The world is now moving towards green and renewable energy. Many countries are trying to put a stop to fossil fuel extraction. But here it’s exactly the opposite. Oil and gas extraction projects are still getting clearance in India, despite the bad toll it’s taking on the environment and human welfare.
Vedanta industries is going to drill 35 oil and natural gas wells in Movva, Gudur, Kalindi, and Machilipatnam mandals of Krishna district. It is an onshore project which comes under Kaza Basin with an area comprising approximately 114.93 Km2.9 hectares (22.25 acres approx) of farmland is hired for each well pad. A total of 144.93 km2 area isrequired for this project.The estimated cost of this project is around INR 650 Crores. The average drilling cost per well is estimated to be INR 15 Crore. Thus, total costs towards drilling and associated activities of all 35 wells would be around INR 525 Crores.
As part of the Government’s effort to increase domestic production, under the Discovered Small Field (DSF) Policy, the Kaza Basin Onshore block was awarded to Vedanta Limited in 2018. The proposed 35 no’s of the hydrocarbon wells to be drilled are distributed as 14 wells in Movva Mandal; 18 wells in Gudur Mandal; two wells in Kalidindi and one well in Machilipatnam. ONGC has drilled three exploratory wells in the year 1985 in the Kaza structure. Out of the three wells, two wells were found to be dry wells, and one well found to have gas discovery. The successful exploration well has discovered gas in Raghavapuram sands. It was noted that further gas extraction is possible through hydro-fracture of the well. Earlier wells were drilled in the depth of 2300 m below the ground level.
Drilling of 35 hydrocarbon wells within the Kaza block area will produce up to 30,000 barrels of oil per day and 30 million metric standard cubic feet of gas per day.
Why is it Harmful
Drilling oil wells and processing hydrocarbons will lead to environmental, sound, and water pollution. Dust emissions from the drilling operations are released into the atmosphere and ignition of hydrocarbons will release harmful gases like nitric oxide, carbon monoxide. Usage of water during drilling and in campsites will eventually cause water shortage in the area and Drilling mud and other chemicals will pollute the surface waters.The chemicals used in drilling will be released into the nearby farming lands making them harmful for cultivation. Improper maintenance of wastes will lead to contamination of soil. Drilling and construction activities will result in a temporary increase in ambient noise levels. Proper recycling and disposal of chemicals and other wastes should be the first priority
What do Experts say
A scientific study says that the extraction of oil and natural gas in the Krishna-Godavari basin may precipitate an environmental disaster in the region. The area, which is barely five feet above sea level, has been found to be sinking. This could lead to flooding of the region by the two rivers. The study by the geology department, Andhra University, Visakhapatnam, has found slow continuous creeping along claystone in some oil fields where the surface has sunk by a few millimeters. Continued exploitation of oil and gas may contribute to the land surface sinking further, says the study by G Krishna Rao.
In the latest issue of the Indian Academy of Sciences Journal, Rao’s study says oil and gas occur at a depth range of 3,000 to 8,000 feet. Probes into the recent blowouts in the EastGodavari district have revealed that reservoir pressure is very high, with the free flow conditions putting the entire area at risk. The study said that in the other areas of the world, like Venezuela and Texas, where over-exploitation of oil and gas has been reported, the land has sunk by as much as five to 25 feet, causing an environmental disaster. The study also mentions that the situation in the Krishna-Godavari basin has been showing early signs of sinking and that the Oil and Natural Gas Commission should take immediate preventive action. One solution was that water injections be used to make up for the vacuum caused by oil extraction so that the dynamics of the earth’s crust are not disturbed. Rao also says that besides an oil and gas zone, the basin is an important rice-growing region and is thickly populated. Repeated oil field fires and land sinking can adversely affect the economy of the coastal region of Andhra Pradesh.
The Krishna-Godavari basin is located on the east coast bordering Andhra Pradesh. The total area of the basin is around 59,000 km 39,000 km offshore and 20,000 km on land. So far, 296 wells have been drilled both on land and offshore in the basin and more than 130 prospects probed. These prospects have yielded 22 gas and 12 oil fields including the Ravva oilfield, being developed by a consortium of Command Petroleum, Marubeni, and Videocon.
According to V K Rao of the Directorate General of Hydrocarbons, who has done extensive work in the basin and has developed a novel hydrocarbon fairway system, the prospects occur at different stratigraphic levels and the reservoirs range in all ages. The prognosis shows that there could occur 575 million tonnes of hydrocarbons on land and 555 million tonnes offshore. Of the total estimated 1,130 million tonnes of hydrocarbons, only 15 percent has so far been established.
The sandstones in the Kaza Basin come under the semi-consolidated rocks category and these are known to have been subjected to compression in oil and gas fields even beyond 2000m depth and created land subsidence all over the world. Drilling in these places results in land destabilization and land subsidence. The same results were experienced while drilling in Godavari districts. Land subsidence will cause water stagnation making the land unfit for agriculture. It also increases the risks of flooding and damaging buildings