超低渗透钻井液井壁稳定机理

Wellbore Stability Mechanism of Ultra-low Permeability Drilling Fluids

在基础钻井液配方里添加聚合醇、纳米乳化石蜡衍化出超低渗透钻井液,通过承压、润滑、吸附、界面张力实验和相关的一系列技术应用,对其特性进行分析后发现超低渗透剂可以在最短时间内完成在井壁的吸附、平衡过程,且吸附能力与可吸附量都极高。文章采用微观研究技术分析其作用机理,该种钻井液体系具备临界浊点温度和临界固液相切换温度,可在井壁上形成致密性较强的胶束薄膜,良好的封堵性能有效抑制了岩层的膨胀,提升对井壁失稳的预防能力,从而为提高井壁稳定性发挥着举足轻重的作用。

The ultra-low permeability drilling fluid is developed by adding polyol and nano emulsified paraffin into the basic drilling fluid formula. After analyzing its characteristics through pressure bearing, lubrication, adsorption, interfacial tension tests and a series of related technical applications, it is found that the ultra-low permeability agent can complete the adsorption and equilibrium process on the well wall in the shortest time, and its adsorption capacity and adsorbable capacity are very high. In this paper, the micro research technology is used to analyze its mechanism. This kind of drilling fluid system has the critical cloud point temperature and the critical solid-liquid phase switching temperature. It can form a micelle film with strong compactness on the well wall. Its good plugging performance can effectively inhibit the expansion of the rock layer and improve the ability to prevent the instability of the well wall, thus playing a decisive role in improving the stability of the well wall.