川东南地区震旦系—志留系下组合有效烃源岩综合研究

COMPREHENSIVE RESEARCH OF EFFECTIVE HYDROCARBON SOURCE ROCK OF LOWER STRATA FROM SINIAN TO SILURIAN SYSTEM IN SOUTHEAST AREA OF SICHUAN PROVINCE

震旦系—志留系是川东南地区油气勘探的新层系、新领域,具有较好的勘探前景,但勘探程度极低。以地表露头、钻井岩芯样品为基础,通过地球化学特征、气源和沥青源对比分析,明确了下寒武统牛蹄塘组、下奥陶统五峰组—下志留统龙马溪组灰黑色泥岩、页岩为区内震旦系—志留系主要烃源岩,其中下志留统龙马溪组烃源岩最为发育,且其发育时期与大地构造格局或沉积盆地性质发生重大变革的转换时期相吻合,还明确了主要烃源岩横向展布特征及其构造沉积主控因素。

The strata from Sinian to Silurian system are new formations and fields with better exploration potential in southeast area in Sichuan province, but the degree of prospecting is quite low. Based on the ground outcrops and drilling core samples, contrasted and analysed the organic geochemical characteristic, gas source and asphalt source, it clarifies that the grey-black mudstone and shale are main hydrocarbon source rocks, included Niu-Ti-Tang formation of lower Cambrian system, Wu-feng formation of lower Ordovieian system and Long-ma-xi formation of lower Silurian system, whose developing periods consist with the converting periods of earth tectonic framework or the important transformation of sedimentary basin character. The hydrocarbon source rock of Long-ma-xi formation of lower Silurian system is most developing among them. At the same time, it also clarifies the lateral continuity and the main controlling factor of the structure and deposition of the chief hydrocarbon source rock.