Q931+rrl reference en le cs

Reservoir Rock Laboratory Course2nd Ed. , 2nd Experience

http://www.iauq.ac.ir/


mailto:[email protected]

http://bit.ly/Q931-RRL

http://about.me/Alaminia




http://about.me/alaminia


1. About This Course

2. Course Learning Outcome

3. Presentation and assessmentA. Class Projects (CLS PRJ)

4. Laboratory related issues

5. Review of Syllabus

6. Resources

7. Training Outline (beta)

8. Communication

A quote on Beginnings

"Before you begin a thing, remind yourself that difficulties and delays quite impossible to foresee are ahead. If you could see them clearly, naturally you could do a great deal to get rid of them but you can't. You can only see one thing clearly and that is your goal. Form a mental vision of that and cling to it through thick and thin"Kathleen Norris

Fall 14 H. AlamiNia Reservoir Rock Laboratory Course (2nd Ed.) 4

Course Scope

Systematic theoretical and laboratory study of physical properties of petroleum reservoir rocks; STRUCTURE AND

PROPERTIES OF POROUS MEDIACoring and Rock sample

preparation

Porosity• Measurement of

Porosity by saturation method and helium porosimeter

• Compressibility

• grain size and pore size distribution of formation

Permeability• effective permeability

by using liquid & gas


Course Scope (Cont.)

STATICS OF FLUIDS IN POROUS MEDIASaturation

• Measurement of fluid Saturation by extraction method, retort method

• Resistivity

Multiphase Phenomena (Fluid flow in porous media, fluid-rock interaction)

• Surface tension and wettability

• Capillary pressure

o capillary

characteristics by porous plate method and mercury injection method

• Relative permeability

Heterogeneity


Course Description

This course is prepared for: 1 semester (or credit) hours and meets for a total of 2

hours a week.

Sophomore or junior level students (BS degrees)

(Major) Petroleum engineering students(Minors) Production, Drilling and reservoir engineering students

Prerequisites: general petrology.

Main objectives:The aim of the laboratory experiments is to give the

students better understanding of reservoir rocks and the factors that affect the fluid flow within the porous media


Learning and Teaching Strategies

This course promotes interactive and thorough engagement in the learning process.

It is essential that you take responsibility for your own learning, and that I facilitate that learning by establishing a supportive as well as challenging environment.


Proposed study method

When studying petroleum engineering, it is important to realize that the things you are learning today will be important to you for the rest of your career. Hence,

you shouldn’t just learn things simply to pass exams!

You will gain maximum benefit from this course by approaching each lecture and in-class activity with an inquiring mind and a critical, analytical attitude.


Study recommendations

In covering the material in the course, I recommend that you follow the procedure outlined below: Carefully read the entire chapter

to familiarize yourself with the material.

Locate the topic area in your text book and study this material in conjunction with the course material.

Attempt the examples before all tutorials. When you feel that you have mastered a topic area,

attempt the problem for the topic.

You are required to complete the assigned readings prior to lectures. This will help your active participation in class activities.

Self-study in advance is always more beneficial.


Main Objectives (minimum skills to be achieved/demonstrated)By the last day of class, the student should be able to:

Define porosity, discuss the factors which effect porosity, and describe the methods of determining values of porosity.

Define the coefficient of isothermal compressibility of reservoir rock and describe methods for determining values of formation compressibility.

describe methods for determining values of absolute permeability.

Explain boundary tension and wettability and their effect on capillary pressure, describe methods of determining values of capillary pressure, and convert laboratory capillary pressure values to reservoir conditions.

Describe methods of determining fluid saturations in reservoir rock and show relationship between fluid saturation and capillary pressure.


Main Objectives (minimum skills to be achieved/demonstrated) (Cont.)Define resistivity, electrical formation resistivity factor,

resistivity index, saturation exponent, and cementation factor and show their relationship and uses; discuss laboratory measurement of electrical properties of reservoir rocks; and demonstrate the calculations necessary in analyzing laboratory measurements.

Define effective permeability, relative permeability, permeability ratio; reproduce typical relative permeability curves and show effect of saturation history on relative permeability; illustrate the measurement of relative permeability; and demonstrate some uses of relative permeability data.


Minor Objectives (other skills to be achieved/demonstrated)Describe three-phase flow in reservoir rock and

explain methods of displaying three-phase effective permeabilities, including ternary diagrams.

Demonstrate the techniques of averaging porosity, permeability, and reservoir pressure data.

Demonstrate capability to perform calculations relating to all concepts above.


Laboratory related outcomes

Apply the knowledge of mathematics, geology, physics, chemistry as well as other engineering sciences.

Conduct experiments safely and accurately and to be able to correctly analyze the results.

Design an engineering process or system to meet desired needs.

Identify, formulate and solve engineering problems.

Understand the impact of engineering solutions in a global, economic, environmental and societal contest.


Side Objectives

Communicational skillsCommunicate

successfully and effectively.

Understand professional and ethical responsibilities.

Work in a team environment

Familiarize with English language

Academic skillsSystematic research

Reporting

Management skillsProject time

Computer knowledgeUnderstand the use of

modern techniques, skills and modern engineering toolsApplication of internet

and EmailMicrosoft OfficeProfessional software


Presentations (Lectures)

Each session Consists of different sections (about 4-5 sections)Consists of about 35 slides Is divided into 2 parts with short break timeWould be available online

The teaching approach to be employed will involve lectures and tutorials.

Lecture presentations cover theoretical and practical aspects, which are also described in the supporting academic texts and teaching resources.You are encouraged to ask questions and express feedback

during classes. You are expected to read prescribed materials in advance of classes to enable active participation.


