青西油田深井定向钻井技术

Technology of Drilling Deep Directional Wells in Qingxi Oilfield

针对青西油田深井定向钻井过程中存在的直井段易井斜、定向造斜段钻速低、井眼轨迹控制难度大等问题,开展了复杂深井井眼轨迹控制与提速技术研究。通过分析区域地质特征、钻井难点等,主要从斜井段井眼轨迹控制与钻井提速等方面进行技术研究并制订了技术方案:在定向稳斜段采用扭力冲击器进行了提速试验,优选中低转速大功率螺杆配合抗冲击、抗研磨性强的螺旋5刀翼PDC钻头和高精度MWD无线随钻测量仪器进行井眼轨迹控制与提速。该技术在现场应用4口井,在满足井眼轨迹控制要求的情况下,斜井段平均机械钻速比采用常规技术提高了74.65%;斜井段最短定向工期达到59.00d,平均定向工期89.79d,比采用常规技术缩短了45.88%。研究表明,高效PDC钻头、中低速大扭矩螺杆钻具、MWD测量系统及扭力冲击器的配套技术,在青西油田深井定向钻井井眼轨迹控制与提速方面效果良好,值得在该地区推广应用。

Drilling deep directional wells in the Qingxi Oilfield have met a series of difficulties,such as well bore quality controlat vertical sections,low rate of penetration（ROP）at build section and well trajectory control,etc.In order to solve these problems,trajectory control and drilling rate improvement in deep complex section were studied.Through the analysis of regional geologic characteristics and drilling difficulties technical research and design were conducted to achieve trajectory control at inclined section and drilling rate improvement.An ROP improvement test was conducted with a torque impacter at the hold section,and the trajectory control and ROP test were adopted for mid-low speed and high-power PDM tools,combined withhigh impact and abrasion resistant five-blade PDC bits as well as high-accuracy MWD.This technique was applied in 4directional wells and an average ROP at deviation sections increased by 74.65%.The results indicated that it met the requirement of trajectory control,while the shortest directional drilling duration was 59.00 days,directional drilling average time was 89.79 d.At the end,there was a reduction of 45.88%in the drilling time versus conventional ways.It was demonstrated that the combined technology of high-efficiency PDC bits,low-speed high-torque PDM tools,MWD and torque impacters had a better result in trajectory control and ROP improvement in deep directional drilling in Qingxi Oilfield.Based on the positive results,it is recommended that the new techniques be promoted and applied in this area.