贵州省复杂地层地热深井钻探工艺

Drilling Technology of Deep Geothermal Wells for Complex Strata in Guizhou Province

贵州省地矿局组织实施了"贵州省地热深井钻探技术攻关"项目,研究了喀斯特地区复杂地层情况下地热深井钻探中螺杆钻井工艺和空气钻井工艺的适应性,攻克了两种工艺在该地区应用受地层特性限制的相关技术难题。螺杆马达平均寿命达200小时以上,螺杆钻井工艺较常规钻井工艺钻进机械钻速提高2～3倍;空气潜孔锤单井应用深度超过1500m,空气潜孔锤钻井工艺较常规钻井工艺机械钻速提高10～29. 5倍。同时研究了单井多工艺转换接力钻进技术,以及与上述工艺配套使用的钻井液体系。最终形成了一套适合贵州省地质条件地热深井钻探施工并能显著提高钻井效率和经济效益的组合工艺技术体系。该成果能将1口2000m以上地热深井施工周期由原来的8～12个月缩短至4～6个月,将单井平均施工成本由450万元降低至410万元以下。

The Bureau of Geology and Mineral Exploration and Development of Guizhou Province has organized and implemented the project“Technology Breakthrough of Drilling Deep Geothermal Wells in Guizhou Province”,which studied the adaptability of screw drilling and air drilling technologies of geothermal wells in complex strata of karst areas,overcoming the related technical problems about application of these two technologies limited by stratigraphic characteristics in this region.The expectancy life of the screw motor reach more than 200 hours,and the drilling mechanical rate of screw drilling technology increases 2~3 times compared with the conventional drilling technology.Single well application depth of the air DTH hammer exceeds 1500 m,and the drilling mechanical rate of the air DTH hammer technology increases 10~29.5 times that of the conventional drilling technology.At the same time,this project has studied the transformation relay drilling technology of single wells and the drilling fluid system matched to above drilling technologies.Eventually this work has formed a combined technology system of drilling deep geothermal wells that is suitable for geological conditions of Guizhou Province.It can markedly improve drilling efficiency and economic benefit.The results will reduce the construction period of a geothermal well more than 2000 m from 8~12 months to 4~6 months,lowering the average construction cost of single wells from 4.5 million yuan to less than 4.1 million yuan.