沉湖地区下古生界油气系统演化与成藏模式

Evolution of Lower Paleozoic Petroleum System and Its Model of Hydrocarbon Accumulation in Chenhu Area

沉湖地区下古生界下寒武统中、上寒武统(·)油气系统烃源岩主要为南斜坡的下寒武统,储集层主要为中、上寒武统,盖层为志留系。加里东末期,油气从生油凹陷向台隆运移、聚集;印支末期,油气向乐乡关潜江隆起上运移,形成以隆起为圈闭的油气聚集区,同时,潜北断层造成部分烃类散失;早燕山末期,位于复向斜与复背斜之间的斜坡带和丫角新沟地区的圈闭对油气运移、聚集、保存有利;喜山期,一方面先期形成油气藏的再分配,另一方面来自乐乡关潜江复背斜上的裂解气及先期古隆起油气聚集区的烃类发生裂解向凸起运移。预测区内可能存在原生油气藏及次生油气藏2大类,勘探对象应以原生油气藏为主,以红丰牌洲区带为最有利区带,牌洲、珂理、戴家场均属首选钻探圈闭。

There is a lower Paleozoic petroleum system about lower Cambrian-middle and upper Cambrian(·)in Chenhu area. It includes lower Cambrian source rocks in south incline, middle and upper Cambrian reservoir rocks and Silurian cap rocks. At the end of Jialidong periods, the hydrocarbon moves and accumulates from Depression to uplift. At the end of Yingzhi periods, hydrocarbon gets together in Yuexiangguang-Qianjiang uplift, therefore forms oil and gas accumulation area, but north Qiangjiang fault might partly make hydrocarbon dissipated. At the end of early Yanshan periods, these traps lie in incline strip between multiple synclines and multiple anticlines, or in Yajiao-Xinggou area. They are considered to be favorable for hydrocarbon migration, accumulation and preservation. At Xishan Periods, hydrocarbon pools formed early distribute again on the one hand, split gas from Yuexiangguang-Qianjiang multiple anticline and hydocarbon formed from early uplift moves to the swell. It is predicted that original hydrocarbon pools and secondary hydrocarbon pool may exist in the predicted area, therefore its exploration will focus on original hydrocarbon pool; The Hongfeng-Paizhou area is considered to be the most favorable exploration region; Paizhou , Keli and Daijiacang traps are considered to be the most favorable traps.