Abstract:

Sapropelic gas could be derived from the cracking of both sapropelic kerogen and sapropelic crude oil. The differences between these two different kinds of genetic gases are: 1 the value of C₂/C₃ of the gas derived fron kerogen remains constant while that of the gas derived from crude oil increases gradually; the difference of carbon isotope of (δ¹³C₂-δ¹³ C₃) is opposite to the above memtioned values. It is considered that the gas in Jilak, Sangtamu and Jiefangqu regions in North Tarim Basin is derived from sapropelic kerogen while the gas in Lunnan, Yinmali regions is derived from crude oil.

Key words: natural gas, kerogen cracking, crude cracking, Tarim