一种基于随钻VSP地震地质导向的钻井轨迹高效优化方法及其应用

塔里木盆地发现多个奥陶系碳酸盐岩缝洞型油气田,随着开发的不断推进,中小型储集规模的缝洞体已经成为产能建设的主力目标.勘探开发过程中,由于受到复杂地层速度的影响,缝洞体系偏移成像、归位存在一定误差,常导致钻井的失利.笔者提出一种基于随钻VSP地震地质导向的钻井轨迹高效优化方法,首先应用VSP速度与基于三角网格的新构造模型高效率地校正原始地震偏移速度场,再联合修正后的各向异性参数场对地震数据进行快速偏移成像.其次,对新数据的全层系地层的构造特征再分析,预测优质储层的发育位置,确定最终靶点.最后,根据工程、地质情况,采用最为经济的优化设计钻井轨迹,钻进入靶.应用表明,该技术在大沙漠腹地塔中地区应用取得了较好的效果,地震资料成像品质得到提升.调整轨迹后的储层钻遇率和钻完井直投率分别提升16%和13.2%,有效地促进了油田实施低成本效益开发方案.

An efficient method for drilling trajectory optimization based on seismological and geological guidance of VSP data during drilling and its application

There are several Ordovician carbonate fractured-vuggy type oil and gas fields in the Tarim Basin.With the continuous development and production of the reservoirs,the small and medium sized fractured-vuggy systems have become the main targets of capacity development.In the process of exploration and development,due to the influence of complex formation velocity,there is a certain error in seismic migration data,which often leads to the failure of drilling.In this paper,an efficient drilling track optimization method based on VSP data for seismic data processing is proposed.First,the VSP velocity and the new triangular mesh model are used to effectively correct the original seismic migration velocity field,and then the modified anisotropic parameter field is used for quick migration.Secondly,the structural characteristics of the whole strata are analyzed in the new data,the positions of the reservoirs are predicted,and the targets are determined.Finally,according to the engineering and geological conditions,the most economical optimal design of the drilling trajectory is used to drill into the target.The application shows that the relatively good effect is obtained in Tazhong area of Tarim Oilfield,and the imaging quality of seismic data has been improved obviously.After well track adjustment,the rates of drilled reservoir and the directly put on production are increased by 16% and 13.2% respectively.The low cost and effective development plan of the oilfield is effectively promoted and implemented.