January 10, 2016 3:55:01 am
T N Singh and team
Rock Sciences and Rock Engineering Laboratory, Department of Earth Sciences, IIT Bombay
Around the year 2000, the United States developed technologies to extract shale gas and in the last 15 years, increasing extraction of shale gas has totally transformed the energy economics in that country. It has triggered shale gas extraction in Canada as well. As of now, shale gas extraction is limited almost exclusively to these two countries. But these are not the only ones to have shale gas deposits. Many other countries, including India, have significant amounts of shale gas. If we are able to extract shale gas like the US, it will go a long way in ensuring our long-term energy security requirements.
Chemically, shale gas is almost the same as natural gas. But it is found in places which make it difficult to extract. Natural gas is trapped mostly between soft sedimentary rocks which are permeable. If sufficient pressure difference is created at one place in the reservoir upon drilling, natural gas is able to permeate the rocks and assemble at the low pressure area. It can be drilled out after that. Shale gas, on the other hand, is found in shale rocks that are hard and impermeable. Pressure difference is not enough to suck them through the rocks. These rocks have to be ‘broken’ to reach the gas. It is done through a process called ‘hydraulic fracturing’ or ‘fracking’, involving a water mixture directed at the shale rocks at very high pressure.
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Fracking is key to shale gas extraction. It has to be done in the right way through right tools. Uncontrolled breaking of rocks can result in the gas spreading to unintended locations and it could lead to problems like groundwater contamination. It is here that technology development comes in.
The technology developed in the United States is proprietary. It is not shared with anyone. The US proprietary software is hugely expensive and increases the cost of exploration and production steeply. Also, they provide little opportunity to modify them as required. Besides, the shale rocks in India are different from the shale rocks in the United States. It is, therefore, important that we develop the technology to extract shale gas on our own.
For the last three years, we at the Rock Science and Rock Engineering laboratory at IIT Bombay are working on a project to develop the right technology for fracking. Key to successful fracking is an understanding of the properties of the shale rocks. Only when we know this inside out will we be able to find a way to ‘break’ them in the right manner.
We have developed our own method and tools to study the properties of these rocks. This study has already been completed. For the first time in India, we have been employing an advance ‘permeameter’, a state-of-the-art instrument to study geochemical properties under different temperatures and pressures. Right now, we are in the process of carrying out numerical modelling for ‘fracking’ using 6-7 types of shale rocks. We expect that it will require an effort of at least two more years before we are able to develop the right fracking technology.
The estimates are different, but India is supposed to have ‘substantial’ reserves of shale gas. If we are able to extract it at reasonable cost, it could make India self-sufficient in energy. This research received international recognition through two research grants by the American Association of Petroleum Geologists (AAPG) and Society of Petroleum Engineers (SPE) to my PhD student Debanjan Guha Roy. This is the first time such grants have been awarded to any Indian researcher working in an Indian institute. We are also trying to develop an alternative to the huge amount of fresh water used in fracking operations.
Understanding the properties of shale rocks and developing a technology to extract gas from them at a reasonable cost
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