水力压裂影响因素的分析与优化

Analysis and optimization of factors affecting hydraulic fracturing

劳斌斌 2　,刘月田 2,屈亚光 2,郭玲玲¹,胥小伟¹

中国石油大学石油天然气工程学院，北京 102249 中国石油大学石油工程教育部重点实验室，北京 102249

Faculty of Petroleum and Gas Engineering, China University of Petroleum, Beijing 102249, China MOE Key Laboratory of Petroleum Engineering, China University of Petroleum, Beijing 102249, China

我国很多油田中存在低渗油藏，对低渗油藏进行压裂是目前提高油藏开发效果及其采收率的有效手段。为了提高压裂措施的增产效果，以尽可能小的投资获得最大的回报，就需要对影响压裂井的因素进行分析。以理论油藏模型和某油田实际油藏模型为基础，引进了敏感系数，通过比较敏感系数绝对值的大小，对压裂井增产效果的影响因素进行了敏感性分析。压裂井油层特性的敏感性从大到小的排列顺序为：含油饱和度、孔隙度、有效厚度、地层压力、渗透率。对压裂井的参数进行了优化设计，对于低渗复杂断块油藏，人工裂缝长度为0.8倍井距时最优；针对一注一采井组，当裂缝方向与注采井连线成45°角左右时増油效果最好；油水井同时压裂时増油效果最好；相对于矩形井网，三角形井网更加适合人工压裂。

There are low permeability reservoirs in many oilfields and fracturing measures are effective means of improving the development effectiveness and recovery ratio in low permeability reservoir. The factors of influencing fractured well should be analyzed in order to improve the fracturing effect and to obtain the greatest recompense as small investment as possible. This article introduces the sensitivity coefficient on the basis of theory reservoir　model and the actual reservoir model of an oilfield. The sensitivity of influencing factors of stimulation effect for fractured well is analyzed through the comparison of absolute value of sensitivity coefficient. According to descending arrangement, the sensitivity of reservoir property in fracture well is oil saturation, porosity, effective thickness, reservoir pressure and permeability. The parameters of fractured well are optimized. Optimal artificial fracture length is 0.8 times of well spacing for the complicated fault-block reservoirs with low permeability. The stimulation effect is optimal when the connection of fracture direction and injection-production wells is 45° in view of the well group of one-well injection and one-well production. The stimulation effect is optimal when oil well and water well are fractured simultaneously. Triangular pattern is more suitable to fracturing than rectangular well pattern