中深地热井复杂地层钻进高温钻井液研制

Research and development of high-temperature drilling fluid for complex strata in deep geothermal wells

摘要:

近年来我国地热行业发展迅速，地热资源开发与利用的重要性显著提升。为有效钻进复杂地层中深地热井，本文针对中深地热井钻遇水敏性地层、涌水地层以及破碎松散等复杂地层和孔内高温出现的技术问题，在大量试验基础上初选了抗高温钻井液配方，通过正交试验确定了优选配方。经有效测试，钻井液在120 ℃高温条件下的滤失量为8.4 mL，漏斗黏度为24 s，动切力为1.43 Pa，表观黏度为14.5 mPa·s，塑性黏度为13.1 mPa·s，pH为8，密度为1.04 g/cm³，在120 ℃温度下钻井液流动48 h抗老化性能良好。表明研制的用于中深地热井（3000 m左右）钻进的抗高温钻井液能满足中深地热井钻进需求，具有良好的流变性、抗高温性、抗老化性及失水造壁性，能有效解决中深地热井复杂地层钻进的问题。

Abstract:

In recent years， the geothermal sector in China has witnessed rapid growth， and the significance of the development and utilization of geothermal resources has significantly escalated. To effectively drill medium-deep geothermal wells in complex strata， this paper focuses on the technical drilling issues that arise in medium-deep geothermal wells when penetrating water-sensitive strata， water-gushing strata， fractured and loose complex strata， as well as high temperatures within the boreholes. Based on a large number of experiments， an initial selection of high-temperature-resistant drilling fluid formulations was made. The optimal formulation was determined through orthogonal experiments. Through effective tests， the water loss of the drilling fluid at a high temperature of 120℃ in the well was 8.4mL， the funnel viscosity was 24s， the yield point was 1.43Pa， the apparent viscosity was 14.5mPa·s， the plastic viscosity was 13.1mPa·s， the pH value was 8， the density was 1.04g/cm³， and the anti-aging performance of the drilling fluid flowing for 48 hours at 120℃ was excellent. It indicates that the high-temperature-resistant drilling fluid developed for medium-deep geothermal well drilling （around 3000m） can meet the requirements of medium-deep geothermal well drilling， featuring good rheological properties， high-temperature resistance， anti-aging properties， and water loss and wall-building properties， and can effectively address the problems encountered during the drilling of medium-deep geothermal wells in complex strata.