机械分层压裂工艺技术在江苏油田的研究和应用

RESEARCH & APPLICATION OF MECHANICAL SEPARATE LAYER FRACTURING TECHNOLOGY IN JIANGSU OILFIELD

江苏油田低渗薄互层油藏层间矛盾日趋严重,层多、跨距大、物性差异大。为缓解层间矛盾,提高最终采收率,必须加强低压低渗油层压裂改造。传统压裂工艺采用多层合压或填砂压裂,多层合压,裂缝便在物性较好的油层中延伸,而低渗透油层难以被压开,影响压裂效果。填砂压裂,施工周期长,工序复杂,费用高。所以利用最小的投入产出比挖掘各油层潜能,应对低压低渗油层实施分层压裂改造工艺。通过对国内外资料进行调研,优选出机械卡封分层压裂工艺。近两年在现场实施了15井次,取得了很好的应用效果。施工、解封均一次成功,压裂工艺成功率100%。做到在不压井、不放喷、不动管柱的情况下,连续对两个物性差异、间距较大层段进行压裂,使每个油层的潜力得到充分的发挥,单井节约压裂费用24.5万元,压裂累计增油近三万吨。同时机械分层压裂比填砂压裂节约了作业耗时2d,为压后及时开抽赢得了时间,取得了明显的社会效益。

Interlayer interference for low permeability thin interbedded reservoirs is becoming more and more serious in JS Oilfield.To ease the interlayer interference and improve the ultimate recovery,the low pressure and low permeability reservoir should be stimulated.Traditional fracturing technology for stimulating this kind of reservoir consists of commingled fracturing and gravel input fracturing.For commingled fracturing,the fracture inclines to extend in high permeability layers and not to low-permeability layers,which affect fracturing effect.For gravel input fracturing with complex procedure,the construction cycle is long and cost is also high.Therefore,mechanical separate layer fracturing technology should be used to develop the low-pressure and low permeability reservoir potential so as to achieve smallest input-output ratio.After investigating and researching the domestic and international data,the technology of mechanical separate layer fracturing is optimized to apply in JS Oilfield.In the past of two years,field application is made in 15 wells with success ratio of 100%.Without killing well,blowing off and moving string,two layers with different physical property and large interval could be fractured continuously,which could stimulate maximal potential energy for each layer.Compared with the gravel input fracturing,mechanical separate layer fracturing could save the operation time of two days which is beneficial for post-fracturing flowback in time.In addition,the fracturing cost could be saved about 0.245 million and the cumulative incremental production is up to 3 104t for each well.