PROSPECT OF SHALE GAS EXPLORATION IN INDIA

1. PROSPECT OF SHALE GAS EXPLORATION IN INDIA

2. Presentation Outline • Salient aspects of shale gas • Shale gas exploitation worldwide • Probable Shale Gas explorationin India • Summary

3. Salient aspects of Shale Gas

4. What is shale gas Unconventional natural gas produced from shale Shale acts as source, reservoir & cap rock for the natural gas Characterized by very less permeability & moderate porosity Lower uncertainty in resource/reserve determination

5. SCHEMATIC GEOLOGY OF SHALE GAS RESOURCE Schematic Geology of Shale Gas Resource Land Surface Conventional non-associated gas Coal Bed Methane Conventional associated gas Oil Seal Sandstone Tight Sand Gas Courtesy Wikipedia gas rich shale

6. Characteristics of shale gas deposits Mature petroleum source rocks Usually thermogenic Very good natural gas in-place volumes Rich in Organic Matter (TOC=0.5-25%) Low in Permeability (K= 0.01md or less). Shale intervals with HGHR - high organic carbon content- most productive.

7. A Typical Gas shale Log • High to very high Gamma-ray count, high resistivity, low density, high neutron & sonic porosity, low Pe. • This will help in • Delineation of shale gas beds • • Quantify gas • - Adsorbed • - Free • Producibility • -Matrix permeability • -Amount and type of fractures • -System permeability • -Pressure • Production prediction (Courtesy Keith Bartenhagen,Schlumberger

8. ELAN processed Shale Gas Log TOC GAS Free & Adsorbed ELAN ELAN processed Shale Gas logs to quantify Total Gas including percentage of adsorbed gas & free gas. Geochemical logs to know Kerogen volume and amount of Kerogen converted to methane and its Petrophysical properties. Gas in shale is stored in three ways in the shales: free gas in the rock pores; free gas in the natural fractures; and adsorbed gas on organic matter and mineral surfaces. (Courtesy Keith Bartenhagen, Schlumberger Total Gas Adsorbed Gas Free Gas

9. Shale gas exploitation worldwide

10. Shale Gas-Some Facts • 40,000 wells in North America • 1,200 Tcf recoverable shale gas reserve • Ultra low permeability, very low porosity, brittle • Often contain concentration of radioactive elements • Require large volumes of water to hydraulically fracture • Require high density drilling, well spacing 10 acres or less

11. An example of an ideal shale gas frac job at site In a typical Shale Gas well, 7-10 stages of Hydrofrac are required & 3-5 lacs gallons of water are required for 1 stage of Hydrofracturing VOLUMETRIC COMPOSITION OF A FRACTURE FLUID

12. Emergence of shale gas as alternative source of energy worldwide Texas Barnett shale gas production(1993 - 2006) • Increasing oil/gas price • Declining conventional oil/gas reserves necessitate unconventional reserves supplementation to meet demand- supply gap • Big discoveries of shale gas in the United States in Barnet & Marcellus shales, Ohio, Fayetteville, Antrim, New Albany, Lewis and Woodford shales and in Horn River & Montney Shales in Canada in the last 1 or 2 decade (s) • Large untapped resource of Shale Gas available • Earlier shale gas wells drilled vertical and non-profitable due to very less permeability & producibility • Introduction of improved modern technologies viz. Horizontal Drilling & Hydro Fracture Courtesy: Ravi Misra, ONGC

13. A Comparative Study of a few Shale Gas Plays in USA Courtesy: Ravi Misra, ONGC

14. Global Shale Gas Resource GIP TCF Source: Rogner 1997 • Over 32,500 TCF of gas identified worldwide from Unconventional Reservoirs

15. Probable Shale Gas exploration in India

16. Indian Scenario

17. Prospective Shale gas deposits in India Huge shale deposits in basins of Gondwana, Cambay, Assam-Arakan, KG, Cauvery, Rajasthan: • Damodar valley - Barren Measures Formation (TOC 6 to 11.0%) in the Gondwana basins. • Cambay shales - (TOC ~14.3%) in Gujarat. • KG Basin - Bhuvanagiri Formation ((TOC ~ 3-5% & permeability ~0.033mD) & Raghavpuram shales (TOC ~ 3-5%) • Cauvery Basins - Mandapeta (K=0.01mD, TOC ~12.8%), Andimadam & Sattapadi shales (TOC ~ 3-8%). • In Rajasthan (TOC up to 4.99% in Baisakhi-Bhadasar Formation, Jaisalmer basin). • in Assam-Arakan Basin • Disang, Kopili, Disang & Barail Coal Shale in Assam • Bokabil & Bhuban Shales in Tripura Source: Web

