Wednesday, February 26, 2025

Oil Hunters Of India

At Independence in 1947, India had just a few operational oil wells situated in the northeastern region of the country. Most of the subcontinent's sedimentary basins remained unexplored for their hydrocarbon potential. The Oil Hunter: Journey of a Geologist for India's Oil Exploration by Dr. Shreekrishna Deshpande is a personal recollection of the immense effort undertaken by Indian geologists to re imagine these basins as hydrocarbon source and reservoir rocks. It is the story of the development of India's oil industry told with unconcealed pride.

Russia, France, and the U.S. offered personnel and technical help along the way, but the lion's share of the credit goes to geologists of the Oil and Natural Gas Corporation for their perseverance and resilience in the face of immense challenges.

Dr. Deshpande joined the ONGC in its early days in 1961 and describes vividly his field experience in remote locales all across the country, from scorching Kutch, to steep Himalaya terrain, to facing personal danger during an insurgency in Assam. There were inevitable career challenges along the way due to changing institutional structure and unrealistic political expectations. Their impact on company work culture and productivity is described in honest and direct language.

One of my favorite passages comes towards the end of the book where he explains the divergence between geologists and management in their basic understanding of exploration and discovery.

"Subsurface discoveries of oil reserves cannot be projected with certainty. The inputs to the discoveries are always deterministic, but the result is never so, and there is a strong factor of probability. Exploration efforts are to reduce the risk factor and increase the probability of discovery. Methods for direct detection of  hydrocarbons from the surface, are  yet to be evolved. This contrasts with any other industry, where the output is more predictable and proportionate to the input. 

.... As a simplistic approach the management decides the cost of discovery of one tonne of oil by dividing the amount of discovered oil by the expenditure met. It is expected by them that similar expenditure should proportionately result in additional discoveries.

When a sedimentary basin turns old and mature, the addition to the existing stock of subsurface oil becomes increasingly difficult. Non-geoscientists then blame geologists for such uncertainty. Only the high profitability in the oil industry is visible; its probabilistic nature and the risks involved are not so obvious. The stochastic nature of oil discoveries is not appreciated by non-explorationists". 

My one complaint about this book is that there is very little geology in it! Dr. Deshpande describes the geology work he and others undertook in very broad strokes. I felt that a few examples of how specific types of geologic data is useful for petroleum exploration would be illuminating for the non specialist reader. 

Let me give an example. Early in his career he is sent to Osmania University, Hyderabad, to analyze some sedimentary rock samples using Differential Thermal Analysis. He simply mentions that the results were used by ONGC in their exploration efforts, but how so? DTA is a way to understand whether the sedimentary rock was baked during burial to temperatures that are conducive for hydrocarbon formation. 

Another example, and one that involves his specialization, could have been a brief passage describing his work on limestones. What is a carbonate sedimentologist looking for in these rocks? The main reservoir of Mumbai High, India's biggest oilfield, are Miocene age limestone beds which were deposited repeatedly during phases of oscillating sea level. Among other things, exploration geologists want to know how open spaces or porosity in these rocks has evolved over time and whether its occurrence can be predicted throughout the sedimentary section. There was a geological detective story waiting to be told there. 

But these are mere quibbles. Overall, this is a very readable account of the productive and remarkable career of a pioneer exploration geologist of India.  Popular accounts of Indian geology and industry are rare. Recently, Himalaya geology expert Dr. Om N. Bhargava released his memoir, Travails and Ecstasy of a Geologist Addicted to the Himalaya, on his experiences of working in the Himalaya. Indian earth scientists are beginning to share the good work they have done with a more general audience, bringing a much needed familiarity with a lesser appreciated but critical field of study. 

No comments:

Post a Comment