WFSD-2孔二开孔斜分析及纠斜施工

汶川地震断裂带科学钻探工程WFSD-2孔钻探工程技术质量要求高，其中，孔斜及取心率尤为重要。但其上部（≤600m）花岗岩、花岗闪长岩、变质火山岩坚硬致密，局部裂隙发育，裂隙面、小断层多且断层倾角大，易造斜，造成岩心堵塞。钻孔结构较复杂，采用大口径牙轮钻进孔斜难以控制，纠斜钻进难度大。二开（47．8—638．01m）施工，从80—311．39m顶角／方位角由0．7°／202．9°到5．8°／222．7°。其后，采用5LZ120×7．0L-5（0．5°、0．75°弯外管）螺杆马达纠斜。从317．43—456．12m顶角／方位角由6．0°／228．3°纠正到0．9°／103．7°，取得了理想的效果。就孔斜及纠斜施工进行总结、分析和归纳。

Analysis on the Second Opening of WFSD-2 Hole and Deviation Correction Construction

WFSD - 2 hole of scientific drilling engineering of Wenchuan earthquake fault zone has high quality requirement, and the hole deviation and coring rate are especially important. But the granite, granodionite and metavolcanic rocks in upper part （≤600m） are hard and compact with fracture development, many fracture surfaces and small faults; the big fault dip made deviation easily occur with core blockage. Because of complicated bore hole structure, the deviation was difficult to control by large diameter roller bit drilling. The satisfied effect was received by second opening（47. 8 -638.01m） construction：in 80 - 311.39m section, top angle/azimuth angle from 0. 7 °/202. 9° to 5. 8 °/222. 7 °; then 5 LZ120 × 7. 0L - 5 screw motor was used in 317.43 ° 456. 12m section, top angle/azimuth angle were corrected from 6. 0° /228.3° to 0.9 °/103.7° . The paper summed up and analyzed the construction of deviation correction.