缝洞型油藏井钻遇大尺度部分充填溶洞数学模型  

Mathematical Model for Wells Drilled in Large-Scale Partially Filled Cavity in Fractured-Cavity Reservoirs

作　　者：雷刚[1,2] 张东晓[1,2] 杨伟[2] 王会杰[2] 

机构地区：[1]北京大学工程科学与新兴技术高精尖创新中心,北京100871 [2]北京大学工学院,北京100871

出　　处：《地球科学（中国地质大学学报）》2017年第8期1413-1420,共8页Earth Science-Journal of China University of Geosciences

基　　金：国家科技重大专项(No.2016ZX05014004-006);中国博士后科学基金项目(No.2017M610706)

摘　　要：缝洞型油藏不同介质间流体窜流的研究对于大尺度溶洞中原油是否能够得到有效开发具有重大意义.基于缝洞型油藏大尺度溶洞充填特征,建立了井钻遇大尺度部分充填溶洞数学模型,采用Laplace变换和Stehfest数值反演,分别得到了基岩-溶洞未充填区域窜流量、溶洞充填区域-溶洞未充填区域窜流量和大尺度溶洞无因次流量,并分析了不同参数对窜流特征曲线的影响.研究结果表明:流体窜流过程可划分为4个流动阶段,流动前期和中前期主要为基质中流体向溶洞未充填部分窜流;流动中后期和后期主要为溶洞充填物流体向溶洞未充填部分窜流.在流动前期,基质和未充填溶洞间流体交换对部分充填溶洞流量贡献较大;而流动后期,溶洞充填物和未充填溶洞间流体交换对部分充填溶洞流量贡献较大.重力会导致溶洞充填物-溶洞未充填部分窜流量减小,而基质-溶洞未充填部分窜流不受到重力影响.溶洞充填程度、溶洞未充填部分和基质系统能量等因素对窜流特征曲线具有重大的影响.研究方法和结果对合理分析缝洞型油藏大尺度溶洞流动特征具有一定的指导意义.It is significant to explore fluid crossflow rule of various medium in fractured-cavity reservoirs for effective development of crude oil in large-scale partially filled cavity.Based on the filling characteristics of the large size cavity in fracturedcavity reservoir,a fluid flow mathematical model for wells drilled in large-scale partially filled cavity in fractured-cavity reservoir has been proposed in this paper.The Laplace transformation and Stehfest numerical inversion are applied to analyze the crossflow rule in the partially filled cavity.The fluid crossflow characteristic curve for the partially filled cavity has been obtained and studied in this paper.The results show that the process of the flow for the partially filled cavity can be divided into four sections,including the earlier period and middle-early period flow for the crossflow between the matrix system and unfilled part of the cavity,the middle-late period and the later period flow for the crossflow between the filler of the cavity and unfilled part of the cavity.In middle-early flow period,the crossflow between the matrix system and unfilled part of the cavity reaches the quasi steady state.And the crossflow between the filler of the cavity and unfilled part of the cavity reaches the quasi steady state at the later period.Gravity is one of the main factors that influences the typical crossflow characteristic curve,leading to the decrease of the crossflow between the filler and the unfilled part of the cavity.However,the inter-porosity flow between the matrix and the unfilled part of the cavity has no relation with gravity.In addition,the cross flow characteristic curve is greatly affected by filling degree of the cavity,the energy parameters of the filler of the cavity and the energy parameters of the matrix.The methods and results of this research can facilitate further studies on the crossflow characteristics of the partially filled cavity in fractured-cavity reservoirs.

关 键 词：缝洞型油藏 大尺度溶洞 充填特征 窜流特征曲线 参数分析 石油地质 

分 类 号：P345[天文地球—水文科学]