Research On Wellbore Integrity Evaluation Of High Pressure Gas Wells

Gas well integrity is the key index to resist structural damage and ensure normal operation of gas wells.For high-pressure gas wells,once the integrity of gas wells has problems,it may lead to gas reservoir loss,blowout and other accidents,even extremely dangerous consequences.The research on the integrity of high pressure gas wells at home and abroad is still in its infancy.Through the study of wellbore integrity of high-pressure gas-wells,the establishment of its integrity evaluation system is of great significance for the safe construction and production of high-pressure gas wells.In terms of the factors affecting the integrity of high pressure gas wells,the wear test results of technical casing and reservoir casing are obtained through experiments.The wear coefficient and friction coefficient obtained from the wear test results are simulated and analyzed by Cwear software,and the casing wear,residual strength of technical casing and reservoir casing are predicted respectively.Wear and lateral force situation;Cementing cement stone evaluation and cementing quality evaluation of Shuangxuan 3 well;Considering the characteristics of high pressure gas well,starting from annulus pressure,the theoretical model of annulus pressure change under thermal effect is established;A ring under different pressure is calealated under different operation conditions in Shuangxuan 3' well.Maximum allowable pressure values in annulus B and C.The maximum allowable annulus pressure of Shuangxuan 3 well is calculated,and annulus pressure control chart is drawn based on the evaluation of wellbore integrity before completion.The principle of gas well integrity barrier is obtained through theory and experiment on wellbore integrity index system,which can be divided into first-class gas well integrity barrier and second-class gas well integrity barrier,which has certain guiding significance for gas wellbore integrity evaluation.