酸压拟三维压降分析模型

Pseudo three dimension acid fracturing pressure decline curve analysis model

黄万书 胡永全 赵金洲

西南石油大学研究生院，四川 成都 610500 西南石油大学油气藏地质及开发工程国家重点实验室，四川 成都 610500

Graduate School of Southwest PetroleumUniversity,Chengdu 610500, China曰2. State Key Lab of Oil& Gas Reservoir Geology and Exploitation, Southwest PetroleumUniversity,Chengdu 610500,China

随着油气藏酸化压裂技术的发展和应用，压裂后裂缝诊断、评估技术越来越受到广泛重视，但是目前针对酸压井压后裂缝参数的诊断、评估和解释模型还研究甚少。基于水力压裂的拟三维模型，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。实例分析表明，压降模型解释酸压井的滤失系数和裂缝几何参数更接近地层的真实情况，可以为酸压技术的设计和评价提供依据。

With the development of acid fracturing technologies, the post-frac diagnostic and evaluation techniques become more and more important. However, few researches have been done in these areas. In this paper, the acid fracturing pressure decline curve analysis model is developed based on the pseudo three dimension (PTD) hydraulic fracturing model, in which the effect of carbon dioxide 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 carbon dioxide, water and calcium chloride etc., carbon dioxide is
treated as super critical fluid truly. The analysis of this case shows that the filtration coefficient and fracture geometry parameters, interpreted from this model, are more close to the formation condition, which can provide criteria for acid fracturing design and evaluation.