井洞相连的串珠状缝洞型油藏试井分析方法  

Well test analysis method for fracture-cavity reservoirs of beads-on-string structure with wellbore-cave connection

作　　者：魏操 程时清[1] 李宗泽 宋佳忆 汪洋[1] 吴嘉鑫 WEI Cao;CHENG Shiqing;LI Zongze;SONG Jiayi;WANG Yang;WU Jiaxin(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing City,102249,China;Offshore Oil Engineering Co.,Ltd.,Tianjin City,300461,China;China National Aviation Fuel Southwest Storage and Transportation Co.,Ltd.,Chongqing City,401254,China)

机构地区：[1]中国石油大学(北京)油气田开发与地质国家重点实验室,北京102249 [2]海洋石油工程股份有限公司,天津300461 [3]中航油西南储运有限公司,重庆401254

出　　处：《油气地质与采收率》2022年第6期85-94,共10页Petroleum Geology and Recovery Efficiency

摘　　要：顺北油田包含溶洞、高角度裂缝、溶蚀孔洞和岩石基质4种储集介质,溶洞与高角度裂缝串联形成垂向串珠状缝洞体是常见的缝洞连通模式,钻井过程中经常出现钻柱放空和泥浆漏失的现象,这些复杂的地质和工程因素导致常规的多重介质模型难以拟合实测的试井数据。提出多个溶洞区域和裂缝区域串联的物理模型表征复杂的垂向串珠结构,溶洞区域仅包含溶洞介质,流体遵守自由流,裂缝区域包含高角度裂缝、溶蚀孔洞和基质,流体遵守达西定律,进而建立井洞相连的串珠状缝洞体试井模型,绘制试井典型图版,进行参数敏感性分析。结果表明:溶洞储集阶段和线性流阶段是串珠状缝洞体的典型流动阶段;根据试井压力导数曲线的斜率能识别溶洞和常规多重介质;重力影响下试井典型曲线会出现类似于封闭边界的压力响应特征,应采取措施降低重力的影响以提高串珠状缝洞体的开发效果。最后,应用所建模型解释了顺北油田典型井,除能解释常规的储层参数外,还能反演现有试井方法无法解释的溶洞等效半径、溶洞等效高度等参数。Shunbei Oilfield contains four types of storage media(i.e.,caves,high-angle fractures,vugs,and rock matrix).The vertical beads-on-string structure formed by caves and high-angle fractures in series is a common fracture-cavity con⁃nection pattern.During drilling,drilling break and mud loss are prone to occur.These complex geological and engineering factors make it difficult for traditional multiple media models to fit the measured well test data.This paper proposes a physi⁃cal model with multiple cave regions and multiple fracture regions in connection in series to characterize the complex verti⁃cal beads-on-string structure.The cave regions only contain caves in which the fluids are assumed to obey free flow.The fracture regions contain high-angle fractures,vugs,and rock matrix in which the flow obeys Darcy’s law.On this basis,the paper constructs a well test model for the beads-on-string structure with a wellbore-cave connection,draws type curves,and conducts a parameter sensitivity analysis.The following results are obtained:the cave storage regime and linear flow re⁃gime are the typical flow stages of vertical beads-on-string structure;the caves and conventional multiple media can be dis⁃tinguished by the slope of pressure derivative curves;the type curves under the influence of gravity show pressure response characteristics similar to a closed boundary,so the measures should be taken to reduce the influence of gravity for improv⁃ing the development effect of the vertical beads-on-string structure.Finally,the proposed model is applied to interpret the representative wells in Shunbei Oilfield.Besides the conventional reservoir parameters,the parameters that cannot be inter⁃preted by existing well test methods can also be obtained by inversion,such as equivalent cave radius and equivalent cave height.

关 键 词：溶洞 垂向串珠状缝洞体 重力 封闭边界 顺北油田 

分 类 号：TE353[石油与天然气工程—油气田开发工程]