深井水平井欠平衡钻井液技术研究

Research on Underbalanced Drilling Techniques for Deep Horizontal Wells

松辽盆地南部深层火山岩埋深在3500m以上,采用直井开发效益低。经论证决定采取水平井技术与欠平衡钻井技术相结合的方式,实现高效开发,更有利地保护气藏。长深平1井面临井底温度高、水平段施工周期长、敏感性气藏保护难等不利因素,分析可能出现的井壁失稳坍塌、高温钻井液携岩差、钻井液污染损害气藏等问题,开展了深井欠平衡水平井的抗高温井壁稳定技术、抗高温携岩润滑技术、气藏保护技术等研究工作,经过现场应用,取得了成功,形成了抗高温深井水平井钻井液技术成果,满足了深层气藏的高效开发需求。

The volcanic rocks are buried in the depth of more than 3,500m in southern Songliao Basin, so the development effect by using vertical wells is not so satisfying. Through demonstration the method of using horizontal wells and the underbalanced drilling technique are decided to be used to realize high-efficiency development and better protect gas reservoirs. Unfavorable factors exist for Changshen horizontal well 1, such as high bottom hole temperature, long time of construction in the horizontal section, and difficult protection of sensitive gas reservoirs. Analysis shows that some problems may exist, such as wall instability and collapse, differential pressure of high-temperature drilling fluid, the pollution and damage of drilling fluid to gas reservoirs. Study is carried out including the high-temperature wall stabilization technique for deep underbalanced horizontal wells, the high-temperature rock-carrying lubrication technique, and the gas reservoir protecting technique. Good results are obtained through field application, and systematic high-temperature deep horizontal drilling techniques are developed, meeting the requirement of high-efficiency development of deep gas reservoirs.