中国石化东部探区古生界原生油气藏勘探前景

中国石化东部探区下古生界烃源岩以海相碳酸盐岩为主，有机质丰度较低。渤海湾盆地南部下古生界烃源岩于中三叠世末进入生油高峰，中生代发生二次生烃，新生代埋深虽然可达万米，但富有机质干酪根绝大部分已转化，生烃潜力有限；南华北地区下古生界烃源岩在晚三叠世达到早成熟阶段，新生代基本未发生二次生烃作用。上古生界是一套海陆交互相的煤系地层，煤层及暗色泥岩在晚三叠世末期和早白垩世末期两次发生深成变质作用。在系统分析前人研究成果的基础上，指出渤海湾盆地南部是上古生界烃源岩二次生烃最有利的地区，油气保存好，原生油气藏勘探前景广阔，有利勘探区为东濮凹陷、临南洼陷、德州凹陷南部、莘县凹陷北部；下古生界的原生油气藏勘探风险较大，渤海湾盆地南部具有一定的勘探前景。图5表4参30

Prospect of primary Palaeozoic oil-gas pools in eastern exploration region, Sinopec

The Lower Paleozoic source rocks in the eastern exploration region of Sinopec are mainly marine carbonates with a low organic content. The rocks in southern Bohai Bay reached early maturation at the end of Mid-Triassic and started secondary hydrocarbon generation at the Mesozoic. To Cenozoic, although subsiding further to more than 10 km, most source rocks in which organic-rich kerogen had already been cracked up were limited in generating hydrocarbon. In the southern North China, the lower Paleozoic source rocks reached primary maturation at late Triassic and the secondary hydrocarbon generation did not occur at the Cenozoic. The Upper Palaeozoic is mainly a set of coal measure sediments with great thicknesses of coal and dark mud beds, which experienced two maturation periods at the end of late Triassic and of early Cretaceous. Based on previous studies, it is concluded that the favorable Upper Paleozoic oil and gas prospects are in the southern Bohai Bay, including Dongpu Sag, Linnan Sub-Sag, southern Dezhou Sag and northern Xinxian Sag. There is risk for the exploration of the Lower Paleozoic proto-petroleum, and the southern Bohai Bay is a preferred place.