Wireline Logging

1

OH Logging Tucker Technologies, Inc. 1


2



3



4



5



6



7



8



9



10



11



12

Open Hole Logging

Measure properties of down holeMeasure properties of down hole formations to determine

Is there an oil reservoir?Where:Upper and lower limitsType of fluid :Oil Water Gas


How much:Thickness(Contacts), PorosityHow movable:(fluid mobility, permeability)


13



14

Answers from O.H. Logging

Measures Rock and Fluid PropertiesMeasures Rock and Fluid PropertiesStructural information

Dip of formationsLocation of well relative to a trapAre there any fracturesF ti


Formation pressureHole TrajectoryCalculate cement required for casing


A set of logs run on a well mean different things toA set of logs run on a well mean different things to different people.The common approach will be reading the logs and understanding the information they provide.

The GeophysicistAre the formation tops where you predicted?


p y pAre the potential zones porous as you have assumed from seismic data?What does a synthetic seismic section show?

15


The GeologistThe GeologistWhat depths are the formation tops?Is the environment suitable for accumulation of hydrocarbons?Is there evidence of hydrocarbons in this well?What type of hydrocarbon?Are hydrocarbons present in commercial quantities?


Are hydrocarbons present in commercial quantities?How good a well is it?What are the reserves?Could the formation be commercial in an offset well?


The Drilling EngineerThe Drilling EngineerWhat is the hole volume for cementing?Are there any Key-Seats or severe Dog-legs in the well?Where can you get a good packer seat for testing?Where is the best place to set a Whipstock?


Where is the best place to set a Whipstock?

16


The Reservoir EngineerThe Reservoir EngineerHow thick is the pay zone?How homogeneous is the section?What is the volume of Hydrocarbon per cubic meter?Will the well pay-out?


Will the well pay out?How long will it take?


The Production EngineerThe Production EngineerWhere should the well be completed (in what zone(s))?What kind of production rate can be expected?Will there be any water production?How should the well be completed?


o s ou d e e be co p e edIs the potential pay zone hydraulically isolated?Will the well require any stimulation?What kind of stimulation would be best?

17



18


Density: gr/cc

Reservoir Fluid Properties

Density: gr/ccGravity: API, Specific (chart)

ViscosityResistivity

ρ =+

14151315.

.API


ResistivityOil, gas and Fresh water: Infinite resistivityNon Fresh water: Depends on the amount of dissolved salts (charts)

19

Oil gravity (API) Vs Density-GOR



20



21



22


23



24



25



26



27

Rock Properties

Resistivity : The resistance offered to electricalResistivity : The resistance offered to electrical current flow presented by a unit volume of rock.Porosity : The void space between grains that is generally filled with liquids or gasses.Saturation : Percentage of the pore space filled with fluids.


Permeability: The ability of the rock to pass fluids through it.Capillary pressure

Rock PropertiesResistivity : The resistance offered by a formation to the electrical current flow It is expressedformation to the electrical current flow. It is expressed in ohms-meter2/meter.R w : Is the symbol for the resistivity of formation (connate) water.R o : Is the wet resistivity of a clean formation when all pore space is filled with connate water (R w). Porosity is 100% water filled Sw = 100%


Porosity is 100% water filled. Sw = 100%R t : Is the resistivity of a formation undisturbed by the drilling process.

28

Rock PropertiesResistivity : The usefulness of resistivity logging rests on the fact that:

water is a conductor ( low resistivity). The resistivity Rt will vary with Rw and 1/Ø.


hydrocarbons and rocks are insulators ( high resistivity).

Water Resistivity

Is the resistivity of formation (connate) waterIs the resistivity of formation (connate) water.Formation matrices are insulators; thus a formation ‘s ability to conduct electricity is a function of the connate water in the formation. Several factors must be considered:the volume of water (porosity).As water filled


pore space in a rock is increased, resistivity decreases.the pore space arrangement (type of porosity).

