Research On Digital Modeling And Twinning Methods For Coiled Tubing Considering Material Damage Characteristics

Compared to conventional tubing,coiled tubing has the characteristics of high operating efficiency and low operating costs.And the technology of coiled tubing operation has been widely applied in oil fields.The bending characteristics and insertion process of coiled tubing operations determine that each operation will experience fatigue and wear,leading to a decrease in material properties and a loss of tubing wall thickness.There is a significant difference between the calculation and prediction before coiled tubing operation and the actual operation situation,which is due to the difficulty in evaluating complex downhole conditions and accurately analyzing the damage suffered,resulting in significant calculation errors in the mechanical analysis of the tubing string.The safety issue of coiled tubing after multiple operations is currently one of the key issues that constrain the application of coiled tubing.This paper conducts research on safety analysis issues during coiled tubing operations.Based on digital twin technology,the key information digital twin of the coiled tubing microelement segment was proposed,and the digital mapping research of the entire process of coiled tubing operation was carried out.The main work contents are as follows:(1)Aiming at the safety analysis problem in the coiled tubing operation process,a multidimensional coupling digital twin of coiled tubing with geometric structure and material characteristics is proposed,and a safety evaluation model of coiled tubing digital twin is established,which effectively solves the fragmentation characteristics of model information existing in the analysis of safety performance,and makes the multi-dimensional model description form strong coupling characteristics.(2)Establish a spatial structural feature model of coiled tubing ground structure,propose a digital twin method for coupling coiled tubing operation with ground structure,and obtain a refined calculation model for plastic deformation evolution of large-scale ultra-long structured coiled tubing;A spatial structure feature model of coiled tubing and wellbore casing has been established,and a digital twin method for coupling coiled tubing entry operations with downhole spatial structure has been proposed.Real-time contact analysis during the insertion process has been achieved,and a quantitative analysis model for coiled tubing operation wear has been obtained.(3)A coupled damage mathematical model for the structure and fatigue of coiled tubing was proposed,and a digital twin method for dynamic damage analysis of coiled tubing was established based on real-time dynamic information of multi-dimensional ground and underground structures during coiled tubing operations.Automated analysis of the entire process of coiled tubing operations was achieved,and an evaluation model for residual strength and service life of coiled tubing was proposed.A safety evaluation method for multiple operations of coiled tubing was established,software implementation has been carried out,and the engineering application effect is good.This article establishes a digital twin safety evaluation model for coiled tubing,effectively solving the problems of fatigue damage and structural damage during coiled tubing operation.It has important guiding significance and engineering value for monitoring the status,mechanical calculation analysis,predicting fatigue life,safety analysis,and building digital oil fields during coiled tubing operation.