巴楚西段海相砂岩储层沥青发育特征及其油气地质指示

Development characteristics and hydrocarbon geological indication of marine sandstone reservoir bitumen, western part of Bachu Uplift

利用岩心、薄片等资料对巴楚西段志留系和泥盆系海相砂岩储层沥青进行了深入分析,结果表明:宏观上沥青主要顺层发育,表现为块状、脉状、线状、尖灭状等多种赋存形态;微观上往往以充填或浸染状存储于粒间、粒内孔隙以及微裂隙之中;研究区内主要发育油质、沥青质和碳质沥青,其次为胶质沥青;志留系储层沥青成因可能主要与加里东晚期—海西早期构造运动抬升致使古油藏破坏而发生沥青化有关,泥盆系东河塘组储层沥青成因与早期油藏遭受构造运动及热蚀变破坏、晚期多次运聚调整及一定的气侵作用等多重因素相关。利用沥青可辅助判断排烃作用对储层溶蚀改造作用发生的影响,并可结合成岩作用推测油气成藏时期及成藏过程。

Using the data of core and thin sections, bitumens from Silurian and Devonian marine sandstone reservoirs were analyzed. The results show that the bitumens, on macroscopic level, are mainly of bedding, their existences are massive, linear,vein and pinch-out like; on micro level, bitumen fills or contaminates the intragranular, inter granular pores and micro fractures.In the study uplift, oil, bitumen and carbonaceous bitumen, and some glial bitumen mainly developed. Silurian reservoir bitumen genesis may be related to late ancient reservoir damage and the occurrence of bitumen, which was caused by the early uplift of Caledonian and Early Hercynian tectonic movement. Devonian Donghetang Formation reservoir bitumen genesis related to multiple factors such as early reservoir suffered tectonic movement and hydrothermal alteration damage, advanced multiple migration accumulation and adjustment of some certain gas invasion, etc. The use of bitumen can assist to identify expulsion influence on reservoir solution reconstruction effect, combined with diagenesis, to predict accumulation period and accumulation process of oil and gas.