Electrical Resistivity Imaging with Borehole Data for Delineation of Surface Position of Faults and Coal Seam Incrops

Coal is the most important fossil fuel India which caters to 55% of energy needs. Around 361.41 Billion tonnes of cumulative Geological Resources of Coal have so far been estimated in the country till 1^st April 2022. The coal deposits are spread over 27 major coalfields, mainly confined to eastern and south central parts of India and primarily present in older Gondwana Formations in eastern & peninsular India and younger tertiary formations of north-eastern, western & southern regions.

Considering the limited reserve of petroleum & natural gas, coal will continue to occupy centre-stage of India’s energy scenario. With the growing demand, it is necessary to fasten the coal exploration programs through an integrated approach for coal exploration i.e. drilling along with geophysical and geological investigations for faster establishment of coal reserves. The coal exploration primarily requires identification of the potential coal bearing area based on the available geological information or regional exploration carried in the area. An exploration plan is designed as per the Indian Standard Procedure (ISP) for Coal Resource Estimation based on the available geological information and objectives covering topographical survey, geological mapping, conventional core/ non-core drilling & geophysical surveys.

The principal surface geophysical methods used for exploration are electrical, magnetic, electromagnetic, radiometric, gravimetric, and seismic surveys. Downhole geophysical logging is also an important for extending data acquisition beyond the drill hole. A combination of surface & downhole geophysical methods for delineation of depths, thickness & physical properties of lithological formations.