改性脂肪酸提切剂的研制及其应用

Synthesis of a modified fatty acid as rheology modifier and its application

合成一种可在油基钻井液中代替有机土的改性脂肪酸提切剂,测定提切剂对乳液流变性能的影响,分析乳液样品的三段式触变性,使用冷冻电镜观察提切剂对乳液微观结构的影响,采用界面流变仪分析提切剂对油水界面流变性的影响,分析提切剂的作用机制,在高密度油基钻井液中进行适用性评价。结果表明:提切剂有利于提高乳液黏度尤其是低剪切速率黏度;加入提切剂后,乳液具有优良的触变性,并观测到蜂窝状结构;提切剂能够显著增强油水界面弹性模量和界面膜强度,有利于乳液稳定;提切剂吸附在油水界面,通过氢键作用在乳液中构建三维网架结构,从而增强弱凝胶结构和提高切力;与含有机土的油基钻井液相比,使用提切剂的无土相油基钻井液具有较优异的流变结构与电稳定性。

A modified fatty acid (MFA) as the rheology modifier was synthesized which can replace organoclay in oil based drilling fluid (OBM).The influence of MFA on the rheological properties of the emulsions was investigated and three-interval thixotropy was analyzed.The effect of MFA on the microstructure of the emulsion was studied by Cryo-scanning electron microscope (cryo-SEM).And the influence of MDA on oil-water interfacial rheology was characterized by the interfacial rheometer,through which the function mechanism of MFA was analyzed.Also,the applicability of MFA in the high-density OBM was evaluated.It is found that MFA could enhance the emulsion viscosity especially the low-shear-rate viscosity.Emulsions containing MFA present good thixotropic property and a honeycomb structure could be observed.MFA could considerably improve the storage modules of oil/water interfaces and interfacial film strength,which is favorable for the emulsion stability.And MFA adsorbs at the oil-water interfaces,which establishs a three-dimensional network structure in the water-in-oil emulsions through hydrogen bonding.In this way,the “weak gel” structure and gel strength of the emulsionsare enhanced.Compared with OBMs containing the organoclay,organoclay-free OBMs using MFA show superior rheological performance and larger electrical stability.