摘要
钻井液对井壁稳定性具有重要影响,研究不同类型钻井液浸泡对岩石理化性能、微观结构等的影响差异性,对安全钻井具有重要指导意义。分别选择2种水基型和1种油基型钻井液,对中江气田沙溪庙组长水平井钻井过程中的泥岩掉块开展浸泡实验,利用XRD、SEM、纳米压痕硬度测试等方法,对比分析两种类型钻井液浸泡对泥岩理化性能、微观结构以及纳米压痕硬度的影响差异性。结果表明,水基型钻井液浸泡后泥岩黏土矿物含量下降率高于油基型钻井液,泥质结构更加疏松,黏土矿物多呈絮粒状,矿物微粒间孔隙、粒边缝,黏土絮粒间微孔缝发育更加明显;两种钻井液浸泡后泥岩纳米压痕硬度均呈明显下降趋势,但在相同浸泡时间内油基型钻井液引起的纳米压痕硬度下降率高于水基型钻井液。在利用纳米压痕硬度变化判断钻井液对岩石的影响时,需结合岩石微观结构综合判断。
Drilling fluid has an important influence on the stability of borehole walls.It is of great guiding significance to study the differences in the effects of different types of drilling fluids soaking on physicochemical properties and microstructure of rocks for safe drilling.Two water-based drilling fluids and one oilbased drilling fluid were selected for soaking experiments on mudstone block drop while drilling a long horizontal well in Shaximiao Formation in Zhongjiang Gas Field.XRD,SEM,nanoindentation hardness test,and other methods were used to compare and analyze the differences in the effects of the two types of drilling fluids on the physicochemical properties,microstructure,and nanoindentation hardness of mudstones.The results show that the decline rate of clay mineral content in mudstones after being soaked by water-based drilling fluid is higher than that of oil-based drilling fluid.The mud structure is looser,the clay minerals are mostly flocculent,intergranular pores of mineral fines,grain edge cracks,and micro-pore cracks between clay floc particles develop more obviously.The nanoindentation hardness of mudstone decreased significantly after soaking in both drilling fluids.Still,the decline rate of nanoindentation hardness caused by oil-based drilling fluid is higher than that of water-based drilling fluid within the same soaking time.When using the change of nanoindentation hardness to judge the impact of drilling fluid on rock,it is necessary to make a comprehensive judgment based on the rock microstructure.
作者
栗涵洁
刘其明
智慧文
张生军
杨丽
Li Hanjie;Liu Qiming;Zhi Huiwen;Zhang Shengjun;Yang Li(Petroleum Engineering Technology Institute,Sinopec Southwest Oil&Gas Company,Deyang Sichuan 618000)
出处
《中外能源》
CAS
2024年第9期48-55,共8页
Sino-Global Energy
基金
中国石化西南油气分公司科技项目“中江气田长水平段水平井建井关键技术研究”(编号:KJ-688-2206)
关键词
钻井液浸泡
泥岩
理化性能
微观结构
纳米压痕硬度
黏土矿物
drilling fluid soaking
mudstone
physicochemical properties
microstructure
nanoindentation hardness
clay minerals
