塔里木盆地塔中隆起奥陶系碳酸盐岩油气运聚主控因素及成藏模式

Accumulation Model based on Factors Controlling Ordovician Hydrocarbons Migration and Enrichment in the Tazhong Uplift,Tarim Basin,NW China

从多元地质条件及其空间匹配关系角度出发,综合地质剖析及地球化学示踪等方法,对塔里木盆地塔中隆起奥陶系油气输导体系、运移方向及分布特征等进行的精细研究。结果显示:断裂、源储接触关系及盖层等共同控制着油气垂向运移的距离及层位;构造背景、不整合面、渗透性输导层、断裂的配置关系等控制着油气侧向运移的方向、通道和距离;海平面升降旋回、优质储层的配置关系控制着油气垂向聚集层位及平面分布规律。进一步结合研究区烃源岩条件、储层类型等研究成果,基于源储纵向接触关系及油气垂向运移距离,目的层油气成藏模式可分为近源混合成藏模式与远源混合成藏模式;根据油气来源区域及油气横向运移距离,又可分为内部源岩叠加混合成藏模式与内外部源岩交叉混合成藏模式。

In order to further clarify the role of different geological conditions on hydrocarbons accumulation process,the major controlling factors of Ordovician hydrocarbons accumulation in the Tazhong Uplift,Tarim Basin are studied based on the view points of diverse geological conditions and their relationship in space.The results showed that the vertical hydrocarbons migration distance and accumulation layers were controlled by vertical source-reservoir distribution,faults,and caprocks.Structures played a major role in lateral direction of hydrocarbons migration.The lateral migration pathways were governed by unconformities,transport faults,and porous permeable carrier beds.Apart from the excellent reservoir controls,hydrocarbons enrichment was controlled by tectonic events.Based on the analysis of factors mentioned above and coupled with oil sources conditions and excellent reservoirs,two types of hydrocarbon accumulation models could be retained based on the vertical hydrocarbon migration distance,including a multi-sourced area model and a single-sourced area model.In addition,the accumulation models could be also classified into near source accumulation and far source accumulation based on the lateral hydrocarbons migration distance.