致密砂岩气藏大型压裂工艺技术研究与应用——以新场沙溪庙组气藏为例

新场沙溪庙组气藏是国内典型的低渗致密砂岩气藏,储层具有＂纵向厚度大、平面展布广、盖层遮蔽性能好、盖层与产层应力差值明显＂等适合于大型加砂压裂改造的地质基础和条件。气藏前期采用中小规模压裂时,单井压后表现出了＂产量递减快、稳产效果差＂等不利于气藏提高采气速度和整体采收率的状况。大型压裂是增加人工裂缝半长,延长气井采气寿命,提高开采效益的重要手段。通过对制约和影响大型加砂压裂改造效果的系列关键工艺技术的攻关研究,研发出了低伤害压裂液体系,提出了压裂液强化破胶和高效返排工艺,并对大型压裂施工参数进行优化设计,最终形成了以＂大砂量、大排量、中—高砂浓度、强化破胶＂为特色,以造长缝为核心的大型压裂关键工艺技术方法,并成功完成了最大加砂规模200.5 m^3的超大型水力加砂压裂现场试验。现场应用实践表明,大型压裂具有＂稳产效果好、勘探评价效益优＂的特点。

Massive hydraulic fracture research and its application to tight sandstone gas reservoir——Taking Shaximiao gas reservoir in the west of Sichuan Basin as an example

Shaximiao reservoir of Xinchang gas field is a typical low permeability and tight sandstone gas reservoir in China with great thickness,large-scale sand body,large well spacing,and obvious stress difference between cover and pay formation,in which massive hydraulic fracture can be carried out to prolong producing time of gas wells.Low damage fracturing fluids was formulated,viscosity break was intensified,high efficiency flowback technology was used,and parameters of massive fracture were optimized.At last,massive hydraulic fracture with the characteristics of large scale,high flow rate,middle-high proppant concentration,and forced viscosity break was successfully operated in field,and the largest scale of fracturing was 200.5 m^3.The field application practice indicated that the fracture effect was exceptionally remarkable.