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Unlocking shale gas potential in India through a reservoir geomechanical approach

Primary Information

Domain

Energy

Project No.

5294

Sanction and Project Initiation

Sanction No: F.NO. 3-18/2015-T.S-I(VOL-III)

Sanction Date: 24/04/2017

Project Initiation date: 21/09/2017

Project Duration: 36

Partner Ministry/Agency/Industry

IRCC, IIT Bombay IITB-Monash Research Academy Jupiter Oxygen Corporation

Role of partner:The partners have supported the following: 1. Equipment 2. Research Scholar 3. Workshop expenses 4. Necessary laboratory infrastructure

Support from partner:The partners have supported in a good proportion with the progress of the project.

Principal Investigator

PI Image

Dr. Vikram Vishal
Indian Institute of Technology Bombay

Host Institute

Co-PIs

PI Image

Prof. T. N. Singh
Indian Institute of Technology Bombay

Scope and Objectives

Responsible domestic shale gas development in India offers a potential path out of fuel poverty and could also help address carbon dioxide emissions through carbon storage in depleted reservoirs. Currently the primary energy resource of India is coal. Discovery of natural gas from unconventional sources such as shale could aid in displacing some of Indian coal for electricity and additionally provide the population with a safe and clean-burning fuel for heating and cooking. USA is a great example of shale gas revolution which could lead to a net zero energy import in less than five next years. The lack of sufficient understanding of shale reservoirs in the Indian context, their potential for domestic gas production and carbon storage, is the prime motivation driving this research project. While coal deposits and the gas content of coal seams are almost clearly understood, realistic estimates for gas shales are not done. Sedimentary basins such as Damodar, Cambay, Kachchh, Krishna Godavari and Cauvery are among the prospective ones and should be investigated for gas recovery potential in a collaborative approach. The aim of this project is to build detailed understanding of the Indian shales through extensive rock characterization, simulation of gas flow, and enhanced extraction Identification of suitable field area and detailed documentation of geological conditions for gas shales. Detailed petrophysical estimation of shales highlighting the changes in permeability at various stages of fracturing at in situ conditions. Detailed geomechanical characterization of shales and the associated rocks under reservoir scenarios and reveal their fracturing and failure characteristics Analysis of pore size distribution, pore volume and surface area for capacity estimations. Numerical simulation to estimate enhanced gas recovery by carbon dioxide injection.

Deliverables

The product includes reservoir models with site-specific features enabling detailed prediction capability for the gas production. This will be a detailed representation of gas storage capacity estimations, pore volume and size distribution capabilities, initiation and migration of hydraulic fractures and fluid flow under in-situ conditions. This will be first-of-its-kind study for Indian shales and the facilities thus built and resources thus acquired will be extended to understand other probable reservoirs. It will help building indigenous expertise and the knowledge will be shared through capacity building workshops. The data, models and information generated will be shared with the beneficiary industries and government sectors and help them proceed with successful exploitation of the low carbon natural gas resources. The procedures and process development is the key product of this investigation. In sync with the objectives of IMPRINT, the developed knowhow on Indian shale reservoirs will be translated into a viable process to extract more natural gas to meet the growing energy demands of the country. The knowledge sharing and technology transfer to the relevant industry will strongly contribute to serious shale gas production in India.

Scientific Output

The project aims to improve the understanding of gas shales in Indian scenario. Indian shale has a very good potential in terms of shale gas production as studied by IEAGHG, 2008. The geomechanical study of the Indian shale would be essential for the classifying the reservoir in terms of mechanical properties, aiding in the understanding of reservoir stability and their long term behavior with changing stress condition and saturation during gas exploration. The low pressure gas adsorption experiments are essential for characterizing the pores and their accessibility for gas exploration and storage. The effect of gas and fluid injection into the reservoir and simultaneous changes in the reservoir condition will be studied. The gas and liquid permeameters will be used to study the permeability under stressed condition and different gas and fluid saturation. The microscale properties determined by the gas adsorption coupled with the geomechanical and permeability studies will help us develop a reservoir model using softwares like COMET3 and COMSOL, which will then be used for simulation of gas exploration or enhanced recovery over long period of time. The simulation will also enable us optimize the production without compromising reservoir stability and apply those optimized injection and production parameters in real condition. Also, hydraulic fracturing is an important factor in shale gas exploration. Simulating hydraulic fracturing in laboratory condition and its effect in the stability and enhancement of permeability of the reservoir would play key role in terms of gas production estimation. Numerical simulations on the reservoir model will help extrapolate laboratory experiment results to reservoir scale.