Timing

Last Session (Review)

Areas Covered in This Lecture

Presentation A

Break Time

Presentation B

Next Session Topics

Last session (Review)

Session Outlook

Presentation ABreak Time

Presentation B

Next Session Topics

Roll Call


Assessment Criteria

Basis for Course Grade:Final exam

(Close book)

AttendanceClass activities

Class ProjectsExaminations

Grade Range:90 ≤ A ≤100 (18 ≤ A ≤20)80 ≤ B ≤ 90 (16 ≤ B ≤18)70 ≤ C ≤ 80 (14 ≤ C ≤16)60 ≤ D ≤ 70 (12 ≤ D ≤14)F < 60 (F <12)

Final exam

Attendance

Class activities


Previous Term Scores out of 20 (Q922)

10.0

15.0

20.0

F DE1 F DE2 F LOG F RE2 F RFP


Previous Term (Q922)Attendance percentageStudents are

expected to be regular and punctual in attendance at all lectures and tutorials. Attendance

will be recorded when applicable.

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

DE1 DE2 LOG RE2 RFP


CLS PRJ Topics:

These are intended topics, addition and/or deletion of certain problems may occur as other problems become available. Multiple assignments from each topic are possible.Porosity (fundamentals and

laboratory measurements).Permeability (fundamentals

and laboratory measurements).

Compressibility of reservoir rocks (derivations/applications).

Flow in channels and

layered reservoir systems (derivations/applications).

Capillary pressure (fundamentals, laboratory measurements, and correlations).

Electrical properties (fundamentals and laboratory measurements).

Relative permeability (fundamentals, laboratory measurements, and correlations).

Statistical analysis and correlation of reservoir data.


Format of the Report:

Title page: Course number, course name,

Experiment number & title, Lab date, Names of the lab group

Sections to include in each report Introduction

Objective/purpose of the experiment Scope of the experiment / Importance

of the parameters measured How (in general) you obtained the

information you are reporting

Methods Describe Equipment Experimental procedure (write it in your

own words) Methods of analysis (if appropriate) How did you analyze the data (principle

/ equations used)

Results: State/tabulate/plot results as applicable Report both observed and measured

results

Discussion: Discuss the importance of results Tie the results of this study to previous

knowledge/works Comment on the quality of results

Conclusions: Findings in the study (stick to the results

you measured)

References Appendices

Raw Data tables Must include sample calculations Derivation of equations (if applicable)

Report late submission Policy: Report must be submitted one week

after experiment unless asked otherwise. Deduction of 10% grade per late submission will be applied.


Deliverable Format Guidelines

General Instructions: You must use predefined templates for reporting the

projects

Follow predefine instructions


Safety:

Wear safety goggles when working in the lab Lab coats or aprons should be worn when appropriate Flip flops and sandals are prohibited Restrain loose clothing, hair and jewelry Never work alone or without an instructor present Never leave heat sources unattended Do not eat, drink or smoke in the lab Dispose of waste properlyWash hands after spill Report any accidents to the instructor Avoid direct contacts with chemicals and reagents


سرفصل آزمایشگاه خواص سنگ مخزن(مصوب وزارت علوم)مغزه گیری

های مغزه برداری روشهای مغزهآزمایشهای سنگینگه داری و آنالیز مغزه

تخلخلآزمایشگاهی تخلخلگیریاندازهازاستفادهباو فرجخللتوزیعتعیین

تراواییمطلق تراواییآزمایشگاهیگیریاندازه

(مایع +گاز)

اشباعسنگاشباعتعیینآزمایشگاهیروشهای

مخزنمعایببیانبیان مزایاهای اشباعدادهاعتبارارزیابی

تراکم پذیریپذیریتراکمگیری آزمایشگاهیاندازه

خواص الکتریکیمقاومتضریبآزمایشگاهیگیریاندازه

سازندالکتریکی


سرفصل آزمایشگاه خواص سنگ مخزن(ادامه( )مصوب وزارت علوم)فشار مویین

گیریاندازهروشهای آزمایشگاهیمویینگی،فشارمویینگی،فشارمنحنیویژگیهایفشار های آزمایشگاهیدادهتبدیل

میدان،دراستفادهجهتمویینگیبامویینگیفشارمتوسطتعیین

،Jرابطهازاستفادهبا عمقنفتاشباعمیزانتعیین

مویینگی،فشارمنحنیمتوسطمویینگیفشارریاضیرابطهتوسعه

سانتریفوژ،آزمایشدر

تراوایی دو فازی و جابجایی سیالگیریاندازهآزمایشگاهیروشهای

نسبیتراوایی(غیر یکنواختویکنواختروش )

های فشاردادهازنسبیتراواییتعیینمویینگی،

تراواییگیریاندازهبرموثرعواملنسبی،

های تراواییدادهدرخاصویژگیهانسبی،

ونسبیهای تراواییدادهارزیابی،coreyهای رابطه توانتعیین

درنسبیهای تراواییدادهاهمیتفازیمحاسبهسیستمهای


سرفصل آزمایشگاه خواص سنگ مخزن(ادامه( )مصوب وزارت علوم)های جریان سیاالت در محیط

متخلخلده مطالعه جریان سیاالت با استفا

های ساده الکتریکی و از مدلزنالکترولیتی در شبیه سازی مخ

ناهمگونی(Heterogeneity) مخازن دراهمیتتعریف

سطحی،ناهمگونیعمقی،ناهمگونی

سازی ناهمگونیکمیلورنزوپارسونردایکستراروشهایاز

ترشوندگی وسطحیکششترشوندگی،گیریاندازهشاخص آموتروشهای

،USBMوهارویآموت

تماسزاویهو


Extra (Beyond scope)

Statistical analysis and correlation of reservoir dataTreating Experimental Data

Simulating experiments using relevant software


منابع پیشنهادی درس آزمایشگاه خواصسیاالت مخزن

منابعی ارایه نشده است.


Texts and Materials:

(ABT) Torsæter, O., and M. Abtahi. "Experimental reservoir engineering laboratory work book."

