注空气采油油井产出气体燃爆特性

Explosion characteristics of oil well produced gas by air injection for improved oil recovery

注空气采油工艺过程中存在产出气爆炸等安全问题,在分析产出气-空气混合物爆炸体积分数极限主要影响因素的基础上,利用Le Chatlier公式和图版计算混合物的爆炸体积分数极限,估算临界氧含量,采用圆柱状爆炸容器,在20～90℃、0.2～1.2 MPa下对产出气-空气混合物进行燃爆特性试验,确定爆炸体积分数极限范围、临界氧含量及爆炸区域,制定油井氧含量的安全标准。结果表明：可燃产出气的爆炸体积分数极限和临界氧含量受温度、压力、氧含量、点火能量、位置和惰性气体等因素的影响;爆炸范围随温度、压力和氧含量的升高而变宽,危险性增大;临界氧含量随温度、压力的升高而降低;高温高压模拟工况条件下,爆炸范围和氧含量随惰性气体体积分数的增加迅速减小,惰性气体体积分数和氧含量对爆炸体积分数下限影响较小,而对体积分数上限影响很大。

The produced gas（hydrocarbon）-air mixture explosion may occur during air injection process for improved oil recovery（IOR）.The theoretical explosion volume fraction limit and critical oxygen content were calculated first by formula Le Chatlier and the chart based on influential factors analysis of hydrocarbon-air mixture explosion volume fraction limit.Then the hydrocarbon-air mixture explosion characteristics experiments were conducted within cylindrical container at 20-90 ℃ and 0.2-1.2 MPa,to determine the range of explosion volume fraction limit,the critical oxygen content and explosion region,and to develop the oxygen content safety standard.The results show that the explosion volume fraction limit and critical oxygen content of flammable produced gas are influenced by many factors such as temperature,pressure,oxygen content,ignition energy,position and inert gas.The explosion range becomes more broad and dangerous with the increase of temperature,pressure and oxygen content.The critical oxygen content decreases with the temperature and pressure increasing.Then under the simulated condition with high temperature and pressure,the range of explosion volume fraction limit and critical oxygen content decrease rapidly with the increase of inert gas volume fraction,and the inert gas volume fraction or oxygen content has more effect on the explosion volume fraction upper limit than the lower limit.