宁夏中卫市深井勘查区松散破碎地层冲洗液护壁技术方法

Drilling fluid wall protection technology for loose and fractured strata in the Shenjing exploration area in Zhongwei City， Ningxia

摘要:

在宁夏中卫市深井勘查区煤炭资源勘探项目钻探施工初期，由于地层条件复杂，岩石松散破碎、漏失，钻孔护壁难度大，导致岩心采取率不达标，施工效率低、成本高，钻机台月效率仅为353 m/台月。通过分析勘查区岩土工程地质特征和岩石物理力学性质，调整了施工工艺和钻进参数，优化了冲洗液配方，采用了低固相聚合物成膜护壁冲洗液体系，改善了冲洗液护壁效果和护心效果，冲洗液滤失量由25 mL/30 min降为9 mL/30 min，降低64%；平均岩心采取率由53%提高至84.41%，提高31.41%；平均台月效率提高至757.87 m/台月，提高115%。后续施工的9个钻孔施工顺利，累计完成钻探进尺4774.6 m，对类似地区钻探施工提供了借鉴。

Abstract:

In the initial stage of drilling construction for the coal resource exploration project in the Shenjing Exploration Area of Zhongwei City, Ningxia Hui Autonomous Region, due to complex formation conditions including loose and fractured rocks and formation loss, it was difficult to stabilize the borehole walls. This resulted in substandard core recovery rates, low construction efficiency, and high costs, with the monthly rig efficiency only reaching 353 meters per month.By analyzing the geotechnical engineering geological characteristics and physical and mechanical properties of rocks in the exploration area, the drilling construction technology and drilling parameters were adjusted, and the drilling fluid formula was optimized. The low-solid-phase polymer film-forming wall-protecting drilling fluid system developed by the Beijing Institute of Prospecting Engineering was adopted, which improved the performance of drilling fluid in protecting borehole walls and cores. The filtration loss of drilling fluid decreased from 25ml/30min to 9ml/30min, a reduction of 64%. The average core recovery rate increased from 53% to 84.41%, an increase of 31.41%, and the average monthly rig efficiency rose from 353m/month to 757.87m/month, an increase of 115%.The subsequent construction of 9 boreholes proceeded smoothly, with a total drilling footage of 4774.6 meters completed, providing a reference for drilling construction in similar areas.