29

Water Resistivitythe temperature of the formation. As water temperature is raised, ionic mobility increases and resistivity decreases. the salinity of the water. As salinity increases, more ions are available to conduct electricity. Rw decreases.Depends on ion Activity:


p yType of salt (predominant NaCl -Why?)PPM

30

Ro :Resistivity of a Clean Rock

filled with waterArchie EquationArchie Equation

Ro= F.RwRo= F.Rw

F = a ⋅ −φ m


Rw :Resistivity of water in rocka m

Ss 0.62 -2.15

Ss 0.81 -2.0

Other 1.0 -2.0

Rt : True Resistivity of a rock with hydrocarbons

RR

RSt

o

wn= n = 2.0

SR F Ron wn= =

⋅


SR Rw

tn

tn= =

31



32


Porosity (Ø)Is the void spaceIs the void space between grains generally filled with liquids or gases.Total Volume of Rock is made up of two spaces:

MatrixNon Matrix : Pore volume


Non-Matrix : Pore volumePorosity φ :φ = 1−Μatrix Vol. X 100 %

Total Volume

33

Porosity (Ø)Types of Porosity

Primary: Original (intergranular) porosity built during depositionSecondary: Due to void space created after deposition e.g. vugs, fractures in carbonates.Total: When shale is present, the pore space occupied by the water in the shale is included with


the pore space in the rock.Effective: In a shaly formation only the rock pore space is considered.

Porosity (Ø)

Factors that affect it:Factors that affect it:

Depth:Compaction and Cementation

Grain:Shape, Size, Sorting


p , , g

34



35

Formation Factor for Resistivity

The ratio between the resistivity of a fully waterThe ratio between the resistivity of a fully water saturated formation and the resistivity of the contained water is called Formation Resistivity Factor.

F = Ro / Rw F is a constant. The value of F for any particular


F is a constant. The value of F for any particular formation depends on:formation porosity, pore distribution, pore size, and pore structure.

Formation Factor for Porosity

Also through empirical measurements it wasAlso through empirical measurements, it was determined that

F = a / Ø ma is a constant or cementation factor.m is the cementation or tortuosity exponent


m is the cementation or tortuosity exponent. Relates to the porosity type and how it will transmit electrical current to the actual rock.

36

Formation Factor for Porosity

Some recommended F and Ø relationships are:Some recommended F and Ø relationships are:

F = 0.62 / Ø 2.15 for Sands

F = 0.81 / Ø 2 for Sands


F = 1 / Ø 2 for Carbonates

37

SaturationFraction of the porous volume that is filled with aFraction of the porous volume that is filled with a given fluid

Water Saturation: Sw . The percentage or fraction of the pore space filled with water:

Sw = Water Filled Pore Volume x 100%


Sw = Water Filled Pore Volume x 100%Total Pore Volume

SaturationHydrocarbon(Oil) Saturation: Shy= 1- Sw .TheHydrocarbon(Oil) Saturation: Shy 1 Sw .The percentage of the pore space filled with hydrocarbon

Shy = Hydrocarbon Filled Pore Volume x 10Total Pore Volume


Swirr : Irreducible water SaturationWater retained in the grains by surface tension, and small interstices. It can not move. Varies from 0.05% to 0.4%

38

Saturation

The percentage Volume of water saturation:The percentage Volume of water saturation:Ø Sw .

The percentage Volume of flushed saturation:Ø Sxo .

The percentage Volume of hydrocarbon


saturation:Ø Shy .


39


Permeability of a Rock

Rock Property

L DP

Rock PropertyIndependent on shapeIndependent on Volume

Measured in Darcies


A

μ = Fluid Viscosity

40

Types of Permeability

Absolute: Only one type of fluid is presentAbsolute: Only one type of fluid is presentkw, ko, kg

Effective: Permeability of a rock to a medium when another is present kwo, kow …

Sum of effective perms is less than the absolute


Sum of effective perms is less than the absolute

Relative: Ratio of effective to absolute kro ...

FormationsClean Formations.

f t th th t “ h l f ” f tirefer to those that are “shale free” formations.Shaly Formations.

formations where some of the formation void space (porosity) is filled with shale. Shale distribution is considered to be:Laminated : thin laminae of sand and shale


Dispersed: shale particles are dispersed in the pore spaceStructural: shale replaces matrix.

41



42



43



44



45



46


47

48


49



50



51



52



53



54



55



56



57



58



59



60



61



62



63


Documents

Wireline Logging