鄂尔多斯盆地宁陕区块深井钻井关键技术

Key drilling techniques for deep exploration wells in Ningshan block of Ordos basin

鄂尔多斯盆地宁陕区块位于鄂尔多斯盆地西缘冲断带,深井普遍存在多套压力体系,部分井的地层倾角大,井斜难控制;下部地层可钻性差、研磨性强。个别井深层温度达217.00℃,钻进过程中易发生漏、垮、卡等多种复杂情况,钻井速度慢,整体钻井周期长,严重影响深层高产气藏的效益化勘探开发。针对上部地层倾角大,采用单弯双稳钻具组合,Power–v垂直旋转导向系统防斜打直。分析下部地层岩性及可钻性,采用“孕镶金刚石+涡轮”复合钻进、氮气钻进等关键技术;针对高温条件下,优选抗高温处理剂及抗高温钻井液体系配方,形成一套适合宁陕区块深井钻井提速技术,对搞清储层空间类型和物性特征有着非常重要的意义。

There are many pressure systems in the deep wells of the Ningshan block of the Ordos basin.Located in the western margin of the Ordos basin,some wells have large dip angle,which is difficult to control;and the lower stratum has poor drillability and strong abrasiveness.The deep layer temperature of individual wells can reach 217.00℃,and various complicated situations such as leakage,collapse,and jamming are prone to occur during the drilling process.The slow drilling speed and long drilling cycle seriously affect the efficient exploration and development of deep high-yield gas reservoirs.In view of the large dip angle of the upper strata,the single bend bistable BHA is used,and the Power-v vertical rotary steering system is used to prevent deviation and straighten.By analyzing the lithology and drillability of the lower strata,the key techniques such as"impregnated diamond+turbine drilling"and nitrogen drilling are adopted.Under high temperature conditions,the formulation of high temperature-resistant treatment agent and high temperature-resistant drilling fluid system is optimized to form a set of speed-up technology suitable for deep well drilling in Changqing area,which is of great significance for understanding the spatial type and physical properties of the reservoirs.