基于多参数敏感性分析的试井设计方法研究与应用  

Research and application of well test design method based on multi-parameter sensitivity analysis

作　　者：于伟强 毛敏 杨毅 赵洪绪 杨志成 张国浩 YU Weiqiang;MAO Min;YANG Yi;ZHAO Hongxu;YANG Zhicheng;ZHANG Guohao(China France Bohai Geoservices Co.,Ltd,Tianjin 300457,China;CNOOC China Limited,Tianjin Branch,Tianjin 300459,China)

机构地区：[1]中法渤海地质服务有限公司,天津300457 [2]中海石油(中国)有限公司天津分公司,天津300459

出　　处：《中国海上油气》2023年第1期89-97,共9页China Offshore Oil and Gas

摘　　要：在压力恢复测试之前进行试井设计,可以有效指导测试方案,但设计参数选取不合理,特别是多个不确定性参数叠加影响时,可能会导致测试资料有效性和解释准确度差。从试井压力和压力导数设计出发,研究了多重不确定性设计参数的Sobol采样方法,建立了基于时间序列的全局敏感性分析总效应指数计算方法,并以“均质油藏+一条不渗透边界”为例介绍了其在试井设计中的应用过程。研究表明,在某个时间段当某参数的总效应指数占绝对优势时,说明压力导数的不确定性主要来自该参数,完成对应时间段测试即可实现参数解释;若某参数的总效应指数非常小,说明压力导数对其敏感性很低,可赋固定值进行降维处理;若各参数的总效应指数都没有绝对占优,则需利用其他时间段进行辅助判断。利用本方法对海上S气井进行了试井设计,得到基于测试时间的总效应指数,显示关井测试260 h可出现径向流的概率在90%以上,实际测试在230 h出现径向流特征,且曲线形态基本一致,验证了本方法的正确性和可靠性。Well test design before build-up test can effectively guide the test scheme, but if the selection of design parameters is unreasonable, especially when multiple uncertain parameters are superimposed, it may lead to poor effectiveness of test data and accuracy of interpretation results. Based on the design of well test pressure and pressure derivative, the Sobol sampling method of multiple uncertain design parameters is studied, and the calculation method of total effect index of global sensitivity analysis based on time series is established. Taking "homogeneous reservoir + impermeable boundary" as an example, its application process in well test design is introduced. The research shows that when the total effect index of a parameter is absolutely dominant in a certain period of time, it shows that the uncertainty of the pressure derivative mainly comes from the parameter, and the parameter interpretation can be realized by completing the test in the corresponding period of time;If the total effect index of a parameter is very small, it indicates that the sensitivity of pressure derivative to it is very low, and a fixed value can be assigned to reduce the dimension;If the total effect index of each parameter is not absolutely dominant, other time periods need to be used for auxiliary judgment. Using this method, the well test design of offshore S gas well is carried out, and total effect index based on test time is obtained. The results show that when the shut-in test lasts for 260 hours, the probability of radial flow is more than 90%. The actual test shows that the radial flow characteristics appear in about 230 hours, and the curve shape is basically the same, which verified the correctness and reliability of this method.

关 键 词：试井设计 不确定性参数 全局敏感性分析 时间序列 总效应指数 现场应用 

分 类 号：TE353[石油与天然气工程—油气田开发工程]