相控地质统计学反演方法及其在油田开发中的应用

The facies-control geostatistical inversion method and its application in development stage of oilfield

渤海油田新近系地层沉积环境复杂,储层发育形式多样,横向厚度变化大,内部多发育泥岩隔夹层,严重影响油田开发阶段注水井及调整井的实施。由于原始地震资料频带宽度有限,基于传统反演方法得到的储层预测结果分辨率难以满足需求,无法有效表征储层的厚度和发育情况。文中从渤海油田新近系储层发育特征出发,首先,开展了正演模拟,分析不同变差函数类型及纵横向变差函数大小对反演结果的影响;随后,结合储层发育规律,模拟分析了不同维度情况下的相控条件对反演结果的影响,并通过对地震、地质和测井等信息的综合统计分析,建立了先验信息与地层砂地比的对应关系,提出了基于相控约束的地质统计学反演方法。相控地质统计学反演结果不仅具备纵向高精度的特点,而且反映的储层横向发育情况更加符合地质规律。应用效果表明,反演结果能更加准确地反映储层发育情况,合理解释油田开发阶段的注采矛盾问题,为油田的综合调整提供了重要资料基础和参考依据。

The sedimentary environment of Neogene in Bohai Oilfield is complex,and the reservoir is characterized by various type,great horizontal thickness change and shale interbeds developed widely,which seriously affects the implementation of water injection wells and adjustment wells in the oilfield development stage.Due to the limited bandwidth of the original seismic data,the resolution of reservoir prediction results based on the traditional inversion methods is difficult to meet the demand,and cannot effectively characterize the thickness and development of the reservoir.Aiming at characteristics of Neogene reservoirs in Bohai Oilfield,firstly,this paper carried out forward modeling to analyze the influence of different types of variograms and the size of vertical and horizontal variograms on the inversion results.Then the influence of different dimensional facies-control conditions on inversion results has been simulated and analyzed based on the reservoir development laws.And the relationship between prior information and sand-stratum thickness ratio was established by statistical analysis on seismic data,geological and well-logging information,so the facies-control geostatistical inversion method is proposed.The results of this facies-control geostatistical inversion method not only have high vertical resolution,but also conform to the geological laws horizontally.The application effects show that the inversion results can correctly delineate the development of the reservoirs,solve the injection-production contradiction problem during the oilfield development,and provide important data basis and reference foundations for the comprehensive adjustment of oilfield.