多级酸压在超深裂缝型碳酸盐岩水平井的应用

塔里木油田奥陶系碳酸盐岩油藏以裂缝、溶蚀孔洞为主要储集空间，具有超深、高压和高温的特点。裂缝以中－高角度缝为主，既是储集空间又是主要的流动通道，孔喉配合度低，连通性差，需要酸压才能建产。影响酸压效果的主要因素是长裸眼井段酸压方式的选择以及酸蚀裂缝是否沟通有效缝洞储集体。针对以上难点，开展了各级酸蚀裂缝长度、导流能力、施工规模、前置液比例和排量等参数优化，优选压裂液和酸液，形成差异化的多级酸压优化设计方案。现场施工效果表明，设计参数合理、有效，多级酸压技术适用于超深裂缝性碳酸盐岩油气藏的增产改造。

Application of Multistage Acid Fracturing Technology for Horizontal Well to Ultra-Deep Fractured Carbonate Reservoirs

The Ordovician carbonate reservoir in Tarim oilfield is dominated by fractures and solution pores and cavities and characterized by ultra?deep, high pressure and high temperature, of which the most fractures with medium?high angle are as both reservoir spaces and the main flow channels. But since such a reservoir is of low pore?throat coordination and poor connectivity, acid fracturing process has to be needed to build its productivity. The main factors affecting the effect of acid fracturing include the selection of acid fracturing process for the long openhole interval and that the acid?etching fractures can communicate the effective fracture?cave reservoir or not. For these reasons, this paper conducts such parameters optimizations as acid?etching fracture length, fluid conductivity, stimulation scale, prepad fluid ratio and expelling amount, etc., and then selects the fracturing and acid liquids to form a differentiated and multistage acid fracturing optimization design scheme. The field application indicates that the designed parameters are reasonable and effective, and the multi?stage acid fracturing technology is suitable for stimulation of the ultra?deep fractured carbonate reservoirs