This document provides an overview of shale gas reservoirs, including their characterization, evaluation, composition, and production methods. It discusses that shale gas is an unconventional natural gas source found within fine-grained sedimentary shale formations with low porosity. The world's largest shale gas reserves are located in China, Argentina, Algeria, and the United States. Shale gas reservoirs are evaluated based on their mineralogy, organic geochemical properties, and fracture systems. Production involves horizontal drilling combined with hydraulic fracturing to stimulate flow from the tight shale formations. While this has led to a significant increase in natural gas production, hydraulic fracturing also poses various environmental risks.

2. SHALE GAS RESERVOIR
Case Study : Shale gas reservoirs characterization, evaluation,
composition and pore structure.
Aamir Ali
Master Candidate, Tongji University

3. CONTENTS…
What is Shale Gas?
Shale gas Distribution
Shale Discovery
Important facts of shale gas
Major role of shale gas in the World
Shale Gas Reservoir Characterization
Shale reservoir storage
Background Shale Gas Production
Evaluation of Shale Gas
Extraction of Shale gas

4. WHAT IS SHALE GAS ?
Shale : fine-Grianed, sedimentary rock characterized by breaks along
thin laminae or parallel layering or bedding, with low porosity and
permeability.
Unconventional deposit
Reserves higher than oil
Enhanced Global Availability

5. SHALE GAS DISTRIBUTION : SHALE
GAS RESERVES ALL OVER THE WORLD

6. Figure Current and predicted situations of shale gas resources in different
countries or regions (from EIA). (a) Natural gas production by type. (b)
Shale gas production in different countries. (c) Natural gas consumption in
different regions. (d) Natural gas supply by type in China. (zhang.B et al
.2020)

7. SHALE GAS BASIN ESTIMATION ON
WORLDWIDE MAP
Map of 38 major shale gas basins in 32 countire

8. SHALE DISCOVERY
Charles Doolittle Walcott
1907 - 1927
Ottoia , Soft-worm,
Burgess Shale
Cambrian Burgess Shale out crop
30/Aug/1909

9. https://www.burkemuseum.org/static/bshale/bigbang.html

10. IMPORTANT FACTS OF SHALE GAS
The permeability of shales is very low- several orders of magnitude
lower that construction-grade cement.
Tight gas development uses the same technology as that contributing
to the recent shale gas boom.
With out stimulation, most shale would not be economic to produce.

11. UNCONVENTIONAL SHALE GAS
DEPOSITS COMPARISON

12. MAJOR ROLE OF SHALE GAS IN
THE WORLD
Shale gas has a great attention and major role for World future.
Shale gas replacements for conventional energy in the future.
Shale Gas is the most important energy development since the discovery of oil: (Fred Julander, CEO
of Julander Energy)
Mission Critical: Can shale gas save the world?(ASPO, Sep 2009).
The United States may be close to self-sufficiency in energy by 2030 because of a "shale revolution"
in the country.”
BP CEO Bob Dudley, January 17, 2013

13. Top 10 Shale Gas reserves in the World
2021 Shale Gas Rating
https://www.oilandgasmiddleeast.com
(Zhang et al. 2020)

14. SHALE GAS RESERVOIR
CHARACTERIZATION
Depositional Environment
i. Marine Shale :lower clay content & high in brittle minerals.
ii. Non-marine Shale: lacustrine & fluvial(high clay content)
Thermal Maturity : Temp needed to breakdown organic matter,
Vitrinite reflectance, higher thermal maturity :
Total organic Carbon (TOC) content: OM(micro-organism, fossils,
plant matter )

15. SHALE RESERVOIR STORAGE
Porosity
Gas dissolved in kerogen
Gas absorbed onto kerogen and clay particle surface
Free gas in natural factures and intergranular porosity.
Permeability
Shale matrix permeabilites of typical shales are very low.
Natural fracture systems or hydraulic stimulation.
Hydrocarbon are effectively trapped unable to flow under normal
circumstances in shale

16. Gas in place
Basic four characteristics : Pressure, Temperature, gas filled porosity
and net organically rich shale.
Pressure: Higher pressure are identified as they have higer gas
concentrations.
Temperature: Temperature gradient of 1 °F per foot
Gas-filled porosity: Determined from Cores & Log Curves.
Fig: Identification of core and thin section

