大尺度缝洞型碳酸盐岩油藏弹性开采特征分析

CHARACTERISTIC ANALYSIS OF ELASTIC DEVELOPMENT IN LARGE SCALE FRACTURED-VUGGY CARBONATE RESERVOIRS

针对单井钻遇大尺度溶洞型油藏有底水或溶洞窜流供给情况下的弹性开采，以弹性理论和渗流理论为基础，建立了室内物理模型。通过理论分析，推导了该类型油藏累计产量与累计压降关系式，分析了累计产量与累计压降关系曲线特征。结果表明：累计产量与累计压降关系曲线具有前期直线、中期上翘、后期又呈直线的特征，第一直线段的斜率表征与井连通的主洞体积的大小和综合压缩系数，上翘段幅度体现着主洞体积、窜流能量及裂缝导流能力的综合影响，第二直线段也体现着主洞体积、窜流能量及裂缝导流能力。通过物理实验验证了理论分析的正确性，并进行了实例应用分析，对现场具有一定的指导意义。

Aiming at the elastic development of large scale cavity reservoir which has the bottom water and cave channeling supply while drilling by single well, a laboratory physical model is established based on elastic theory and filtration theory. Through the theoretical analysis, the relational expression of cumulative production and cumulative pressure drop of this kind of reservoir is derived, and meanwhile the characteristic curve of the relationship between cumulative production and cumulative pressure drop is analyzed. The result shows that： the relation curve of cumulative production and cumulative pressure drop has the feature of being straight at early period, upward at middle period and straight again at late period. The slope of the first linear portion represents the volume of the main cavity connected with wells and the comprehensive compressibility coefficient. The amplitude of the upward portion represents the comprehensive influences of main cavity volume, channeling energy and fracture conductivi- ty. The second linear portion represents the main cavity volume, channeling energy and fracture conductivity. The validity of the theoretical analysis has been verified through physical experiments, and meanwhile an application analysis of a case is conducted, which has certain guiding significance for field.