渤海河流相油田剩余油形成与分布研究

Formation and distribution of remaining oil in fluvial facies reservoirs in Bohai Oilfield

渤海河流相油田具有储层厚度薄,砂体横向连通性差,分布不稳定,边底水较发育的特点,储层剩余油的形成原因和分布复杂。渤海A油田明下段V油组1708砂体为典型曲流河沉积,是依托单砂体水平井开发的构造-岩性油气藏。投产后,平面水驱不均,层内矛盾突出,东北一侧自喷高产且不含水,西南部产量相对较低且含水快速突破到80%以上。结合地震、测井、钻井等静态资料和生产动态、数值模拟等动态资料综合分析认为,A9井自喷主要是高部位平面上边部能量供给,A12H井自喷受平面上边部能量供给和顶部气层的双重影响;而结合砂体纵向韵律性认为A15H井和A16H井是由于边水突破形成次生底水,平面上和垂向上储层非均质性差异导致该砂体南北侧出现明显层内矛盾。在此基础之上,阐述了该砂体的剩余油形成及分布规律。

The fluvial facies in Bohai Oilfield has characteristics of thin reservoir,poor lateral connectivity of sandbody,unstable distribution,and relatively developed edge-bottom water,and it is complex the formation and distribution of residual oil in the reservoir.The 1708 sandbody of Lower Minghuazhen Formation in Bohai A Oilfield,which is a typical meandering fluvial deposition,is a structural-lithological hydrocarbon reservoir developed by horizontal wells in single sandbody.After the oilfield putting into production,the dynamic performance showed that the waterflooding front is uneven in plane,and the interference in layers is serious.The oil wells in the northeastern part are high flowing productions without water,but ones in the southwestern part are low yields and water-cut rapidly rising to 80%.According to static data of seism,well logging,and drilling,and dynamic data of production performance and numerical simulation,it was concluded that the flowing production of A9 well was mainly affected by edge water drive in the plane of higher part,the flowing production of A12H well was mainly controlled by the dual effect of gas cap and edge water drive in the plane.Combined with the vertical rhythm of the sandbody,A15H and A16H wells in the southwestern part were rapid water-cut rising due to secondary bottom water formed by quick breakthrough of edge water.Therefore,the areal and vertical heterogeneity leads to obvious contradiction of dynamic production performances between southern and northern parts.On this basis,it was described the formation and distribution of remaining oil in this area.