摘要
四川盆地储层埋深大于3 500m的页岩气的地质条件复杂,钻井工程面临井底温度与溢漏风险高等挑战,水平井在造斜-水平段实现"一趟钻"的比例低,导致钻井周期长、工程成本高.文章系统总结了川南地区深层页岩气实现"一趟钻"所面临的难点和挑战,详细分析了复杂地质构造、目的层温度、地层压力和钻井液性能等影响因素,从井眼轨迹、井底温度控制等方面总结了该地区"一趟钻"关键技术进展与应用成效,并在此基础上,从地质、井身结构、钻井液和工具装备等多方面综合考虑,提出了钻井液密度与ECD精细管控、井筒传热与相变降温材料研究、试验"瘦身井"钻井技术等攻关方向与建议.
Abstract
The geological conditions of shale gas with reservoir depth greater than 3 500 m in Sichuan Basin are complex,the drilling engineering is faced with the challenge of high bottomhole temperature and high kick-overflow risk,and the ratio of single-trip drilling through build-up and horizontal sections in deep shale gas horizontal wells is low,which leads to long drilling cycle and high engineering costs.This paper systematically summarizes the difficulties and challenges in achieving"single-trip drilling"for deep shale gas in southern Sichuan,analyzes the influencing factors such as complex geological structures,target formation temperature,formation pressure,and drilling fluid properties,and reviews the current key technological advancements and application results in"single-trip drilling"in this area.Based on these findings,the paper proposes research directions and recommendations,including the precise control of drilling fluid density and ECD,studies on borehole heat transfer and phase-change cooling materials,and the testing of"slim hole"drilling technology,taking into account factors such as geology,well structure,wellbore trajectory,drilling fluids,and equipment.
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