Shale Gas in India

November 6, 2015 November 9, 2023

Shale refers to a sedimentary rock resulted from compaction process of small old rocks containing mud and minerals – such as quartz and calcite, trapped beneath the earth surface. The shale gas is the natural gas trapped within these shale rocks. It is one of the unconventional type of natural gas along with coal bed methane, tight sandstones, and methane hydrates.

Problems in Extraction

The importance of shale gas can be gauged from the fact that an estimated 35% of world surface rock is made of shale formations. However, extraction of shale gas is difficult and tardy process. The difficulty is mainly because of less permeability of the shale rocks, which does not allow significant fluid flow. Due to low permeability, commercially viable production of shale gas needs fracturing of the rocks for, the fracturing provides permeability. For many years, this gas was produced from natural fractures, but as there was development of modern technologies such as horizontal drilling / hydraulic fracturing (aka fracking); more and more artificial fractures around the well bores were created. This skyrocketed the production of shale gas and led to the so called Shale Gas Boom in United States. This shale gas boom has also contributed partially in the recent fall of global oil prices. The hydraulic farming aided shale gas production has rejuvenated the natural gas industry in the United States.

Extraction process

The extraction process of shale gas involves two methods:-

Horizontal drilling

Under this technique a vertical well is drilled to the targeted rock formation and then at the desired depth, the drill bit is turned horizontally, exposing the well to more of the producing shale.

Hydraulic Fracturing

In this technique, water along with chemicals and sand are pumped into the well and a fracture or crack is developed in the shale rock to release the hydrocarbons trapped in shale formations to flow from the shale into the well.

Hydraulic fracturing when used in conjunction with horizontal drilling, it enables gas producers to extract shale gas at reasonable cost and rapidly as it enhances the flow of gas quickly to the desired well.

Shale Gas in India

Various estimates, including those by leading firms, put Indian reserves of shale oil and gas at large numbers describing Shale oil and gas are more widespread than natural oil and gas. Major regions of availability are Gujarat, Rajasthan, central India, KG Basin and offshore areas in Bay of Bengal. The assessment of shale formations has started in India at various sites. Also, a MoU have been signed between USA and India for sharing technical knowledge in shale-gas exploration.