致密气藏气井递减方法研究

Research on gas well decline method in tight gas reservoir

目前国内对产量递减规律的研究较多,对产能递减规律的研究较少,并且对两者的区分不是很明确。苏里格致密砂岩气藏目前的递减方法大部分为产量递减规律多,对产能递减规律的研究及应用相对较少,而且在应用方面相对的比较模糊。苏里格气田因特殊的生产工艺条件,气井井底压力、产量之间具有较好的两项式拟合,即气井在节流器条件下生产,随着井底压力的减小,气井产量逐渐减小,但不存在绝对意义上的稳产。气井产量是一个生产状态参数,反映气井目前的生产现状,随地层压力和气井生产能力的降低,可以通过工艺措施来维持恒定产量,但最终仍将以一定规律递减。气井产能是一个生产能力参数,反映油气井目前的生产能力,主要受储层地质条件的影响,随地层压力的降低,产能始终是逐渐递减。由于目前对气井产量递减规律与产能递减规律的研究在概念上有相互混淆的状况,利用苏里格气田实例对产量递减规律与产能递减规律做一明确的分析,可以为苏里格气田选择适合致密砂岩气藏的递减分析方法。

There are some researches on the rules of production decline at home,but less on the productivity decline,and the distinction between them is not clear.Now most of the decline methods in Sulige tight sandstone gas reservoirs are the rules of production decline,the research and application on the rules of productivity decline are relatively less,and the application is fuzzy.Because of the special production technology conditions in Sulige gasfield,there is a good binomial fit between the bottom hole pressure and production,that is,the gas well is produced under the condition of throttling,and the production of the gas well decreases gradually with the decrease of the bottom hole pressure,but there is no absolute sense of stable production.Gas well production is a production state parameter,which reflects the current production status of gas wells.With the decrease of formation pressure and gas well production capacity,constant production can be maintained through technological measures,but it will eventually decrease in a certain order.Gas well productivity is a productivity parameter,which reflects the current productivity of oil and gas wells and is mainly affected by the geological conditions of the reservoir.With the decrease of formation pressure,the productivity decreases gradually.Due to the concept confusion on the rules of production decline and productivity decline,we can use the example of Sulige gasfield to make a clear analysis on production and productivity decline rules,and choose the decline analysis method suitable for tight sandstone gas reservoirs for Sulige gasfield.