Dr. B. KUMAR - COSTAR Shale Occurrence & their Reserve Estimates • Oil shale occurrence in India...
Transcript of Dr. B. KUMAR - COSTAR Shale Occurrence & their Reserve Estimates • Oil shale occurrence in India...
Dr. B. KUMAR
Scientist Emeritus, Gujarat Energy Research & Management Institute, Gandhinagar-382007 & (Former) Chief Scientist ,
National Geophysical Research Institute, Hyderabad -50007
Ph. 91- 8141800166 (Off.) ; 91- 9849934935 (Res.)
E-mail: [email protected] ; [email protected]
Re-assessment of Shale Oil & Gas Resource Potential of Indian Sedimentary Basins
• Assam-‐Arakan • Cambay • Rajasthan • Bengal • Krishna-‐ Godavari • Cauvery • Gondwana • Vindhyan
Poten?al Oil Shale & Shale Gas Basins of India
No BASIN GROUP/
FORMATION AGE
DEPOSITIONAL /ENVIRONMENT
1 Cambay Cambay Shale Eocene
Deltaic- Nearshore Marine Tarapur Shale Oligocene
2 Gondwana Raniganj Fm.
Late Permian Swamp Coastal Barren Measures
3 Krishna-Godavari
Raghavapuram Shale Early Cretaceous Marginal Marine to Inner Shelf
Chintalapalli Shale Late Jurassic-Cretaceous Bathyal Kommugudem Shale Permian Fluvio- Lacustrine
4 Assam-Arakan Disang Eocene
Marginal Marine Barail Oligocene
5 Cauvery
Portonovo Shale Late Cretaceous (Campanian-Maastrichtian)
Marine
Kudavasal Shale
Satapadi Shale mid-Cretaceous
(Albian-Cenomanian) Andimadam Shale mid-Cretaceous (Albian)
Karaikal Shale Eocene
6 Vindhyan
Bijaigarh Shale Mesoproterozoic
Marine Rampur Shale Mesoproterozoic Kajarahat Fm.
Paleoproterozoic Deoland Fm
7 Pranhita-Godavari
Barren Measures Early Permian Swampy Coastal
Shale sequences of the Indian Sedimentary Basins with their age & the depositional environment
India’s Issues • Development of viable policy for explora?on and exploita?on of Oil
Shale & Shale Gas • Compila?on of available geoscien?fic data ( Geological, Geophysical,
Geochemical, Petrophysical and borehole logs) for poten?al shale gas basins of India ( Cambay, Damodar and Assam-‐Arakan etc.)
• SeNng up of centre of excellence for geochemical, petrophysical, & mineralogical studies for evalua?on of shale oil & gas poten?al of sedimentary basins of India
• Drilling of experimental wells for collec?on of fresh core samples • Interna?onal collabora?on in the area of sub-‐surface retor?ng,
horizontal drilling and hydro-‐fracturing • Environmental policy for use of water while drilling and fracturing and
for disposal of hydraulic fracturing fluid
Draft Policy for Exploration and Exploitation of Shale Oil & Gas
• Attract private investment in shale oil & gas exploration • Offer of acreages through international competitive bidding • First right of refusal for bidding to existing contractor • Distinct account to be maintained if the same contractor is
operating both conventional and unconventional blocks • All data gathered during course of operation will be property of Government of India • Environment impact assessment for the exploration block by
Ministry of Environment & Forest • Exploration of shale oil/gas will be according to the law of land, including water and air pollution act of India
Oil Shale Occurrence & their Reserve Estimates
• Oil shale occurrence in India at the shallow surface/sub-surface are mostly confined to Assam – Arakan Basin.
• The Barail coal-shale unit occurs as outcrops towards south of the oilfields in a region called the Belt of Schuppen. The estimated in place oil reserve of these carbonaceous shales of NE India is greater than 15 billion tons.
• The deeper horizons of Barail shale unit of Assam –Arakan Basin and Kalol shale unit of Cambay basin are oil shale bearing and their in-place oil reserve estimates have to be worked out.
