基于浓缩理论的大型压裂破胶优化技术及应用

针对储层孔、渗条件很差的致密砂岩油气藏，常规的破胶剂加量技术已经不能满足大型压裂对破胶的更高要求，在考虑了压裂液在地层中由于滤失而产生浓缩效应的基础上，提出了一种新的压裂液破胶优化技术。通过压裂施工裂缝温度场模拟，不同温度条件下的破胶实验以及考虑液体滤失浓缩后的破胶实验，认为大型压裂施工现场破胶剂加量应该在常规加量基础上进行一定程度的增加，才能保证大型压裂的破胶效果，实现快速排液，降低伤害。该破胶优化技术在CX491井155.6m³大规模压裂施工成功应用，开井17h液体返排率达到了74.9%，且返排液破胶彻底，天然气测试产量从射孔后的0.2×10⁴m³/d（敞井）增加到14×10⁴m³/d（井口压力22MPa），目前该技术正在川西地区大型压裂施工中逐步推广。

Classif ication，Genesis and Significance of Nodular Limestone of Early Silurian in NW Sichuan

Aiming at the tight sandstone reservoirs in which,there is poor porous and permeability condition,large scale fracturing is the effective way to improve the development effect.Because the conventional technology of gel breaker addition amount can not satisfy the higher requirements of gel breaking,a new optimization technology of fracturing fluid gel breaking is proposed which is on the basis of considering concentration effect caused by filtration of the fracturing fluid in the formation.Through simulating the temperature field of fracture,gel breaking test under the different temperature condition and considering the gel breaking after concentration of fracturing fluid filtration,it is suggested that on the spot of large scale fracturing gel breaker addition amount should be higher than conventional amount,as to be able to ensure the gel breaking effect of the large scale fracturing,to realize the quick flowing back,decrease damage.The new gel breaking optimization is applied successfully in large scale fracturing,the technology is successfully applied in well CX491155.6 m³ fracturing,the flowback efficiency is 74.9% after 7hours opening well and flowback fluid is intensive.Testing recovery rate increase to 14×10⁴m³/d (the wellhead pressure is 22MPa) from 0.2×10⁴m³/d after perforation.The technology is popularized gradually in large scale fracturing in Weston Sichuan.