超深超高温潜山气井AT-6X井小井眼侧钻技术

Slim-hole sidetracking techniques used in Well AT-6X, a gas well in the ultradeep and ultrahigh temperature buried hill

马鸿彦 孔凡刚 杨金生 赵会忠 李汉月 刘长柱

MA Hongyan KONG Fan’gang YANG Jinsheng ZHAO Huizhong LI Hanyue LIU Changzhu

中国石油集团渤海钻探工程有限公司定向井技术服务分公司

为解决华北油田首口超深、超高温潜山内小井眼侧钻井AT-6X井在施工过程中遇到的地层岩石可钻性差、新老井眼分离困难、摩阻扭矩大及井温高等技术难题，进行了侧钻工具优选、送钻方式选择、抗高温低固相钻井液体系设计及抗高温MWD仪器优选等方面的研究。通过建立侧钻工具力学模型对不同条件下钻具侧向力进行分析，选用PDC钻头+直螺杆+2.5°弯接头作为侧钻的最优工具；以间接方位角校正法为基础设计了方位角校正系统，提高井眼轨迹的精度；采用半主动半自动送钻方式提升侧钻效率；优选抗高温低固相钻井液体系提高高温条件下的稳定性。上述技术在超深超高温潜山小井眼侧钻井AT-6X井进行了应用，将工具面调整为140°并结合半自动送钻方式成功完成了该井的侧钻施工，完钻井深6 059 m。该井采取的技术措施有效解决了侧钻难题，为高温工况下超深井侧钻提供了经验和借鉴。

Well AT-6X is the first slim-hole sidetracking well in the ultradeep and ultrahigh temperature buried hill of Huabei Oilfield, and in the process of its construction, it underwent several technical difficulties, such as poor rock drillability, difficult separation of new and old holes, large friction torque and high well temperature. In order to solve these problems, a series of studies were carried out from the aspects of sidetracking tool selection, bit feeding mode selection, design of the drilling fluid system of high temperature and low solid phase, and high temperature MWD instrument selection. In this paper, the mechanics model of sidetracking tool was established to analyze the side forces of drilling tools, and PDC bit +straight screw rod +2.5° bent sub was taken as the optimal sidetracking tool. The azimuth correction system was designed based on the indirect azimuth correction method to improve the precision of hole trajectory. The semi-active and semi-automatic bit feeding mode was adopted to increase the sidetracking efficiency. The drilling fluid system of high temperature and low solid phase was selected to improve the stability under high temperature. These techniques were applied in Well AT-6X. Its sidetracking operation is completed successfully by adjusting the tool face angle into 140° and adopting the semi-active and semi-automatic bit feeding mode, and its total depth is 6 059 m. The application of these techniques effectively solves the sidetracking difficulties in Well AT-6X, which provides the experience and reference for the sidetracking of ultradeep wells under the working conditions of high temperature.

10.13639/j.odpt.2020.02.004