白银市土红湾-李家沟煤炭资源详查23-2孔冲洗液技术

Drilling fluid technology for Hole 23-2， detailed investigation of coal resources in Tuhongwan-Lijiagou， Baiyin City

摘要:

甘肃省白银市土红湾-李家沟煤炭资源详查23-2孔地质条件极其复杂，既有水敏性强的泥岩，还有松散破碎的煤层等，其间还夹杂着不同程度的盐膏，孔内容易出现坍塌、掉块等问题，冲洗液易受到污染，对冲洗液性能提出了更高的要求。以往该矿区施工，常发生孔壁坍塌、冲洗液粘度显著降低等问题，严重时导致埋钻及沉砂卡钻等孔内事故，影响成孔和施工效率。针对以上问题，分析了钻遇地层孔壁失稳的原因，评价了盐膏侵对冲洗液性能的影响，并有针对性的开展了体系的适应性研究，先后优选出成膜防塌冲洗液和抗盐膏侵成膜环保冲洗液。施工中，针对水敏性分散剥落地层和松散地层选用成膜防塌无固相冲洗液，在发现盐膏侵后将其转化为抗盐膏侵成膜环保冲洗液，并通过对冲洗液配方、性能参数的合理调整与维护以及采用绳索取心钻探等工艺措施，较好地解决了上述问题。

Abstract:

The geological conditions of Hole 23-2， detailed investigation of coal resources in Tuhongwan-Lijiagou， Baiyin City， Gansu Province are extremely complex， including mudstone with strong water sensitivity， loose and broken coal seam， etc.， and salt paste in between， the hole is prone to collapse， clumping and other problems， and the drilling fluid is easy to be polluted， which puts forward higher requirements for drilling fluid properties. In the past drilling construction of this mining area， problems such as hole wall collapse and significant reduction of drilling fluids viscosity often occurred， which in serious case led to buried drill， solids setting stuck and other drilling accidents， and thereby affecting the efficiency of hole-forming and construction efficiency. In view of the above problems， the causes of borehole wall instability when drilling are analyzed， the effects of salt-paste penetration on the properties of the drilling fluids are evaluated， the adaptability of the system is studied in a targeted way and the film-forming anti-collapse drilling fluids and salt-paste encroachment film-forming environment friendly drilling fluids are selected. During the driiling process， aiming at the water sensitive and spalling and loose strata， the film-forming anti-collapse solid free dilling fluid was selected， and transferred to salt-paste encroachment film-forming environment friendly drilling fluid when encountered salt encroachment. Moreover， technology such as reasonable adjustment and maintenance of drilling fluid formula and performance parameters， wire-line core drilling are adopted to solve the above problem.