茶亭铜多金属矿区深孔岩心钻探工艺与事故处理

Deep hole core drilling technology and accident treatment in Chating copper polymetallic mining area

摘要:

针对茶亭铜多金属矿区深孔岩心钻探工期紧、事故多发的难题，结合矿区地层与工程实践，分析孔斜超差、套管脱落、钻杆断裂、烧钻等孔内事故机理。矿区设计钻孔62个，孔深1000~2000 m，总工作量96240 m，勘探间距50 m，按孔深采用三开、四开钻孔结构，配套孕镶金刚石钻头及膨润土/氯化钾聚磺分级冲洗液体系，并优化钻进规程参数。结果表明：地基未完全固化开钻、套管不到位及人为误操作是事故主因；采用螺杆钻具定向纠斜、水泥人工孔底、修孔、套管隔离绿泥岩、反丝钻杆打捞、磨铣对接及无内管捞取钢丝绳等处置技术后，ZK4503孔顶角由700 m处4.82°降至1000 m处0.4°，ZK4714孔多重事故经46 d处理恢复钻进。开孔质量直接决定深孔钻探成效，高质量开孔可减少15%~30%非钻进时间。研究可为该矿区及类似条件矿区深孔岩心钻探提供工程借鉴。

Abstract:

To address the problems of tight schedule and frequent accidents in deep-hole core drilling in the Chating copper polymetallic mining area， the mechanisms of downhole accidents such as out-of-tolerance borehole deviation， casing fall-off， drill pipe fracture， and bit burning were analyzed in combination with the formation conditions and engineering practice of the mining area. A total of 62 boreholes were designed， with depths of 1000~2000 m， a total drilling footage of 96240 m， and an exploration spacing of 50 m. Three-spud and four-spud borehole structures were adopted according to hole depth； impregnated diamond bits and bentonite/KCl polymer-sulfonate staged drilling fluid systems were used； and drilling parameters were optimized. The results show that spudding-in before foundation solidification， improper casing placement， and human operational errors were the main causes of accidents. After the application of treatment techniques such as directional deviation correction with a positive displacement motor， artificial bottom hole with a cement plug， hole reaming， casing isolation of chloritic rock， reverse-thread drill pipe fishing， milling and jointing， and wire rope fishing without an inner tube， the drift angle of borehole ZK4503 decreased from 4.82° at 700 m to 0.4° at 1000 m， and drilling in borehole ZK4714 was resumed after 46 days of treatment for multiple downhole accidents. Spudding-in quality directly determines the effectiveness of deep-hole drilling， and high-quality spudding-in can reduce non-drilling time by 15%~30%. This study provides an engineering reference for deep-hole core drilling in this mining area and mining areas with similar conditions.