andturning clockwise turn.

The cell is closed at the bottom by a lid fitted with a screen, by placing the lid firmly againstthe filter paper, and turning to the right until hand tight. This forces the filter paper againstthe O-ring fitted in the O-ring grove at the base of the cell. Pressure is supplied by a CO2cartridge, and may be released by a bleed-off valve prior to uncoupling the cell. (The bleed-off valve is screwed in).

Standard API Test Procedure:

1. Pour the mud sample into the cell, secure the lid and make sure all valves are in the correct

positions to permit the application of pressure to the sample to be filtered. If necessary,place a fresh CO2 cartridge in the holding cylinder and screw the cylinder on quickly andsecurely to puncture the cartridge.

2. Place an appropriately sized, granulated cylinder under the filtration tube.3. Using the pressure gauge as an indicator, apply 700 kPa (100 psi) pressure to the sample

and begin timing the test.4. Collect the filtrate in the graduated cylinder for 30 minutes. At this time, remove the

graduated cylinder, turn off and relieve the pressure on the test sample.5. Report the volume of collected fluid as the fluid loss in millimeters, making sure the volume

is doubled if a half area filter press is used.6. Disassemble the test cell, discard the mud, and use extreme care to save the filter paper

with minimal disturbance to the filter cake. Remove excess mud from the filter cake by lightwashing, or lightly sliding a finger across the filter cake.

Measure the thickness of the filter cake and report in millimeters. If desirable, the filter caketexture may also be noted as being dry to slick, and mushy to firm to provide an indication ofits friction factor and compressibility.

7. Wash all components thoroughly fresh water, and wipe dry with a clean cloth or paper towel.

High Temperature High Pressure Filtration Test

1. Baroid, OFI HT - HP Filter Presses

These instruments are O-ringed valve stems that act as valves which are closed when thestem is tightened in the mud cell, and opened by unscrewing the valve stem approximately turn. The pressure regulator and back pressure cylinder is attached to the valve stems

with locking pins. The cell of this type of instrument is loaded by unscrewing the set screwsin the cell body until the cap can be removed.


12/408

Page-11

With the valve stem in the body and closed (tightened), mud is added to the cell to within 10-15 millimeters from the top. Filter paper is place on top of the O-ring which has its owngroove in the cell body. The cap is placed in the cell making sure that the set screw seats inthe cap match the screws in the cell. The pressure source is a CO 2 cartridge located in the

barrel of the regulator assembly. The back pressure attachment is required only for testsconducted at temperatures above 95 degrees C. The mud cell is placed into the heatingjacket, and seated on the alignment pin located in the jacket.

The filtrate volume obtained from this instrument must be doubled in order to correctthe volume to the full sized paper.

2. Magcobar, OFI HT HP Filter Presses

These instruments are threaded valve stems with valves to which the pressure regulatorassembly and back pressure assembly are secured using a lock ring and slip couplingassembly.

The cell is filled by closing the valve on the cell, inverting it and then adding the drilling mudto within 10-15 mm from the top. Filter paper is placed on the O-ring in its groove. The capof the cell is secured using set screws and lowered into the heating jacket which hasprovision to pass the valve and valve stem assembly of the cell through its base. The backpressure assembly is used for test with temperatures in excess of 95 degrees C. Pressureis supplied from CO2 cartridges in the barrel of the regulator assembly. The cartridge ispunctured when the barrel is tightened onto the regulator assembly.

This is a half area instrument whose filtrate volume must be doubled to correct it tothe standard full size test.

High Temperature High Pressure Filtration Test Procedure:

The following is the standard procedure adopted by the API for testing at 149 degrees C (300degrees F), and 3450 kPa (500 psi) differential pressure.

1. Connect the heating jacket to the correct voltage, place a thermometer in the well of thejacket, and preheat the jacket to 155 deg. C. Adjust the thermostat in order to maintain aconstant temperature.

2. Take warm mud from the flowline, and preheat to 50-55 deg. C while stirring.3. Load the cell as recommended by the manufacturer. Care should be exercised not to fill the

cell closer that 15 mm from the top to allow for expansion.4. Place the cell in the heating jacket with both the top and bottom valves closed. Transfer the

thermometer from the heating jacket to the well of the test cell.5. Place the pressure assembly on the top valve stem and lock into place. Place the bottom

pressure receiver and lock into place. Apply 700 kPa (100 psi) to both pressure units withthe valves closed. Open the top valve, and apply 700 kPa (100 psi) while heating.

6. When the temperature reached 149 deg. C (300 deg. F), open the bottom valve andincrease the pressure on the top assembly to 4150 kPa (600 psi) to start filtration. Collectthe filtrate for 30 minutes, maintaining 149 deg. C (300 deg F) temperature, 2 deg. C.

If desired, record the volume after 2 seconds. If the back pressure rises above 700 kPa (100psi) during the test, cautiously bleed off pressure by collecting a portion of the filtrate.Record the total volume.


13/408

Page-12

7. The filtrate volume should be corrected to a filter area of 4581 mm2. Double the filtratevolume and report.

8. At the end of the test, close both valves. Back the T-handle screw off the regulator, andbleed of the pressure from both regulators.

9. Caution: The filtration cell will still contain 3500 kPa (500 psi) pressure. Maintain

the cell in a upright position and cool to room temperature. After the cell is cool,continue to hole the cell upright (cap down), and loosen the top valve to bleed off thepressure slowly.

10. After the cell has cooled and the pressure has been bled off, the cell may be inverted toloose the cap screws with an Allen wrench. Remove the cap with a gentle rocking motion.Carefully retain the filter cake for analysis and thoroughly clean and dry all components.

11. Do not use the filtrate for chemical analysis.12. If filter cake compressibility is desired, the test can be repeated using 1400 kPa (200 psi) on

the top pressure unit, and 700 kPa (100 psi) for the bottom pressure unit.13. Record both temperature and pressure with the results of the filtration test at all times. The

temperature of 149 deg. C (300 deg. F) is normally selected, so as to be within the rangewhere high temperature mud treating procedures and chemicals are required.

Note: At any time when utilizing any HT-HP filter press, if the CO2

pressure runs out inthe middle of the test and a replacement cartridge has to used, remember to shut the topand bottom valves prior to replacing the CO2 cartridge. Remember the filtration cell willstill contain 500 psi pressure.

1.6 SAND CONTENT Return to Table of Contents

The API sand content is defined to be that portion of the drilling mud solids whose size is greaterthan 74 microns. The test can be used to give a qualitative, relative indication of the solidsremoval equipment effectiveness, the relative amount of coarse Barite present, and theabrasiveness of the mud.

Equipment:

The sand content set consists of a 63.5 mm, 74 micron (200 mesh) sieve, a small funnel to fitsnugly over the sieve, and a conical glass tube graduated in percent, and having two fluid levelindicator lines.

Test Procedure:

1. Fill the glass measuring tube to the indicated mark with the mud to be tested. Add water tothe next mark. Close the mouth of the tube and shake vigorously.

2. Pour the mixture onto the screen tapping it lightly to aid passing of the diluted mud throughthe screen. Add more clean water, and repeat this wet screening procedure until the washwater in the tube is clear. Wash the sand retained on the screen to free it of any remainingmud.

3. With the sieve in an upright position, fit the funnel over the sieve. Invert slowly and fit the

funnel tip into the mouth of the cleaned measuring tube.

Back wash the sand from the sieve using a fine spray of clean water with the measuring tubepositioned vertically upright, allowing the sand to settle in the tube for a few minutes.

Report the sand content as the volume fraction of sand, (the volume percent divided by 100).

