This presentation discusses petrophysical properties of various rock types including organics, carbonates, coal, clay, sand, and shale. It defines key petrophysical properties such as porosity, permeability, water saturation and describes how these properties vary based on the mineralogy and depositional environment of the different rock types. Measurement techniques including well logs, core analysis, and well tests are also summarized. Finally, a case study of the Bombay offshore field in India is provided to demonstrate heterogeneity in a carbonate reservoir and typical property ranges.

1. भारतीय प्रौद्योगिकी संस्थान (भारतीय खनन विद्यापीठ), धनबाद
INDIAN INSTITUTE OF TECHNOLOGY (ISM), DHANBAD
पेट्रोलियम अलभयांत्रिकी विभाि
Department of Petroleum Engineering
Term Presentation on;
‘Petrophysics of Organics, Clay, Sand and Shale’
PRITISH BARMAN
1ST Year, M.Tech (2016-18)

2. Content
 OBJECTIVE
 INTRODUCTION
 Petrophysics of ORGANICS
 CARBONATES
 COAL
 Petrophysics of CLAY
 Petrophysics of SANDS
 Petrophysics of SHALES
 Data Acquisition
 Case Study
 CONCLUSION
 REFERENCES

3. Objective
PETROPHYSICS Definition
Petrophysical Properties
Φ, k, Sw, F, Pc, Wettability
Measurement Techniques
W/Log, Core, Well Test, MWD/LWD
Rock Types
Clastic / Non-Clastic

4. Introduction to Petrophysics
 (rock physics) - branch of applied geology relating to the
study of reservoir and cap rock properties and their
interactions with fluids (gases, hydrocarbon, and
aqueous solutions)
 based on fundamental methods of physics, chemistry
and mathematics
 mineralogy and geology
 Rock Classification
 Sedimentary, Igneous and Metamorphic
 Clastic / Non-Clastic

5. Petrophysical Properties
 Porosity, Φ : Absolute & Effective
 Permeability, k : Absolute & Relative
 Water Saturation: Initial, Connate.
 Formation Factor, F : Archie’s Equation
 Capillary Pressure, Pc : Fluid Displacement
 Wettability : Drainage and Imbibition

6. Organics
 Organic Matter Origin
Carbonate: lime (Cao)-secreting animals, plants, and
bacteria live in the shallow water.
 Precipitation of Calcite
Coal: thermal maturity of plant matter.
 Overburden Pressure and Time
 Methane is generated, Adsorbed in Cleat.

7. Carbonate Rock
 Carbonate rocks are a class of sedimentary rocks
 composed primarily of carbonate minerals.
 major types are
 Limestone: calcite or aragonite (different crystal forms of CaCO3)
 Dolostone: composed of the mineral dolomite (CaMg(CO3)2)
PROCESS FAVORABLE EFFECTS UNFAVORABLE EFFECTS
Leaching Increase ¢ & K -
Dolomitization Increase K Can also Decrease ¢ & K
Fracturing Joints Breccia Increase K Increase Channeling
Recrystallization
May Increase
Decrease ¢ & K
Decrease ¢ & K
Cementation By Calcite
Anhydrite
Pyro-bitumen Silica
-
Decrease Pore Size & K

8. Coal
 Coal is a chemically complex organic aggregate
of Carbon
 Combustible solid consisting of a mixture of
altered plant remains.
 Organic matter constitutes more than 50% of coal
by weight and more than 70% by volume.
 Coals are described and classified by differences
in composition (type), purity (grade), and maturity
(rank).
 Main Interest of Coal to the Hydro-Carbon
Industry is Coal Seam Gas/ or CBM.
 Natural dual porosity system – Face and Butt
Cleat
 Permeability 0.1–50 Md.
Fig. Coal Cleat System

9. Clay
 Claystone is a sedimentary rock made of more than 67
percent clay-size (<1/256 millimeter) particles
 Types of Clay: Swelling and Non-Swelling
 Swelling Clay: Smectite
 Non-Swelling Clay: Keolonite, Illite type.
Fig. SEM images of a
smectite-rich sandstone.

10. Sand
 Particles are relatively larger with grains between 1 to 1/16 mm.
 Average Porosity in between 10-30 %
 Permeability between 15-300 mD
 With continued diagenesis, large amounts of cement would develop,
reducing the pore volume.
Fig . Common sandstone textures include point
contacts, cements, and micro-fractures. These
microstructures determine the properties of the
rock on a whole.
Fig. Microscopic view
of a sand face

11. Shale
 Shales exhibit low very low permeability in the range of 1µD to
1mD. The porosity however can be as high as 20%.
 Organic Content of the Shale is characteristic of the
environment of deposition.
 Quality of the organic matter, Kerogen is essential in the
generation of hydrocarbon.
Fig. . Thin-section image of an organic-rich siltstone

12. DATA ACQUISITION

13. CASE STUDY: Bombay Offshore
 It came into existence during Upper Cretaceous time
 Predominantly Carbonate Reservoir Rock
 Main producing zone, L-III, consisting of many sedimentary
cycles.
 Capped by a post-middle Miocene shale
 Heterogeneity is high
 85% Wells on Gas Lift
 Average Water Cut 65 %
Petrophysical Property Value Range
Porosity 15-35 %
Permeability 10mD to 1D

14. Conclusion
 The Petrophysics - function of the environmental conditions
prevalent during the time of deposition.
 Rocks are classified primarily with respect to their average grain
size, Clay <Shale < Sand
 Carbonate rocks are formed by the secretion of marine animals and
plants, and often by precipitation of calcite.
 The main Petrophysical properties of importance to the
hydrocarbon exploration include
 porosity,
 permeability,
 water saturation,
 formation resistivity factor,
 capillary pressure, and
 wettability.

15. References
 [1] Leonid Buryakovsky, George V. Chilingar, Herman H. Rieke, and
Sanghee Shin, 2012 –Fundamentals of the Petrophysics of Oil and Gas
Reservoirs.
 [2] Djebbar Tiab & Erle C. Donaldson, Third Edition 2012 –Petrophysics,
Theory and Practice of Measuring Reservoir Rock and Fluid Transport
Properties
 [3] Daniel Jardine and John William Wilshart, Esso Resources Canada
Limited, SPE 10010 Society of Petroleum Engineers, -Carbonate
Reservoir Description
 [4] By C. Jenkins, DeGolyer and MacNaughton, D. Freyder, Freyder
Enterprises Inc., J. Smith, Great Plains Energy, and G. Starley, Devon
Energy Corp. Vol6_Page_247 –Petroleum Engineering Handbook.
 [5] Meng Lu, SPE and Luke D. Connell, SPE, Division of Earth Science and
Resource Engineering, CSIRO, Australia, SPE 133100 - Dual Porosity
Processes In Coal Seam Reservoirs