Analysis of Casing Mechanical Characteristics During Pick-up and Release Processes in Shale Oil Horizontal Wells
In order to improve the casing running ability of shale oil horizontal wells,the technology of pick-up and release has become an essential part of casing running.However,in the process of pick-up and release for many times,the wellbore casing generally breaks and fails.Therefore,based on the actual casing running operation of a shale oil horizontal well,combined with elastic-plastic theory,this paper uses finite element software to establish the dynamic model of casing pick-up and release in the whole well section,and studies the axial force,friction and Mises stress distribution of the casing in the single and multiple operations.It is found that in the process of pick-up and release,the cumulative elastic energy of casing is released in the pick-up stage,and accumulated again in the release stage.The Mises stress,frictional resistance and axial force of downhole casing decrease significantly after a single pick-up and release operation,and the running ability of casing is improved to some extent.In the process of multiple pick-up and release in a short period of time,with the rapid accumulation and release of elastic energy of local casing,some casing is always in an accumulation state under the action of friction,and e-ventually the local casing buckling behavior is further aggravated.Therefore,the mechanical behavior and risk analysis during casing pick-up and release can provide some guidance for the efficient and safe running of casing in horizontal wells of shale oil.
shale oil horizontal wellcasing downrunning frictionpick-up and releaseelastic energy
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