For example, if the sand content is read as %, the volume fraction is reported as 0.0025%


14/408

Page-13

1.7 LIQUID AND SOLIDS CONTENT (RETORT / SOLIDS ANALYSIS)


The retort apparatus is used to determine the amount and type of solids and liquids present in adrilling mud sample. Mud is placed in the steel container and then heated until the liquid portionis vaporized. The vapor is passed through a condenser in which it is cooled, and then collectedin a graduated cylinder.

The volume of the water and oil is measured as a fraction of the total mud volume. For accurateresults, a true mud density should be used for calculations, an accurate air free sample must beused, and a volume correction factor should be determined for oil content if it is present in themud.

Test Procedure:

Fann Ministill

1. Fill the lower chamber with a freshly obtained mud sample.2. Place the calibration lid on the chamber allowing any excess mud to escape.3. Remove the calibration lid from the chamber, and scrape any excess mud from the lid into

the chamber.4. Add 5-6 drops of liquid steel wool to the mud in the sample cup, or pack steel wool around

the upper portion of the immersion heater.5. Screw the lower retort chamber into the upper chamber while maintaining both chambers in

an upright position.6. Screw the immersion heater into the cup/chamber assembly.7. Attach the assembled retort to the condenser.8. Add a drop of wetting agent (Aerosol) to a 100% by volume graduated cylinder, and place it

under the drain of the condenser. Heating time is usually 20-30 minutes depending on mud

type.

Removable Retort

1. Lift the retort assembly from the insulator block. Using a spatula as a screwdriver, removethe sample cup from the retort chamber.

2. Pack the upper chamber with fine steel wool, or add 5-6 drops of liquid steel wool to themud in the sample cup.

3. Fill the lower sample cup with a freshly stirred mud sample, and replace the calibration lid,allowing any excess to escape.

4. Wipe off any excess mud and screw the lower sample cup (with calibration lid still in place)into the upper chamber, maintaining both upper and lower chambers in the upright position.Screw condenser onto the outlet hose of the upper chamber.

5. Replace the retort assembly in the insulator block, and close the insulating cover.6. Add a drop of wetting agent (Aerosol) to a 10 cm3 or 50 cm3 graduated cylinder (depending

on the size of retort being used), and place it under the drain of the condenser. Plug in theretort and turn it on. Continue heating until liquid no linger drips from the condenser. Whenusing a thermostat retort, the light will go out at the end of the test.


15/408

Page-14

Handling and Instrument Care:

1. Use the spatula to scrape the dried mud form the mud chamber an lid to assure correctvolume.

2. Use the high temperature lubricant on the threads of the mud chamber and lid to makedismantling easier.

3. Remove and replace any mud caked steel wool.4. Use a pipe cleaner to clean the drain tube and condenser.5. The retort should be cooled prior to dismantling. It is extremely hot during and after the

test.

1.7.1 SOLIDS CALCULATIONS Return to Table of Contents

Most retorts are only accurate to within 1.0-2.0%. For that reason, most low solids muds, i.e.:muds with low mud densities that contain no Barite, salt or oil, use the following formula tocalculate the volume fraction of solids:

Volume Fraction of Solids (% Solids) = [(Mud Weight (kg/m3) / 1000) 1] X 0.625

If a Fann Ministill is used, the % by volume water and oil is read directly. The volume fraction ofeach constituent is the % by volume divided by 100.

If a Baroid Retort is used, read the volume of oil and water. Calculate the fractions as follows if a10 cm3 retort is used:

Fo (volume fraction of oil) = cm3 oil / 10Fw (volume fraction of water) = cm3 of water / 10Fs (volume fraction of solids) = 1.00 total liquid fraction

To completely analyze a drilling fluid for the amount of solids present, the following calculationsshould be used.

UNWEIGHTED SYSTEMS

1. Low Density, Unweighted Mud (No Oil, No Salt)

Procedure:

1. Measure Mud Density, D (kg/m3)2. Measure Bentonite from Methylene Blue Test, MBT (kg/m3)

a. Volume Fraction of Solids, Fs

Fs = [(D /1000) 1] X 0.625

b. Volume Fraction of Water, Fw

Fw = 1 Fs

c. Total Amount of Low Gravity Solids, LGS (kg/m3)

LGS = D (Fw X 1000)


16/408

Page-15

d. Amount of Drilled Solids, DS (kg/m3)DS = LGS MBT

Example (No Oil, No Salt):

1. Density, D = 1080 kg/m3

2. Bentonite, MBT 75 kg/m3

a. Volume Fraction of Solids, FS

Fs = [(D /1000) 1] X 0.625Fs = [(1080 / 1000) 1] X 0.625

= (1.08 1) X 0.625= 0.08 X 0.625= 0.05


Fw = 1 FsFw = 1 0.05

= 0.95


LGS = D (Fw X 1000)LGS = 1080 (0.95 X 1000)

= 1080 950= 130 kg/m3 of Low Gravity Solids

d. Amount of Drilled Solids, DS (kg/m3)

DS = LGS MBTDS = 130 75

= 55 kg/m3 of Drilled Solids

2. Low Density, Unweighted Mud (With Oil, No Salt)

Procedure:

1. Measure mud density, D (kg/m3)2. Measure Bentonite from Methylene Blue Test, MBT (kg/m3)3. Read the volume fraction of oil from the retort, Fo


Fs = [(D / 1000 1) + (0.2 X Fo)] X 0.625


Fw = 1 (Fs + Fo)


LGS = D [(Fo X 800) + (Fw X 1000)]


17/408

Page-16

e. Amount of Drilled Solids, DS (kg/m3)

DS = LGS MBT

Note: The oil fraction is obtained from the retort. The volume fraction of solids isobtained from the formula. This is done because small errors in reporting thevolume fraction of solids can occur when taken from a retort in a unweighted lowdensity mud.

Example (With Oil, No Salt):

1. Density, D = 1080 kg/m3

2. Bentonite, MBT = 75 kg/m3

3. Volume Fraction of Oil, Fo = 0.02 (from the retort)


Fs = [(D / 1000 1) + (0.2 X Fo)] X 0.625Fs = [(1080 / 1000) 1) + (0.2 X 0.02)] X 0.625= [(1.08 1) + (0.004)] X 0.625= (0.08 + 0.004) X 0.625= 0.084 X 0.625= 0.0525


Fw = 1 (Fs + Fo)Fw = 1 (0.0525 + 0.02)

= 1 0.0725= 0.9275

c. Total Amount of Low Gravity, LGS (kg/m3)

LGS = D [(Fo X 800) + (Fw X 1000)]LGS = 1080 [(0.02 X 800) + (0.9275 X 1000)]

= 1080 (15 + 927.5)= 1080 942.5= 137.5 kg/m3 Total Solids

d. Amount of Drilled Solids, DS (kg/m3)

DS = LGS MBTDS = 137.5 75

= 62.5 kg/m3 Drilled Solids


18/408

Page-17

3. Low Density, Unweighted Mud (With Salt, No Oil)

Note: These calculations should be used for fluids containing chlorides over 10,000mg/L.

