页岩气藏压裂水平井物质平衡模型的建立

Study on the Establishment of Material Balance Model for Fractured Horizontal Well in Shale Gas Reservoir

郭小哲 李景 张欣

GUOXiaozhe LIJing ZHANGXin

中国石油大学(北京)石油工程学院, 北京 昌平 102249 中国石油玉门油田勘探开发研究院, 甘肃 酒泉 735000 兰石能源装备工程研究院, 山东 青岛 266000

School of Petroleum Engineering, China University of Petroleum(Beijing), Changping, Beijing 102249, China Research Institute of Exploration and Development, Yumen Oilfield, PetroChina, Jiuquan, Gansu 735000, China Lanshi Energy Equipment Engineering Institute, Qingdao, Shandong 266000, China

针对页岩气藏压裂水平井中裂缝、基质、游离气和解吸气等对产气量贡献比例定量计算的难点问题，开展了动态渗流分区的物质平衡模型的建立与分析研究，研究中采用了不同渗流区域内压力降传播速度及平均地层压力的计算方法，进行了动态渗流分区设计，给出了压裂液返排后储层受渗吸作用的含水饱和度计算方法，建立了由12项构成的综合物质平衡方程。通过模型的实例应用与分析，获得了气井生产的7个渗流阶段，揭示了不同生产时间的供气结构比例变化规律，认识到基质储层的游离气是气井长期生产的主要供给气来源，其次是解吸气。模型的建立简化了多尺度渗流方程的描述和复杂求解过程，为理论分析和现场应用提供了一种新的方法，也为深入理解和研究页岩气藏渗流特征提供了依据。

To solve the difficulty in calculating the contributions of fractures, matrix, free gas, and desorbed gas to gas output, the establishment of and an analytical study on static seepage sub-regions were carried out in this work. A dynamic seepage sub-region was designed. A calculation method for reservoir water saturation under the effect of imbibition after fracturing fluid flow back was determined by calculating the propagation speed of the pressure drop and the average formation pressure in different seepage zones, with an integrated material balance equation consisting of 12 items. A total of seven seepage stages of gas well production was obtained by means of model case application and analysis. This revealed the variation law of air supply structure and proportion during different production times and the fact that it was the free gas of the matrix reservoir; and that desorbed gas was the major factor that maintained long-term production of gas wells. Establishment of the model simplified the description and solution procedure of the complex multi-dimensional seepage equation. This provides a new approach for theoretical analysis and field application, as well as a basis for in-depth understanding of and study on seepage characteristics of shale gas reservoirs.

10.11885/j.issn.1674-5086.2015.08.05.02