Wu X.,China University of Petroleum - Beijing |
Wu X.,The State Key Laboratory of Petroleum Resources and Prospecting |
Li N.,China University of Petroleum - Beijing |
Zhou L.,Petrochina |
And 2 more authors.
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2015
Based on the statistics of the natural gas composition, and by combining the areal structural evolution, the maturity of source rock and analysis of the key gas reservoir, this paper determined the distribution and the main controls of the molecular nitrogen in Kokpansor Depression, which include the maturity of source rock, the process of gas accumulation and the high radioactivity of the basement rock. The results show that the content of molecular nitrogen in natural gas is lower in the Lower Carboniferous, higher in the Upper Devonian and the highest in the Lower Permian. In Upper Devonian, most of the source rock was over-matured so that it generated the nitrogen-rich natural gas. The exploration risk in some deep buried traps maybe very high in such a case. On the other hand, gas pools in the Lower Permian belong to exogenetic accumulations and faults are the main channels of the gas input from the source rock. The higher nitrogen content in the Lower Permian is closely related to the long distance vertical migration of the over-matured natural gas. As a result, the exploration outlook of the Lower Permian is very limited. ©, 2015, Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science). All right reserved.