Procedure:

1. Measure Mud Density, D (kg/m3)2. Measure chloride content, Cl (mg/L)3. Measure Bentonite form Methylene Blue Test, MBT (kg/m3)4. Read the volume fraction of water from retort, Fw5. Read the volume fraction of Oil from retort, Fo6. Read the volume fraction of Salt in the mud from Figure 1.1, F Salt

a. Amount of Salt in Mud, S (kg/m3)

S = [(1.65 X Cl) X (Fw + Fsalt)] / 1000

b. Amount of Low Gravity Solids, LGS (kg/m3)

LGS = 1.625 {D [1000 (1 Fsalt) ] + (160 X Fo) } (0.375 X S)

c. Amount of Drilled Solids, DS (kg/m3)

LGS = LGS MBT

d. True Volume Fraction of Water, True Fw

True Fw = [1.625 (1 Fsalt)] [(D + S) / 1600]

e. Volume Fraction of Solids, Fs

Fs = 1 True Fw

Example:

1. Mud Density, D = 1120 kg/m3

2. Chlorides, Cl = 20,000 mg/L3. Bentonite, MBT = 45 kg/m3

4. Volume Fraction of Water, Fw = 0.91 (from retort)5. Volume Fraction of Oil, Fo = 0.00 (from retort)6. Volume Fraction of Salt, Fsalt = 0.011 (From Figure 1.1)

a. Amount of Salt is Mud, S (kg/m3)

S = [(1.65 X Cl) X (Fw + Fsalt)] / 1000S = [(1.65 X 20,000) X (0.91 + 0.011)] / 1000

= ( 33000 X 0.921) / 1000= 30393 / 1000= 30.4 kg/m3 Salt


19/408

Page-18


LGS = 1.625 {D [1000 (1 Fsalt) ] + (160 X Fo) } (0.375 X S)LGS = 1.625 {1120 [1000 (1 0.011) ] + (160 X 0} (0.375 X 30.4)

= 1.625 {1120 (1000 X 0.989) + 0} 11.4= 1.625 (1120 989) 11.4= (1.625 X 131) 11.4= 212.9 11.4= 201.5 kg/m3 Low Gravity Solids


LGS = LGS MBT= 201.5 45= 156.5 kg/m3 Drilled Solids


True Fw = [1.625 (1 Fsalt)] [(D + S) / 1600]True Fw = [1.625 X (1 0.011)] [(1120 + 30.4) / 1600]

= [(1.625 X 0.989) (1150.4 / 1600)= (1.607) (0.719)= 0.89


Fs = 1 True FwFs = 1 0.89

= 0.11

4. Low Density, Unweighted Mud (With Salt, With Oil)

Note: These calculations should be used for fluids containing chlorides over 10,000mg/L.

Procedure:

1. Measure Mud Density, D (kg/m3)2. Measure Chloride content, Cl (mg/L)3. Measure Bentonite form Methylene Blue Test, MBT (kg/m3)4. Read the volume fraction of water from retort, Fw5. Read the volume fraction of Oil from retort, Fo6. Read the volume fraction of Salt in the mud from Figure 1.1, Fsalt


S = [(.65 X Cl) X (Fw + Fsalt)] / 1000


LGS = 1.625 {D [1000 (1 Fsalt) ] + (160 X Fo) } (0.375 X S)


20/408

Page-19


LGS = LGS MBT


True Fw = [1.625 (1 Fsalt)] [(D + S) / 1600]


Fs = 1 (True Fw + Fo)

Example:


2. Chlorides, Cl = 30,000 mg/L3. Bentonite, MBT = 45 kg/m3

4. Volume Fraction of Water, Fw = 0.90 (from retort)5. Volume Fraction of Oil, Fo = 0.05 (from retort)6. Volume Fraction of Salt, Fsalt = 0.016 (From Figure 1.1)


S = [(.65 X Cl) X (Fw + Fsalt)] / 1000S = [(1.65 X 30,000) X (0.90 + 0.016)] / 1000

= ( 49500 X 0.916) / 1000= 45342 / 1000= 45.3 kg/m3 Salt


LGS = 1.625 {D [1000 (1 Fsalt) ] + (160 X Fo) } (0.375 X S)LGS = 1.625 {1120 [1000 (1 0.016) ] + (160 X 0.05} (0.375 X 45.3)

= 1.625 {1120 (1000 X 0.984) + 8} 16.99= 1.625 {(1120 984) + 8} 16.99= (1.625 X 144) 16.99= 234 16.99= 217 kg/m3 Low Gravity Solids


LGS = LGS MBT= 217 45= 172 kg/m3 Drilled Solids


True Fw = [1.625 (1 Fsalt)] [(D + S) / 1600]True Fw = [1.625 X (1 0.016)] [(1120 + 45.3) / 1600]

= [(1.625 X 0.984) (1165.3 / 1600)]= (1.599) (0.728)= 0.87


21/408

Page-20


Fs = 1 (True Fw + Fo)Fs = 1 (0.87 + 0.05)

= 1 0.92= 0.08

WEIGHTED SYSTEMS

Procedure:

1. Measure the mud density, D (kg/m3)2. Measure the Chlorides, Cl (mg/L)3. Measure the Bentonite from Methylene Blue Test, MBT (kg/m3)4. Read the volume fraction of water from the retort, Fw5. Read the volume fraction of oil from the retort, Fo6. Read the volume fraction of Salt in the mud from Figure 1.1, F Salt7. Determine the volume fraction of solids from the retort, Fs

a. Amount of Salt in mud, S (kg/m3)

S = (1.65 X Cl) (Fw + F Salt)/1000

b. Amount of Total Undissolved Solids, TS (kg/m3)

TS = D [(Fo X 800) (Fw X 1000)] S

c. Average Relative Density of Undissolved Solids, Dr

Dr = TS / (Fs F Salt) X 1000

d. Amount of Barite in Mud, BAR (kg/m3)

BAR = TS X [2.62 (6.82/Dr)]

e. Amount of Low Density Solids, LDS (kg/m3)

LDS = TS BAR

f. Amount of Drilled Solids, DS (kg/m3)

DS = LDS MBT


22/408

Page-21

1. Example Weighted Mud (With Oil, No Salt)



3. Volume Fraction of Water, Fw = 0.73 (from Retort)4. Volume Fraction of Oil, Fo = 0.01 (from Retort)5. Volume Fraction of Solids, Fs = 0.26 (By Difference)


No Salt in Mud = 0


TS = D (Fo X 800) (Fw 1000) S= 1560 [(0.01 X 800) (0.73 X 1000)] - 0= 1560 (8) (730) 0

= 822 kg/m

3


Dr = TS / (Fs F Salt) X 1000= 822 / (0.26 0) X 1000= 822 / 0.26 X 1000= 822 / 260= 3.16


BAR = TS X [2.62 (6.82/Dr)]= 822 X [(2.62 (6.82/3.16)]

= 822 X (2.62 2.16)= 822 X 0.46= 378 kg/m3


LDS = TS BAR= 822 378= 444 kg/m3


DS = LDS MBT

= 444 65= 379 kg/m3


23/408

Page-22

2. Example Weighted Mud (With Oil, With Salt)


2. Chlorides, Cl = 20000 mg/L


3. Volume Fraction of Water, Fw = 0.65 (from Retort)4. Volume Fraction of Oil, Fo = 0.05 (from Retort)5. Volume Fraction of Solids, Fs = 0.30 (By Difference)6. Volume Fraction of Salt, F Salt = 0.008 (From Figure 1.1)


S = (1.65 X Cl) (Fw + F Salt) / 1000= (1.65 X 20000) (0.65 + 0.008) / 1000= (33000) (0.658) / 1000= 21714 / 1000= 21.7 kg/m3


TS = D (Fo X 800) (Fw 1000) S= 1680 [(0.05 X 800) (0.65 X 1000)] 21.7= 1680 (40) (650) 21.7= 968 kg/m3


Dr = TS / (Fs F Salt) X 1000= 968 / (0.30 0.008) X 1000= 968 / 0.292 X 1000= 968 / 292

= 3.32


BAR = TS X [2.62 (6.82/Dr)]= 968 X [(2.62 (6.82/3.32)]= 968 X (2.62 2.05)= 968 X 0.57= 552 kg/m3


LDS = TS BAR

= 968 552= 416 kg/m3


DS = LDS MBT= 416 30= 386 kg/m3


24/408

Page-23

Figure 1.1

WATER IN MUD, volume fraction


25/408

Page-24

VOLUME FRACTION SALT (As NaCl) in the WATER PHASE

Chloride Content (mg/L) Volume Fraction (Salt) Specific Gravity5000 0.003 1.004

10000 0.006 1.010

20000 0.012 1.021

30000 0.018 1.032

40000 0.023 1.043

60000 0.034 1.065

80000 0.045 1.082

100000 0.057 1.098

120000 0.070 1.129

140000 0.082 1.149

160000 0.095 1.170

180000 0.108 1.194

188650 0.114 1.197

1.8 CATION EXCHANGE CAPACITY Return to Table of Contents

The Methylene Blue Dye Test, (MBT), is used to determine the Cation Exchange Capacity of thesolids present in a water base drilling mud. Only the reactive portions of the clays present areinvolved in the test and materials such as Barite, Carbonates, and Evaporites do not affect theresults of the test, since these materials do not adsorb the Methylene Blue.

