关键词: 低渗透砂岩油田, 有裂缝砂岩储层, 裂缝延伸压力, 沿裂缝线, 状注水

Abstract: Natural fractures in low permeability sandstones can be divided into two types, microfracture and macrofracture. Reservoirs of low permeability sandstone can also be divided into two types, microfractural and macrofractural. Some identifying criteria are proposed in this paper. The microfractural reservoir is sensitive to water injection pressure. It takes the fracture spreading pressure as a critical injection pressure, over or under which, the ressrvoir will have quite different performance. Microfractural reservoir, injected at a pressure over the critical value, as well as macrofractural ones, can have a benefit of high water injection rate, under the condition of linear injection pattern along the only one fracture direction, without any fracture open in cap rocks.