裂缝性致密变质岩气藏钻井液漏失损害机理  

Mechanisms of Formation Damage by Lost Drilling Fluids in Fractured Tight Metamorphic Rock Gas Reservoirs

作　　者：游利军[1] 邹俊 康毅力[1] 白瑞婷 刘玉明 谭伟雄 李鑫磊 YOU Lijun;ZOU Jun;KANG Yili;BAI Ruiting;LIU Yuming;TAN Weixiong;LI Xinlei(State Key Laboratory of Oil and Gas Reservoir Geology and Development Engineering,Southwest Petroleum University,Chengdu,Sichuan 610500;CNOOC China Limited,Tianjin Branch,Tianjin 300459)

机构地区：[1]西南石油大学油气藏地质及开发工程国家重点实验室,成都610500 [2]中海石油(中国)有限公司天津分公司,天津300459

出　　处：《钻井液与完井液》2024年第6期719-727,共9页Drilling Fluid & Completion Fluid

基　　金：非常规油气层保护四川省青年科技创新研究团队项目“页岩气层氧化协同水力压裂减量增渗方法研究”(2021JDTD0017)。

摘　　要：裂缝性致密储层基块岩样致密、天然裂缝发育,钻井液漏失易诱发储层损害,堵塞孔喉与裂缝,降低储层渗流能力,阻碍油气井稳产。以渤海湾盆地某区块潜山裂缝性致密变质岩储层为研究对象,开展了流体敏感性、钻井液动态损害、钻井液滤饼承压评价实验,明确了钻井液的动态损害程度和滤饼承压能力,分析了储层流体敏感损害机理。结果表明:储层基块强盐敏、中等偏弱碱敏和弱水敏;钻井液固相颗粒粒度与储层裂缝开度不配伍导致固相颗粒侵入储层深部堵塞裂缝造成储层损害,钻井液体系对裂缝宽度在150μm及以下的裂缝具有良好的封堵效果,对300μm及以上的裂缝封堵效果较差;裂缝性致密变质岩储层黏土矿物和重矿物发育,钻井液漏失导致黏土矿物水化膨胀和微粒运移,与重矿物反应生成氢氧化铁沉淀加剧储层损害。变质岩储层应强化300μm及以上宽度裂缝保护,重视变质岩与工作液作用诱发的储层损害,最后提出了地层损害保护措施。When drilling into a naturally fractured tight reservoir,mud losses into the fractures can easily induce reservoir damage,block the pore throats and fractures in the reservoir formation,thereby reducing the permeability of the reservoir and hindering the stable production of oil and gas.In this study,the buried hill fractured tight metamorphic rock reservoir in a block in the Bohai Bay Basin was taken as the object of study,experiments such as fluid sensitivity,dynamic damage by drilling fluid and pressure bearing capacity of mud cakes were conducted.With these experiments,the degree of drilling fluid dynamic damage to the reservoir and the pressure bearing capacity of mud cakes were understood and the mechanisms of reservoir damage by fluid sensitivity were analyzed.The study results show that the matrices of the reservoir rocks have strong salt sensitivity,moderate to weak alkali sensitivity and weak water sensitivity.The incompatibility between the drilled solids particle sizes and the opening widths of the fractures in the reservoir causes the solids particles to invade into the deep fractures,plugging them and damaging the permeability of reservoir rocks.The drilling fluid used has good ability to plug fractures with opening widths≤150μm,but is unable to effectively plug fractures with opening widths≥300μm.The fractured tight metamorphic rock reservoir contains plenty of clay minerals and heavy minerals,mud losses cause the clay minerals to become hydrated and swollen,and migration of particles takes place,reacting with the heavy minerals to produce iron hydroxide precipitates which in turn exacerbate reservoir damage.When drilling metamorphic rock reservoirs,the protection of fractures with opening widths greater than 300μm should be strengthened,and special attention paid to the reservoir damage induced by the interaction between the metamorphic rocks and the work fluids.Also presented in this paper are the measures to be taken in protecting reservoirs from being damaged.

关 键 词：裂缝性 致密储层 储层损害 漏失 流体敏感 重矿物 

分 类 号：TE254.3[石油与天然气工程—油气井工程] TE282