超低渗岩性油藏水平井分段注水实践

Water injection practice of horizontal wells in ultra-low permeability lithologic reservoirs

鄂尔多斯盆地X油田长7超低渗岩性油藏砂体薄层发育、储层物性致密,地层能量不足,常规直井开发产能低,水平井压裂投产可以获得较高产能,但天然能量开发条件下产量递减快,整体采出程度低。通过论证开展注水开发先导试验,采用水平井注采井网、水井超前注水、分段注水在提高地层压力的同时扩大注水波及,油井采用分段压裂投产,与水井水线形成交错缝注采驱替,注采排距40~50 m。应用后油井初产提高,可以稳产4~5个月,产量递减明显减缓,显示了水平井超前注水、分段注水开发在薄油层较好的潜力。

There are thin layers of sand bodies,dense physical properties,and insufficient formation energy in the Chang 7 ultra-low permeability lithologic oil reservoir,X oilfield of Ordos Basin.The development capacity of conventional vertical wells is low,and higher productivity can be obtained by fracturing the horizontal wells.However,under the conditions of natural energy development,the production declines rapidly and the overall recovery is low.Pilot test of water injection development through demonstration,horizontal well injection-production well pattern,advanced water injection,and sub-stage water injection are adopted to increase formation pressure and extend water injection,oil wells are put into production by staged fracturing,which the injection-production displacement with intersecting fractures formed by water well waterline,with the injection and mining row spacing 40~50 m.After the application,the initial production of the oil well is improved,which can stabilize the production for 4~5 months,and the production decline is slowed down significantly,which shows the better potential of the horizontal well segmentation advanced water injection development in thin oil layers.