Read this essay to learn about Petroleum. After reading this essay you will learn about: 1. Origin and Occurrence of Petroleum 2. Reserve and Production of Petroleum 3. Exploration.
Essay # Origin and Occurrence of Petroleum:
Since the beginning of discovery of petroleum, scientists promulgated different theories regarding the origin of petroleum. Undoubtedly, the organic theory is most widely accepted. It states that rocks of marine origin of tertiary age, specially sedimentary rocks, generally contain petroleum. Several thousand years ago, during the submergence of many areas, a large amount of organic matter also went down below the ocean floor.
Later on, chemical decomposition of the organic matter separated the hydrocarbons. Gradually these hydrocarbons accumulated within the rock floor. In India, three types of structures are recognized as the possible oil-bearing regions. These are anticline, fault and stratigraphic trap of tertiary sedimentary rocks.
Number of areas were earmarked as potential oil-bearing regions for future exploration work.
1. Assam-Arakan arc:
Comprising the entire north-eastern India. According to the available estimates, apart from the existing oil-producing zone in Assam, a number of other regions adjacent to the state may be considered potential oil-bearing zones. Besides Assam, Tripura, Manipur and Meghalaya possesses a substantial oil reserve.
2. Gujarat-Cambay Region:
This region is already producing a large amount of oil. The Cambay-Kutch area contains huge amount of oil.
3. Bombay Off-shore Region.
4. West Bengal Basin:
Prospecting and exploration work is going on in several places.
5. Cauvery Basin.
6. Andaman and Nicobar Islands.
7. Tamil Nadu and Andhra Pradesh Coast.
At present, oil is exploited from three different regions in India.
1. Assam region,
2. Gujarat region and
3. Bombay High
1. Assam Region:
The oldest oil-field in India is located in Digboi field in Assam. After some years, several oil wells were opened up around Digboi.
At present, at least 750 oil wells produce oil. Important among these are:
(a) Nahar Katia,
(c) Hugri jan,
(n) Anguri, and
Oil-fields in Assam are situated in two distinctly separate regions of upper Assam and Barak-Surma Valley. The entire region is composed of tertiary rocks. The oil extracted from this region is of high quality.
2. Gujarat-Cambay Region:
A coordinated effort by ONGC and Geological Survey of India yielded positive results regarding oil exploration in Gujarat. Since 1958, after the discovery of the famous Ankleswar oil-well, a number of oil-wells were discovered in this region. Anticlinal ridge of miocene series generally contain petroleum in this region. Cambay basin and Varuch district possesses most of the oil-fields. The oil-fields are:
Discovered in 1958, situated very near Gulf of Cambay and north of Surat.
Situated near Ahmedabad, possessing huge amount of oil.
Adjacent to Kalol.
3. Bombay High:
In the year 1974, huge amount of oil was discovered in Bombay High, situated 173 kms. South-west of Bombay. 2,000 square kms. area in the continental shelf of Arabian Sea contains a vast amount of petroleum. Two sophisticated vessels, namely ‘Sagar Samrat’ and ‘Sagar Bikash’, were entrusted with the drilling and exploration work.
Essay # Reserve and Production of Petroleum:
According to the estimates of ONGC in 2005-06, the total on land recoverable reserves of oil in the country is 369.56 million tonnes. There are also 32.53 million tonnes of oil off the eastern coast.
The respective recoverable reserves of Assam and Gujarat are 163.88 and 173.99 million tonnes.
Rajasthan, where Cairn Energy has discovered some small and mid-sized fields recently, has emerged as the third state with 11 million tonnes of recoverable reserves of oil.
According to recent data (2005-06) compiled by the petroleum ministry, Tamil Nadu has 8.17 million tonnes of recoverable.
Arunachal Pradesh, with 5.21 million tonnes of recoverable reserves, ranks higher than Andhra Pradesh, which has only 4.72 million tonnes of reserve.
However, according economic survey report of April, 2004 total recoverable reserves of the country was about 1.6 billion tonnes of which 0.7 billion tonnes of oil and 0.9 billion tonnes of oil equivalent gas.
In the year 2003-04, total Indian crude oil production was 33.37 million tonnes worth Rs. 18,946 crore which has registered a modest increased in the following year
In 2004-05, crude oil production reached to 34 million tonnes, worth Rs. 18,946 crore.
The natural gas production in 2004-05 was 30,820 MCM worth Rs. 8,940 crore.
The year 1989-90 had witnessed the discovery of several new oil-wells throughout India. Exploration works yielded positive results, mostly in Tamil Nadu, Gujarat, Assam and Andhra Pradesh.
Oil and gas structures have been discovered in Adiyakkamangalam in Tamil Nadu, Andada in Gujarat, Khoraghat in Assam, Lingala in Andhra Pradesh, Bombay off-shore and Kutch offshore.
At present, ONGC has about 4,800 wells, of which more than, 2,900 are oil-wells and 1941 are oil-flowing wells. Over a thousand are remaining idle.
ONGC was primarily formed in 1956 and entrusted with oil exploration and production. The former Burmah Oil Co. was converted to Indian Oil Company in 1981 and entrusted the drilling operation of oil-wells in Mahanadi basin, Rajasthan and Gujarat. A number of foreign companies, specially a Soviet collaboration, was sought for further exploratory work. Intensive search for oil is going on in Cambay, Cauvery, Bengal basin and Bengal off-shore.
Oil has been struck in some of these areas. According to the experts, success rate of oil availability is quite high, 1 out of every 12 drilled wells are oil-bearing. So, the prospect of Indian petroleum production in near future is quite hopeful.
To reduce the over dependence on import of foreign crude Govt., of India is very keen to explore new oil fields within the national territories. A new exploration licensing policy was launched in 1999. The country was divided into blocks and the exploration responsibilities were given to different interested private companies.
This had paid a rich dividend. Among the 90 exploration blocks were given, 19 discoveries have already been made so far in cambay onshore, North-East Coast and Krishna-Godavari deep water areas of these, North Surat and Bhima fields in Cambay onshore block have been under production since 2004. For improved oil recovery schemes, the incremental crude oil output of ONGC is anticipated about 120 million tonnes in 2030.
However, Government owned Navaratna Company ONGC is also engaged in exploration and acquisition beyond Indian shores. The ONGC Videsh limited has acquired 25 per cent in Greater Nile oil project in Sudan. It has also acquisitioned exploration block in Cote d ‘ Ivoire, Russia, Sudan, Vietnam, Iran, Libya, Syria, Myanmar, Iraq, and Australia.