Source: DGH
Structural map of Assam-Arakan Basin
STRATIGRAPHIC SUCCESSION OF UPPER ASSAM SHELF
ROCK-EVAL HI vs. OI PLOT SHOWING KEROGEN TYPES
800
600
400
200
0 50 100 150
TYPE - III
TYPE - II
TYPE - I
Barail (Oligocene)
Eocene
OXYGEN INDEX
HYD
RO
GEN
IND
EX
Source: DGH
CHARACTERISTICS OF BARAIL
• Average vitrinite reflectance in oil shale ranges from 0.5 to 0.7%.
• Rock-eval Tmax values are less than 435oC, indicating low thermal maturity
• The organic matter is predominantly type-II + type-III
• Biomarker ratios indicate a dominance of land plant derived kerogen: preponderance of C29 ααα 20R steranes and high hopane/sterane ratio
Source: World Shale Gas Resources: An Initial Assessment, 2011
Shale Gas Reservoir Properties and Resources of India
Geologic provinces, Total petroleum systems(TPS), And assessment units(AU)
AU probability
Field type
Total undiscovered resources Oil(MMB) Gas(BCF) NGL(MMB) F95 F50 F5 Mean F95 F50 F5 Mean F95 F50 F5 Mean
Cambay province, Mesozoic - Cenozoic Composite TPS Cambay Shale Gas South AU
1.0 Gas 383 787 1,966 924 12 27 69 31
Cauvery Province, Mesozoic – Cenozoic Composite TPS Sattapadi – Andimadam Shale – Gas AU
1.0 Gas 444 887 2,660 1,123 14 31 95 39
Krishna - Godavari Province, Mesozoic – Cenozoic Composite TPS Ragahavapuram Shale Gas AU
1.0 Gas 1,406 3,387 9,133 4,080 28 73 207 90
Total Continuous resources
6,127 160
Using a performance-based geologic assessment methodology, the U.S. Geological Survey estimated a technically recoverable mean volume of 6.1 trillion cubic feet of potential shale gas in the Bombay, Cauvery, and Krishna–Godavari Provinces* of India.
Forma?on Thickness (m)
TOC% V Ro% Kerogen type
Olpad 340-‐2700 1.5-‐4.0 0.75 II & III
Older Cambay
500-‐900 1.5-‐4.0 0.75-‐0.85 II & III
Younger Cambay
520-‐1500 1.00-‐4.00 0.75-‐0.85
II & III
Kalol 200-‐300 0.75 II & III
Tarapur 60-‐40 0.53 II & III
Upper Disang Group
2000-‐3000 0.69-‐4.0 0.9-‐1.94 II & III
Kopili >500 1.0-‐6.2 0.92-‐1.44 II & III
Jenam 900-‐1200 2.5-‐4.5 0.64-‐1.20 II & III
Bhuban 800-‐1000 0.90-‐1.00 II & III
Bokabil 400-‐1000 II & III
Cambay Basin Resource: 90 Tcf
Assam Basin Resource: 55 Tcf
(After Rao, 2010)
Characteristics of shales of selected Indian Sedimentary Basins & their resource potential
Forma?on Thickness(m) TOC (%) VRo (%) Kerogen Type
Up.Disang Gp. 2000-‐3000 0.69-‐4.0 0.90-‐1.94 II & III
Kopili >500 1.0-‐6.2 0.92-‐1.44 II & III
Jenam 900-‐1200 2.5-‐4.5 0.64-‐1.20 II & III
Bhuban 800-‐1000 0.90-‐1.00
Characteris?cs of Gas Shales of Assam-‐Arakan Basin
Generalized geological map of Cambay basin.
Cambay Basin
Generalized stra?graphy of the Cambay basin (modified from Kundu et al., 1997).
