Abnormal overpressure distribution and natural gas accumulation in foreland basins, Western China

查看全文 作　　者：SONG [1,2]Yan;XIA [1]Xinyu;HONG [1]Feng;QIN [1]Shengfei;FU [1]Guoyou 机构地区：[1]Research Institute of Petroleum Exploration and Development,PetroChina,Beijing 100083,China;[2]Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550002,China 出　　处：《Chinese Science Bulletin》索引2002年第47卷第S1期,共7页 摘　　要：Abnormal overpressure occurs in the forelandbasins of Kuqa, South Junggar and West Sichuan in China.The pressure coefficients are high. Overpressure exists inwide areas and various strata. The layers of overpressurehave a very close relationship with lithology, and the area ofoverpressure is controlled by the piedmont depression. Themechanisms of overpressure formation in the Kuqa andSouth Junggar Depression include disequilibrium compac-tion and tectonic compression; the importance of these twofactors varies in different basins and in different stages of thesame basin. Different models of gas accumulation are estab-lished to explain the relationship between overpressure dis-tribution and gas pool formation, and the influence of over-pressure on the gas pools. These models include: (i) theviolent tectonic movement leads to the pool formation inoverpressure belt (Kela-2 gas field in Kuqa); (ii) the pres-sure releases at shallow part and the gas pool forms in latetime (Hutubi gas field in southern Junggar Basin); (iii)through the pressure transfer the gas migrates and accumu-lates (Xinchang gas field in Western Sichuan Basin). 关 键 词：FORELAND basin ABNORMAL pressure GENESIS natural gas accumulation.