气藏中CO_2含量对气井产能的影响

Influence of CO_2 Content on Gas Well Deliverability

我国松辽盆地火山岩天然气气藏组分中均含有一定量的CO2,其含量为3%～98%。CO2气体在储层高温高压条件下呈超临界状态,是一种非常稠密的气体,这对气井产能会造成一定影响。分析表明,随着CO2含量的增加,地层条件下的拟压力降低,从而导致无阻流量即产能降低。根据该结论,可对相似储层条件下未知气井的产能作定性判断和定量评价。

Volcanic natural gas reservoirs in Songliao Basin contain a certain quantity of CO2, with content of 3%-98%. Under high temperature and high pressure, CO2 which exists in a supercritical state is a very dense gas. This will to some extent influence gas well deliverability. Analysis shows that as CO2 content increases, the pseudopressure under formation condition drops, which results in a decrease of open flow capacity (namely, deliverability). Based on the conclusion, the qualitative judgment and quantitative estimation of the deliverability can be made for unknown gas wells under similar reservoir conditions.