(Q931+RRL+L00) Lecture notes from classThese materials may include

handouts provided in class.

computer files available on the course weblog

…


Class Lectures


Major References

(ABT) Torsæter, O., and M. Abtahi. "Experimental reservoir engineering laboratory work book." Department of Petroleum Engineering and Applied Geophysics, Norwegian University of Science and Technology (NTNU), Trondheim (2003).


Major References (Cont.)

Mostafa Mahmoud Abdel Latief Kinawy, "Lecture of Reservoir Engineering Laboratory“ Petroleum and Natural Gas Engineering Department of King Saud University (2009).


Side References

Ahmed, T. (2010). Reservoir engineering handbook (Gulf Professional Publishing). Chapters:


(کمکی)منابع فارسی (ترجمه )سیالوی، رحیم .

مهندسی مخازن . 1386هیدروکربوری


Class Schedule (Beta)

Lec. 1 Introduction

Lec. 2

Lec. 3

Lec. 4

Lec. 5

Lec. 6

Lec. 7

Lec. 8

Lec. 9

Lec. 10


Details (Beta)

Date Lecture Topic Reading Assignment (prior to class)

01

02

03


Communication Methods

Preferred methodsBreak time and mid class

First Point of Contact via email (Limited)Will be answered with

some delay (an hour to a week according to importance and requirements)

Mention your personal and educational info in emails (Name, Student #, Course title, Subject)

Avoid following communication methodsAppointments

Phone calls

Short Message Service (SMS)

Instant message (IM) chats


Frequently Asked Questions (FAQ)

Class schedule:Almost all sessions will

be held

Preferred topics:Course relatedResearch study Paper for International

conferencesArticles for national

journals

Avoided helps:Other courses

Sources, exams, exercises, class works and so on

B.Sc. ThesisAside supervised ones

M.Sc. Conquer TraineePrivate classEducational problemsPersonal problemsNational conference

paper













1. Petrophysics

2. Coring and Plugging

Petrophysics definition

Petrophysics (from the Greek petra, "rock" and physis, "nature") is the study of physical and chemical rock properties and their

interactions with fluids.

A major application of petrophysics is in studying reservoirs for the hydrocarbon industry. Petrophysicists are employed

to help reservoir engineers and geoscientists understand the rock properties of the reservoir, particularly how pores in the subsurface are interconnected,

controlling the accumulation and migration of hydrocarbons.

Some of the key properties studied in petrophysics are lithology, porosity, water saturation, permeability and density.


key aspect of petrophysics

A key aspect of petrophysics is measuring and evaluating these rock properties by acquiring well log measurements - in which a string of

measurement tools are inserted in the borehole,

core measurements - in which rock samples are retrieved from subsurface, and

seismic measurements.

These studies are then combined with geological and geophysical studies and reservoir engineering to give a complete picture of the reservoir.


Categories of measured properties

While most petrophysicists work in the hydrocarbon industry, some also work in the mining and water resource industries.

The properties measured or computed fall into three broad categories: conventional (or reservoir) petrophysical properties,

Reservoir models are built upon their measured and derived properties to estimate the amount of hydrocarbon present in the reservoir, the rate at which that hydrocarbon can be produced to the Earth’s surface.

rock mechanical properties, and

ore quality


conventional (or reservoir) petrophysical properties,Lithology: rock's physical characteristics:

grain size, composition and texture and etc.By using log measurements,

such as natural gamma, neutron, density and resistivity

Porosity: from neutrons or by gamma rays, also sonic and NMR logging.

Water saturation: from an instrument that measures the resistivity of the rock

Permeability: From Formation testing, and empirical relationships with

other measurements such as porosity, NMR and sonic logging.

“Net Pay”


Rock mechanical properties

Some petrophysicists use acoustic and density measurements of rocks to compute their mechanical properties and strength. They measure the compressional (P) wave velocity of

sound through the rock and the shear (S) wave velocity and use these with the density of the rock to compute the rocks' compressive strengthThese measurements are useful to design programs to drill

wells that produce oil and gas.

also used to design dams, roads, foundations for buildings,

They can also be used to help interpret seismic signals from the Earth, either man-made seismic signals or those from earthquakes.


Methods of analysis

Coring and core analysis is a direct measurement of petrophysical properties. In the petroleum industry rock samples are retrieved

from subsurface and measured by core labs of oil company or some commercial core measurement service companies. This process is time consuming and expensive, thus cannot be

applied to all the wells drilled in a field.

Well Logging is used as a relatively inexpensive method to obtain petrophysical properties downhole. Measurement tools are conveyed downhole using either

wireline or LWD method.


routine core analysis (RCAL)

routine core analysis isThe set of measurements

normally carried out on core plugs or whole core. These generally include

porosity, grain density, horizontal permeability, fluid saturation and a lithologic description.

Routine core analyses often include a core gamma log and measurements of vertical permeability.

Measurements are made at room temperature and at either atmospheric confining pressure, formation confining pressure, or both.

Recommended practices for routine core analysis are available in the API document RP40.


Special core analysis laboratory (SCAL)

In the petroleum industry, special core analysis, often abbreviated SCAL or SPCAN, is a laboratory procedure for conducting flow

experiments on core plugs taken from a petroleum reservoir.

Special core analysis is distinguished from "routine or conventional core analysis" by adding more experiments, in particular including measurements of two-phase flow properties,

determining relative permeability and

capillary pressure.


major sources of petrophysical propertiesKnowledge of petrophysical and hydrodynamic

properties of reservoir rocks are of fundamental importance to the petroleum engineer. These data are obtained from two major sources:

core analysis and well logging. In this course we present some details about the analysis of

cores and review the nature and quality of the information that can be deduced from cores.

Cores are obtained during the drilling of a well by replacing the drill bit with a diamond core bit and a core barrel. The core barrel is basically a hollow pipe receiving the

continuous rock cylinder, and the rock is inside the core barrel when brought to surface.


