海上160 ℃高温砂岩气藏螯合酸解堵体系的研制与现场应用

Development and Field Application of Chelating Acid System for Formation Damage Remove In 160 ℃ High-temperature Offshore Sandstone Gas Reservoirs

程宇雄 彭成勇 武广瑷 史伟奇 陈明贵 姜 浒 吴百烈

CHENG Yuxiong PENG Chengyong WU Guang’ai SHI Weiqi CHEN Minggui JIANG Hu WU Bailie

海上WC油田160 ℃高温砂岩油气藏酸化中，黏土矿物如伊利石在盐酸中水化分解造成微粒运移和储层伤害，导致油气井产能降低。为解决常规土酸高温反应快、伊利石敏感、酸液穿透距离短的问题，通过高温岩心溶蚀、岩心流动和产出液体离子分析等实验，优选出5% GLDA+8%乙酸+1% HF+1.5%黏土稳定剂NW-1+1%缓蚀剂CT-1的螯合酸体系。该酸液体系在 160 ℃下反应 16 h后的溶蚀率为 15.2%，对N80 钢片的腐蚀速率为3.7451 g/（m2·h），防膨率为 90.9%，酸液与岩心作用后 Si4+、Ca2+、Mg2+、Fe3+含量逐渐增加，说明螯合酸具有多价金属离子螯合作用，避免了酸液对岩心的二次和三次伤害，实现酸液对地层深部穿透的作用。针对螯合酸酸化设计没有成熟的专业软件，使用简化的酸岩反应平面径向流模型，考虑氢氟酸的物质平衡，用MATLAB 语言编制了螯合酸酸化模拟设计软件，计算A井优选酸注入排量为2 m3/min，每段酸液用量不超过 70 m3。使用螯合酸体系对海上5口注水井成功实施了酸液解堵措施，措施后平均日增注量均达到了110 m3以上，注水压力下降明显，最高降压12 MPa。该螯合酸体系对160 ℃高含伊利石砂岩气藏具有良好的解堵增注效果。

During the acidification of 160 ℃ high temperature sandstone reservoirs in offshore WC oilfield，the clay minerals such as illite are hydrated and decomposed in hydrochloric acid，causing particle migration and reservoir damage，resulting in reduced productivity of oil and gas wells. To solve the problems of fast reaction at high temperatures，sensitivity of illite clay，and short penetration distance of conventional mud acid，experiments such as high-temperature acid dissolution，core flooding，and produced liquid ions analysis were carried out，and a high-temperature resistant chelating acid，composed of 5% GLDA+8% acetic acid+1%HF+1.5% clay stabilizer NW-1+1% corrosion inhibitor CT-1，was proposed. The chelating acid achieved a dissolution rate of 15.2% at the temperature of 160 ℃ for 16 hours，a corrosion rate of 3.7451 g/（m2·h），and an anti-swelling rate of 90.9% . After the chelating acid interacted with the rock core，Si4+，Ca2+，Mg2+，and Fe3+ content gradually increased，indicating that the chelating acid had a multivalent metal ion chelating effect，which could avoid secondary and tertiary damage to the rock core by the acid solution，achieving the effect of the acid dissolution on deep penetration of the formation. In response to the lack of mature professional software for chelating acid acidification design，a simplified acid rock reaction plane radial flow model was used， considering the material balance of hydrofluoric acid，a chelating acid acidification simulation design software was developed using MATLAB language. The optimal acid injection rate for Well A was calculated to be 2 m3/min，and the volume of acid used in each section did not exceed 70 m3. The chelating acid system was successfully used to remove blockages in 5 offshore water injection wells. After the measures，the average daily injection volume increased by more than 110 m3，and the injection pressure decreased significantly，with a maximum pressure drop of 12 MPa. The chelating acid system had a good effect on removing blockages and increasing injection in the 160 ℃high illite sandstone gas reservoir.

10.19346/j.cnki.1000-4092.2025.01.009