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.

摘要： 低渗透砂岩油田的天然裂缝可分为微裂缝和显裂缝两类.有天然裂缝的砂岩储层可分为微裂缝型和显裂缝型两类.本文提出了它们的鉴别标志.微裂缝型储层对注水压力很敏感,以裂缝延伸压力为注水压力的临界条件表现明显不同的动态特点.显裂缝型储层以及不得不超临界值注水的微裂缝型储层可以利用裂缝的高吸水能力,条件是只有一个方向裂缝吸水,采取治裂缝线就注水并防止隔层进水.

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