Coring

Continuous mechanical coring is a costly procedure due to:The drill string must be pulled out of the hole to replace the

normal bit by core bit and core barrel.The coring operation itself is slow.The recovery of rocks drilled is not complete.A single core is usually not more than 9 m long, so extra trips

out of hole are required.

Coring should therefore be detailed programmed, especially in production wells.

In an exploration well the coring cannot always be accurately planned due to lack of knowledge about the rock.


sidewall coring

Now and then there is a need for sample in an already drilled interval, and then sidewall coring can be applied. In sidewall coring a wireline-conveyed core gun is used,

where a hollow cylindrical “bullet” is fired in to the wall of the hole.

These plugs are small and usually not very valuable for reservoir engineers.


The fluid content of the core

During drilling, the core becomes contaminated with drilling mud filtrate and the reduction of pressure and temperature while bringing the core to surface results in gas dissolution and further expansion of fluids.

The fluid content of the core observed on the surface cannot be used as a quantitative measure of saturation of oil, gas and water in the reservoir. However, if water based mud is used the presence of oil

in the core indicates that the rock information is oil bearing.


routine core analysis

When the core arrives in the laboratory plugs are usually drilled 20-30 cm apart throughout the

reservoir interval .

All these plugs are analyzed with respect to porosity, permeability, saturation and lithology. This analysis is usually called routine core analysis.

The results from routine core analysis are used in interpretation and evaluation of the reservoir.


1. “Petrophysics.” Wikipedia, the free encyclopedia 13 July 2014. Wikipedia. Web. 22 July 2014.

2. (KSU) M. Kinawy. “Reservoir engineering laboratory manual" Petroleum and Natural Gas Engineering Department, King Saud University, Riyadh (2009).












1. Without Distillation methods

2. Soxhlet Extraction method

3. Dean-Stark Distillation-Extraction and Vacuum DistillationA. Saturation Determination Experiment

4. Conclusions and Recommendations

Cleaning and Saturation DeterminationObjectives:

Cleaning and drying the core samples

Introduction and Theory:Before measuring porosity and permeability,

the core samples must be cleaned of residual fluids and thoroughly dried.

The cleaning process may also be a part of fluid saturation determination.Fluid saturation is defined as the ratio of the volume of fluid in a

given core sample to the pore volume of the sampleNote that fluid saturation may be reported either as a fraction of

total porosity or as a fraction of effective porosity. • Since fluid in pore spaces that are not interconnected cannot be

produced from a well, the saturations are more meaningful if expressed on the basis of effective porosity.


Saturation calculation

The weight of water collected from the sample is calculated from the volume of water by the relationship

The weight of oil removed from the core may be computed as the weight of liquid less weight of water

WL is the weight of liquids removed from the core sample in gram.

Oil volume may then be calculated as Wo/ρo. Pore volume Vp is

determined by a porosity measurement.and oil and water

saturation may be calculated by

Gas saturation can be determined using


Direct Injection & centrifugal methodsDirect Injection of Solvent

The solvent is injected into the sample in a continuous process.

The sample is held in a rubber sleeve thus forcing the flow to be uniaxial.

Centrifuge FlushingA centrifuge which has been fitted with a special head

sprays warm solvent onto the sample.

The centrifugal force then moves the solvent through the sample.

The used solvent can be collected and recycled.


Gas Driven method

Gas Driven Solvent ExtractionThe sample is placed

in a pressurized atmosphere of solvent containing dissolved gas.The solvent fills the pores of sample.

When the pressure is decreased, the gas comes out of solution, expands, and drives fluids out of the rock pore space.

This process can be repeated as many times as necessary.


Soxhlet extractor

A Soxhlet extractor is a piece of laboratory apparatus invented in 1879 by Franz von Soxhlet.

It was originally designed for the extraction of a lipid from a solid material.

Typically, a Soxhlet extraction is only required where the desired compound has a limited solubility in a solvent, and the impurity is insoluble in that solvent. Soxhlet mechanism


Soxhlet Extraction Apparatus

A Soxhlet extraction apparatus is the most common method for cleaning sample, and is routinely used by most laboratories. As shown in the Figure,

samples to be cleaned are placed in a porous thimble inside the Soxhlet.


Procedure

The solvent (toluene) is brought to a slow boil in a Pyrex flask;

Electric or gas heaters are used to vaporize the solvent. its vapors move upwards

and the core becomes engulfed in the toluene vapors (at approximately 110 C).Eventual water within the

core sample in the thimble will be vaporized.

The toluene and water

water falls from the base of the condenser onto the core sample in the thimble; the toluene soaks the

core sample and dissolves any oil with which it come into contact.

When the liquid level within the Soxhlet tube reaches the top of the siphon tube arrangement,


Procedure (Cont.)

The extraction process continues for several hours and is terminated when no more oil remains in the samples. This is recognized when the condensing vapors remain

clean because no oils is left in the cores to be dissolved.

After the extraction, samples are dried in an electric oven. Sometimes vacuum may also be applied to the oven.

The dried samples are kept in a desiccator sealed with grease and has some moisture absorbents at its bottom.


Remarks

A complete extraction may take several days to several weeks in the case of low API gravity crude or presence of heavy residual hydrocarbon deposit within the core.

Low permeability rock may also require a long extraction time.


Dean-Stark apparatus

The Dean-Stark apparatus or Dean-Stark receiver or distilling trap or Dean-Stark Head is a piece of laboratory glassware used in synthetic chemistry to collect water (or occasionally other liquid) from a reactor. It was invented by E. W. Dean

and D. D. Stark in 1920 for determination of the water content in petroleum.


Dean-Stark distillation procedure

The Dean-Stark distillation provides a direct determination of water content.

The oil and water area extracted by dripping a solvent, usually toluene or

a mixture of acetone and chloroform, over the plug samples.


Calculation of water and oil contentIn this method,

the water and solvent are vaporized,

recondensed in a cooled tube in the top of the apparatus and

the water is collected in a calibrated chamber.

