中国中、低丰度大油气田基本特征及形成条件  

Principal characteristics and forming conditions for medium-low abundance large scale oil/gas fields in China

作　　者：赵文智[1] 汪泽成[2] 王红军[2] 王兆云[2] 

机构地区：[1]中国石油天然气股份有限公司 [2]中国石油勘探开发研究院

出　　处：《石油勘探与开发》2008年第6期641-650,共10页Petroleum Exploration and Development

基　　金：国家重点基础研究发展计划973项目(2007CB209502)

摘　　要：近年中国陆上发现的一批中、低丰度大型油气田具有低孔渗、小油(气)柱、低储量丰度和规模大等特点。中、低丰度油气藏大面积成藏的有利条件是:大型敞流湖盆腹地发育大型牵引流成因砂体,与烃源岩呈"三明治"结构大面积间互,为成藏奠定了基础;小油气柱、常压—低压系统降低成藏对盖层质量的要求;储集体内部非均质性强烈,气藏整体连通性差,降低了气体逸散能量,保证油气在包括地质条件相对劣质区的大范围成藏;抬升卸载环境导致气源岩解吸面状排烃,有利于晚期大面积成藏。研究表明,中国陆上大型坳陷盆地向斜区具有发现大型岩性油气藏的良好前景,这一认识已在鄂尔多斯、松辽和四川盆地向斜区油气勘探中发挥了指导作用,推动油气储量大幅度增长,未来仍有良好发展潜力。In recent years, some of large-scale oil or gas fields with medium-low abundance have been discovered in onshore China. They have such characteristics in common as low porosity and permeability, small oil or gas column, low reserves abundance, and large scale. Studies conducted by the authors show that the formations of wide reservoirs with medium-low abundance have the following favorable conditions： the large-scale sandbodies caused by drag flow in the hinterland of large lacustrine basins, alternating broadly with source rocks like ＂ sandwich-type＂ architecture of reservoir-source rock association, provide fundamental basis of oil/gas accumulation in large scale; the small oil or gas column and normal to low pressure system reduce the restrict requirement on cap-rock quality which leads to large-scale reservoir formation; the strong reservoir heterogeneity with poor connectivity minimizes gas escape energy and ensures wide oil/gas accumulations even in the area with poorer geological conditions; the late uplifting and unloading environment makes it possible for source rock desorb and discharge hydrocarbon to form reservoirs with young generation. Studies indicate that there are nice prospects in discovering large-scale lithological reservoirs in the synclinal areas of large terrestrial depression basins of China. This concept has guided the oil/gas discoveries in synclinal areas of Ordos, Songliao and Sichuan Basins, promoting the great increase of oil and gas reserves and showing a good potential for future exploration.

关 键 词：大油气田 大面积成藏 中 低丰度 岩性油气藏 理论新进展 坳陷盆地 

分 类 号：TE122.1[石油与天然气工程—油气勘探]