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: baleshk@yahoo.com ; balesh.k@germi.res.in

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