The solvent overflows and drips back over the samples.

The oil removed from the samples remains in solution in the solvent. Oil content is calculated by

the difference between the weight of water recovered

and the total weight loss after extraction and drying.Fall 14 H. AlamiNia Reservoir Rock Laboratory Course (2nd Ed.) 84

Vacuum Distillation

The oil and water content of cores may be determined by this method.

As shown in the Figure, a sample is placed

within a leak-proof vacuum system and heated to a maximum temperature of 230 C.

Liquids within the sample are vaporized and passed through a condensing column

Vacuum distillation ApparatusFall 14 H. AlamiNia Reservoir Rock Laboratory Course (2nd Ed.) 85

The Experiment Description

Description:The objective of the experiment is to determine the oil,

water and gas saturation of a core sample.

Procedure:Weigh a clean, dry thimble.

Use tongs to handle the thimble.

Place the cylindrical core plug inside the thimble, then quickly weigh the thimble and sample.

Fill the extraction flask two-thirds full with toluene. Place the thimble with sample into the long neck flask.


The Experiment Procedure

Tighten the ground joint fittings, but do not apply any lubricant for creating tighter joints.

Start circulating cold water in the condenser.

Turn on the heating jacket or plate and adjust the rate of boiling so that the reflux from the condenser is a few drops of solvent per second. The water circulation rate should be adjusted so that excessive

cooling does not prevent the condenser solvent from reaching the core sample.

Continue the extraction until the solvent is clear. Change solvent if necessary.


The Experiment Procedure (Cont.)

Read the volume of collected water in the graduated tube. Turn off the heater and cooling water and place the sample into

the oven (from 105 C to 120 C), • until the sample weight does not change.

The dried sample should be stored in a desiccater.

Obtain the weight of the thimble and the dry core.

Calculate the loss in weight WL, of the core sample due to the removal of oil and water.

Measure the density of a separate sample of the oil.

Calculate the oil, water and gas saturations after the pore volume Vp of the sample is determined.


Saturation Determination from The ExperimentData and calculations:

Worg: Weight of original saturated sample

Wdry: Weight of desaturated and dry sample

Equations:

D and L are diameter and length of the core sample, respectively.


direct-injection, centrifugal and gas driven-extraction methodsThe direct-injection method is effective, but slow.

The method of flushing by using centrifuge is limited to plug-sized samples. The samples also must have sufficient mechanical

strength to withstand the stress imposed by centrifuging.

However, the procedure is fast.

The gas driven-extraction method is slow. The disadvantage here is that it is not suitable for poorly

consolidated samples or chalky limestones.


Distillation methods

The distillation in a Soxhlet apparatus is slow, but is gentle on the samples. The procedure is simple and very accurate water content

determination can be made.

Vacuum distillation is often used for full diameter cores because the process is relatively rapid. It is also frequently used for poorly consolidated cores

since the process does not damage the sample.

The oil and water values are measured directly and dependently of each other.


solvents

In each of these methods, the number of cycles or amount of solvent which must

be used depends on the nature of the hydrocarbons being removed and the solvent used.

Often, more than one solvent must be used to clean a sample.

The solvents selected must not react with the minerals in the core.


Common solvents

The commonly used solvents are:Acetone

Benzene

Benzen-methol Alcohol

Carbon-tetrachloride

Chloroform

Methylene Dichloride

Mexane

Naphtha

Tetra Chloroethylene

Toluene

Trichloro Ethylene

Xylene

Toluene and benzene are most frequently used

to remove oil and

methanol and water is used to remove salt

from interstitial or filtrate water.

The cleaning procedures used are specifically important in special core analysis tests, as the cleaning itself may

change wettabilities.


Drying remarks

The core sample is dried for the purpose of removing connate water

from the pores, or

to remove solvents used in cleaning the cores.

When hydratable minerals are present, the drying procedure is

critical since interstitial water must be removed without mineral alteration.

Drying is commonly performed in a regular oven or

a vacuum oven at temperatures between 50 C to 105 C.

If problems with clay are expected, drying the samples

at 60 C and 40 % relative humidity will not damage the samples.


1. (ABT) Torsæter, O., and M. Abtahi. "Experimental reservoir engineering laboratory work book." Department of Petroleum Engineering and Applied Geophysics, Norwegian University of Science and Technology (NTNU), Trondheim (2003). Chapter 2A. (KSU) M. Kinawy. “Reservoir engineering

laboratory manual" Petroleum and Natural Gas Engineering Department, King Saud University, Riyadh (2009).

2. “Soxhlet Extractor.” Wikipedia, the free encyclopedia 5 July 2014. Wikipedia. Web. 22 July 2014.

3. “Dean-Stark Apparatus.” Wikipedia, the free encyclopedia 5 July 2014. Wikipedia. Web. 22












1. Porosity definitions

2. Porosity determination

3. Determination of Bulk VolumeA. Determination of Bulk Volume By Mercury Pump

4. Determination of Grain Volume

5. Pore Volume DeterminationA. Pore Volume Determination (Gas Expansion)

6. Effective Porosity Determination by Helium Porosimeter Method

7. Porosity Determination by Liquid Saturating Method

Porosity importance

One of the essential properties of a reservoir rock is that it must be porous.

Porosity is therefore an important property and its accurate determination is relevant to reserve estimates and other petroleum engineering calculations.

The porosity of a material defined as the fraction (or the percentage) of the bulk volume occupied by pores. Thus porosity is a measure of the storage capacity of the

rock.

The more porous is the rock, the more is its capacity to store fluids (oil, gas and water) in its pores. Fall 14 H. AlamiNia Reservoir Rock Laboratory Course (2nd Ed.) 102

Definition of the total (absolute) porosity and effective porositySome of the pores in a rock may be

sealed off from other pores by cementing materials. These pores, although present and contribute to the

porosity, do not allow passage or withdrawal of fluids.

