摘要:
华北地区是我国东部的主要含油气区,其上古生界烃源岩主要以煤系和暗色泥岩为主。由于石炭—二叠系烃源岩埋藏深,热演化程度高,且古生代以来构造条件复杂,为上古生界烃源岩的二次生烃提供了条件。一次生烃多数发生在印支期,而二次生烃发生在燕山期和喜马拉雅期。烃源岩主要分布于本溪组、太原组和山西组中,且南北厚、中间薄,据参数分析属于中等—好烃源岩。其储层分布于下古生界的白云岩和上古生界的碎屑岩中,原生孔隙不发育,储集空间以次生孔隙为主。物性差,为低孔低渗储层。峰峰组碳酸盐岩、本溪组铝土岩及铝土质泥岩及上覆煤系地层、石千峰组及下三叠统紫红色泥岩及粉砂质泥岩是华北地区的有效盖层,与储集层匹配形成多套储盖组合。圈闭以断背斜、断鼻和断块为主,大部分圈闭形成于主要生烃期之前,是有效圈闭。通过成藏条件分析认为,华北地区的成藏主控因素是生排烃史和构造发育史的匹配以及成藏后的保存条件,因此将来应主要寻找那些二次生烃区的古构造或喜马拉雅期形成的新构造。
Abstract:
Huabei basin is an important hydrocarbon-generation area in East China. Source rocks in upper Paleozoic consist of coal-measure strata and dark mudstone. Because they were deeply buried and highly evolved and structural conditions are complicated after Paleozoic, there exists secondary hydrocarbon-generation in Carboniferous-Permian source rocks. Primary hydrocarbon-generation occurred in Yinzhi stage, while secondary occurred in Yanshan stage and Ximalaya stage. Source rocks distribute in Benxi Formation, Taiyuan Formation, and Shanxi Formation. And thickness in south and north areas is big while that in middle area is small. According to lots of parameters, source rocks are attributed to middle to good. Reservoirs exist in dolomite of lower Paleozoic and clastic rocks of upper Paleozoic. Primary pore poorly developed, so reservoir space mainly consists of secondary pore. And reservoir rocks are poor in physical properties, which are characterized by low porosity and low permeability. Carbonates in Fengfeng Formation, bauxite and bauxitic mudstone and overlying coal-measure strata in Benxi Formation, reddish purple mudstone and silty mudstone in Shiqianfeng Formation and lower Triassic are good cap rocks, which formed several reservoir-cap assemblages matching reservoir rocks. Traps are mostly fault anticline, fault nose and fault block. And they are good because they formed before hydrocarbon-generation period. Through analysis of reservoir-formed conditions, the formation of pools in Huabei basin mainly depended on the match of hydrocarbon-generation history, expulsion history and structural history and the preservation conditions of pools after their formation. So the future plays of the Huabei basin should be focused on the paleostructure and new structure formed Ximalaya stage where exist secondary hydrocarbon-generation.
点击查看大图
下载:
