动态法划分流动单元——以现河庄油田为例

Dynamic division of flow units:taking Xianhezhuang oilfield as an example

根据单采层无水采油期每米采油指数、分布特征以及所对应的空气渗透率和相对渗特征,将河43断块沙河街组二段储层分为5类流动单元:Ⅰ类储层渗透性最好,Ⅱ类储层渗透性较好,Ⅲ类储层渗透性一般,Ⅳ类储层渗透性较差,Ⅴ类储层渗透性差。平面上,厚度大于3.5m的主力小层主要以Ⅰ,Ⅱ和Ⅲ类流动单元为主,厚度小于3.5m的非主力小层主要以Ⅳ和Ⅴ类流动单元为主;垂向上,流动单元分布复杂,甚至同一口井5类流动单元都有。这一特征说明河43断块沙河街组二段储层具有较强的非均质性。不同的流动单元,其相相对渗特征不同,物性好的流动单元油相相对渗透率下降较缓,水相相对渗透率上升较快;反之则油相相对渗透率下降较快,水相相对渗透率上升较缓。

The 2nd member of Shahejie Formation in He 43 block is divided into 5 flow units according to productivity index per meter of single layer production during water-free oil production period, distribution characteristics and the corresponding characteristics of air-permeability and relative permeability. Permeability of type Ⅰ flow unit is the best, that of type Ⅱ is relatively good, type Ⅲ medium, type Ⅳ relatively poor, and type Ⅴ poor. Laterally, the major subzones with thickness of over 3.5m are mainly of type Ⅰ,Ⅱ and Ⅲ flow units, while the non-major subzones with thickness of less than 3.5m are mainly of typeⅣ and Ⅴ flow units. Vertically, the distribution of flow units are complex, and even all of the five types of flow units can exist concurrently in a single well. This characteristic shows that the reservoirs in the 2nd member of Shahejie Formation in He 43 block have strong heterogeneity. Different flow units have different relative permeability characteristics. Oil-phase relative permeability in flow units with good poroperm characteristics decline slowly, while water-phase relative permeability goes up quickly. On the contrary, oil-phase relative permeability declines quickly, while water-phase relative permeability goes up slowly.