17. Fig. Different types of shale:
showing the siliceous shale was
mainly formed in the
dysoxic/anoxic
environment,and the
argillaceous shale and silty
shale were formed in the oxic
environment.J. Zhao et al. /
Petroleum Research 2 (2017)
209e221218

18. Porosity of Shale
SEM images: (a). OM pores & pyrite B). OM pores and cleavage sheet. C) Fluid-inclusion intrapores D) Cleavage-sheet
intrapores. G) fulid inclusion intrapores H) Intercrystalline pores I) cleavage-sheet intrapores. J) Pores different shape

19. Fig. a. intracrystalline pore. b,. Pyrite intracrystaline pore, c. calcite recrystallization intracrystalline
pore, d. dissolved fracture, e. pores formed hydrocarbon generation f. pores formed by organic acid
solution. G. margin of organic matter, h. interlayered fracture, I. Tectonic micro fracture.

20. Shale gas Reservoir

21. SHALE GAS PRODUCTION COST
CURVE

22. BACKGROUND SHALE GAS
PRODUCTION
Rapid shale gas growth in US : Largest Natural gas production
I. 7 million ton-LNG : 47% total gas production by 2035 in DOE’s
estimate
Global Potential of Shale Gas

23. EVALUATION SHALE GAS
Shale Gas play:
Natural gas accumulation that exhibit similar geological
characteristics .
Mineralogy
Lithology and structure : shale / Mudstone , Fracture system
Organic geochemical characteristics
Reservoir Storage Space

24. KEY FACTORS OF SHALE PLAY
Fracability : capacity of reservoir to be fracture
Productibility : completion plain to sustain commercial production.
Sustainability : field of development to meet both economic and environment.

25. MINERALOGY OF SHALE
Quartz, Dolomitic siltstone, Calcite, pyrite.
Longmaxi shale formation
A. Nonlaminated mudstone.Quartz
B. Dolomitic siltstone
C. Limy shale: Calcite
D. Argillaceous siltstone
E. Rich organic matter : quartz
F. Fine grained silt sandstone: calcite
G. Dolomite crystal
H. Shale rich : pyrite
(Liu et al. 2013)

26. A.Siliceous shale & pyrite )
B.Replaced by Quartz
C.Dolomitic minerals
D.Replaced by silica
(Liu et al. 2013)

27. SHALE STRUCTURAL FEATURE
Different types of pores and
structural feature.
Outcrop and SEM images
A. Tectonic extensional
feature
B. Shear feature
C. Interlayer Bedding feature
D. Convergent fracture
E. Pressure fracture
F. Intergranular pores
(Zhang et al. 2020)

28. A. Pyrite framboid micropores .
B. Intercrystalline micropores, illite sheets
C. Dissolution pores in feldspar
D. Dissolution along fracture
E. Pores filled with mica and ankerite
F. Mircofracture rich area with quartz.
(Zhang et al. 2020)

29. GEOCHEMICAL APPROACH
Major factor plays in geochemistry study :
TOC %(Total organic Carbon )
Kerogen Types
Thermal maturity Ro
Thermal Maturation

30. TOC :
Identification the productivity of the Shale

31. TYPES OF KEROGEN

32. Kerogen types

33. GEOLOGICAL APPROACH
Deposition of Shale is Low-energy environments
Shale formation are a series of thin laminations and fracture
Laminar layers of siliceous or carbonaceous material
Shale Core Sample

34. GEOPHYSICAL APPROACH
 Vp/Vs is the most optimally sensitive parameter for shale gas
reservoir identification and evaluation
Vp/Vs inversion profile across W1 well.

35. GEOPHYSICAL, PETRO PHYSICAL &
GEO-MECHANICAL APPROACH
Geophysical study based on the seismic interpretation : regional extent, mapping
the structure and fault .
Well Log interpretation
Potential reservoir to product

36. EXTRACTION OF SHALE GAS
Leasing Hand
Drilling
Exploration
Drilling :
Hydraulic fracturing
Horizontal drilling

37. HYDRAULIC FRACTURING
Requirement for sealed natural fracture shale gas system

39. DISADVANTAGES OF FRACKING
Fracking is major problem to exploration of shale reservoir