鄂尔多斯盆地马岭油田长81储层不同流动单元可动流体赋存特征及其影响因素

鄂尔多斯盆地马岭油田长8₁储层是典型的低孔—低渗透油藏，渗透率的强非均质性制约了油气储层品质的提高。通过开展核磁共振实验，结合恒速压汞和高压压汞、图像粒度、铸体薄片等微观实验研究储层的微观孔隙结构特征，同时选取砂厚、孔隙度、渗透率、含油饱和度、流动带指数5个参数，借助SPSS数据分析软件，将马岭油田长8₁段储层的流动单元划分为E、G、M、P等4类，进而分析不同类型流动单元微观孔隙结构特征及其对可动流体饱和度的影响，结合生产动态数据分析不同类型的流动单元产能的差异。结果表明:不同流动单元的微观孔隙结构有着明显的差异，是造成可动流体饱和度差异的主要因素。其中，喉道半径分布形态及主流喉道半径大小起了决定性作用。生产动态数据表明，在油气田勘探开发阶段E类和G类流动单元的产能最高，应根据不同流动单元的微观孔隙结构差异性特征，实施合理有效的开发方案。 

Characteristics of movable fluids and controlling factors in different flow units of Chang 81 reservoir in Maling oil field,Ordos Basin

The Chang 8₁ reservoir of the Maling oil field in the Ordos Basin has low porosity and low permeability. The quality of oil and gas reservoirs is constrained by the strong heterogeneity of its permeability. We analyzed the characteristics of its microscopic pore structure by conducting an NMR experiment and microcosm experiments including constant speed mercury injection, high pressure mercury injection, image granularity, and casting lamella. We then divided the flow units into 4 classes E, G, M and P, using SPSS data analysis software on the basis of 5 chosen parameters, including sand thickness, porosity, permeability, oil saturation and flown zone exponent. We analyzed the microscopic pore structure characteristics in different types of flow unit and the impacts on movable fluid saturation. The results showed that there are obvious differences in the microscopic pore structure characteristics in different flow units, which are the main factors that caused different movable fluid saturation. The distribution and size of pore throat radius played a crucial role. Production performance data demonstrated that classes E and G acquired the highest capacity in the oil and gas field development. Reasonable and effective development programs should be implemented according to the microscopic pore structure characteristics of different flow units.