渭北油田超浅层水平井优快钻井技术

针对渭北油田超浅层水平井钻井过程中摩阻大、托压严重、钻井周期长、钻速慢等问题，以井身结构优化为核心，研究形成了渭北油田超浅层水平井优快钻井技术:采用二开井身结构，二开采用φ215.9 mm钻头钻进；采用“直-增-平”三段式井眼轨道，以保证井眼轨迹平滑，降低钻进摩阻与扭矩；采用倒装钻具组合，以保证钻头有效加压，提高机械钻速；优选钾铵基聚合物钻井液，造斜段摩阻系数控制在0.08以内，水平段摩阻系数控制在0.06以内，以避免或减少托压现象。该技术在8口井进行了现场应用，平均钻井周期为17.81 d，与同区块三开井身结构水平井相比钻井周期缩短了51.06%。渭北油田超浅层水平井优快钻井技术解决了该油田超浅层水平井钻井中存在的技术难点，为超浅层油藏的高效开发提供了技术支持。 

High Quality and High Speed Drilling Technology for Ultra-Shallow Horizontal Wells in the Weibei Oilfield

Crews involved in the drilling of an ultra-shallow horizontal well in Weibei Oilfield encountered multiple problems, such as high friction, serious weight on bit (WOB) stack, long drilling cycle and low ROP. Focusing on optimization of casing program, a high quality and high speed (HQHS) drilling technology was developed. Specifically, a casing program with two spudding well sections was used, and φ215.9 mm drill bits were used to drill the second section. The "straight-increase-flat" well trajectory was adopted in order to ensure the hole smoothness and reduce the friction and torque. The inverted BHA was selected to ensure that the WOB could be increased effectively to improve the ROP. In order to avoid or eliminate WOB stack, a potassium amino polymer drilling fluid system was selected to control the friction coefficient to keep the building up section less than 0.08 and the friction coefficient in the horizontal section less than 0.06. Field application in 8 wells showed that the average drilling cycle was 17.81 d, which was 51.06% less than a horizontal well with three spudding well sections in the same block. The HQHS drilling technology for ultra-shallow horizontal wells had been successfully applied in Weibei Oilfield, providing technical reference for effective development of ultra-shallow reservoirs.