致密高含水气藏调整生产制度后动态变化及影响因素——以东胜气田锦30井区为例

Dynamic changes and influential factors in tight gas reservoirs with rich water after adjustment of working system:An example from Jin 30 well area,Dongsheng gasfield

为了充分认识致密高含水气藏调整生产制度后的生产规律,以鄂尔多斯盆地北缘东胜气田的锦30井区为研究对象,通过对调产井按调产比例、生产液气比、日产气量大小进行分级,分析压降速率及单井可采储量(EUR)生产动态指标变化及产生的原因,总结调产后气井的生产规律。研究结果表明:①下调生产制度井的压降速率受下调比例影响明显,随着下调比例的增加,压降速率下降比例呈直线上升;②下调生产制度井的EUR受生产液气比影响明显,随着生产液气比的增大而增大;③当提产比例小于50%时,上调生产制度井的压降速率基本不受提产比例影响,当压降速率大于50%时,上调生产制度井的压降速率受提产比例影响明显,随着提产比例增加快速上升,同时压降速率还受日产气量影响明显,随着日产气量增加而减少;④上调生产制度井的EUR受生产液气比影响明显,随着生产液气比增大而增大。结论认为:①上调井应选择日产气量大、生产液气比小的气井提产,且提产比例应小于50%;②下调生产制度井应选择生产液气比较大的气井,在满足携液的基础上尽可能增加下调比例。

Jin 30 well area,Dongsheng gasfield,northern Ordos Basin,was taken as an example in an effort to comprehend full production laws in tight gas reservoirs rich in water after the adjustment of working system.And some changes of production dynamic indexes such as pressure-drop rate and EUR were analyzed through the classification of adjusted production wells dependent on the adjusted rate,produced liquid-to-gas ratio,and daily gas production.Then,reasons for these changes were found out.Additionally,new production laws after adjusting production were summed up.Results show that(i)for a few wells with the adjusted production rate downward,the pressure-drop rate is significantly sensitive to the adjusted percent,namely the decrease of pressure-drop rate rises linearly as this percent increases;(ii)the EUR is obviously affected by the produced liquid-to-gas ratio,that is the former increases with the latter;(iii)for others with the adjusted production rate upward,the pressure-drop rate is greatly dependent upon both adjusted percent and daily gas production,namely,the decrease of pressure-drop rate remains stable when the adjusted percent is less than 50%.But it rises rapidly when this percent is above 50%and declines with the increase of daily production;and(iv)the EUR is obviously impacted by the produced liquid-to-gas ratio,that is the former increases with the latter.It is concluded that,among certain wells with the adjusted production rate upward,those with high daily production and small produced liquid-to-gas ratio should be selected for upward production adjustment by the percent below 50%,whereas for others with the rate downward,those with high produced liquid-to-gas ratio should be selected for downward production adjustment by a high percent where allowable for carrying liquid.