Question: When was crude oil first discovered in nigeria?

Disambiguated questions and answers:
context: The history of oil exploration in Nigeria dates back to 1903 when Nigerian Bitumen Corporation conducted exploratory work in the country, at the onset of World War I the firm's operation were stopped. Due to the lack of technological and financial resources by small oil companies, large oil companies took over the exploration of commercial oil in the country. Thereafter, licenses were given to D'Arcy Exploration Company and Whitehall Petroleum but neither company found oil of commercial value and they returned their licenses in 1923. A new license covering was given to Shell D'arcy Petroleum Development Company of Nigeria, a consortium of Shell and British Petroleum (then known as Anglo-Iranian). The company began exploratory work in 1937. The consortium was granted license to explore oil all over the territory of Nigeria but the acreage allotted to the company in the original license was reduced in 1951 and then between 1955 and 1957. Drilling activities started in 1951 with the first test well drilled in Owerri area. Oil was discovered in non-commercial quantities at Akata, near Eket in 1953. Prior to the Akata find, the company had spent around 6 million pounds on exploratory activities in the country. Shell-BP in the pursuit of commercially available petroleum found oil in Oloibiri, Nigeria in 1956. Other important oil wells discovered during the period were Afam and Bomu in Ogoni territory. Production of crude oil began in 1957 and in 1960, a total of 847,000 tonnes of crude oil was exported. Towards the end of the 1950s, non-British firms were granted license to explore for oil: Mobil in 1955, Tenneco in 1960, Gulf Oil and later Chevron in 1961, Agip in 1962, and Elf in 1962. Prior to the discovery of oil, Nigeria (like many other African countries) strongly relied on agricultural exports to other countries to supply their economy. Many Nigerians thought the developers were looking for palm oil. But after nearly 50 years searching for oil in the country, Shell-BP discovered the oil at Oloibiri in the Niger Delta. The first oil field began production in 1958.
question: When was non-commercial amounts of crude oil first discovered in nigeria?
short_answers: 1953
wikipage: Petroleum industry in Nigeria
context: The history of oil exploration in Nigeria dates back to 1903 when Nigerian Bitumen Corporation conducted exploratory work in the country, at the onset of World War I the firm's operation were stopped. Due to the lack of technological and financial resources by small oil companies, large oil companies took over the exploration of commercial oil in the country. Thereafter, licenses were given to D'Arcy Exploration Company and Whitehall Petroleum but neither company found oil of commercial value and they returned their licenses in 1923. A new license covering was given to Shell D'arcy Petroleum Development Company of Nigeria, a consortium of Shell and British Petroleum (then known as Anglo-Iranian). The company began exploratory work in 1937. The consortium was granted license to explore oil all over the territory of Nigeria but the acreage allotted to the company in the original license was reduced in 1951 and then between 1955 and 1957. Drilling activities started in 1951 with the first test well drilled in Owerri area. Oil was discovered in non-commercial quantities at Akata, near Eket in 1953. Prior to the Akata find, the company had spent around 6 million pounds on exploratory activities in the country. Shell-BP in the pursuit of commercially available petroleum found oil in Oloibiri, Nigeria in 1956. Other important oil wells discovered during the period were Afam and Bomu in Ogoni territory. Production of crude oil began in 1957 and in 1960, a total of 847,000 tonnes of crude oil was exported. Towards the end of the 1950s, non-British firms were granted license to explore for oil: Mobil in 1955, Tenneco in 1960, Gulf Oil and later Chevron in 1961, Agip in 1962, and Elf in 1962. Prior to the discovery of oil, Nigeria (like many other African countries) strongly relied on agricultural exports to other countries to supply their economy. Many Nigerians thought the developers were looking for palm oil. But after nearly 50 years searching for oil in the country, Shell-BP discovered the oil at Oloibiri in the Niger Delta. The first oil field began production in 1958.
question: When was commerical amounts of crude oil first discovered in nigeria?
short_answers: 1956
wikipage: Petroleum industry in Nigeria

Long-form answers:
long_answer: Although the history of oil exploration in Nigeria dates back to 1903, non-commercial quantities of oil were not discovered there until 1953. Commercial amounts of crude oil were later discovered in Oloibiri, Nigeria in 1956.
knowledge: content: Nigeria is the largest oil and gas producer in Africa.
wikipage: Petroleum industry in Nigeria
content:  Crude oil from the Niger delta basin comes in two types: light, and comparatively heavy – the lighter around 36 gravity and the heavier, 20–25 gravity.
wikipage: Petroleum industry in Nigeria
long_answer: Nigeria is the largest oil and gas producer in Africa. Crude oil from the Niger delta basin comes in two types: light, and comparatively heavy. Oil was discovered in non-commercial quantities at Akata, near Eket in 1953. Shell-BP in the pursuit of commercially available petroleum found oil in Oloibiri, Nigeria in 1956.