一种耐高温强吸附型高效页岩抑制剂的制备及机理研究

Study on the preparation and mechanism of a high-efficiency shale inhibitor with high temperature resistance and strong adsorption

针对目前页岩储层开采过程中存在的井壁失稳问题,通过分子结构设计,以二乙烯三胺、丙烯酸甲酯、缩水甘油三甲基氯化铵、γ-缩水甘油醚氧丙基三甲氧基硅烷为单体,甲醇为反应溶剂,制得一种耐高温、强吸附型高效页岩抑制剂(HBP-NTK)。通过线性膨胀、岩屑滚动回收、抑制造浆等实验评价HBP-NTK的抑制性能,结果表明,与同类型超支化结构抑制剂相比,HBP-NTK能更加有效抑制膨润土的水化分散与膨胀,并表现出优异的耐温性,与现场钻井液体系适配性良好。所提出的机理表明,HBP-NTK分子结构中的强吸附基团胺基和硅氧基能够吸附插层在黏土晶片间,依靠分子链的桥连和锚固作用,将黏土颗粒牢固束缚在一起,有效防止黏土的水化分散;分子结构中的NH+4嵌入黏土网状结构中进行离子交换压缩扩散双电层,与外层吸附包裹在黏土颗粒表面的胺基、硅氧基分子链形成内部抑制水化膨胀、外部抑制水化分散的协同抑制机制,有效减弱了黏土的水化膨胀与分散。

Aiming at the current problem of well wall instability in the process of shale reservoir mining,a high efficiency shale inhibitor(HBP-NTK)with high temperature resistance and strong adsorption was prepared by using molecular structure design with diethylene triamine,methyl acrylate,glycidyl trimethylammonium chloride andγ-glycidyl ether oxypropyltrimethoxysilane as monomers and methanol as reaction solvent.The inhibition performance of HBP-NTK was evaluated by linear expansion experiment,rock debris rolling recovery experiment,and inhibition slurry formation experiment.The results show that compared with the same type of hyperbranched structure inhibitors,HBP-NTK can more effectively inhibit the hydration dispersion and expansion of bentonite,and shows excellent temperature resistance and good compatibility with the field drilling fluid system.The proposed mechanism shows that the strong adsorption groups of amine and siloxo groups in the molecular structure of HBP-NTK can be adsorbed and intercalated between the clay chips,and the clay particles can be firmly bound together by the molecular chain bridging and anchoring,which effectively prevents the hydration and dispersion of the clay.In addition,the NH+4 in the molecular structure is embedded in the clay network structure for ion exchange compression and diffusion of the double electric layer,and the amine and silyl molecular chains on the surface of the clay particles are adsorbed with the outer layer to form a synergistic inhibition mechanism of internal inhibition of hydration expansion and external inhibition of hydration dispersion,which effectively reduces the hydration expansion and dispersion of the clay.