南堡深层潜山水平井欠平衡钻井技术研究与实践

Research and practice of underbalanced horizontal well drilling technology in deep buried-hill reservoirs in Nanpu Oilfield

南堡潜山油气成藏条件复杂、纵横向非均质性强,为有效地提高裂缝钻遇率和实现经济开发,研究应用了水平井欠平衡钻井技术。针对油层埋藏深、井温高、气油比高、安全密度窗口窄、易漏易涌、安全钻进风险大等难点,通过研究抗高温水包油钻井液体系、气油比对欠平衡工艺影响,监测随钻地层压力与评价储层,设计欠平衡与控压钻进参数,分析南堡潜山钻进过程动静温度变化规律及潜山裂缝钻遇时的各项异常特性规律,形成了一套适合于南堡深层高温潜山水平井欠平衡钻井配套技术。应用结果表明,该技术有效地实现了南堡深层高温潜山安全钻进和经济高效开发,对同类油气藏的钻井施工提供了借鉴。

The reservoir forming condition of buried-hill is complex in Nanpu Oilfield,and the vertical and horizontal heterogeneityis very strong.In order to effectively raise fracture penetration rate and achieve economic development,underbalanced drilling technologyfor horizontal wells was researched and applied.For the following drilling risk situations,such as： deeply buried,high temperature,high gas-oil ratio,narrow density window,prone to lost circulation and well kick,etc,a series of studies are conducted,such as optimizinga temperature resistant oil-in-water drilling fluid system,analyzing the gas-oil ratio and the application of real-time pressuremonitoring and reservoir evaluation technology,designing the underbalanced and managed pressure drilling parameters,monitoringdynamic and static temperature variation and the abnormal characteristics when drilling buried-hill fracture,a set of underbalanced drillingtechnology was developed for horizontal wells in deep buried-hill reservoirs with high temperature in Nanpu oilfield.The resultsof application show that the technology is able to ensure safe drilling and economic development for buried-hill reservoirs in NanpuOilfield,and also to give references for drilling the same type of reservoirs.