氧化性入井液对富有机质页岩渗透率的影响  

Effect of oxidizing working fluid on permeability of organic-rich shale

作　　者：游利军 周洋 康毅力 豆联栋 程秋洋 YOU Lijun;ZHOU Yang;KANG Yili;DOU Liandong;CHENG Qiuyang(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu,Sichuan 610500,China)

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

出　　处：《油气藏评价与开发》2020年第1期56-63,共8页Petroleum Reservoir Evaluation and Development

基　　金：国家自然科学基金项目“富有机质页岩氧化致裂增渗加速气体传输机理研究”（51674209）;非常规油气层保护四川省青年科技创新研究团队项目“水力压裂页岩气井热处理解除损害及强化产能研究”（2016TD0016）;“十三五”国家科技重大专项“彭水地区常压页岩开发技术与政策研究”（2016ZX05061003）

摘　　要：富有机质页岩沉积于缺氧的还原环境,富含黄铁矿、绿泥石和有机质等还原性组分。油气储层开发过程中有大量氧化性入井液进入储层,与储层岩石流体不配伍,打破页岩储层与油气水等地层流体的物理和化学平衡状态。选取四川盆地川东南彭水地区志留系龙马溪组富有机质页岩开展氧化性流体与富有机质页岩作用实验,分析氧化性入井液对页岩储层渗透率的影响。研究结果表明,富有机质页岩接触氧化性流体后,渗透率会随着流体氧化还原电位(Eh)的变化而改变,即氧敏性;流体氧化还原电位小于450 mV时,产生Fe2O3、Fe(OH)3、菱铁矿(FeCO3)、二水硫酸钙(CaSO4·2H2O)、MgSO4和BaSO4等化学沉淀固相微粒和页岩岩屑固相微粒,导致页岩渗透率降低。调控入井流体Eh来抑制氧敏损害,发挥氧化致裂增渗作用,是处于还原环境下油气藏储层保护完井液的发展方向。Organic-rich shale deposits in the anoxic reductive environment,and is rich in pyrite,chlorite,organic matter and other reductive components.In the process of oil and gas development,a large amount of oxidizing working fluids enter the reservoir,which is incompatible with rock and fluids in reservoir,thus breaking the physical and chemical equilibrium between shale reservoir and formation fluids such as oil,gas and water.The organic-rich shale of Silurian Longmaxi Formation in Pengshui area of southeast Sichuan Basin was selected to conduct the experiment on the interaction between oxidizing fluid and organic-rich shale,so that to analyze the effect of oxidizing working fluid on shale reservoir permeability.The results show that the after the contact of organic shale and oxidizing working fluid,the permeability will change with the fluid oxidation-reduction potential(Eh),which is called oxygen sensitivity.When the fluid oxidation-reduction potential is less than 450 mV,the generated chemical precipitation solid particles and solid particles of shale debris,such as Fe2O3,Fe(OH)3,siderite(FeCO3),calcium sulphate dihydrate(CaSO4·2H2O),MgSO4 and BaSO4,lead to the reduction of shale permeability.Regulating Eh of working fluid,inhibiting oxygen sensitivity damage,and playing the role of oxidation and permeability enhancement are the development direction of completion fluid of oil and gas reservoirs under reductive environment.

关 键 词：页岩 氧敏性 储层损害 还原性矿物 微粒运移 氧化还原电位 

分 类 号：TE37[石油与天然气工程—油气田开发工程]