The Research Of Cable Driven Casing Cutter

With the development of oil and gas engineering,it is difficult to avoid various forms of casing wear.In order to avoid more serious accidents such as well collapse and sticking,it is necessary to timely cut,salvage the damaging casing and replace the new casing.For the more or less flaws of traditional tools,it is very important to design a safer and more efficient downhole cutting tool.This paper designs a cable delivery casing cutter,which has the following features: simpler cutting process,shorter working time,higher cutting quality,more accurate cutting,and multiple cutting operations in a single operation.This article has detailed design from the aspects of driving,transmission,sealing,anchoring and cutting.Because of the traditional anchoring mechanism can’t meet the anchoring requirements,this paper designed a two-degree-of-freedom slider linkage mechanism for anchoring.The theoretical calculation and optimization of the anchoring force are carried out.A slip structure with a large equivalent friction coefficient is used.The finite element analysis is performed on the stress distribution of the slip tooth profile and the contact between the slip and the casing.The anchorage mechanism is analyzed.The problem of dead point will moving and the instability of the initial state caused by the degree of freedom is analyzed.For these problems,an optimization scheme is proposed.Through the study of the spindle rotation,radial feed and the circumferential feed motion during the cutting process of the cutter,the tool movement is studied and calculated;A series of special reducers,such as the NGWN(II)type of large reduction gear reducer,GW type gear reducer and helical gear linear motion and rotary motion conversion mechanism are selected.The basic parameters of the special structure of reducer has been designed and calculated.In view of the uncertainty of the motion of the anchoring mechanism in the design,the dynamics simulation of the anchoring mechanism is carried out by the using of ADAMS software to verify the correctness of the theoretical analysis.The LS-DYNA software is used to show the kinetics analysis of the cutter about cutting process.The contact stress between tool and bushing is analyzed.Compared with the existing downhole cutting tools,this cutter has certain advantages and promotes the research of cutting downhole tubular columns,which has certain reference value.