Two types of porosity may be measured: total or absolute porosity and effective porosity. Total porosity is the ratio of

all the pore spaces in a rock to the bulk volume of the rock.

Effective porosity ϕe is the ratio of interconnected void spaces to the bulk volume.


Differences between Absolute and Effective PorosityThus, only the effective porosity contains fluids

that can be produced from wells.

For granular materials such as sandstone, the effective porosity may approach the total porosity,

however, for shales and for highly cemented or vugular rocks such as some limestones, large variations may exist

between effective and total porosity.

The difference between absolute and effective porosity is known as the dead porosity.


primary vs. secondary porosity

Porosity may be classified according to its origin as either primary or secondary. Primary or original porosity

is developed during deposition of the sediment.

Secondary porosity is caused by some geologic process subsequent to formation of the deposit. These changes in the original pore spaces

may be created by ground stresses, water movement, or various types of geological activities after the original sediments were deposited.

Fracturing or formation of solution cavities often will increase the original porosity of the rock.


Porosity of different packing types

A maximum theoretical porosity of 48% is achieved with cubic packing (a)

of spherical grains.

The porosity of the Rhombohedral packing (b), which is more

representative of reservoir conditions, is 26%.

If a second, smaller size of spherical grains is


Effective parameters on porosity

For a uniform rock grain size, porosity is independent of the size of the grains.

Thus, porosity is dependent on the grain size distribution and

the arrangement of the grains,

as well as the amount of cementing materials.

Not all grains are spherical, and grain shape also influences porosity.


Effect of Compaction on Porosity

Compaction is the process of volume reduction due to an externally applied pressure. For extreme compaction pressures,

all materials show some irreversible change in porosity. This is due to

distortion and crushing of the grain or matrix elements of the materials, and in some cases, recrystallization.


Formation compressibility

The variation of porosity with change in pressure can be represented by

ϕ2 and ϕ1 are porosities at pressure P2 and P1 respectively, and

cf is formation compressibility.

Formation compressibility is defined as summation

of both grain and pore compressibility.

For most petroleum reservoirs, grain compressibility is considered to be negligible. Formation compressibility can be expressed as

• dP is change in reservoir pressure.

• For porous rocks, the compressibility depends explicitly on porosity.


Porosity definition

By definition

It is sometimes convenient to express porosity in percent. So

Since a rock is composed from pores and grains or rock matrix, it is obvious thatBulk volume = grain volume + pore volume

Vb = Vg + Vp and

Vp = Vb – Vg


Porosity calculation

It is clear from the above relations that any two of the three values Vp, Vg and Vb are sufficient to determine the value of porosity.Porosity from pore and bulk volumes

Porosity from pore and grain volumes

Porosity from grain and bulk volumes


Some Notes about Porosity

It must be noticed that the two volumes used to determine the porosity

must be for the same sample.

Sometimes the bulk and grain densities may be used instead of bulk and grain volumes.

Depending on the method used, either absolute or effective porosity will result.


Porosity determination techniques

The porosity of reservoir rock may be determined byCore analysis, Well logging technique, Well testing

The question of which source of porosity data is most reliable cannot be answered without reference to a specific interpretation problem. These techniques can all give correct porosity values

under favorable conditions. The core analysis porosity determination has the advantage

that no assumption need to be made as to mineral composition, borehole effects, etc.

However, since the volume of the core is less than the rock volume which is investigated by a logging device, porosity values derived from logs are frequently more accurate in heterogeneous reservoirs.


Measurement Methods for the porosity determination

Pore V

olu

me

Gas Expansion

• Mercury Pump with a vacuum

• helium Gas

Saturation Method

Mercury Pump

Washburn Bunting

Grain

Vo

lum

e

Dry, ϕe(Unsaturated)

• Gas Expansion

• helium Gas

Saturated, ϕe

• Gravimetric (Loss of Weight)

• Russell Volumeter

• Pycnometer

Crushed , ϕt


• Pycnometer

Bu

lk Vo

lum

e

Dimensional

Coated Sample


• Gravimetric (Loss of Weight) Method

• Mercury Pycnometer

• Mercury Pump


Bulk Volume Measurement

Although the bulk volume may be computed from measurements of the

dimensions of a uniformly shaped sample,

the usual procedure utilizes the observation of the volume of fluid displaced by the sample.

The fluid displaced by a sample can be observed either volumetrically or gravimetrically. Gravimetric determinations of bulk volume can be

accomplished by observing the loss in weight of the sample when immersed in a fluid or by change in weight of a pycnometer with and without the core sample.


Sample isolation methods

In either procedure it is necessary to prevent the fluid penetration into the pore space of the rock.

This can be accomplished (1) by coating the sample

with paraffin or a similar substance,

(2) by saturating the core with the fluid into which it is to be immersed, or

(3) by using mercury.


Bulk Volume Determination:By Measuring the DimensionsFor a regularly shaped sample, the bulk volume is

found by measuring the dimensions of the sample. For a cylindrical sample with diameter D and length L,

the bulk volume is given by:

For a sample with rectangular cross section

A sliding caliper is used to measure the dimensions. Different reading are usually taken for the diameter and

length and the average values are used.


Bulk Volume Determination:By Russell Volumeter

In this case a sample must by saturated completely with a non-reacative fluid or coated by paraffin wax and then placed in the volumeter. The difference in the fluid level

before and after the sample gives the bulk volume of the sample.

If the sample is coated the volume of the coating material must be found and subtracted from the reading. This obtained by noting the weight

of the coating wax which is the difference between the weight of the sample before and after


Bulk Volume Determination:Gravimetric (Loss of Weight) MethodA coated sample is weighed suspended in air and

then suspended in a liquid (water or kerosene).

The difference in weight is the buoyancy force which is equal to the volume of displaced fluid multiplied by the density of the fluid.

