低渗多敏感性油藏酸化增注配方的研制

Development of acidification and annotation formula for low permeability and multisensitivity reservoir

低渗油藏文33块沙三上油藏存在速敏、水敏及酸敏等多种敏感性,采取常规酸化措施增注效果不明显。针对此问题,通过岩心溶蚀率、骨架破碎率与二次沉淀定量评价,优选出弱敏感的无机酸与有机酸,并将其复合,添加黏土稳定剂、铁离子稳定剂等添加剂,形成了弱敏感增注配方。该配方中少量的氢氟酸能够减少水化硅等二次沉淀,潜在酸A适于较强速敏的试验油藏,有机酸以及铁离子稳定剂与黏土稳定剂的加入减小了酸敏及水敏造成的伤害。该酸液的二次沉淀量为常规土酸的1/12、防膨率达81.3%、稳定铁离子能力达140.7 mg/mL,性能较好。

There are many sensitive factors in the oil reservoirs in S3 upper intervals in low permeability reservoir Block Wen 33,such as velocity sensitivity,water sensitivity,and acid sensitivity,etc.The effect of increasing injection by conventional acidification measures is not obvious.In view of this problem,weakly sensitive inorganic and organic acids were selected and compounded through the quantitative evaluation of core dissolution rate,broken rate of skeleton and secondary precipitation.Additives such as clay stabilizer and iron ion stabilizer were added to form a weakly sensitive injection formulation.The low concentration hydrofluoric acid in this formula can reduce secondary precipitation such as hydrated silicon,etc.Potential acid A is suitable for strong speed sensitive test reservoirs.The addition of organic acids,iron ion stabilizers and clay stabilizers reduce the damage caused by acid sensitivity and water sensitivity.The 1/12 of secondary precipitation amount of conventional soil acid,anti-swelling rate 81.3%,and the iron ion stability 140.7 mg/mL shows this acid solution has good properties.