The Cation Exchanged Capacity of some typical clays is:

Clay CEC(milliequiv. / 100 gm moisture free)

Wyoming Bentonite 75

Soft Shale 45

Kaolinite 10

Drilled Cuttings 8-12

For Bentonite based mud systems, the MBT provides an indication of the amount of reactiveclays which are present in the drilling mud solids and for Bentonite free, water based mud

systems, the MBT reflects the reactivity of the drilled solids. The test cannot distinguish betweenthe type of clays but, if a reactivity for the drilled solids is known or assumed, it can be used todetermine the amount of Bentonite present in the Bentonite based systems.


26/408

Page-25

Equipment:

1. Erlenmeyer flask2. Hot plate or bottle warmer3. Stirrer Rod

4. Hydrogen Peroxide Solution (3%)5. Sulfuric Acid 5N6. Methylene Blue Solution: (solution strength may vary depending upon supplier)7. 10 ml pipette8. 3 ml syringe9. No. 4 Whatman Filter Paper ( Standard filter paper may be substituted)10. 25 ml Graduated Cylinder

Test Procedure:

1. Using the completely filled, 3 ml syringe, measure 2.0 ml of mud sample to be tested into theErlenmeyer flask containing 10-15 ml of distilled water.

2. Add 15 ml Hydrogen Peroxide and 1 ml of 5N Sulfuric Acid. Swirl or stir as required tomixed the solution

3. Boil gently for approximately 10 minutes, and dilute with 20 ml fresh water.

4. Add Methylene Blue Dye in 1.0 ml increments. After each dilution, swirl the flask and stirvigorously for at least 20 seconds, and remove a drop of sample on the end of the stirringrod.

5. Apply the drop to a piece of filter paper making the drop with the amount of Methylene Blueadded between each increment. The approximate end point is reached when a blue ringspreads out from the blue spot on the filter paper.

At this point, without further addition of Methylene Blue, swirl the flask an additional 2

minutes, and place another drop on the filter paper. If the blue ring is again apparent, theend point has been reached.

If the ring did not appear, continue with the Methylene Blue increments until a blue ringpermanently forms after two additional minutes of swirling.

Note: For increased accuracy, 0.5 ml increments may be used as the end point isapproached. The blue ring is more apparent on the reverse side of the filter paperfrom which the drop is placed.

Calculations:

Note: There are 2 different strengths of Methylene Blue dye that is used to determine theEquivalent Bentonite Content. One will have to determine which strength of dyethe chemical testing company is supplying.

1. Stronger Strength of Methylene Blue:

kg/m3 Reactive Clay ( Equivalent Bentonite Content)

= 14.25 X ml Methylene Blueml of Mud Sample


27/408

Page-26

2. Weaker Strength of Methylene Blue (as supplied by Canamera United Supply Ltd.)

kg/m3 Reactive Clay ( Equivalent Bentonite Content)

= 10 X ml Methylene Blueml of Mud Sample

Care of Reagents:

The Methylene Blue Dye and Hydrogen Peroxide should be stored in a cool, dark place toextend the life. These solutions should be replaced every 4 months.


28/408

Page-27

1.9 pH DETERMINATION Return to Table of Contents

The acidity or alkalinity of a drilling mud is indicated by the Hydrogen ion concentration, which iscommonly expressed in terms of pH. A perfectly neutral solution has a pH of 7.0, whereas

alkaline (basic) solutions have a pH range between 7.0-14.0, and acidic solutions have a pH lessthan 7.0.

The pH measurement is used as well to indicate the presence of contaminants such as cementor anhydrite.

The two most common field methods for determining pH are described as follows:

pHydion Paper:

1. This method may be used on the mud filtrate, or whole mud directly.2. Place a 25 mm (1 inch) strip of indicator paper on the surface of the mud to be tested and

allow it to remain until the liquid has wet the surface and the color has stabilized. This takes

approximately 1 minute.3. Compare the color standards provided with the test paper (which was not in contact with themud solids) to the color standards provided with the test paper, and estimate the pH of themud accordingly.

Color pH Strips:

1. This method applies only to the mud filtrate.2. After obtaining a sample of mud filtrate, totally immerse the colored portion of the color pH

strip into the filtrate, and remove immediately.3. After a short period of color stabilization (10-15 seconds), compare the color of the wetted

strip with the color standards provided in the color pH plastic container.

An estimate may be necessary if a color does not exactly match a particular pH value.

1.10 CHLORIDE DETERMINATION Return to Table of Contents

Chloride ions exist in a mud system as Salts of Sodium, Magnesium, Calcium, or Potassium.The determination of the Chloride ion present in the mud filtrate may give an indication of a Saltwater flow, or the presence of a Salt formation or stringer.

In mud systems to which Salt has been added, the Chloride measurements show the amount ofsalinity present in the mud.

Equipment:

1. Silver Nitrate solution:- 0.0282 N for low Chloride concentrations- 0.282 N for high Chloride concentrations

2. Potassium Chromate indicator3. Sulfuric Acid (N/50)4. Phenolphthalein indicator5. Pipettes (1 ml)6. White titration dish7. Stirring rod


29/408

Page-28

Test Procedure:

1. Measure 1.0 ml of filtrate into a white titration dish and dilute to a convenient volume withdistilled water.

2. Add a few drops of Phenolphthalein indication solution. If a pink color develops, add N/50Sulfuric Acid until the pink color completely disappears. It is not necessary to record thevolume of N/50 Sulfuric Acid added.

3. Add 4-5 drops of Potassium Chromate indicator to obtain a yellow color.4. Add Silver Nitrate while swirling or stirring until the color changes from yellow to orange-red

(brick red), and persists for 30 seconds.

Calculations:

1. If 0.0282 N Silver Nitrate is used:mg/L Chlorides = 1000 X ml of Silver Nitrate added

2. If 0.282 N Silver Nitrate is used:

mg/L Chlorides = 10000 X ml of Silver Nitrate added

Remarks:

1. mg/L Salt (NaCl) = 1.65 X mg/L Chlorides2. The Chloride test may be run on the same sample used in the Pf determination, if the Mf test

was not performed.3. Avoid contact with the Silver Nitrate solution. Wash immediately with water if Silver Nitrate

gets on the skin or clothing.4. The end point of the reaction is when the Silver Chromate is when the first detectable

permanent color change from yellow to a light brick red occurs.

When using the weak Silver Nitrate solution, the end point is approached very gradually.Therefore, the formation of the Silver Chromate can be seen by a color change for yellow to

brick red.

If the strong Silver Nitrate is used, the end point is approached much more rapidly. Hencethe early formation of the Silver Chromate, and is brick red color may be missed due to thelarger amounts of Silver Nitrate being added. The color change will go from yellow to red.As soon as the red color is seen, the titration is complete.

5. White lumps of Silver Chloride form when titrating high concentrations of Salt. This shouldnot be mistaken for the end point.

