PETROLEUM EXLORATION -A GLIMPSE by S. K. De GTC Session -11th Dec 2011 At Elita Promenade, Bangalore.
PETROLEUM EXPLORATION – A GLIMPSE Wealth of a Country consists of Forest, Agriculture, Mineral and Human Resources. Mineral Wealth comes from Rocks of the Earth. Rocks are of three types : Igneous, Sedimentary and Metamorphic. Interior of the Earth consists of Crust, Mantle and Core. Crust consists of Soil, weathered & sub weathered layer and Rocks.
PETROLEUM EXPLORATION – A GLIMPSE Mapping of the surface of the Earth is done by Survey of India. Top sheets are prepared by Surveyors. Mapping of Rocks are done by Geological Survey of India. Geologists are engaged in this task. This leads to discovery of Minerals. Ground Water and Petroleum occur in the sub-surface. Ground water mapping is done by the Central Ground Water Board.
PETROLEUM EXPLORATION – A GLIMPSE Petroleum consists of Oil and Gas. First discovered in India in 1886 at Digboi by Britishers while laying the Railway Line in Assam. Petroleum search started by Burmah Shell and later by Oil India. Work remained confined to Assam. In 1956 separate Oil Ministry was formed by India under Mr. K. D. Malaviya. ONGC was set up for Petroleum Exploration in India.
PETROLEUM EXPLORATION – A GLIMPSE Oil discovery game consists of Exploration, Drilling and Production. Petroleum is found deep within the Earth. Requires exploration by Indirect means and found only in Sedimentary rocks. Subsurface mapping of the sedimentary basins leads to discovery of Oil and Gas. Professionals involved in the exploration are Geologists, Geo Physicists and Geo Chemists.
PETROLEUM EXPLORATION – A GLIMPSE Geological Mapping leads to locating areas of sedimentary basins. Petroleum generally forms in Deep sea conditions due to decomposition of micro organisms under conditions of high temperature and pressure over million of years time. Source rocks are known as Shales. Geophysical methods of subsurface mapping are Gravity – Magnetic, Electrical and Seismic. Airborne , Land and marine surveys are undertaken.
PETROLEUM EXPLORATION – A GLIMPSE Seismic methods are direct methods viz., Reflection and Refraction. It measures Rock properties of the Earth. Method involves data acquisition, Data Processing and data Interpretation. Exploration leads to release of locations for Drilling. Conditions necessary for Oil and Gas discovery are Source rock, Reservoir rock , Cap rock and Entrapment.
PETROLEUM EXPLORATION – A GLIMPSE Depth of burial and reserve estimation are also important factors. After discovery, Oil and Gas fields are delineated by Drilling more wells. Thereafter production starts from the field and Crude Petroleum is sent to Refineries. Oil and Gas disovered in Assam, Gujarat, Krishna – Godavari and Cauvery basins and also at Bombay High.
PETROLEUM EXPLORATION – A GLIMPSE Till 1997, ONGC & Oil India did the exploration work. Therafter, Government of India offered the undiscovered areas for exploration to bidding by National and International Oil Companies. Main discoveries since has been the discovery of Oil in Barmer area of Rajasthan by Cairn Energy and Gas in East coast deep waters and Godavari Offshore by Reliance Industries Ltd.
PETROLEUM EXPLORATION – A GLIMPSE Oil constitutes over 35% of Primary energy consumption. Present level of demand is about 120 million metric tons. Demand will be over 250 million tons by the end of 2011-12. India imports 70% of its requirement. Import bill is huge. Present crude oil price is around USD 125 per barrel.