贵州仁怀县震旦系灯影组古油藏成藏条件及油气地质意义

野外观察和研究表明，贵州仁怀县震旦系灯影组古油藏储层为一套碳酸盐台内浅滩环境沉积，主要岩性为砂屑云岩、鲕粒云岩、藻屑云岩和细晶云岩，沥青充填于白云岩晶间孔、粒间孔及岩石溶蚀孔洞内，呈黑色固态物质产出。固体沥青呈块状，质地坚硬，有污手性，镜下观察沥青具中间相结构和镶嵌状结构特征，实测沥青反射率为2.95%~3.86%，双反射明显，热演化程度高，显示储层在地质历史时期曾经遭受高温热演化作用。区域地质及沉积相分析认为，灯影组沉积晚期在上扬子地区存在一个边缘浅滩，并可能存在若干碳酸盐台内浅滩，这种沉积格局控制了滩相储层的发育与展布，震旦纪末期桐湾运动形成的古暴露对该套滩相沉积的颗粒云岩进行溶蚀改造，形成大量孔洞缝，并形成有利的储集体。震旦系陡山沱组和下寒武统牛蹄塘组黑色页岩有机质丰度高、类型好，烃源岩的发育为古油藏的形成提供了丰富的物质基础，下寒武统巨厚的泥页岩组合为油气藏的形成提供了得天独厚的封盖条件，形成了良好的生储盖组合，灯影组和牛蹄塘组之间的不整合面提供了油气运移的通道，加里东运动早期黔中隆起的形成为油气聚集创造了条件。

The discovery and petroleum geological significance of Dengying Formation paleo-reservoirs in Renhuai, Guizhou

Field observation and investigation shows that the paleo-reservoir in Sinian Dengying Formation in Renhuai of Guizhou Province has the depositional environment of bank facies with doloarenite, oolitic dolomite, algal dolomite and fine-crystalline dolomite. The black solid bitumen is massive, hard, staining hands, and filled in the intercrystal pores, interparticle dissolution pores and dissolution caves of the rocks. Microscopic observation of asphalt shows the intermediate phase structure and the mosaic-like structural features, bitumen reflectance is 2.95%~3.86%, there exists double reflection and a high degree of thermal evolution, and the reservoir once experienced exposure to high temperature thermal evolution. The investigation and research on regional geology and sedimentary facies show that there probably existed platform-marginal shoal facies and shoal facies of open platform facies in Late Dengying period. The deposition pattern controlled shoal reservoir development and distribution. The formation of ancient exposures controlled the reformation of shoal dolomite in late Sinian period and Tongwan tectonic movement. Sinian Doushantuo Formation and Lower Cambrian Niutitang Formation black shales had a high organic matter abundance and good organic matter type, thus providing the ancient oil reservoir with a wealth of materials, and Lower Cambrian shale provided oil and gas with a favorable cover conditions, thus forming a good combination of reservoirs. The unconformity between Dengying Formation and Niutitang Formation controlled the channel for hydrocarbon migration, whereas the Early Caledonian movement in central Guizhou uplift created a structural and lithologic traps for oil and gas accumulation.