重庆松藻矿区复杂地层钻探技术探讨

Probe into Complex Strata Drilling Technology in Songzao Mining Area,Chongqing

重庆松藻矿区强风化地层厚度在700m左右,结构松软、涌水、漏失及水敏性地层反复出现。该区钻孔易出现坍塌、掉块、吸水膨胀缩径、孔斜等现象,施工难度较大,另外煤心采取率极低。在该矿区小鱼沱井田钻进时,采用快干水泥浆封堵及跟管钻进相结合的钻进工艺,并严格控制双聚低固相泥浆配方;在跟管钻进过程中,掌握控制其压力、转速,防止因压力过大或钻进太快而出现套管断脱。该孔历时4个月,终孔深度1 261.72m,终孔斜度为8,°钻孔质量为特级。CK-28井成孔经验表明,在该区复杂地层钻进,采用边钻进边封堵及跟管钻进等技术,可有效解决易塌、涌水、漏失、孔斜等难题。

The thickness of strongly weathered strata in the Songzao mining area, Chongqing is about 700m, crumbly textured, over flowing, circulation losing, water sensitive strata appearing time and again. Drilling in the area is easy to collapse, cave-in, water swelling borehole diameter contraction, borehole deflection etc. as well as low coal core recovery make the drilling very difficult. During the drilling in the Xiaoyutuo minefield in the mining area, quick cement slurry sealing combined with casing while drilling technology and strictly controlled bipolymer low solid mud formula; during casing while drilling, grasping and controlling of its drilling pressure and rotary speed to prevent casing break off because of over pressure or over drilling speed. The drilling last a period of 4 months, with finishing depth 1261.72m, deflection 8°, and achieved superfine grade of quality. The No.CK-28 borehole completion experience has demonstrated that drilling in the complex strata in the area by the use of technologies of casing and sealing while drilling etc. can solve collapsing, over flowing, circulation losing and borehole deflection effectively.