特种油气藏2026，Vol.33Issue(4)：59-65,7.DOI:10.3969/j.issn.1006-6535.2026.04.008
气体组分动态演变对稠油注氮热采井安全影响
Safety impact analysis of dynamic evolution of gas compositions on heavy-oil thermal recovery wells with nitrogen injection
摘要
Abstract
During heavy-oil development operations with nitrogen injection,downhole explosion hazards may still exist during field operations even when the purity of injected nitrogen meets industry standards.With a typical field downhole explosion accident as the research object,this study systematically analyzed the dynamic evolution mechanism of explosion-inducing factors in nitrogen-injection thermal-recovery wellbores from four dimensions:crude-oil properties,combustible forma-tion,oxidant conditions,and ignition sources.The results show that hydrocarbon components in formation crude oil undergo cracking and volatilization reactions in high-temperature,high-pressure wellbore environments,continuously generating combustible hydrocarbon gases such as methane.Dissolution and dissipation of ni-trogen in the wellbore lead to imbalance in gas composition,causing the oxygen volume fraction in the system to gradually increase.The mixed-gas parameters enter the methane explosion-limit range,ultimately forming a highly hazardous explosive gas mixture.During steam-injection operations,mechanical collision of the tub-ing string,string friction,and fluid electrostatic accumulation can all generate energetic ignition sources,satisfying all conditions required for an explosion.Field measured data and comparative tests from adjacent wells in the same horizon verified the dynamic evolution pattern of gas compositions in the wellbore and the for-mation mechanism of explosive gas mixtures,clarifying the root cause of downhole explosion accidents.Based on the explosion-triangle theory,a risk prevention and control system for heavy-oil development with nitrogen injection was constructed,providing theoretical support for safety-risk identification and hazard prevention and control in heavy-oil nitrogen-injection thermal recovery.Targeted technical recommendations were also proposed for key links,including optimization of the ni-trogen-injection process,real-time monitoring of wellbore gas,and source control of ignition sources,providing a scientific reference for field safety management.关键词
安全风险/注氮热采/井筒爆炸/动态演变/稠油Key words
safety risk/nitrogen-injection thermal recovery/wellbore explosion/dynamic evolution/heavy oil分类
能源科技引用本文复制引用
张如韵,张来斌,董绍华..气体组分动态演变对稠油注氮热采井安全影响[J].特种油气藏,2026,33(4):59-65,7.基金项目
中国石油一体化创新基金项目"油气田注氮受效井氧气含量在线监测设备研发"(CNPC-20260204) （CNPC-20260204）
