酸压过程中酸蚀裂缝导流能力研究

ACID ETCHED FRACTURE CONDUCTIVITY STUDY IN ACID FRACTURING

酸蚀裂缝导流能力是影响酸压效果的关键参数之一。由于酸岩反应随机性强,酸蚀裂缝导流能力难以准确预测。影响酸蚀裂缝导流能力的因素较多,采用自行研制的DP-I型裂缝导流能力试验仪,综合研究了岩石嵌入强度、闭合应力、酸液用量、酸接触时间、酸液滤失以及注酸排量等主要因素对酸蚀裂缝导流能力的影响。在理论计算模型方面,迄今为止主要包括N—K模型、Gangi"钉床"模型、Walsh模型、Tsang&Witherspoon孔隙模型和GongM模型,文章对各种计算模型进行了综合分析,就目前而言,国内外仍主要采用N-K经验关系式来预测酸蚀裂缝导流能力,其他模型因为所需参数难以确定,无法在实际中应用。

The acid etched fracture conductivity is one of the key parameters to affect acid fracturing.Due to the high randomness for acid-rock reaction,it is difficult to predict the acid etched fracture conductivity.The factors of affecting the acid etched fracture conductivity are more.In this paper,the influence of rock embedment strength,closure stress,acid volume,acid-rock contact time,acid leakoff and injection acid rate on the acid etched fracture conductivity was comprehensive analyzed by adopting the DP-I fracture conductivity test equipment.Up to now,theory calculation models including N-K model,Gangi model,Walsh model,Tsang& Witherspoon model and Gong M model were synthetically analyzed in this paper.At present,the N-K model is often used to predict the acid etched fracture conductivity,the other models isn't used in practical application because they are difficult to determine the parameters.