6. A high pH will precipitate Silver Oxide.

1.11 FILTRATE HARDNESS (Total Hardness, Calcium & Magnesium)


Water containing large amounts of Calcium or Magnesium Salts is commonly referred to ashard water. Make up waters that are hard make it difficult to obtain the maximum yield fromBentonite, so it becomes necessary to treat out excess Calcium. As a general rule, the totalhardness as Calcium should be brought to less tan 40 mg/L. The presence of Calcium in themud filtrate may also indicate the presence of contaminants, such as anhydrite or cement.


30/408

Page-29

Equipment:

1. Titraver Solution, 1 ml = 1 mg CaCO32. Strong Buffer Solution

3. Manver Indicator4. 1 ml Pipettes5. Distilled Water6. Stirring Rod7. Calver II Indicator (to distinguish Calcium form Magnesium)8. Potassium Hydroxide (8N) solution to distinguish Calcium from Magnesium)

Test Procedures:

Total Hardness (as Calcium):

1. Using a pipette, measure 1.0 ml of filtrate into a white titration dish, and dilute to aconvenient volume with distilled water.

2. Add 4-5 drops of strong Buffer solution, and 2-3 drops of Manver Indicator. A red or winecolor will develop if Calcium is present.3. While swirling or stirring continuously, add Titraver with a pipette until the color changes from

red to blue. At this end point, record the number of milliliters of Titraver added.

Calculations:

mg/L Hardness (as Calcium) = 400 X ml Titraver added

Calcium Hardness:

1. Using a pipette, measure 1.0 ml of filtrate into a white titration dish, and dilute with a smallamount of distilled water.

2. Add 2-3 drops of 8N KOH (Potassium Hydroxide) solution.3. Add several grains of Calver II, and swirl or stir to mix.4. Using a pipette. Titrate with Titraver solution to a color change from red to blue.

Calculations:

mg/L Calcium Ion = 400 X ml Titraver added

Magnesium Hardness:

The Magnesium hardness is calculated as follows:

mg/L Magnesium = mg/L Total Hardness (as Calcium) mg/L Calcium


31/408

Page-30

1.12 GYPSUM (Calcium Sulfate) CONCENTRATION


This test essentially repeats the test for total hardness as performed on the mud filtrate, but thistest uses a sample of whole mud. The result in terms of total Gypsum is then deducted.

Equipment

1. Versenate Solution, 0.01M EDTA2. Strong Buffer (made up from 7.0 grams Ammonium Chloride in 970 ml Ammonium

Hydroxide made up to 1000 ml with distilled water)3. Calmagite (1 gram per litre in distilled water)

Test Procedure

1. Add 5 ml of mud to 245 ml of distilled water. Stir the mixture for 15 minutes, then filter withan API filter press through standard test paper. Discard any cloudy filtrate.

2. Pipette 10 ml of the clear filtrate into a titration dish.3. Continue as per the procedure for total hardness to titrate with Standard Versenate. Record

the number of ml Versenate = Vt.4. Titrate 1 ml of mud filtrate obtained as per the standard fluid loss test procedure, using the

standard total hardness test procedure. Record the number of ml of Versenate = Vf.

Calculations

Total Gypsum (Calcium Sulfate) kg/m3 = 6.8 X Vt

Excess Gypsum kg/m

3

= 6.8 Vt 1.97 Vf X Fw

Where Fw = volume fraction of water

1.13 MUD FILTRATE ALKALINITY Return to Table of Contents

Acidity is one measure of alkalinity that is indicated by the pH. However, the nature and amountof other ions such as Carbonates or Bicarbonates can also effect mud filtrates alkalinity. Forfresh water mud systems, these ions can be indicative of the rheological stability of such mudsystems. Concentrations of either ion can result in high, low shear rate viscosity (Yield Point)and high, progressive Gel Strengths.

Three methods can be employed for the determination of Carbonate and Bicarbonateconcentration. The very common Pf / Mf method is restricted to mud systems having a loworganic content, whereas the P1 / P2 method or Garret Gas Train may be used for better, morequantitative method, especially in the systems with high organic content.


32/408

Page-31

1.13.1 Pf / Mf Method Return to Table of Contents

Equipment:

1. Phenolphthalein Indicator Solution2. Bromo Cresol Green Indicator Solution3. Distilled Water4. N/50 Sulfuric Acid5. White Titration Dish6. Stirring Rod7. 1 ml Pipette

Test Procedure:

1. Using a 1 ml pipette, measure 1 ml of filtrate into a white titration dish. Dilute with distilledwater.

2. Add 2-3 drops of Phenolphthalein Indicator.

- if no color change occurs, then the Pf = 0; continue to step 4- if a pink or red color develops, the Pf > 0; continue to step 3

3. Using a pipette, add N/50 Sulfuric Acid continuously while swirling or stirring until the samplechanges from pink to colorless (or original filtrate tint).

4. The number of ml of N/50 Sulfuric Acid to reach this point is recorded as the Pf value.5. To the sample, which has been titrated to the Pf end point, add 2-3 drops of Bromo Creosol

indicator solution to obtain a light blue color. Continue titrating with swirling (or stirring) untilthe color changes from light blue to apple green (pH 4.0-4.5).

This end point is recorded as the Mf end point.

Calculations:

Use the following table to estimate the Carbonate (CO3), Bicarbonate (HCO3), or Hydroxyl (OH)alkalinity present in the mud system.

Pf / Mf Relation Bicarbonate(mg/L HCO3)

Carbonate(mg/L CO3)

Hydroxyl(mg/L OH)

Pf = 0 1220 X Mf 0 0

Pf = Mf 0 0 340 X Mf

2Pf = Mf 0 1200 X Pf 0

2Pf > Mf 0 1200 (Mf Pf) 340 (2Pf Mf)

2Pf < Mf 1200 (Mf 2Pf) 1200 X Pf 0

1.13.2 P1 / P2 Method Return to Table of Contents

Inorganic ions such as Borate, Silicate, Sulfide, and Phosphate ions can have a real effect onmud alkalinity. Additionally, organic compounds (ex: anionic organic thinners, fluid lossadditives, or other Polymers) and their degradation by-products, may also affect thedetermination of the relative amounts of Carbonate, Bicarbonate, or Hydroxyl ion in solution.The P1 / P2 method eliminates these effects.


33/408

Page-32

Equipment:

1. Sodium Hydroxide Solution (0.1 N)2. Barium Chloride Solution

3. Phenolphthalein Indicator Solution4. N/50 Sulfuric Acid5. White Titration Dish6. Stirring Rod7. Distilled Water8. Pipettes (1 ml)

Test Procedure:

1. Determine the Pf end point as outlined in steps 1-3 of the Pf/Mf method. If the Pf = 0, thereare no carbonates present.

2. Place 1 ml of filtrate into a white titration dish, and dilute with distilled water.

3. Add a measured 2 ml of 0.1 N Sodium Hydroxide solution to convert all Bicarbonate toCarbonates. Check the pH if it is less than 11.5, continue to add 0.1N Sodium Hydroxide in12 ml increments, until the pH exceeds 11.5. Make a record of the total amount of SodiumHydroxide added in this step.

4. Add a measured amount (2-4 ml) of Barium Chloride to precipitate all the possibleCarbonates. Add 2-4 drops of Phenolphthalein solution and stir with a stirring rod.

5. Using a 1ml pipette, tritrate immediately to the end point with N/50 Sulfuric Acid. Record thenumber of mls N/50 Sulfuric Acid added as the P1 end point.

6. Place exactly the same amounts of 0.1N Sodium Hydroxide, Barium Chloride, and indicatorinto 25 ml of distilled water, and titrate to the end point using N/50 Sulfuric Acid, and recordthis as the P2 end point.

