低渗透凝析气藏储层损害特征及钻井液保护技术  

Characteristics of formation damage and protection drilling fluids for condensate gas reservoirs with low-permeability

作　　者：耿娇娇[1] 鄢捷年[1] 邓田青[1] 鄢小琳 舒勇[3] 

机构地区：[1]中国石油大学石油工程教育部重点实验室,北京102249 [2]中国石油长城钻探工程有限公司,北京100101 [3]中国石油勘探开发研究院,北京100083

出　　处：《石油学报》2011年第5期893-899,共7页Acta Petrolei Sinica

基　　金：国家自然科学基金项目(No.50974129);国家科技重大专项(2009ZX05009-005)联合资助

摘　　要：低渗透凝析气藏储层孔喉细小,渗透性差,黏土含量高,非均质性严重,因而容易因各种入井工作液侵入储层造成水敏、水锁等损害,并经常发生其特有的反凝析损害。结合吐哈油田巴喀低渗透凝析气藏,系统分析了低渗透凝析气藏的储层损害特征。室内评价实验表明,水锁是该储层的主要损害因素之一,渗透率损害率为65.23%-91.01%。在该区原用聚磺钻井液基础上,优选可有效降低油/水界面张力的表面活性剂,应用成膜技术与理想充填＂协同增效＂的储层保护新方法,优化设计出保护储层低损害钻井液;通过开展配伍性、动态污染等实验对该钻井液的储层保护特性进行了评价。室内实验结果表明,该钻井液具有良好的流变性与配伍性,可使储层岩心的渗透率恢复值从63.2%增至84.7%,具有明显的储层保护效果。Condensate gas reservoirs with low-permeability are characterized by a tiny size of pore throats,poor permeability,high content of clay minerals and severe heterogeneity.Therefore,this type of reservoirs is susceptible to the damage of water sensitivity,water blocking,etc.caused by invasion fluids,and frequently to the damage of specific retrograde condensation.We analyzed mechanisms of formation damage systematically based on reservoir characteristics of the Baka condensate gas reservoir with low-permeability,the results showed that water blocking was the major damage to this reservoir and the damage ratio induced by water blocking ranged from 65.23% to 91.01%.On the basis of the sulphonic polymer drilling fluid previously used in this area,surfactants capable of effectively reducing the interfacial tension of oil/water contact were optimized,a new protection method characteristic of ＂synergetic effectiveness＂ by combining film forming with ideal packing was adopted,and consequently a drilling fluid with low damage was developed.The protection effect of this fluid on reservoirs was verified in compatibility tests and dynamic damage tests.The results showed that this fluid was of excellent rheological performance and compatibility,being capable of increasing the returned value of core permeability from 63.2% to 84.7% and of distinct protection of reservoirs.

关 键 词：低孔隙低渗透 凝析气藏 反凝析损害 低损害钻井液 储层保护 

分 类 号：TE258[石油与天然气工程—油气井工程]