Design And Research On Cutting And Retrieving Tool Of Deepwater Subsea Wellhead System

With the increasing development of offshore oil and gas exploration, the increasing protection of the people on the Marine environment, the cutting and retrieving of wellhead system becoming one of the critical operation during well abandonment operation. In this paper, based on the subsea wellhead cutting and retrieving operation as the research object, to develop new type cutting and retrieving tool of deepwater subsea wellhead system. And according to the design tools made the operation parameters, optimizing supporting tools.This paper studied the cutting and retrieving principle and method of different casing in the typical well bore, identified the technological solutions of cutting and retrieving 20 "+ 30" casing and wellhead using the hydraulic cutter as the tool to cut casing. Analyzed principles and operation of stretch cutting, determined the cutting tool assembly of the operation.Proposed the structure scheme of the key equipment —the outside stretch latch tool, and designed structure according to the drill pipe rotary cutting and downhole power cutting, completed the detailed design of the outside stretch latch tool, designed the two dimensional drawings and created 3D digital prototype.Simulated the design tool assembly process and operation method.Based on finite element analysis software ANSYS, outside stretch latch tool strength analysis has been done. Adapt PDM drill as power source of downhole cutting and designed the corresponding outside stretch latch tool. Analyzing hydraulic parameters requirements, matching reasonable liquid displacement and cutter piston nozzle diameter, choosing the appropriate PDM guarantee the smooth realization of the cutting process. Compared the advantages and disadvantages of drill pipe rotation dynamic cutting and downhole cutting method, guarantee the operation suit different sea condition.