Calculations:

Pf = 0 There are no Carbonates present

P1 > P2:

mg/L Bicarbonates (HCO3) = 0mg/L Carbonates (CO3) = 1200 [Pf (P1-P2)]mg/L Hydroxyls (OH) = 340 (P1-P2)

P2 > P1:

mg/L Hydroxyls (OH) = 0mg/L Carbonates (C03) = 1200 x Pfmg/L Bicarbonates (HCO3) = 1220 (P2 P1)

WARNING: The reagents may be hazardous to the health and safety of the user ifinappropriately handled.


34/408

Page-33

1.13.3 GARRET GAS TRAIN METHOD (Carbonates)


Either of the above methods is still subject to some error and certain situations may required yetanother method.

The Garret Gas Train separates gas from liquid, thereby preventing contamination of the CO 2detecting Drager tube by the liquid phase. The CO2 Drager tube responds to the CO2 passingthrough it by progressively staining (purple) along its length as the hydrazine chemical and theCO2 react, causing a methyl violet indicator to turn purple. The stain length is dependent on theamount of CO2 present, and the total gas volume that passed through the tube.

Consequently, for accurate results, the gas exiting the train must first be captured in a one litregas bag to allow the CO2 to mix uniformly with the carrier gas. Then the contents of the bag aredrawn through the tube using 10 strokes of the Drager hand pump. This will draw exactly one(1) litre of gas through the tube.

Test Procedure:

1. Be sure the Gas Train is clean, dry, and on a level surface2. With the regulator T-handle backed off, install and puncture a Nitrogen (N2) gas cartridge.3. Add 20 ml distilled water to Chamber #1. (The chambers are numbered beginning at the

regulator).4. Add 5 drops of Octanol Defoamer to Chamber #1.5. Install the top of the Gas Train and evenly hand tighten to seal all the O-rings.6. Attach the flexible tubing from the regulator onto the dispersion tube of Chamber #1.7. Inject with syringe an accurately measured sample of filtrate into Chamber #1. See table

below:

Drager Tube Identification

Carbonate Rangemg/L

Sample Volume Drager TubeIdentification

Tube Factor

25-750 10.0

50-1500 2.5 CO2 0.01 / A 25000

250-7500 1.0

8. Flow carrier gas through the Gas Train for 1 minute to purge the system of air. Stop gasflow.

9. Install one end of a piece of flexible tubing onto the stopcock which is fitted directly into the

gas bag. Have the gas bag full collapsed. Fit the other end of the tubing onto the outlet tubeof Chamber #3.10. Slowly inject 10 ml of Sulfuric Acid solution into Chamber #1 through the septum using the

syringe and needle. Gently shake the Gas Train to mix acid with the sample in Chamber #1.11. Open the stop cock on the gas bag. Restart Nitrogen flow gently and allow the gas bag to

fill. When the bag is full, (DO NOT burst it) shut off and close the stop cock. Immediatelyproceed to the next step.

12. Remove the tubing from Chamber #3 outlet and re-install it onto the upstream end of theCO2 0.01% / A Drager Tube. (Observe that the arrow indicates the gas flow direction).Attach the Drager hand pump to the other end of the Drager Tube.


35/408

Page-34

13. Open the stop cock on the bag. With a steady hand pressure, fully depress the hand pumpthen release it so that the gas flows out of the bag, and through the Drager Tube. Operatepump 10 times. This should essentially empty the bag.

14. Observe a purple stain on the Drager Tube if CO2 is present. Record the stain length in theunits marked on the Drager Tube.

Calculations:

mg/L CO2 = 25000 X Tube Stain Lengthml of sample volume

Care and Cleaning:

To clean the Gas Train, remove the flexible tubing and gas train top. Wash out the chambersusing a brush with warm water and mild detergent. Use a pipe cleaner to clean the passagesbetween the chambers. Wash, rinse, and then blow out the dispersion tube with air or nitrogengas. Rinse the unit with distilled water, and allow to drain dry.

Garret Gas Train


36/408

Page-35

1.14 ALKALINITY OF THE MUD (Pm) Return to Table of Contents

This test measures the alkalinity of the whole mud. When used in conjunction with the filtrate

alkalinity determination, the amount of excess Lime present in the mud can be determined.

Equipment

1. Titration dish2. Syringe, 3 ml3. Distilled water4. Phenolphthalein indicator solution5. N/50 (0.02 N) Sulfuric Acid

Test Procedure

1. Measure 1 ml of a freshly stirred sample of mud into a titration dish using a syringe.2. Dilute the mud in the dish with about 50 ml of distilled water.3. Add 4-5 drops of Phenolphthalein indicator solution.4. If the sample does not change color, record the Pm as 0.5. If the sample turns pink, titrate rapidly with N/50 Sulfuric Acid until the pink color disappears.

Calculations

Report the alkalinity of the mud, Pm as the number of ml of N/50 Sulfuric Acid added until thepink color disappears.

Note: If the mud sample is deeply colored and the color change is hard to see, use 0.5 mlof mud, and report the Pm as the volume of Sulfuric Acid added X 2.0. If N/10 (0.1N)Sulfuric Acid is used, the Pm is reported as the volume of acid added to 1 ml of mud X5.0.

1.15 SULFATE ION CONCENTRATION Return to Table of Contents

Sulfate ions are present in many natural, ground and surface waters. In Bentonite based mudsystems, flocculation and a high viscosity can result from Sulfate ion concentrations approachingor exceeding 2000 mg/L. A qualitative or more quantitative test can be performed to establishthe Sulfate concentration.

1.15.1 QUALITATIVE TEST

Equipment:

1. Dropper bottle of Barium Chloride.2. Dropper bottle of strong Nitric Acid.3. Test Tube.


37/408

Page-36

Test Procedure:

1. Place 2-4 ml of filtrate in a test tube and add a few drops of Barium Chloride.2. Shake the tube gently, and observe the presence of a milky, white precipitate. This indicates

the presence of Carbonates and/or Sulfates.3. Add a few drops of Nitric Acid and shake again. If the precipitate dissolves and disappears,

completely, only carbonates were present. If the precipitate remains, its intensity can beused for a qualitative estimate of the Sulfate concentration.

Results:

Trace - the precipitate is barely discernable- less than 50 mg/L Sulfate ions are present

Show - the precipitate is a translucent white suspension- up to 500 mg/L Sulfate ions are present

Light - the precipitate is a milky white suspension- up to 1000 mg/L Sulfate ion are present

Heavy - the precipitate is a heavy curdly white suspension- more than 1500 mg/L Sulfate ions are present- the precipitate could be diluted for a more accurate determination of

the concentration

1.15.2 QUANTITATIVE TEST Return to Table of Contents

One method of quantitatively determining the Sulfate ion concentration is with the use of theHach Model SF-1 Sulfate Test Kit.

1. Fill the calibration tube to the top with filtrate to be tested.2. Pour this sample into the mixing tube.3. Add the contents of one Sulfaver IV powder pillow. Swirl to mix. A white, turbid precipitate

will appear if Sulfates are present.4. Allow to stand for 5 minutes.5. Hold the calibrated tube in such a manner so that it can be viewed through the top. Slowly

pour the prepared sample into the tube. Continue pouring until the image of the black crosson the bottom of the tube just disappears from view. At this point, the tube will appear as auniform field of view.

6. Read mg/L of Sulfates (SO4) from the scale on the side of the calibrated tube.

Note: The difference between mg/L and ppm is not significant until the Sulfate

concentration exceeds 7000 mg/L.

Warning: The reagents may be hazardous to the health and safety of the use ifinappropriately handled.


38/408

Page-37

1.16 AMMONIUM SULFATE TEST ( Hach Ammonia Nitrogen Test Kit (N1-8)


Sample Preparation

Add 0.25 ml filtrate to a 100 ml graduated cylinder. Dilute with distil led water to the 100 ml mark.Cover with palm of hand and invert cylinder several times. From this 100 ml solution, pipette 1.0ml to the 10 ml graduated cylinder. Dilute to the 10 ml mark with distilled water. Invert thecylinder several times.

