文96储气库注采井井筒完整性研究

Study on Wellbore Integrity of Injection-production Wells in Wen96 Underground Gas Storage

文96地下储气库已经历了七个完整的注采周期,经过反复高强度注采运行,对注采井井筒密封性要求更为苛刻。结合已投产注采井井筒实际情况,建立了力学分析模型,开展不同工况注采运行模式下注采井固井水泥环力学评价,引入失效判别准则评价其力学性能。通过注采载荷等效设计和时间等效设计,建立了井筒完整性等效物理试验装置,开展周期性注采及不同压力差下水泥环模拟试验,探讨注采井井筒完整性影响因素,为文96地下储气库后期科学注采提供技术支撑。以地层(井壁)—水泥环—套管力学评价模型和室内评价试验为基础,综合研究储气库注采井的生产制度和补救措施。针对文96储气库注采井,开发了一套防止气体泄漏的井筒安全保障技术。

Wen96 underground gas storage experienced seven complete injection-production cycles.After repeated high-strength injection-production operation,the sealing requirements of wellbores were more stringent.Based on the actual practice of injection-production wells,the mechanical analysis model was established,mechanical evaluation of cement sheath under different operation conditions was carried out,and the failure criterion was introduced to judge its mechanical properties.Through the load equivalent design as well as the time equivalent design,equivalent physical test of the wellbore integrity was established.Then simulation tests of the cement sheath under different pressure difference of periodic injection and production were carried out to explore the influencing factors of wellbore integrity,which provided technical support for scientific injection and production of Wen96 underground gas storage in the later stage.According to the mechanical evaluation model of stratum-cement sheath-casing along with laboratory evaluation test,production system and remedial measures of the injection-production well were comprehensively studied.Moreover,safety guarantee technology to prevent gas leakage was established for injection-production well in Wen96 gas storage.