氮气泡沫压裂优化设计与应用实践

Optimal Design and Application of Nitrogen Foam Fracturing in Sulige Gasfield

苏里格气田地层压力系数低,部分区块水敏、水锁问题突出,常规水基压裂用水量大、压后排液困难,进而严重影响气井产能发挥,采用氮气泡沫压裂是该类气藏提高单井产量有效手段之一。为提升氮气泡沫压裂液整体性能、评价泡沫压裂液体系,应用闭式混砂车和微泡沫发生器等辅助设备、优选?88.9 mm施工管柱和“变冻胶液浓度+变泡沫质量+变粒径陶粒”的施工参数。在苏X井进行了氮气泡沫压裂现场试验表明,优化后的泡沫压裂液稳泡性能、造缝效率、携砂能力明显提升,与同区块常规胍胶压裂相比,地面最高砂浓度达1452 kg/m^(3),用水量减少62%,排液周期缩短47%,测试无阻42.9×10^(4)m^(3)/d,实现了用水少、携砂高、见气早的改造目的,在低压致密气藏的储层改造中显示出良好应用前景。

The formation pressure coefficient of Sulige gas field is low,and the problems of water sensitivity and water lock are prominent in some blocks.Using conventional water-based fracturing has the problems of large water consumption and difficulty in discharging the flowback fluid,which seriously affects the production capacity of gas wells.Nitrogen foam fracturing is one of the effective means to increase the production of single well in this kind of gas reservoir.In order to improve the overall performance of nitrogen foam fracturing fluid,the foam fracturing fluid system was evaluated,auxiliary equipment such as closed sand mixer and micro-foam generator was applied,theØ88.9 mm pipe string and the operation parameters of"variable gel concentration+variable foam quality+variable particle size ceramic particle"were selected.Su X well was taken as an example to carry out the nitrogen foam fracturing field test.After optimization,the foam fracturing fluid's bubble stability performance,fracture-forming efficiency and sand carrying capacity were significantly improved.Compared with conventional guanidine gum fracturing in the same block,the maximum surface sand concentration reached 1452 kg/m^(3),the water consumption was reduced by 62%,the liquid discharge cycle was shortened by 47%,and the test open flow achieved 429,000 square meters/day.It realizes the purpose of less water consumption,high sand carrying and early gas discovery,and shows a good application prospect in the reservoir reconstruction of low pressure tight gas reservoirs.