南海北部湾A油田水力脉冲酸化技术研究与应用

Study and Application of Hydraulic Pulse Acidification Technology in Beibu Gulf A Oilfield of South China Sea

摘要: 针对南海西部南海北部湾A油田高温高盐储层特征，开展定向水力脉冲酸化技术研究，重点探讨了常规酸化体系在水平井应用中存在的酸岩反应不可控、管柱腐蚀严重、摩阻损失大及二次伤害风险高等技术瓶颈。通过开展酸液溶蚀性试验、酸岩反应速度测试、酸液腐蚀速度测试、酸岩反应产物及状态分析以及酸液降阻率测试，同时开展酸液配伍性、表面张力、稳铁、防膨、破乳等常规性能评价，优化设计酸液配方。根据实验结果构建酸化配方：12%盐酸 + 2%氢氟酸 + 3% AC + 0.5% AB较为适合北部湾储层，酸后岩心孔隙度提高3.6倍，连通孔隙比例提高了26.6%，孔喉半径峰值提高25%，储层物性的改善与黏土矿物的降低具有的相关性。研究成果为海上深层低渗油藏高效开发提供了新型酸化解决方案，现场试验阶段单井最大超配产82%，具有显著的技术经济价值。

Abstract: This study is aimed at the characteristics of high-temperature and high-salt reservoir in Beibu Gulf A Oilfield in the western part of South China Sea, and carries out the research on directed hydraulic pulse acidizing technology. Based on the engineering characteristics of reservoir physical properties, mineral composition and horizontal well section length in the target block, the study focuses on overcoming the technical bottlenecks of conventional acidizing system in horizontal well application, such as uncontrollable acid-rock reaction, serious corrosion of tubing and columns, large friction loss, and high risk of secondary injury. We optimize the design of acid formulation by conducting acid corrosivity test, acid rock reaction speed test, acid corrosion speed test, acid rock reaction product and state analysis and acid resistance reduction rate test, and at the same time, we carry out the evaluation of acid compatibility, surface tension, iron stabilization, anti-expansion, emulsion breakage and other conventional performance. According to the experimental results, the acidizing formula: 12% hydrochloric acid + 2% hydrofluoric acid + 3% AC + 0.5% AB is more suitable for Beibu Gulf reservoir, the porosity of the core increased by 3.6 times after the acid, the proportion of connected pores increased by 26.6%, and the peak pore-throat radius increased by 25%, and the correlation between improvement of the physical properties of the reservoir and the reduction of clay minerals was found. The research results provide a new type of acidizing solution for the efficient development of offshore deep low-permeability reservoirs, and the maximum over-allocated production of a single well is 82% in the field test stage, which has significant technical and economic value.