摘要
黏土矿物在不同的水化阶段所吸附的结合水有不同的结构和性质,可分为强结合水和弱结合水,他们和黏土的连结形式不同。定量分析黏土结合水,研究不同结合水类型和含量对力学参数的影响,可以为建立力学与化学耦合模型提供定量化参数。实验用热分析法定量测定了黏土的结合水类型、含量以及水化程度,结果表明,TG曲线上的台阶不明显,难以确定温度点,而利用DTG曲线可以清楚地看到自由水和弱结合水的温度拐点;确定了DTG曲线上的温度界限是一个区间,即自由水的温度界限是75℃±5℃,弱结合水的温度界限是140℃±5℃,强结合水的温度界限是210℃±5℃;随着电导率的降低,DTG曲线上的第一个负峰逐渐向左漂移,即自由水与弱结合水的温度界限在降低,DTG曲线上的第2个、第3个负峰越来越明显,即强弱结合水的温度界限越来越明显,证明了电解质对黏土结合水的热分析有非常大的影响;不同电导率的黏土结合水的水化程度都大于1,说明黏土不仅饱和吸附了强结合水,而且还吸附了弱结合水。实验证明,DTG曲线可以定量分析黏土结合水类型以及结合水含量,但必须去除电解质的影响。
Clay bound water has different structure and property in the clay hydration stage,which can be divided into strong and weak bound water.Quantitative study of clay bound water can provide parameters for mechanical and chemical coupling mould. Thermal analysis experiment shows that the inflection point on TG curves is not obvious,but the free water and weak bound water temperature inflection points can be got clearly from DTG curves.Temperature limit were separately 75℃±5℃,140℃±5℃, 210℃±5℃ for free water,weak and strong bound water.The peak change on curve demonstrated that electrolytes have great influence on clay bound water.Both strong and weak bound water were absorbed on clay.The conclusion is the information of structure and content of clay bound water can be got from DTG curves without considering the electrolytes' effect.
出处
《钻井液与完井液》
CAS
北大核心
2013年第6期1-4,91,共4页
Drilling Fluid & Completion Fluid
基金
国家重大科技专项"复杂地层井壁稳定技术研究"(2011ZX05021-004-013-001)
关键词
泥页岩水化
强结合水
弱结合水
水化程度
电解质
DTG曲线
Shale hydration
Strong bound water
Weak bound water
Degree of hydration
Electrolytes DTG curves
