碱性工作液对含酸性气碳酸盐岩储层的损害机理

以哈萨克斯坦扎纳若尔油田和中国四川盆地中部及东北部地区含酸性气碳酸盐岩储层岩心为研究对象,开展了流体敏感损害实验。结果表明,岩心均存在一定程度的流体敏感性,尤以碱敏损害最为严重。经岩相学分析,研究地区碳酸盐岩储层发育黏土矿物、白云石、方解石、微晶石英、石膏、硫化钙、沥青等敏感矿物。高pH值工作液侵入储层后,使原始酸性环境改变,碱液中和酸性流体并破坏流体-岩石界面,致使储层岩石中敏感矿物更多地暴露并发生物理化学变化而引起更为强烈的储层损害,同时碱性工作液侵入,改变了硫的附存环境,引起硫沉积损害。针对储层损害机理,建议钻井完井作业时,采用屏蔽暂堵技术以有效保护储层。

Damage Mechanism Among Rock Interface,Acid Gas and Alkaline Fluids in Carbonate Gas Reservoirs

Based on the cores of carbonate reservoir with high content H_2S and CO_2 gas in Kazakhstan Zhanazhol,middle and northeast parts of Sichuan Basin of China,the fluid sensitive experiments was carried out.Results showed that there was certain fluids sensitivity in cores,and alkali sensitivity was the most serious.Petrography analysis indicated that dol omite,calcite,microcrystalline quartz,gypsum,CaS,asphalt are common in the carbonate reservoir.Alkali working fluids invaded into the reservoir and changed its...