西南石油大学学报(自然科学版)

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Affection of Simulating Water-flooding by Water Injection
Tests on Reservoir Properties

Shi Changlin1, Zhang Fenghong2, Chen Ping1   

  1. 1. CNOOC Energy Technology & Service-oilfield Engineering Research Institute,Tanggu,Tianjin 300452,China
    2. Tianjin Branch of CNOOC,Tanggu,Tianjin 300452,China
  • Online:2013-10-20 Published:2013-10-20

Abstract:

With the samples of mid-porosity and mid-permeability reservoir from the oilfield in Bohai Bay,by scanning electronic
microscope,cast thin section and mercury penetration test,the changes of reservoir properties before and after water
injection simulation tests were studied. The tests indicate that the macroscopic and microscopic characteristics of and fluid
distribution characteristics of the reservoir petrophysical properties changed complicatedly after displacement with water.
After displacement with water,the average porosity and permeability of the reservoir above 500.0 mD increased while the
permeability below 500.0 mD decreased;the maximum pore throat radius and the average coordination number of pore throat
increased,but the average radius of pore throat and mercury saturation median radius had different levels of reduction;the
average diameter of pore and pore throats enlarged in the medium-coarse sandstone(median size above 1.5µm),but reduced in
the fine-grained sandstone(median size below 1.5 µm);the microscopic homogeneous coefficient of reservoir decreased while
variation coefficient increases,and the micro-heterogeneity of reservoir became stronger;the resident oil mainly distributed on
the surfaces of grains,in the corners of intergranular pores,micropores and pore throats that cannot be swept by water.

Key words: water injection simulation test, water-flooding, permeability, pore structure, reservoir heterogeneity, resident oil