Fill one tube to the white line with this solution. Fill the other tube to the white line with distilledwater.

1. Add 3 drops Nessler solution to each tube and swirl. Allow 10 minutes for colordevelopment.

2. Insert the filtrate containing tube in the right opening in the top of the color comparator.

3. Insert the distilled water sample in the left opening in the top of the color comparator.4. Hole the color comparator up to a light such as the sky (preferable), a window of lamp and

view through the two openings in the front. Rotate the color disc until a color match isobtained. Read the number in the scale window.

Calculation:

Ammonium Sulfate (NH4)2SO4, kg/m3 = 19 X number in scale window

1.17 SULFITE ION CONCENTRATION Return to Table of Contents

In many mud systems, especially those which contain high levels of Salt, it is necessary to use

an Oxygen scavenger to reduce the dissolved Oxygen content in the mud in order to reduce drillstring corrosion to acceptable levels.

One method of reducing Oxygen corrosion is with the use of an Oxygen seeking ion, like theSulfite (SO3) ion, which will react with the dissolved Oxygen present in the drilling mud. In orderto minimize Oxygen corrosion, it is necessary to maintain a residual Sulfite concentration in thedrilling mud at all times. Usually, residual concentrations in the order of 300 mg/L or greater arerequired to reduced corrosion levels to an acceptable range. Corrosion results should always beverified with the use of corrosion rings.

One method of determining the residual Sulfite concentration is with the use of the HACH ModelSU-5 Sulfite Test Kit. The Sulfite concentration may be determined using mud or filtrate.

Equipment:

Hach Model SU-5 Sulfite Test Kit


39/408

Page-38

Test Procedure:

1. Measure a sample by filling the sample bottle to the indicated mark, (10 ml).2. Add the contents of Sulfite #1 reagent powder pillow. Swirl to mix.

3. Add the contents of one Sulfamic Acid powder pillow. Swirl to mix.4. Tritrate with Sulfite #3 reagent using the eye dropper, (low and high range Sulfite #3 reagent

is available). Add the reagent drop wise with continual swirling of the sample until apermanent gray-blue color develops. Note the number of drops required to reach the endpoint.

Calculations:

mg/L Sulfites (SO3) = 0.64 X No. of drops low range Sulfite #3

mg/L Sulfites (SO3) = 6.4 X No. of drops high range Sulfite #3

Warning: The reagents contained in the kit are harmful. Avoid contact with eyes and skin.Do not ingest. Read warning on chemical container.

1.18 HYDROGEN SULFIDE CONCENTRATION Return to Table of Contents

In many areas Hydrogen Sulfide is found by itself, or in association with hydrocarbons,especially gas. Hydrogen Sulfide gas (H2S) is not only very lethal, but also extremely corrosive.Therefore, when H2S is encountered in the mud, it must be reduced to acceptable levels so that

it does not pose a health hazard, or create a drill string failure.

The concentration of Hydrogen Sulfide present may be determined using the Hach Model HS-7Hydrogen Sulfide Test Kit, or more quantitatively, using the Garrett Gas Train.

1.18.1 HACH H2S TEST

Equipment

Hach Model HS-7 Hydrogen Sulfide Kit

Test Procedure

1. Fill the sample vial to the 25 ml mark with recently filter pressed filtrate from the mud to betested. (If 25 ml is not available, use a known amount of filtrate and dilute to 25 ml usingdistilled water. Five or more ml of filtrate is recommended).

Note: For most accurate results, the test should be performed using a recentlyobtained mud sample. If the sample has been aerated or allowed to stand for sometime, much if not all of the Hydrogen Sulfide gas will be lost by aeration or oxidation.


40/408

Page-39

2. Place a circle of Hydrogen Sulfide test paper (lead acetate paper) inside the cap of thesample vial.

3. Add an Alka Seltzer tablet to the sample and IMMEDIATELY snap the cap containing thetest paper onto the vial.

4. After allowing ample time for the tablet to dissolve, remove the cap and test paper.5. Compare the color of the test paper with the color chart accompanying the test kit, and

record the amount of H2S gas present.

Calculations

H2S Present = 25 X H2S recordedml of filtrate used

1.18.2 GARRETT GAS TRAIN (H2S) Return to Table of Contents

Equipment

1. Garrett Gas Train with H2S Drager tubes, and floating ball flow meter2. Lead Acetate Hach paper discs as an alternative to Drager tubes (for a more qualitative test)3. Sulfuric Acid, 5N4. Dropper bottle with Octanol Defoamer or equivalent5. Hypodermic syringe (10 ml with 21 gauge needle)

Test Procedure

1. Be sure the Gas Train is clean, dry and on a level surface.

Note: Moisture in the flow meter can cause the ball to float erratically.

2. With the regulator T-handle backed off, install and puncture a CO2 gas cartridge.3. Add 20 ml distilled water to Chamber #1 (the chambers are numbered beginning at the

regulator).4. Add 5 drops of Octanol Defoamer to Chamber #1.5. Measure the sample into Chamber #1 according to the following table:

Drager Tube Identification

Sulfide Range(mg/L)

Sample Volume Drager TubeIdentification

Tube Factor

1.5-30 10.0

3.0-60 5.0 H2S 100/a 15

6.0-120 2.5

60-1020 10.0

120-2040 5.0 H2S 0.2% / A 600

240-4080 2.5


41/408

Page-40

6. Select the proper Drager tube in accordance with the identification table. Break the tips fromeach end of the tube, and apply Lubriseal to each end.

7. Install the tube with the arrow pointing downward into the bored receptacle. Likewise, installthe flow meter with the word TOP upward. Be sure the O-rings seal around the body of

each tube.8. Install the top on the gas Train, and evenly hand tighten to seal all O-rings.9. Attach the flexible tubing from the regulator onto the dispersion tube of Chamber #1, and

from the outlet tube of Chamber #3 to the Drager tube.10. Adjust the dispersion tube of Chamber #1 to within 5 mm from the bottom.11. Flow CO2 gas gently through the Train for 10 seconds to purge the system of air. Stop the

gas flow.12. Slowly inject 10 ml Sulfuric Acid into Chamber #1 through the septum using the syringe and

needle.13. Immediately restart CO2 flow. Using the regulator, adjust the flow so that the ball remains

between the two lines on the flow meter tube.

Note: One CO2 cartridge should provide 15-20 minutes of flow at the rate.

14. Observe a color change on the Drager tube if H2S is present. In the units marked on thetube, note and record the maximum darkened length before the front start to smear.Continue flow for 15 minutes, although the front may attain a diffuse, feathery coloration. Onthe high range tube, an orange color may appear ahead of the black front if sulfites arepresent. The orange region should be ignored when recording the darkened length.

Calculations

mg/L Sulfides = Tube Factor X Tube Stain Lengthml Sample Volume

Care and Cleaning

To clean the Gas Train, remove the flexible tubing and Gas Train top. Take the Drager tube andflow meter out of the receptacles, and plug with stoppers to keep them dry. Wash out thechambers using a brush with warm water and mild detergent. Use a pipe cleaner to clean thepassages between the chambers. Wash, rinse and then blow out the dispersion tuber with air orCO2 gas. Rinse the unit with distilled water and allow to drain dry.

Note: A lead acetate Hach paper disc fitted below the O-ring of Chamber #3 can besubstituted for the Drager tube in the Gas Train. The lead acetate paper, although notpreferred for quantitative work, will show the presence of Sulfides.

WARNING: The reagents in this kit may be hazardous to the health and safety of the userif inappropriately handled. Please read all warnings before performing the test and use

appropriate safety equipment.


