低渗透油藏注水开发储层动态特征变化

为了解低渗透油藏长期注水后储层特征的变化及其机理,以马岭油田南二区延9油藏为例,通过室内物理模拟实验法研究注水开发前后储层物性、孔隙特征和渗流特征的变化。研究结果表明:长期注水后,储层渗透率明显增大,孔隙度增加较小,且储层渗透率越高,水洗程度越大,储层物性的增加幅度越大;储层物性的增加主要与水洗后黏土矿物含量的降低有关,其中伊利石和伊蒙混层的相对含量明显降低,高岭石相对含量明显增大;水洗后储层岩石表面油膜脱落,岩石润湿性由亲油性变为亲水性;注入水与储层岩石的相互作用使油水相流动能力增强,两相区范围变宽,水驱油效率提高。可见马岭油田南二区延9油藏注水开发中储层的变化有利于油田的开发。

Study on reservoir characteristics changes in waterflooding development in Yan 9 reservoir of nan2 district of ma ling oilfield.

In order to understand the variation of the reservoir characteristics and its mechanism after long-term water injection in Yan 9 reservoirs of the second district in of Maling oilfield south, based on the results of laboratory experiments and t two Wells in the oilfield, the changes of reservoir physical properties, micro pore characteristics and seepage characteristics were studied in this paper.The results show that, after long-term water injection, the permeability of reservoir is obviously increased, porosity is increased, and the permeability of reservoir is higher and the displacement degree is greater, and the increase of reservoir property is larger. The increase of reservoir property is mainly related to the decrease of clay mineral content after washing, in which the relative content of illite and illite/smectite formation is obviously decreased, and the relative content of kaolinite is obviously increased. After washing, the oil film on the surface of reservoir rock falls off, and the wettability of the rock changes from the hydrophilic to hydrophilic. The interaction between the injected water and the rock of the reservoir makes the oil-water phase flow capacity increase, the scope of the two-phase zone becomes wider, and the water displacement efficiency increases, which is beneficial to the development of the oil field. It can be seen that the changes of reservoir in the water injection development of Yan9 reservoir in Nan2 District of Maling Oilfield is beneficial to the development of oil fields.