梨树断陷油气成藏规律及主控因素分析

在三维地震的基础上,通过精细的构造解释,对梨树断陷的构造格架进行重新划分,对油气成藏的基本模式、油气成藏的主控因素进行了分析。划分深部、中部、浅部三套成藏组合,存在近源侧向运移为主的自生自储型成藏模式、远源垂向运移为主的下生上储型成藏模式;将梨树断陷层构造单元划分为:毛城子斜坡带、八屋隆起带、小宽洼陷、小城子斜坡带、桑树台洼陷、双龙洼陷等6个构造单元;认为陡坡带存在构造(断鼻)油气藏,主洼槽带(断槽)存在岩性(湖底扇)油气藏,中央隆起带存在构造、岩性、潜山、地层油气藏;次洼槽带存在岩性、构造-岩性油气藏、斜坡带存在构造-岩性、地层油藏;八屋隆起带(中央隆起带)有效的储层和保存条件是油气成藏的主控因素;小城子、毛城子斜坡带(东部、北部斜坡带),不整合面和泥岩对油气的封堵是该领域成藏的主控因素;桑树台洼陷陡坡带,有效的储层和圈闭是该领域成藏的主控因素。

Rule in Lishu Fault Depression and the Key Factors

Through fine structure interpretation based on three--dimensional seismics, the author has again divided tectonic framework of Lishu fault depression and analyzed basic mode governing oil and gas accumulation and the key factors. Dividing deep, intermediate and superficial sections into three reservoir combinations, there are two accumulation models： one model which is auto-- product and auto--reservoir migrates toward the sides; the other which is lower product and upside reservoir migrates vertically. Dividing Lishu fault depression into six tectonic elements including Maochengzi and Xiaochengzi slope belts, Bawu upwarping zone, Xiaokuan, Shangshutai and Shuanglong depressions, it is believed that structure（fault--nose） reservoir occurs in slope belt; lithologic reservoir in main trough fault; structure reservoir, lithologic reservoir, buried hill reservoir or stratigraphic reservoir in central uplift zone; structure--lithologic reservoir in secondary trough fault. It is also found that the effective reservoir and conservation condition of Bawu upwarping zone contributes to the accumulation; oil and gas blocked off by unconformities and mud rock in Maochengzi and Xiaochengzi slope belts to the accumulation; effective reservoir and trap of Shangshutai depression slope zone to the accumulation.