Continuous Tube Erosion Wear And Residual Life Study

With the horizontal well is widely used in low permeability reservoirs,and the rapid development of coiled tubing(CT)technology,the fracturing technology of CT started with its flexible drag and the superiority of water-jet perforating fracturing point has been widely used in horizontal well fracturing.The fracturing technology of CT is the use of high-pressure pump fracturing fluid with high viscosity through continuous tube or annulus fracturing fluid into the reservoir,but in the process of fracturing through high speed will cause severe impact on the wall pipe,and causing the erosion of CT's wall.Erosion makes CT's wall thinning,pits and cracks in the coupling effect of multi load.The parts of the serious erosion wear in CT's wall will be prone to plastic deformation,perforation or fracture failure,and resulting in failure of fracturing wells or even scrapped.In this paper,the problem of the failure of CT in the high speed fracturing fluid is studied.Based on the domestic and international literatures on the research of hydraulic fracturing technology and erosion wear,the erosion of CT' wall in hydraulic fracturing technology is studied by using the fluid mechanics CFD technique.Based on the relationship between erosion wear and residual service life,the remaining service time of CT is predicted,and some suggestions are put forward.During the thesis,the works of the following aspects have been done:(1)The research status of hydraulic fracturing and erosive wear at home and abroad is summarized,which is helpful to the study of CT erosion.(2)Through the comparison of the numerical results and the experimental results,combined with the theory of erosion wear,a feasible numerical model of CT erosion wear is established.The residual life prediction model is used to reveal the law of erosion and wear of CT by combining the numerical calculation of the erosion results of CT with the remaining service life.(3)Based on the numerical model of erosion and wear of CT and the prediction model of remaining service life,the erosion and wear law of CT under different sand adding modes in hydraulic fracturing technology is studied.The purpose of this paper is to find out the law of erosion and abrasion of CT and the serious erosion wear.(4)Based on the theory of fluid solid coupling,the erosion behavior of CT under vibration is studied and compared with that of CT.(5)By using the numerical model of CT erosion wear,the erosion of CT with defects was studied.To find out the main factors causing the erosion of CT with defects.The research work of this paper,it is helpful to reveal the continuous erosion mechanism of tube hydraulic fracturing operations,different parameters and different working conditions of continuous tube erosion rules and guide the on-site operation,effectively reduce the erosion of coiled tubing in hydraulic fracturing.Combined with the residual life prediction model.it can be used as a guide for the rational use of the worn CT.