Since the volume of the displaced fluid is the same as the volume of immersed solid, then: volume of coated sample = (W1 – W2) / ρ

W1 = weight in air

W2 = weight in liquid

ρ = density of liquid

The volume of the coating material must be found and subtracted as explained earlier.


Bulk Volume Determination:By Mercury Pycnometer

A special steel pycnometer is used Figure. It is first filled with mercury.

The top is removed and the sample placed at the mercury surface.

The top is then pressed down allowing excess mercury to overflow into a beaker.

The excess mercury is then collected and its volume determined in a graduated cylinder. For more accuracy, the mercury

may be weighed and the volume determined by dividing the weight


the bulk density

If the weight of a dry clean sample is determined before coating or saturating the sample, the bulk density of the sample is found from the measured bulk volume.


Mercury porometer

Mercury porometer is designed to measure the gas space and bulk volume of a freshly recovered core sample.

The instrument consists of a hand operated pump,

a sample cell The cell

can accommodate a sample with a bulk volume of 10 to 15 cm3 (a sample with 2.5cm length).

equipped with a needle valve mounted on its lid.


Bulk Volume Determination:Mercury Pump, ProcedureThe pump consists of

a core chamber, pump cylinder with piston and wheel, scales and gauges.

First mercury is brought to a fixed mark above the sample chamber and the pump is brought to zero reading.

The piston is removed withdrawing mercury from the chamber.

The sample is then placed in the chamber and mercury is brought back to the fixed mark.

The reading of the pump scale gives the bulk volume of the sample.


Mercury injection pump (a) and porosity through mercury injection (b)


Methods of Grain Volume MeasurementThe grain volume of pore samples

is sometimes calculated from sample weight and knowledge of average density.

Formations of varying lithology and, hence, grain density limit applicability of this method.

Boyle’s law is often employed with helium as the gas to determine grain volume. The technique is fairly rapid, and

is valid on clean and dry sample.


Methods of Grain Volume Measurement (Cont.)The measurement of the grain volume of

a core sample may also be based on the loss in weight of

a saturated sample plunged in a liquid.

Grain volume may be measured by crushing a dry and clean core sample.

The volume of crushed sample is then determined by (either pycnometer or) immersing in a suitable liquid.


By Russell Volumeter

The Russell Volumeter may be used in the same way as described in bulk volume determination to determine the grain volume of a crushed sample.A part of a clean (extracted) dry sample

is crushed into individual grains.

The grains are weighed by analytical balance and the volume is determined by Russell Volumeter (as in the case of bulk volume determination.)


By Pycnometer

ProcedureThe pycnometer

is weighed empty (W0)and then filled with water (or kerosene) (W1).

The crushed sample is weighed then placed in the empty pycnometer and the weight is determined (W2).(W2 – W0) is the weight

of the crushed grains.

This is more accurate than the use of the weight of the grains before

and the total weight is determined (W3).

The grain volume is then calculated as follows:

W1 = weight of pycnometer filled with fluid

W0 = weight of empty pycnometer

W2 = weight of pycnometer +


Grain volume: Saturating samples in Russell Volumeter and pycnometer The grain volume of a sample (uncrushed) can also

be obtained by Russell Volumeter or the pycnometer methods provided the sample is unsaturated (dry) and enough

time is allowed for the fluid to penetrate the pores of the sample before the readings are taken.


Grain volume: Loss of Weight MethodThe weight of a dry clean sample W1 is

determined.

The sample is then fully saturated with a non-reactive liquid (instead of a coated sample as in bulk volume). The weight of the sample

suspended in the liquid W2 is then determined.

The difference (loss) of weight is divided by the density of the liquid to find the grain volume of the sample.

The grain volume determined by this method is the effective grain volume which includes any pores that are sealed off.


Gas Expansion Method (General)

Many porosimeters are designed to use the principle of Boyle’s law of gas expansion to determine the grain volume. The idea is to allow the remaining volume of a chamber

in which a core is placed (V1 – Vg) at pressure P1 to expand by an additional volume V2 and read the final pressure P2.

From Boyle’s Law (at constant temperature).(V1 – Vg) P1 = (V1 – Vg + V2) P2

knowing V1, V2, P1 and P2 allows the calculation of grain volume Vg.Vg = V1 – [(P2 / (P1 – P2)] V2


The helium porosimeter

The helium porosimeter uses the principle of gas expansion, as described by Boyle’s law. A known volume (reference cell volume) of helium gas

[V2], at a predetermined pressure [PA], is isothermally expanded into a sample chamber.

After expansion, the resultant equilibrium pressure is measured [PB].

This pressure depends on the volume of the sample chamber [V1] minus the rock grain volume [Vg], and then the porosity can be calculated.PA*V2=PB*(V2+V1-Vg)

Vg=V1+V2-(PA/PB)V2=V1-[(PA-PB)/PB]V2


Calculation of grain density

If we know the weight of the dry clean sample for which the grain volume is determined, the grain density can be calculated by:


Pore Volume Measurement

All the methods measuring pore volume yield effective porosity. The methods are based on either the extraction of a fluid from the rock or

the introduction of a fluid into the pore spaces of the rock.


Saturation Method Procedure

A dry clean sample is weighed and placed in a suction flask with two connections to a vacuum pump and a Separatory funnel. First the valve is closed and vacuum is applied.

After sufficient vacuum is reached the vacuum pump is shut off, the valve to the funnel is opened and the liquid is allowed to saturate the sample.

The sample is kept immersed in the liquid for some time to allow complete saturation.

The saturated sample is drained from excess liquid and weighed.


Pore volume calculation by Saturation MethodThe pore volume is then calculated as:

Vp = (W2 – W1) / ρW2 = weight of saturated sample

W1 = weight of dry sample

ρ = density of saturating fluid

Notes:A wetting non-reactive liquid must be used.

Kerosene or tetrachlorethane are usually used.


