Mechanical Analysis Of Casing Deformation And Hydraulic Plastic Restoration In Horizontal Well

At present, the casing damage is increasing year by year, and the problem of casing damage is becoming more and more serious, Casing damage can lead to many problems, such as oil well can not be normal production, the decline of production, the loss of reserves and so on,seriously plagued the development of oil fields, Therefore, in order to ensure the normal operation of casing damage and the stable production of oil field and reduce the direct and indirect economic losses that caused by casing damage wells. plastic operation of the horizontal well casing is different from straight well, Firstly shaping tool into the well is not centered, The shaping process is prone to bias wear,secondly the curvature of horizontal well is too large. Plastic tools lift and down difficultly, Vertical expansion is difficult. Therefore, in order to better guide the horizontal well casing plastic operation, to carry out the analysis of casing deformation and the mechanical analysis of hydraulic pressure reduction in horizontal wells is of great significance.In this paper, it mainly develops the analysis and research on the tube shaping of the necking deformation and ellipse deformation. Hydraulic ball shaper device is used in horizontal well casing deformed, The ball shaper device is divided into six levels, to plastic for casing step by step. The casing、cement sheath and strata are selected as the research objects, using finite element analysis method of elastic plastic and large deformation, established elastoplastic mechanical model of necking deformation, Respectively, in the case of cement sheath intact, partial damage of the cement sheath and the complete damage of the cement sheath, the radial force needed for the shaping of the hydraulic ball shaping device is calculated, It is concluded that with the increasing of the shaping series, casing radial force is gradually reduced,In the case of complete damage of the cement sheath, with the increase of the casing steel grade, the axial force of the hydraulic ball shaping device is increased. When the casing is ellipse deformation, the calculation method is as above,finally in elliptical flat rate constant, with the shaper stages increasing, the axial force of the casing is gradually increasing,with the increasing of the ellipticity, The axial force of the plastic device required for each stage is decreasing, and with the increasing of ellipticity hydraulic ball shaping final shaping effect is worse. The calculation of the radial force of the casing tube has provided an effective numerical calculation method for the plastic deformation, and provide reasonable construction parameters and theoretical basis for casing plastic construction.