绳索取心定向钻井工艺在陡倾角岩层中的应用

贵州威宁阳关寨勘查区位于格目底向斜南西翼的西段，主要含煤地层为宣威组。勘查区西南部岩层较陡，倾角60。以上，特别是ZK102、ZK202、ZK302钻孔岩层倾角超过80°。如按常规垂直井设计，钻孔深度超过1400m，施工难度大。在分析勘查区绳索取心直井钻进困难和定向钻进优点基础上，对小口径绳索取心定向钻进技术可行性进行分析后认为：如把钻孔轨迹的曲率控制在10°／100m以内、增大曲率半径减小最大井斜、配备适合的定向仪器、增购高强度钻具，将定向钻井技术与绳索取心工艺相结合的方案是可行的。并以ZK202为例，介绍了定向孔井身轨迹的设计、钻进技术参数的选择、冲洗液的要求、造斜段措施等。钻探实践表明，采用绳索取心定向钻进技术在该区共施工3个钻孔，与原直井设计比较，减少钻探工程量2000余米，节约勘探成本约150万元，同时缩短工期约3个月，且控制目标煤层精确，完全达到地质设计目的。通过本次施工，为类似地层钻进积累了丰富的实践经验。

Application of Wire-line Core Directional Drilling in Steep-dipping Strata Area

The Yangguanzhai exploration area, Weining, Guizhou is situated in western sector of the Gemudi syncline west limb; its main coal-bearing strata belong to the Xuanwei Formation. The southwestern part of the exploration area has steep-dipping strata with dip angle over 600, especially over 800 in boreholes ZKI02, ZK202 and ZK302. If using conventional vertical drilling when depth 〉 1400m is hard to drill. In consideration of the hard vertical drilling situation and strongpoint of directional drilling, studied small diame- ter wire-line core directional drilling feasibility, considered that if controlled the borehole curvature within 100/100m, to increase radi- us of curvature reduce maximum borehole deviation, equipped with adaptive direction finder and high strength drilling tools, combined directional drilling technology and wire-line coring process is feasible. Taking the borehole ZK202 as example, introduced directional borehole configuration design, drilling technical parameter selection, flushing fluid requirement and measures adopted in deflecting sec- tor etc. Practices have shown that compared with original vertical design, 3 boreholes using wire-line core directional drilling have re- duced drilling workload 2000＋ meters, save drilling cost about 1.5 million RMB, shorten time limit about 3 months, target coal seams accurately controlled, thus fully accomplished the aim of geological design. Through this drilling operation, has gathered abundant prac- tical experiences for reference in similar strata drilling henceforth.