Isopach map of Cambay Shale (DGH, 2009) Tectonic block of Cambay Basin
Forma?on Thickness(m) TOC (%) VRo (%) Kerogen Type
Olpad 340-‐2700 1.5-‐4.0 0.75 II & III
Older Cambay Shale 500-‐1900 1.5-‐4.0 0.75-‐0.85 II & III
Younger Cambay Shale 520-‐1500 1.00-‐4.0 0.75-‐0.85 II & III
Kalol 200-‐300 0.75 II & III
Tarapur 60-‐400 0.53
Shale characteris?cs of Cambay Basin
Geological map of Cauvery Basin
After Sahu, 2008
After Sahu, 2008
Cauvery Basin – Lithostra?graphic Column
Forma?on Thickness(m) TOC (%) VRo (%) Kerogen Type
Ariyalur-‐ Pondicherry
1500 0.31-‐2.78 1.15 II & III
Tranquebar 2000 0.31-‐4.76 0.65-‐0.79 II & III
NagapaNnam 1500 1.68 0.45-‐0.34 II & III
Mannar 2000 1.5 1.0-‐1.12 II & III
Shale characteris?cs of Cauvery Basin
Damodar Valley Coal Fields
Generalised stratigraphy of Damodar Valley
Ranigunj Coal Fields
Geological map of Vindhyan Basin (after Soni e t al.,1987)
Correlation Chart of the Vindhyan Rocks (Srivastava., et al, 1983)
TOC up to 8.08%
TOC up to 6.43%
TOC up to 8.08%
Forma?on Thickness(m) TOC (%) VRo (%) Kerogen Type
Chakaria Olive shale
185 0.60-‐1.04 II & III
Hinota shale 90 0.56-‐3.89 II & III
Rewa shale 225 0.07-‐0.40 II & III
Pulkova shale 210 35.0-‐37.85 II & III
Suket shale 100 0.04-‐0.37 II & III
Shale characteris?cs of Vindhyan Basin
Centre of Excellence for Evaluation of Shale Oil & Gas Potential of Sedimentary Basins of
India
• Set up a Centre of excellence for the determination of Petrophysical (Porosity & Permeability), Optical (Vitrinite Reflectance) and Geochemical (organic carbon content, kerogen type & Tmax) properties of shales / shale cores.
• Analyze the shale samples from three potential sedimentary basins viz: Assam – Arakan, Cambay, & Damodar for above parameters and re-evaluate the technically recoverable shale gas & oil potential of these basins.
• Work out the scientific & technical plan in collaboration with DGH for evaluating the shale oil & gas potential of other sedimentary basins of India.
Work Plan
• Setting up the laboratory facility for Geochemical, Petrophysical and Optical Characterization of shale rock/core samples comprising of Hawk Rock Data Station; High Pressure Hg Injected Porosimeter with software for permeability calculation and Coal Organic Petrographic System ( Coal Pro- II ).
• Field collection of shale rock/shale core samples from three potential shale oil/ gas basins of India namely Assam – Arakan, Cambay and Damodar.
• Laboratory analysis of shale samples for TOC, S1, S2, Tmax. HI, OI, porosity and vitrinite reflectance measurements etc.
• Compilation of data and comparing of data from potential shale basins of World and shale oil/gas resource evaluation.
Free Gas In-Place
• A - area, in acres • h - net shale thickness, in feet • φ - porosity, dimensionless • (1-SW) - fraction of the porosity filled by gas (Sg) instead of water (SW), • P - pressure, in psi • Bg - gas volume factor
Controlling factors: - Pressure - Temperature - Gas-filled porosity - Net organically-rich shale
thickness.
• DGH (Directorate General of Hydrocarbons) is planning to auction shale gas blocks in 2013
• It may be possible that Government may adopt integrated policy where in E&P company may be allowed to explore for shale gas along with conventional oil and gas in the block allotted to the companies under NELP
• ONGC in collaboration with Schlumberger launched a pilot shale gas project in Damodar valley
• GSPCL in collaboration with Oilex had drilled a concept horizontal well in Cambay basin
Shale Gas Explora?on: Indian Scenario
• BPCL had acquired two acreages in Australia • RIL (E&P), RNRL & Genpact have shown interest in exploring
shale gas in India
• RIL invested USD 1.77 Billion to acquire 40% share in Atlas energy leasehold in the Marcellus shale gas play, in the Eastern US
• Heramec Ltd., in associaaon with a joint venture with an experienced well-‐reputed Canadian company, (experts in exploring and exploitaaon of aght reservoirs) is studying the possibility of producing the oil and gas from the various aght reservoirs of Kanawara, North Kathana, Allora, & Dholasan fields of Cambay basin. The discussions are sall in formaave stage
Shale Gas Explora?on: Indian Scenario