Washburn Bunting Method Procedure (obsolete and seldom used)This method is based on liberating the air from the

pores of the sample by creating vacuum. This is achieved by first raising the mercury level above

the sample while the valve is open, closing the valve and then lowering the mercury reservoir so that the mercury falls below the sample in the chamber.

The collected air is measured under atmospheric pressure by raising the mercury reservoir until the mercury level is the same in the two sides.

Air is then allowed to escape and the process is repeated until no more air is extruded.

The total volume of air (under atmospheric pressure) is recorded.


Washburn –Bunting type

The experiment is first run without a sample to determine the volume of air adsorbed on the glass surface of the apparatus. This volume is

subtracted from the total air volume obtained before to get the pore volume of the sample.


Pore volume Determination:By Mercury PumpWhen a rock has a small fraction of void space,

it is convenience to measure porosity by Mercury injection rather than other methods. The principle consists of forcing mercury

under relatively high pressure in the rock pores.

A pressure gauge is attached to the cylinder for reading pressure under which measuring fluid is forced into the pores.

The volume of mercury entering the core sample is obtained from the device with accuracy up to 0.01 cm3.(Approximately a cube with the length of 2 mm)


Mercury Injection procedure

The mercury pump procedure is as follow: After a dry sample is placed in the core chamber

and the bulk volume is determined, pressure is applied by moving the piston clockwise allowing mercury to enter the pores of the sample.

Pressure vs. volume of injected mercury is recorded until a pressure of 1000 psia is reached.

The final volume reading gives the pore volume of the sample.

Notes:Macropores and fractures can be detected by a flat

curve at the start where increase in volume is noted without appreciable rise in pressure.

Capillary pressure curves


Gas Expansion Method: by mercury pump (with a vacuum)The mercury pump (with a vacuum) gauge is used.

After the bulk volume is determined and mercury fills the chamber but does not penetrate the sample, the air in the pores is allowed to expand by withdrawing the mercury from the chamber.

If the volume of mercury withdrawn is V which is read on the pump scale then from Boyle’s Law:Vp P1 = (Vp + V) P2 So: Vp = V[(P2 / (P1 – P2)]

• P1 is initial pressure (atmospheric)

• P2 is the final pressure read on the vacuum gauge

It is clear that if P2 = ½ P1 then Vp = V• So the pore volume would be equal to the volume of mercury

withdrawn from the chamber to reduce the pressure in the chamber to half its original (atmospheric) value.


the helium Gas advantages

Helium has advantages over other gases because: (1) its small molecules rapidly penetrated small pores,

(2) it is inert and does not adsorb on rock surfaces as air may do,

(3) helium can be considered as an ideal gas (i.e., z = 1.0) for pressures and temperatures usually employed in the test,

and

(4) helium has a high diffusivity and therefore affords a useful means

for determining porosity of low permeability rocks.


the helium technique procedure

The helium porosimeter has a reference volume V1, at pressure p1, and a matrix cup with unknown volume V2, and initial pressure p2. (Pressure p1 and p2 are controlled by the operator;

usually p1 = 100 and p2 = 0 psig).

The reference cell and the matrix cup are connected by tubing; the system can be brought to equilibrium

when the core holder valve is opened, allowing determination of the unknown volume V2 by measuring the resultant equilibrium pressure p.

When the core holder valve is opened, Fall 14 H. AlamiNia Reservoir Rock Laboratory Course (2nd Ed.) 150

the helium technique calculation

Boyle’s law is applicable if the expansion takes place isothermally. Thus the pressure-volume products are equal before and

after opening the core holder valve:P1V1 +P2V2 = P(V1+V2)

Solving the equation for the unknown volume, V2:V2 = (P-P1)V1/(P2-P1)

Since all pressures in the equation must be absolute and it is customary to set p1 = 100 psig and p2 = 0 psig, the Eq. may be simplified as follows:V2 = V1(100-P)/P

• V2 in cm3 is the unknown volume in the matrix cup, and

• V1 in cm3 is the known volume of the reference cell.

• p in psig is pressure read directly from the gauge.Fall 14 H. AlamiNia Reservoir Rock Laboratory Course (2nd Ed.) 151

the helium technique correction factorSmall volume changes occur in the system,

including the changes in tubing and fittings caused by pressure changes during equalization.

A correction factor, G, may be introduced to correct for the composite system expansion. The correction factor G is determined for porosimeters

before they leave the manufacturer, and this correction is built into the gauge calibration in such a way that it is possible to read the volumes directly from the gauge.


Schematic diagram of helium porosimeter apparatus


Descriptions

The determination of the effective liquid porosity of a porous plug is the initial part of the measurement of capillary

pressure using porous plate method in core laboratories.

Before the capillary pressure is determined the volume of the saturating liquid (brine or oil)

in the core must be known.

Thus, the effective liquid porosity of the core can be calculated in the beginning of capillary pressure measurement.


Procedure:

Weigh dry Berea plug Wdry, measure its diameter D, and length L, with calliper (1 core for each group).

Put the cores in the beaker inside a vacuum container, run vacuum pump about 1 hour.

Saturate the cores with 36 g/l NaCl brine, ρ brine = 1.02g/cm3.

Weigh the saturated cores, Wsat.


Calculations and report

Calculate the saturated brine weight, Wbrine = Wsat-Wdry.

Calculate the pore volume (saturated brine volume), Vp = Wbrine/ ρbrine.

Calculate effective porosity, ϕ e = Vp/Vb.


1. (ABT) Torsæter, O., and M. Abtahi. "Experimental reservoir engineering laboratory work book." Department of Petroleum Engineering and Applied Geophysics, Norwegian University of Science and Technology (NTNU), Trondheim (2003). Chapter 5A. (KSU) M. Kinawy. “Reservoir engineering

laboratory manual" Petroleum and Natural Gas Engineering Department, King Saud University, Riyadh (2009).