泥线下多层套管切割技术研究及适用性优选

Cutting Technology Research and Applicability Optimization for Multi-layer Casings under Mudline

为解决海上油气井永久性弃置面临的泥线下多层带水泥环套管高效切割问题,针对常用的水力割刀切割技术及磨料射流切割技术,分析了两种技术的特点及优势,从切割层次、切割尺寸、切割效率及服务费用等方面开展了研究工作;建立了考虑切割层数、切割工期等切割技术经济性比选公式;研究了两种切割技术的适用性,形成了基于套管尺寸和切割层数的多层套管切割技术优选原则。研究结果表明,当切割层数<3层且最外层导管尺寸≤609.6 mm时,推荐水力割刀工具;当切割层数≥3层或最外层导管尺寸>609.6 mm时,推荐磨料射流工具。结合现场应用实例分析,对比了两种技术对3层及以上套管的切割效果,验证了两种技术的适用性。该研究可为海上油气井多层套管整体切割提供技术依据。

In order to solve the cutting problem of multi-layer casings with annulus cement faced during offshore well permanent abandonment,aiming at the commonly used hydraulic cutter technology and abrasive jet cutting technology,the characteristics and advantages of them were analyzed in details,based on the analysis of casing layers,cutting size,cutting efficiency and sevice cost,the economic comparison formula of cutting technology was developed with consideration of cutting size and cutting duration.The applicability of two cutting technologies was studied,and?the optimization principle of multi-layer casing cutting technology based on casing size and cutting layers was formed.The results show that when the casing layers number is less than 3 and the outer conductor size is 609.6 mm or less,hydraulic cutter is recommended.When casing layers number is 3 or more,and the outer conductor size is larger than 609.6 mm,abrasive jet cutting technology is recommended.Combining with field application analysis,results of the two technologies for cutting 3 layers casing were compared,and the applicability of the two technologies was verified.The study will provide technical basis for offshore well multi-layer casing cutting.