高温条件下的固井第一界面水力胶结强度实验研究

EXPERIMENTAL STUDY OF HYDRAULIC CASING-CEMENT BONDING STRENGTH UNDER HIGH TEMPERATURE CONDITIONS

针对深水固井水泥环所处的高温高压环境及复杂温度变化,研制了一套全尺寸高温高压水泥环密封完整性评价装置.基于此装置,利用气窜法测试了高温高压养护条件下的固井第一界面水力胶结强度,开展了水泥浆养护温度、养护时间以及温度变化等因素对固井第一界面水力胶结强度的影响实验.实验结果表明,水泥浆养护时间72 h时,随着养护温度的升高,水力胶结强度逐渐增加;水泥浆养护温度200℃时,随着养护时间的增加,固井第一界面水力胶结强度呈增加趋势,且养护时间达到5d时,水力胶结强度达到最大值,随后逐渐稳定;温度变化对固井第一界面水力胶结强度影响较大,随着温度的升高,水力胶结强度增大,反之,水力胶结强度减小.

According to the complex temperature variation in high temperature and high pressure(HTHP)deep water wells,a full-size HTHP experimental device is developed to evaluate the seal integrity of cement sheath.By the device,the hydraulic bonding strength(HBS)between casing and cement is measured and the effects of high temperature and its variation on the HBS are investigated.The results show that the HBS behaves differently to the different cement slurry curing time,different curing temperature and different temperature variation.With the increasing of curing temperature in the same curing time,the HBS increases gradually.While the HBS increases first and then inclines to stable value with the increasing of curing time in the same curing temperature.The temperature variation has significant effects on HBS.HBS increases obviously with the increase of temperature.This study will be a certain guideline for evaluating the sealing integrity of cement sheath in HTHP wells.