库车裂缝性砂岩气藏渗透率模型研究与应用

裂缝性气藏中孔隙介质包括压裂裂缝、天然裂缝及基质孔隙。考虑裂缝与基质间的物质交换,建立了考虑压裂裂缝的多重孔隙介质渗流数学模型,研制了裂缝性气藏压裂后生产动态模拟器。根据库车天然裂缝发育程度综合量化分类,天然裂缝发育程度是影响压裂后产能的重要因素之一;裂缝系统连通差、发育差的气藏,压裂后也难以获得理想的增产效果。统计分析了裂缝参数与渗透率的关系,裂缝密度与测试渗透率相关性好,给出了裂缝密度与渗透率的关系,建立了渗透率地质模型。结合裂缝性砂岩气藏压裂井生产动态模拟器,通过拟合试采压力校正渗透率,打破了关井测试计算地层渗透率的传统做法。通过实例计算表明,所建立的多重介质渗流数学模型和渗透率地质模型是合理的,试采压力拟合精度高,校正渗透率准确且误差较小,为油田开发提供了一种新思路。

Research and application of fractured sandstone gas reservoir permeability model in Kuqa

Fractured gas reservoir includes artificial fracturing, natural fractures and matrix. Considering material exchange between cracks and the matrix system, multiple media flow mathematical model is established, and dynamic production simulator of fracturing gas reservoir is developed. According to the comprehensive quantitative classification of natural fractures in Kuqa, the development degree of natural fractures influences production capacity. Because fracture system connectivity is poor, it is difficult to get a good yield after fracturing. According to statistical analysis of the relationship between the fracture parameters and permeability, fracture density and testing penetration have good relevancy, then the relationship between fracture density and permeability is given, permeability geological model is established. Using dynamic production simulator of fracturing gas reservoirs, it corrects the permeability by fitting the pressure of pilot production, which breaks the traditional practice of calculating formation permeability through shut-test. The examples show the established multi-media flow mathematical model and permeability geological model are reasonable and accurate.