18. Why Gondwana • The Gondwana sediments are more matured & occur at shallower depth • The Barren Measure has organic rich shales having TOC = 8-10%, VRo= 0.8, Tmax= High, Kerogen Grade-III • Shale of Barakar Formations are also organic rich • Cluster Analysis or Tight Rock Analysis (TRA)-high organic rich silty shale band of 150-200m in Barren Measure as against a 100-120ft & 170ft of similar kind of organic rich bands in Barnet Shale & Marcellus Shales respectively. • Geochemical data : Barren Measure Shale section of Damodar Valley - bottom 200m above Barakar as most matured, organic rich & may be gas prone). Source: Web

19. Why Gondwana Contd. • Due to shallower occurrence of Shales Hydrofrac jobs or horizontal wells would also be easier & cheaper – hence techno-economically more viable. • Availability of large amount of water for HF in this part is much easier as discharged water from mines, CBM wells & other huge water bodies are available in plenty. • There is scope of recycling the released frac water for reuse in other wells after a little chemical treatment, as development/production wells are drilled at a space of 10 acres.

20. Why Cambay Basin • The OCS in Cambay Basin : organic rich dark grey shales : TOC = 0.7-14.25%, VRo= 0.8, Tmax= High (437-453’C), Kerogen Grade-II & III: Matured shale with maximum source potential • Availability of abundant source rock data & other data • Maximum availability of Infra structure facilities • More than 5000 wells drilled - 200 wells through Cambay Shales • Prospectivity may be better than many famous gas rich global shales • 1 or 2 operators already reported gas production from Cambay Shale . • Various lows from NW to SE & North to South of the basin appear to offer Different type of plays Source: Web

21. Why KG Basin • Source rock HC potential is generated in Gondwana, Mesozoic & Tertiary Sediments. • Maturity data of effective source rocks indicate right kind of Geochemical data for Shale Gas Resource Assessment. • Data of TOC, VRo, S1, S2 peaks, HI, OI, Tmax etc from a few selective wells of KG Basin prove that HCG values from Shales give a good indication of Shale Gas potentiality in Mesozoic shales. • Source: A Banerjee, et.al , Integration of Geochemical Data of KG Basin, • ONGC Report, 2008

22. Requisites for optimal Shale Gas exploitation in India • Technology Transfer, know how & adoption of best practices from successful projects worldwide • Globally experienced player with modern improved technologies such as - drilling horizontal wells - introduction of modern rigs - hydro fracturing

23. Requirement of Technology and Data • Shale Gas exploration has taken off in India • Technology for resource characterization, prospect generation, fracture identification, water management are to be generated by R & D with help of experts • Horizontal drilling and well completion technologies, including multi stage hydraulic fracturing • Identification and development of shale gas resources

24. Methodology • Mapping of prospective Shale of Indian sedimentary basins. • Collect ion of core samples from drilled wells or through drilling of selective coreholes into such shales to generate the following data: • Lithology : Data on shale lithology, mineralogy, clay content, thickness. • Extent: Extension of high gamma ray zones and intercalations of sandstones or siltstones. • Rock property data (porosity, permeability, density). • Rock Eval / Pyrolysis data to identify the type and maturity of organic matter and to detect hydrocarbon potential in sediments. • Thermal Maturity data - vitrinite reflection data, Tmax, S1, S2 peaks. • Gas Content data • Reservoir Characterization

25. Prospect Generation Rock-Eval Parameters • Type and amount of Organic Matter: Data on shale TOC (total organic carbon), HI and OI data from Rock-Eval/Pyrolysis, Kerogen type. • Recording, Analysis & Interpretation of different log data. • Developing data base, building geologic models & assessment of resource potential of basins, also assessing the recoverable resources in shale gas. • Prospect Generation & assessment of its techno-economic viability. • Identification of potential Shale Gas block based on above methodology.

26. SUMMARY & CONCLUSION

27. SUMMARY & CONCLUSION • Shale Gas exploitation is no longer uneconomic - improved technology. Demand and preference for clean form of gas has made Shale Gas, a well sought after energy. • Reserve accretion, production & development world over is rapidly increasing. • India also has development of prolific matured shale distributed in different sedimentary basins e.g. Damodar Valley, Cambay, Assam-Arakan, Krishna-Godavari, Cauvery and Rajasthan. • Vast shale deposits with high TOC and maturity value in the above mentioned sedimentary basins with available improved modern technologies can make India a top player of Shale Gas.

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