Results and outcome till date

Complete literature survey of the potential field areas was studied during the first year of the project. Based on that, field works were conducted in coal mines under Eastern Coalfields Limited (ECL) and Western Coalfields Limited (WCL) for sample collection and relevant studies. The samples were brought in our lab, then powdered and sieved for further analysis. The mineral content was analysed using XRD (XRay Diffraction) while the volatile and organic matter elemental composition was determined using CHNSO (Carbon-Hydrogen-Nitrogen-Sulphur-Oxygen) elemental analyser. The maturity of the shale samples was measured using the Tmax determined using Rock Eval pyrolysis. Low pressure nitrogen gas adsorption studies of the shale samples using in house Quantachrome Autosorb iQ reveal the pore size distribution and the specific surface area upto mesopore range in terms of gas accessibility. 1x1x1 cm3 chunks of the shale samples were dried and used for FEG-SEM (Focussed Electron Gun-Scanning Electron Microscope) study for the visualization of the pores and the matrix framework for individual samples at a very high resolution. The FEG-SEM study combined with image analysis using ImageJ, helped in quantitative modeling of pore structure and determine porosity at a very finer scale of observation. Small angle neutron scattering/Ultra small angle neutron scattering (SANS/USANS) helped determine the pore size distribution as well as fractal dimension of the pores at a very finer scale. By virtue of the lattice structure study that could be done in SANS/USANS, the relation of fractal dimension with dissolution or deposition could be established. Stitching the pore sizes obtained by LPGA, FEG-SEM and SANS/USANS analysis helped us establish the pore size distribution from micro scale to macroscale. The relation between the pore size distribution of the shale samples and their mineral composition and maturity has been established. Cores are prepared from representative shale samples so far for triaxial and permeability experiments.

Societal benefit and impact anticipated

Shale gas is one of the most potential unconventional energy resources. Due to the gradual depletion of fossil fuels, usage of unconventional energy should be promoted promptly to avoid energy crisis. The US has tapped their shale gas reserve almost 30 years ago and due to their huge reserve of shale gas and technological advancement, their dependency on conventional fossil fuels has decreased a lot. India also has a huge reserve of shale gas, which can be used to meet our energy demand. But before the exploration, proper study of the reservoir from microscale to core scale to reservoir scale is needed. The work carried out in this project will help us enhance the understanding of Indian shale reservoirs and also enable us to do a reservoir simulation to study the gas exploration potential for the coming years. Industries associated with the energy sector in India as well as major stakeholders would be benefited from our study. This study will also help understand the reservoir stability and its potential for hydraulic fracturing and enhanced gas recovery with simultaneous CO2 sequestration into the reservoir. The shale gas industry will in turn help us reduce effective CO2 emission and make Indian completely independent in terms of energy requirement.

Next steps

We have placed the purchase orders for pulse decay permeameter for studying liquid and gas permeability of shales under sub-surface reservoir conditions. We are also upgrading and optimizing our triaxial facility for studying the mechanical properties of shales. An add-on for the Autosorb iQ to conduct low pressure CO2 adsorption experiments for studying the micropores has also been processed for purchase. Data and samples will be gathered from few more fields in India. A customized core cutting machine has also been purchased for extracting cores of soft rocks like shale. Finally the experimental and field results will be collated to generate geomechanical based numerical models to investigate shale gas production and reservoir behavior over time.

Publications and reports

B. Hazra, D. A. Wood, V. Vishal, A. K. Varma, D. Sakha, A. K. Singh, 2018, Porosity controls and fractal disposition of organic rich Permian shales using low-pressure adsorption techniques. Fuel, Vol. 220, pp. 837 to 848. B. Hazra, D. A. Wood, V. Vishal, A. K. Singh, 2018, Pore-characteristics of distinct thermally mature shales: influence of particle sizes on low pressure CO2 and N2 adsorption. Energy and Fuels, Vol. 32, pp. 8175 to 8186.

Patents

NA

Scholars and Project Staff

PhD students: Debanjan Chandra (2017-2021) Nikhil Jain (2016-2020) MSc students: Avik Das (2016-2018) Masa Dutta (2016-2018) Mtech students: Asim Debbarma (2017-2019)

Challenges faced

NA

Other information

NA

Financial Information

  • Total sanction: Rs. 8640000

  • Amount received: Rs. 6500000

  • Amount utilised for Equipment: Rs. 3150000

  • Amount utilised for Manpower: Rs. 0

  • Amount utilised for Consumables: Rs. 262000

  • Amount utilised for Contingency: Rs. 27000

  • Amount utilised for Travel: Rs. 89000

  • Amount utilised for Other Expenses: 0

  • Amount utilised for Overheads: Rs. 1083000

Equipment and facilities

Quantachrome Autosorb iQ single station physisorption analyzer Purchase orders placed for the following: Add-on CO2 recirculating dewar, bath circulator, H2O level assembly from Anton Paar Pulse decay permeameter by Porous Materials Inc.