Identification of genetic types of natural gases produced from deep sag in Dongying depression
A series of high-production natural gases have been discovered in deep sag of the northern Dongying depression in recent years, which is a great breakthrough in the oil-rich basin. It comes a debate among the geological explorers about the gas origins whether the gas is the thermal degradative gas from source rocks or the cracking gas from oil. The authors investigated on the geology and geochemistry of natural gases discovered in the Minfeng area, a typical gas accumulation area in the deep sag of the northern Dongying depression, especially conducted thermal simulations on gas generations from either source rock or oil, and found useful identification parameters on the two genetic types of the natural gases. For the source-rock-degradative gas, the ratio of ln(CC5/nC6) <-l, (MCC5+CC6)AiC6< 0. 8, (CC5+MCC5+CC6)/(nC5+nC6) <0.5, DMCC5/CC5 > 0. 6 and ratio of toluere/benzene is greater than 1. 1. For oil-cracking gas, all the ratios are in opposing numbers. The results conclude that the natural gases discovered from the Minfeng area are mainly source-rock-degraded gas and subordinately oil-cracking gas.
source-rock-degraded gasoil-cracking gasgenetic type identificationnatural gas in deep sagDongying depression
国家科技期刊平台
NSTL
万方数据
维普
