超深气井环空带压分析与控制研究

Research on Analysis and Control of Annular Pressure in Ultra-deep Gas Wells

超深气井在生产过程中受到高温、高压和腐蚀介质等复杂工况影响,导致井筒完整性面临严峻挑战,其中环空带压风险是亟需关注的技术问题之一。针对超深气井环空带压问题,文章系统总结了国内外专家学者相关研究成果和进展,主要包括环空压力的产生机理、预测方法及其对其井筒完整性的影响,并考虑环空最大允许压力值、环空带压类型诊断和井筒完整性检测等关键环节,提出了一套环空压力安全管控流程,以期为超深气井安全高效开发提供有益参考。分析认为:准确预测环空压力是评估环空带压风险的基本前提,在计算中应充分考虑环空温度、流体性质、流体体积和环空体积的变化;环空带压风险主要体现在套管的承载能力和水泥环的密封可靠性;环空压力安全管控流程可分为计算环空最大允许压力值,诊断环空带压类型和检测井筒完整性三个步骤。从而为有效预防环空带压提供技术思路。

Ultra-deep gas wells are affected by complex working conditions such as high temperature,high pressure,and corrosive media,leading to severe challenges to wellbore integrity.Annular pressure risk is one of the important technical problems in wellbore integrity.Focusing on the problem of annular pressure in ultra-deep gas wells,this paper systematically summarizes the research progress and achievements of domestic and foreign experts and scholars,including the formation mechanism,prediction method,and its influence on wellbore integrity of annular pressure.Finally,a safety control process of annular pressure is proposed from the aspects of the maximum allowable value of annular pressure,annular pressure type diagnosis and well integrity monitoring,which provides a valuable reference for the safe and efficient development and design control of ultra-deep gas wells.The analysis indicates that accurately prediction of annular pressure is the basic premise for evaluating the risk of annular pressure.It is necessary to fully consider the changes in temperature,fluid properties,fluid volume,and annulus volume in the calculation.The risk assessment of annular pressure is mainly reflected in the loading capacity of the casing and the sealing reliability of the cement sheath.The wellbore pressure safety management process divides three steps:calculation of the maximum allowable annular pressure,diagnosis of annular pressure types,and integrity testing of the wellbore,which can provide technical ideas to effectively prevent the potential risk of annular pressure.