42/408

Page-41

Garret Gas Train

1.19 HYDROGEN SULFIDE SCAVENGING ABILITY AND ZINC CARBONATE


When Zinc Carbonate is used as a drilling mud additive to scavenge Hydrogen Sulfide (H 2S) in asour gas well, it is possible to obtain an estimate of the scavenging ability of the drilling mud, aswell as the amount of Zinc Carbonate present.

Quantitatively, the scavenging ability of the mud and therefore the amount of Zinc Carbonatepresent, can be determined using the Garret Gas Train. A more qualitative method to determinethe amount of Zinc Carbonate present employs the Hach Hydrogen Sulfide test kit.

1.19.1 ESTIMATION of ZINC CARBONATE CONCENTRATION (Qualitative)


Equipment and Reagents

1. Hach Model HS-7 Hydrogen Sulfide Kit2. Filter Press

3. Hamilton Beach mixer or equivalent4. Hypodermic syringe, 5 ml5. Fresh Sodium Sulfide (Na2S), stock solution 100 gm Na2S/litre6. Concentrated Hydrochloric Acid (18%), or 5N Sulfuric Acid7. Distilled Water8. Octanol Defoamer or equivalent.

Test Procedure


43/408

Page-42

1. Using the hypodermic syringe, add 2.5 ml of Sodium Sulfide stock solution (Na2S) to 250 mlof mud,

2. Agitate the sample in the mixer at medium speed for 5 minutes.3. Using the filter press, obtain at least 3 ml of filtrate for each test.4. Place a circle of Hydrogen Sulfide test paper (lead acetate paper) inside the cap of the

sample vial.5. Measure 2 ml of filtrate into the sample vial using the syringe and dilute the sample with

approximately 20 ml of distilled water. Acidify the solution with 2 drops of acid, quickly dropan Alka Seltzer tablet into the solution, and close the sample vial with the cap.

6. After allowing ample time for the tablet to dissolve, remove the cap and test paper. Thepresence of brown coloration on the lead paper indicated that the Zinc Carbonateconcentration is less than 1.1 kg/m3.

7. If the acetate paper is white (negative), the Zinc Carbonate concentration is more than 1.1kg/m3. In order to define the end point more accurately, repeat the entire test using anadditional 2.5 ml of Sodium Sulfide stock solution each time until a brown coloration isapparent on the lead acetate paper.

Calculations

Approximate kg/m3 Zinc Carbonate = 0.44 X Maximum Number Milliliters Sodium SulfideSolution Used

1.19.2 H2S SCAVENGING ABILITY and ZINC CARBONATE CONCENTRATION


Equipment and Reagents

1. Garrett Gas Train with H2S Drager tubes and floating ball flow meter, and CO2 gas

cartridges.2. Sulfuric Acid, 5N3. Dropper bottle with Octanol Defoamer or equivalent.4. Hypodermic syringe with 21 gauge needle, 10 ml5. 2, minimum 400 ml jars with lids6. Osterizer blender, blade type, 10 speed7. Filter press8. Fresh Sodium Sulfide (Na2S) stock solution (100 grams Na2S per litre)

Test Procedure

1. Label 2 jars, A and B.2. Measure 350 ml of drilling mud into jar A.3. Measure 350 ml of distilled water into jar B.4. Measure 20 ml of stock Sodium Sulfide (Na2S) solution into each jar. Close both jars and

shake vigorously by hand for 30 seconds. Transfer the contents of jar A to the Osterizermixing jar, replace the lid, and stir at the slowest speed for 15 minutes. Transfer the drillingmud H2S system back to jar A.

Note: Some drilling muds will thicken severely when the Na2S solution is added. Ifthickening occurs, add a dispersant from the rig stock at about 3 kg/m3 (roughly acone shaped pile on a dime). If thickening is observed during the first of a series oftests, the mud should be pretreated with a dispersant prior to a Na2S addition.


44/408

Page-43

5. Extract 10 ml of dilute Sodium Sulfide (Na2S) stock solution from jar B and label this filtrateB.

6. Prepare the Garrett Gas Train for testing as outlined below.a. Be sure the Gas Train is clean, dry, and on a level surface.

Note: Moisture in the flow meter can cause the ball to float erratically.

b. With the regulator T-handle backed off, install and puncture a CO2 gas cartridge.c. Add 20 ml distilled water to Chamber #1 (the chambers are numbered beginning at the

regulator).d. Add 5 drops of Octanol Defoamer to Chamber #1.e. Install the top on the Gas Train and evenly hand tighten to seal all O-rings.f. Select a high range Drager tube (H2S 0.2% / A tube factor is 1500) for installation.g. Break off the ends of the tube, apply Lubriseal to both ends and install the tube with the

arrow pointing downward into the bored receptacle. Likewise, install the flow meter withthe word TOP upward. Be sure O-rings deal around the body of each tube.

h. Attach the flexible tubing from the regulator onto the dispersion tube of Chamber #1 and

from the outlet tube of Chamber #3 to the Drager tube.

Note: Use only latex rubber or inert plastic tubing. Do not clamp tubing.Unclamped tubing provides a pressure relief in the event the Gas Train is overpressured.

i. Adjust the dispersion tube of Chamber #1 to within 5 mm from the bottom.j. Flow CO2 gas gently through the Train for 10 seconds to purge system of air. Stop the

gas flow.7. Proceed to the Garrett Gas Train operating procedure outlined below:

a. Using the hypodermic syringe, inject 4.0 ml of filtrate (B) into Chamber #1.b. Slowly inject 10 ml 5N Sulfuric Acid solution into Chamber #1 through the septum using

the syringe and needle.c. Immediately restart CO2 flow. Using the regulator, adjust the flow so that the ball

remains between the 2 lines on the flow meter tube. One CO2 cartridge should provide15-20 minutes of flow at this rate.

d. Observe a color change on the Drager tube. In the units marked on the tube, note andrecord the maximum darkened length before the front starts to smear. Continue flow for15 minutes although the front may attain a diffuse, feathery coloration. On the highrange tube, an orange color may appear ahead of the black front if Sulfites are present.The orange region should be ignored when recording the darkened length.

8. Label the darkened, stained length as B.9. Filter the mud (A) to obtain at least 4 ml of filtrate, label filtrate A.10. Clean the Gas Train as outlined below:

To clean the Gas Train, remove the flexible tubing and Gas Train top. Take the Drager tubeand flow meter out of the receptacles, and plug with stoppers to keep them dry. Wash out

the chambers using a brush with warm water and mild detergent. Use a pipe cleaner toclean the passages between the chambers. Wash, rinse and then blow out the dispersiontuber with air or CO2 gas. Rinse the unit with distilled water and allow to drain dry.

11. Run the Gas Train using 4.0 cm3 of filtrate A (from the mud) repeating paragraphs 6 and 7.Label the darkened length A.

12. Be sure to clean the Gas Train after each test.


45/408

Page-44

Calculations

mg/L H2S Scavenging Ability = 375 (B-A)

kg/m3

Zinc Carbonate = 0.0037 X mg/L H2S Scavenging Ability

WARNING: The reagents in the kit may be hazardous to the health and safety of the userif inappropriately handled. Please read all warnings before performing the test and useappropriate safety equipment.

NOTE: The 100 gram/L Na2S solution can deteriorate with time. If the 4.0 cm3 of filtrateB results in Drager tube lengths which are too short, the filtrate volumes can beincreased. If filtrate sample volume is indeed increased, the equation used to calculateH2S scavenging ability is changed from:

mg/L H2S Scavenging Ability = 375 (B-A)

to:

mg/L H2S Scavenging Ability = 1500 (B-A)new volume (ml)

1.20 IRONITE SPONGE

Documents

Advantage Mud Manual .pdf