天然气藏欠平衡水平井钻井技术在HW801井的应用

HW801井是新疆油田第1口采用欠平衡方式实施的天然气藏大位移水平井,也是新疆油田首次部署水平段长达1000 m左右的水平井。长水平段延伸钻进中存在钻具摩阻、扭矩大,井眼净化困难,容易形成岩屑床,轨迹控制效率和精度低,采用液相欠平衡控压钻井作业,如何有效实现井控目标等技术难题。通过优化钻具组合和钻井参数,保证了钻压的有效传递,井眼轨迹平滑;FJQ-245型井下封井器和双节流管汇的合理应用,实现了三开全套欠平衡钻井作业;利用固控设备来控制好钻井液性能,以"净化"保"优化",满足有效携岩的要求。通过解决以上难题,HW801井安全钻进至井深3358 m,其中水平段长1051.92 m,为以后欠平衡大位移水平井钻井提供了成功经验。

Application of Natural Gas Underbalanced Horizontal Well Drilling Technology in HW801 Well

Well HW801 is the first natural gas underbalanced horizontal well in XinJiang oilfield, and also the first 1000 m horizontal section length well. In drilling the extended long horizontal section, these problems protrude relatively; including drilling rig＇ s driving torque, cuttings transportation, well path control, well control in liquid phase underbalanced drilling, and so on. By optimizing make up of string and drilling parameter,ensure drill bit weight can be transmitted effectively, well trajectory is smooth; the application of FJQ-245 down hole BOP and bi-choke manifold fulfill the complete under balanced drilling in third section; the solids control system optimized drilling fluid, can meet the satisfy of cuttings transportation. After these problems solved, well HW801 was finished at measured depth of 3358 m with 1051.92 m horizontal section,provide referenced successful experience for posterior under balanced extended horizontal well.