碳酸盐岩裂缝性油藏酸压压降曲线分析

Pressure decline curve analysis for acid fracturing in carbonate rock fractured reservoirs

陈利 张士诚 甘云雁

CHEN Li ZHANG Shi-cheng GAN Yun-yan

中国石油大学, 北京 102249

China University of Petroleum, Changping 102249, Beijing, China

基于径向裂缝模型推导了酸压压降曲线分析模型。考虑了酸液溶蚀的碳酸盐以及酸岩反应生成的二氧化碳对人工裂缝体积的影响,针对裂缝内由二氧化碳、水、氯化钙等物质组成的高压相平衡体系,将二氧化碳真实地处理为超临界状态,其体积由适用于超临界流体的BWR状态方程求解。通过构造G函数、ψ函数可判断储层的滤失特性,确定裂缝闭合点从而得到裂缝的几何尺寸以及滤失系数等参数,进而指导酸压的施工设计和完善酸压工艺。将该方法应用到塔河油田酸压井的压降曲线分析中取得了较好的效果。

In this paper,the acid fracturing pressure decline curve analysis model is developed based on the radial fractured model,in which the effect of CO2 generated by acid soak carbonate and the interaction of acid-rock,on artificial fracture volume is taken into consideration.For the high pressure phase equilibrium system composed of CO2,H2O,CaCl2,etc.,CO2 is treated as Super Critical Fluid truly,the volume of which is estimated by BWR state equation suitable for super critical fluid.Based on estimating the type of filtration by constructed G and ψ fraction,and determining the fracture closed point,the parameters such as the geometry of fracture,the leak-off coefficient can be calculated,and furthermore it can direct the acid fracturing design and improve the acid fracturing technology.Good results have been achieved in the pressure decline analysis of the acid fracturing well in Tahe Oilfield.

10.3969/j.issn.1000-7393.2007.01.015