抗钙复合膨润土的研制与评价  

Development and Evaluation of a Calcium-Resistant Compound Bentonite

作　　者：叶井亮 陈娟 刘福林 金纯正 杨现禹 蔡记华[2] YE Jingliang;CHEN Juan;LIU Fulin;JIN Chunzheng;YANG Xianyu;CAI Jihua(Wuhan Yucheng Qianli Construction Co.Ltd.,Wuhan,Hubei 430051;Faculty of Engineering,China University of Geosciences,Wuhan,Hubei 430074)

机构地区：[1]武汉誉城千里建工有限公司,武汉430051 [2]中国地质大学(武汉)工程学院,武汉430074

出　　处：《钻井液与完井液》2024年第4期458-466,共9页Drilling Fluid & Completion Fluid

摘　　要：在地下连续墙、桩基工程等施工过程中,钻井液频繁与混凝土接触,钙离子不断侵入钻井液,钻井液的工作性能会逐渐恶化,在施工结束后会产生大体量的废弃浆液。为提高钻井液的抗钙能力,减少废浆产量,有必要对天然膨润土进行改性处理。优选高速离心法对天然膨润土进行提纯,选用含碳碳双键的亲水性单体BX、含磺酸基团的亲水性单体AS和AP为聚合单体,在提纯后的膨润土层间发生自由基原位聚合反应,合成了抗钙复合膨润土ACB-16。傅立叶红外光谱、粒径分布、扫描电镜和透射电镜结果表明,单体成功在膨润土层间原位聚合。抗钙复合膨润土超过了OCMA级膨润土标准,所配制的钻井液表观黏度为26 mPa·s,API滤失量为7.6 mL,具有合适的流变性和良好的降滤失性,抗钙性能良好:在1%CaCl2污染下,钻井液流变性与滤失性性能稳定,极限抗Ca^(2+)能力可达6300 mg/L(以CaCl2计为1.75%),可完全满足基础工程领域的钻井液抗钙需求。结合粒径分析与扫描电镜方法,分析其作用机理。位于膨润土网架结构中的高分子聚合物阻止Ca^(2+)与膨润土发生离子交换作用,维持膨润土的水化膜厚度及层间距,支撑膨润土水化所形成的网架结构。直接将抗钙复合膨润土与水混合便可得到性能优异的抗钙钻井液,使用方便,在基础工程等领域具有良好的应用前景,也可以为盐膏层防塌钻井液等高钙环境钻井液的设计提供参考价值。In underground diaphragm wall and pile foundation engineering operations,calcium ions from the concrete continually invade into the drilling fluids because of the frequent contact of the drilling fluids with the concrete,leading to gradual deterioration of the basic properties of the drilling fluids and large amount of waste muds after the operations.To improve the calcium resistance of the drilling fluids and minimize the amount of waste drilling fluids produced,the natural bentonite used to formulate the drilling fluids needs to be modified.A calcium-resistant compound bentonite ACB-16 is synthesized with natural bentonite purified through high-speed centrifuging and monomers for polymerization,such as a hydrophilic monomer BX with double carbon bonds,hydrophilic monomers AS and AP with sulfonic acid groups.In the polymerization reaction,the monomers enter into the crystal spaces of the purified bentonite,reacting with each other through in-situ free radical polymerization.Studies on the polymerization products with FT-IR,particle size distribution test,SEM and TEM show that the monomers successfully in-situ polymerize in the crystal spaces of the bentonite.The quality of ACB-16 exceeds the quality of the OCMA bentonite.A drilling fluid formulated with ACB-16 has an apparent viscosity of 26 mPa∙s,an API filter loss of 7.6 mL,a good rheology and filtration property as well as a good calcium resistance.When contaminated with 1%calcium chloride,the rheology and filtration property of the drilling fluid are still stable.The limit of calcium resistance of a drilling fluid formulated with ACB-16 is 6,300 mg/L(equivalent to 1.75%CaCl2),perfectly satisfying the requirements for a drilling fluid to resist calcium contamination in foundation engineering.Using particle size analysis and SEM,the working mechanism of ACB-16 is studied.The high molecular weight polymers located on the networking structures of the bentonite hinder the ion exchange between the calcium ions and the bentonite,thereby maintaining the thickness

关 键 词：钻井液 抗钙 膨润土改性 自由基原位聚合反应 

分 类 号：TE254[石油与天然气工程—油气井工程]