Scenario of Shale Gas Exploration in India

8/2/2019 Scenario of Shale Gas Exploration in India

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Salient aspects of shale gas

Probable Shale Gas exploration in India

Summary

Presentation Outline


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Unconventional natural gas produced fromshale

Shale acts as source, reservoir & cap rock for

the natural gas

Characterized by very less permeability &

moderate porosity

Lower uncertainty in resource/reserve

determination


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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.


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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

An example of an ideal shale gas frac job at site


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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 andWoodford 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

Texas Barnett shale gas production

(1993 - 2006)

Courtesy: Ravi Misra, ONGC


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ONGC created an exploration landmark when gasflowed out from the Barren Measure shale at a depthof around 1,700 metres, in its first R&D well, RNSG-1,near Durgapur at Icchapur, West Bengal,


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The R&D project, which involved drilling of four wellsin the Damodar Basin two wells in the Raniganjsub-basin in West Bengal and two wells in the NorthKaranpura sub-basin in Jharkhand, was

operationalised with the help of Schlumberger.

The estimated expenditure is about Rs 168 crore andthe total project is expected to be completed within

520 days,


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India's 1st ever shale gas exploration bidding by 2013-end, says PM

[Courtesy -The Economic Times,3 days ago]

In November 2010, a Memorandum of Understandingwas signed between India and the US government onShale gas resources while US president visited India.


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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


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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

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 richbands in Barnet Shale & Marcellus Shales respectively.

Geochemical data : Barren Measure Shale section of Damodar Valley - bottom 200mabove Barakar as most matured, organic rich & may be gas prone).

Source: Web


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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 10acres.


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The OCS in Cambay Basin : organic rich dark grey

shales : TOC = 0.7-14.25%, VRo= 0.8, Tmax= High(437-453C), Kerogen Grade-II & III: Matured shalewith maximum source potential

Availability of abundant source rock data & other data

Maximum availability of Infra structure facilities

More than 5000 wells drilled - 200 wells throughCambay Shales

Prospectivity may be better than many famous gas richglobal shales

1 or 2 operators already reported gas production fromCambay Shale .

Various lows from NW to SE & North to South of thebasin appear to offer Different type of plays

Source: Web


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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.


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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


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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


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Mapping of prospective Shale of Indian sedimentary basins.

Collect ion of core samples from drilled wells or through drilling of selective coreholes into suchshales 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 detecthydrocarbon potential in sediments.

Thermal Maturity data - vitrinite reflection data, Tmax, S1, S2 peaks.

Gas Content data Reservoir Characterization


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Type and amount of Organic Matter: Data on shale TOC (total organic carbon), HI andOI data from Rock-Eval/Pyrolysis, Kerogen type.

Recording, Analysis & Interpretation of different log data.

Developing data base, building geologic models & assessment of resource potential ofbasins, 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.


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Scenario of Shale Gas Exploration in India

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