莺歌海盆地地层超压成因与定量评价方法  

A quantitative evaluation method for predicting polygenetic overpressure in Yinggehai Basin

作　　者：郭书生 陈现军 廖高龙 王世越 赵凯[3] GUO Shusheng;CHEN Xianjun;LIAO Gaolong;WANG Shiyue;ZHAO Kai(CNOOC China Limited,Hainan Branch,Haikou 570312,China;Zhanjiang Branch of China France Bohai Geoservices Company Limited,Zhanjiang 524057,China;College of Petroleum Engineering,Xi an Shiyou University,Xi an 710065,China)

机构地区：[1]中海石油(中国)有限公司海南分公司,海南海口570312 [2]中法渤海地质服务有限公司湛江分公司,广东湛江524057 [3]西安石油大学石油工程学院,陕西西安710065

出　　处：《中国石油大学学报（自然科学版）》2022年第6期143-148,共6页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：国家自然科学基金项目(52074224)。

摘　　要：地层超压的复合成因是莺歌海盆地地层的重要特征之一,由于缺乏复合成因的孔隙压力计算方法,极大地影响了随钻孔隙压力的预测精度。利用多井测井曲线组合法、Bowers声波-密度交会图法对莺歌海盆地地层超压成因进行识别;开展轴压和围压条件下的室内三轴压缩试验,得到考虑岩石卸载密度变化的加载、卸载特征方程;通过孔隙压力与密度关系,建立复合成因超压中单成因贡献率的数学模型,实现多成因条件下单成因定量计算。结果表明:乐东A井复合超压中以卸载型超压为主,其对孔隙压力的贡献率为40.9%;该定量评价方法有助于掌握目标区域地层超压的主要成因及其贡献率,可为提高孔隙压力预测的精度提供新途径。The polygenetic formation overpressure is one of the important characteristics in Yinggehai Basin.Due to the lack of effective pore pressure calculation methods,the prediction accuracy of pore pressure while drilling is greatly affected.In this paper,firstly,the causes of the formation overpressure in Yinggehai Basin were analyzed using the logging curve combination method,the Bowers method,and the acoustic-density cross-plot method.Indoor tri-axial compression experiments under axial pressure and confining pressure were also carried out,in order to figure out the loading and unloading characteristic equations considering the change of rock unloading density.Secondly,based on the relationship between pore pressure and bulk density,a mathematical model considering monogenetic contribution rates for the polygenetic overpressure was established,and the monogenetic quantitative calculations under polygenetic conditions were achieved.It is determined that unloading overpressure is the main part of the polygenetic overpressure in Ledong well A,and its contribution rate to the total pore pressure is of 40.9%.The quantitative evaluation method can be useful to understand the main causes and contribution rate of the formation overpressure in the target area,providing a new means to improve the accuracy of pore pressure prediction.

关 键 词：莺歌海盆地 复合成因超压 单成因贡献率 定量评价 

分 类 号：TE12[石油与天然气工程—油气勘探]