沧东凹陷页岩油水平井优快钻井技术

Optimized and Fast Drilling Technologies for Horizontal Shale Oil Wells in the Cangdong Sag

在沧东凹陷页岩油水平井钻井过程中,面临机械钻速低、安全风险大、固井质量难以保证等问题。为解决这些问题,预测了地层漏失压力和坍塌压力,进行了井身结构和井眼轨道优化、PDC钻头个性化设计,并集成盐水钻井液、旋转导向钻井技术、韧性水泥浆和漂浮顶替固井等配套技术,形成了沧东凹陷页岩油水平井优快钻井技术。该技术在沧东凹陷20口页岩油水平井进行了应用,应用结果显示:固井质量优质率提高了30.4%;井深超过4 500.00 m井的平均机械钻速提高了20.2%,平均钻井周期缩短了30.6%;井深小于4 500.00 m井的平均机械钻速提高了82.9%,平均钻井周期缩短了49.9%。研究与应用结果表明,该技术满足了沧东凹陷页岩油水平井优快钻井需求,为页岩油水平井高效开发提供了技术手段,也为国内各油田非常规油气藏钻井技术优化提供了借鉴。

During the drilling of horizontal shale oil wells in the Cangdong Sag,the low ROP(Rate of Penetration),high safety risk,and uncertain cementing quality impeded the efficient exploration and development of shale oil.To address these problems,investigations were implemented on the detailed prediction of formation leakage pressure and collapse pressure.They were then carried out the optimization of casing programs and borehole trajectories and the personalized design of PDC bits.Further,the matching technologies such as brine drilling fluid,rotary steering drilling,ductile cement slurry,and floating displacement cementing were integrated,forming an optimized and fast drilling technology for the horizontal shale oil wells in the Cangdong Sag.This technology was applied in 20 horizontal shale oil wells in the Cangdong Sag,and the cementing quality was improved by 30.4%.For the wells with a depth of more than 4500.00 m,the average ROP increased by 20.2%,and the average drilling cycle was shortened by 30.6%.For wells with a depth of lower than 4500.00 m,the average ROP increased by 82.9%,and the average drilling cycle was shortened by 49.9%.These results demonstrated that the proposed technology could meet the requirement for the optimized and fast drilling of horizontal shale oil wells in the Cangdong Sag,providing a technical means for the efficient exploration and development of horizontal shale oil wells and also a reference for the drilling technology optimization of unconventional oil and gas reservoirs in the oilfields of China.