致密砂岩气藏水基欠平衡钻井损害评价  

EVALUATION ON THE DAMAGE DEGREE OF WATER-BASED UNDER-BALANCED DRILLING TECHNOLOGY APPLIED IN TIGHT SANDSTONE GAS RESERVOIRS

作　　者：王滢[1] 唐洪明[1,2] 谢晓永[2] 叶珏男[1] 刘岩[1] 

机构地区：[1]西南石油大学资源与环境学院,610500 [2]“油气藏地质及开发工程”国家重点实验室·西南石油大学

出　　处：《天然气工业》2008年第12期71-73,共3页Natural Gas Industry

基　　金：中国石油天然气集团公司中青年科技创新基金项目(编号:06E1019);四川省教育厅青年基金项目(编号:2006B061)的资助

摘　　要：致密砂岩气藏储层具有孔喉细小、强亲水、裂缝发育等特点,在作业过程中易于受到损害。采用水基钻井液欠平衡钻开致密砂岩气藏时,易发生逆流自吸效应及敏感性损害。这些损害究竟对致密砂岩气藏水基欠平衡钻井的储层保护效果产生多大影响,目前还没有一套完整的实验方法来模拟其对气藏的损害程度。为解决致密砂岩气藏水基欠平衡钻井的储层保护,设计了一套实验装置和实验方法来模拟水基欠平衡钻井。利用这套装置对川中某气田典型岩心进行了不同欠压值的储层损害程度评价,研究了水基欠平衡钻井的损害机理以及影响因素。实验结果表明:水基欠平衡钻井对储层损害程度弱,平均为11.8%,钻井液循环2h滤液及固相侵入深度小于1cm,侵入深度浅。为定量评价水基欠平衡钻井对储层损害程度提供了一套实用装置和方法。The tight sandstone gas reservoir is featured by tiny pore throat,strongly hydrophilicity and rich in fractures,the sensitivity of damage and back flow self absorption effect will easily happen when using the water-based under-balanced technology to spud in the tight sandstone gas reservoirs. In order to evaluate the damage degree of water-based under-balanced drilling technology applied in tight sandstone gas reservoirs and achieve better reservoir protection,this study designed a set of laboratory apparatus and experimental ways to simulate the water-based under-balanced drilling,and carried out an evaluation on the damage degree of representative core samples selected out from a certain gas field of Central Sichuan basin under different pressures. The mechanism and influencing factors of reservoir damage by the water-based under-balanced drilling were made clearly by using this evaluation method. The results demonstrate that the damage degree is low when using the water-based under-balanced drilling technology with an average ratio of 11.8%.After the water-based under-balanced drilling fluid circulates for two hours,the depth of solid phase and filtrate invasion is less than 1cm. This evaluation method has been proved to be reliable and practical.

关 键 词：欠平衡钻井 水基钻井液 致密砂岩 气藏 实验 损害 

分 类 号：TE249[石油与天然气工程—油气井工程]