塔河油田石炭系卡拉沙依组三角洲薄层砂体刻画

Characterization of thin deltaic sand bodies of Carboniferous Karashayi Formation in Tahe Oil Field

塔河油田石炭系卡拉沙依组地层埋深大,砂体厚度薄,横向变化快,常规波阻抗难以区分砂泥岩,砂体刻画难度大,制约了该区的勘探开发进程。在砂体地质模型的约束下,采用地震波形指示反演与地层切片分析相结合的方法,对塔河油田卡拉沙依组砂体进行刻画。研究表明,地震波形指示反演技术使砂体的纵横向识别精度同步提高,实现了研究区卡拉沙依组3m以上薄砂层的预测,反演结果与已知钻井匹配程度较高,后验井符合率达88.1%,有效提高薄层砂体的识别能力;地层切片分析目的层段砂体的变化特征,能较好地反映研究区水进和水退的沉积演化,刻画出三角洲薄层砂体的平面分布范围,可为寻找有利砂体发育区提供地质依据。

The Carboniferous Karashayi Formation in the Tahe Oil Field has a large burial depth,thin sand body thickness and fast lateral changes.Conventional wave impedance cannot easily distinguish sand and mudstone,and it is difficult to characterize sand bodies,which restricts the exploration and development in this area.Under the constraints of a sand body geological model,the combination of seismic waveform inversion and stratigraphic slice analysis was used to describe the sand bodies.The seismic waveform inversion technology can improve the vertical and horizontal identification accuracy of sand bodies synchronously,and realize the prediction of thin sand layers more than 3 m thick in the Karashayi Formation of the study area.The inversion results are highly matched with wells,and the post-test well-matching rate is 88.1%,which effectively improves the recognition ability of thin sand bodies.Stratigraphic slice analysis of the variation characteristics of the sand bodies in the target interval better reflect the sedimentary evolution of transgression and regression in the study area,and characterize the plane distribution of the thin sand bodies in the delta,providing a geological basis for finding favorable sand body development zones.