抗高温超前护壁膨润土胶质液研制与性能评价

Research and performance evaluation of high-temperature resistant advanced borehole wall protection bentonite gel liquid

摘要:

针对岩心钻探中破碎地层取心率低、常规护壁技术效果有限的问题，本文提出一种“超前护壁”的技术思路，并研制了一种抗高温超前护壁膨润土胶质液。通过材料筛选与正交试验优化，确定最佳配方为“2%河北钻井级膨润土+8%海泡石+20%硅酸盐水泥”。室内性能测试表明，该胶质液在常温下表观黏度达87.5 mPa·s，150 ℃老化16 h后表观黏度超过150 mPa·s，全滤失时间仅68 s，形成的滤饼经150 ℃干燥48 h后抗压强度达2.4 MPa，并在高温高压砂床模拟实验中展现出良好的渗透与胶结能力。该胶质液可在不使地层完全固化的前提下超前注入，增强地层的整体性，为提高破碎地层取心率与钻探效率提供了新方案，具有良好的工程应用前景。

Abstract:

To address the issues of low core recovery in fractured formations during core drilling and the limited effectiveness of conventional borehole wall protection technologies， this paper proposes a technical approach of "advanced borehole wall protection" and develops a high-temperature resistant advanced borehole wall protection bentonite gel liquid. Through material screening and orthogonal experiment optimization， the optimal formula was determined as 2% Hebei drilling-grade bentonite， 8% sepiolite， and 20% Portland cement. Laboratory performance tests indicate that the gel liquid has an apparent viscosity of 87.5 mPa·s at room temperature and its apparent viscosity exceeds 150 mPa·s after aging at 150 ℃ for 16 h. The total filtration time is only 68 s. The compressive strength of the formed filter cake reaches 2.4 MPa after drying at 150 ℃ for 48 h. Furthermore， the gel liquid exhibits good permeability and cementation capabilities in high-temperature and high-pressure sand bed simulation experiments. This gel liquid can be injected in advance without completely consolidating the formation， thereby enhancing the formation''s overall integrity. It provides a new solution for improving core recovery and drilling efficiency in fractured formations and holds promising engineering application prospects.