优快钻井技术在环玛湖凹陷斜坡区的应用

Application of the optimized fast drilling in the slope area of the circum-Mahu depression

环玛湖凹陷斜坡区是新疆油田重点探区之一,该区地层压力系统复杂、区域变化大,下部地层可钻性较差,机械钻速低,漏失频繁,钻井周期长。通过综合分析环玛湖斜坡区地层的岩性、压力系统等钻井工程因素,完善了井身结构设计。应用比能法对已使用钻头进行评价,优选了一套适用于环玛湖凹陷斜坡区的钻头序列,结合井下提速配套工具,钻井提速效果显著。优化钻井液体系配方,防漏堵漏技术取得良好成效。通过不断强化钻井配套技术,环玛湖斜坡带20口直井平均机械钻速提高22%,平均钻井周期缩短11.89 d,井下钻井复杂事故明显减少。

The slope area of the circum-Mahu depression is one of the Xinjiang oilfield key exploration area, the area is characterized by complicated pressure system, large regional variations, poor drillability, low rate of penetration（ROP）, frequent leakage, long drilling cy-cle. Through a comprehensive analysis of drilling engineering factors of the slope area of the circum-Mahu depression including lithological character, pressure systems, improved casing design. Specific energy method has been used to evaluate the used drill bit, preferably a set of drill bit series for the slope area of the circum-Mahu depression, combined with speed matching downhole tools, drilling speed effect is remarkable. By optimizing the formula of drilling fluid system, lost circulation controlling and plugging technology has achieved good results. By continue to strengthen drilling matching technologies, the average rate of pene-tration （ROP）of 20 vertical wells which have been drilled has increased by 22 % in the slope area of the circum-Mahu depression, the average drilling cycles has decreased by 11.89 d, and reduced the complicate drill accident obviously.