特低渗透砂岩油藏储层微观孔喉特征

Characteristics of micro-pore throat in ultra-low permeability sandstone reservoir

通过岩心样品的恒速压汞测试,对特低渗透砂岩油藏储层微观孔喉特征进行的研究结果表明,储层有效喉道半径、有效喉道体积、有效孔隙半径、有效孔隙体积及孔喉比等特征参数与孔隙度、渗透率之间具有较好的相关性;对于孔隙度、渗透率较高的岩样,有效喉道、有效孔隙发育程度较高,孔喉比较低;特低渗透砂岩油藏储层孔隙结构具有中等孔隙和小喉道发育、孔喉连通性差及孔喉性质差异大的特点,开发过程中可能存在潜在的贾敏效应伤害。特低渗透砂岩油藏储层性质主要由喉道控制,喉道半径分类明显。渗透率越低,喉道半径与渗透率的相关性越好。喉道控制储层渗透性,进而决定开发难度和开发效果。

The features of micro-pore throat in the ultra-low permeability sandstone reservoir were analyzed by using the constant-rate mercury injection technology. The effective throat radius, the effective throat volume, the effective pore radius, the effective pore volume and the pore-to-throat ratio are correlative with the porosity and permeability of reservoirs. For the rock samples with higher porosity and permeability, the effective throat and pores are better, while the pore-to-throat ratio is lower. The ultra-low permeability sandstone reservoirs are characterized by medium pore, fine throat, poor connectivity of pore with throat as well as great difference in properties of pore and throat. There will be the Jamin effect in the development of the ultra-low permeability reservoir. The quality of this kind of reservoir is mainly controlled by throat, and the radius of throat has the obvious classification features. When the permeability of reservoir gets lower, the correlation of throat radius with permeability gets better. The throat controls the permeability of reservoir and also determines the development effectiveness.