全球碳酸盐岩大油气田分布特征及其控制因素

碳酸盐岩大油气田是以碳酸盐岩为主要储层的一类油气田。据不完全统计,截至2012年底,世界上共发现了1021个大型油气田,其中碳酸盐岩大油气田321个。运用统计分析、资源评价、沉积学等方法理论分析了其中226个主要碳酸盐岩大油气田的地理位置、层系分布、储层规模与埋深及圈闭类型等。分析表明,碳酸盐岩储层主要分布于波斯湾盆地、墨西哥湾盆地、锡尔特盆地、滨里海盆地、美国阿拉斯加北坡、二叠盆地、四川盆地和塔里木盆地等;其中的油气资源主要集中在上古生界、侏罗系、白垩系、古近系和新近系。碳酸盐岩大油气田类型主要为生物礁类、颗粒滩类、白云岩类和不整合与风化壳类,通常规模较大,埋深一般小于3000m,埋深较大的主要为白云岩和超压石灰岩。通过对碳酸盐岩大油气田的分布特征和成藏研究,发现碳酸盐岩大油气田的现今地理位置与垂向分布受控于碳酸盐岩的平面与地层分布,古气候、古纬度控制了烃源岩的生成和碳酸盐岩的发育,古构造及其演化控制了碳酸盐岩的储层规模及油气富集程度,沉积成岩作用控制了碳酸盐岩大油气田的储集性能,有利的生储盖配置是碳酸盐岩大油气田形成的关键。

Distribution Patterns and Controlling Factors of Giant Carbonate Rock Oil and Gas Fields Worldwide

Giant carbonate rock oil and gas fields are those whose reservoirs are made mainly of carbonate rock. Based on the statistical figures, at the end of 2012, a total of 1021 giant oil and gas fields were found worldwide, of which 321 ones were giant carbonate rock oil and gas fields. By means of statistical analysis, assessment of resources and sedimentology, this paper theoretically analyzes 226 giant carbonate rock oil and gas fields, focusing on their geographical locations, strata distribution, scale and buried depth of reservoirs, and types of traps. The analysis indicates that carbonate rock reservoirs are distributed mainly in the Persian Gulf Basin, the Gulf of Mexico Basin, Sirte Basin, Pre-Caspian Basin, North Slope of Alaska in the United States, Permian Basin, Sichuan Basin and Tarim Basin. Of those areas, the oil and gas resources of carbonate rock reservoirs are accumulated mainly in the Upper Paleozoic, Jurassic System, Cretaceous System, Paleogene System and Neogene System. Giant carbonate rock oil and gas fields can be classified mainly as biological reef, grain beach, dolomite, unconformity and weathering crust. Usually they are large in scale, with a buried depth of less than 3000 meters. However, the reservoirs with a large buried depth are mostly dolomite and high-pressure limestone. Based on the research on distribution patterns and accumulations of giant carbonate rock oil and gas fields, it is found that the current geophysical locations and vertical distribution of giant carbonate rock oil and gas fields are controlled by the carbonate rock plane and distribution of strata. The palaeoclimatc and palaeolatitude controlled formation of hydrocarbon source rock and development of carbonate rock. The palaeostrncture and its development controlled the scale of carbonate rock reservoirs and oil and gas abundance. The sedimentary diagenesis controlled reservoir functions of giant carbonate rock oil and gas fields while favorable r-cap assemblage holds the key to formation of giant carbonate rock oi