Method For The Classification Of Porous Media Of Daqing's Peripheral Low Permeability Reservoirs And Application

In order to exploit low permeability reservoirs economically, reasonably and effectively, we must develop a scientific and systematic classification method. Disparitis in development characteristics of different low permeability reservoirs are closely related to rock physical properties and pore structures. Permeability is not the only factor that impact the development effect of low permeability reservoir. The key to correctly classify and effectively exploit low permeability reservoirs is deeply understanding pore structure characteristics and percolation flow characteristics of low permeability reservoir.In this paper, main factors influencing development effect of Daqing's peripheral low permeability reservoirs were studied by SEM and rate-controlled mercury penetration pore structure analysis and MRI movable fluid saturation measuring technique. classification parameters for low permeability reservoir has been found, which is based on the impact of flooding efficiency and recovery percent, regarding penetration, movable fluid saturation, the average throat radius and the starting pressure gradient. The porous media of low permeability reservoirs in Daqing peripheral oilfield was classified by applying the cluster analysis method. Classify by one parameter to three parameters, the results show that classification based on the three-parameter of movable fluid saturation, average throat radius, starting pressure gradient can better reflect the basic characteristics of the porous media of low permeability reservoirs and the approximate degree of reservoirs, the classification results are more scientific and reasonable.Based on the three-parameter classification results, specific technical measures were made to improve the development effect of different types low-permeability reservoir. Gl-type(excellent level) reservoirs improve the development effect mainly by wells-net optimization and encryption of water injection development and microbe method. G2-type (good level) reservoirs through the heat recovery technology to improve development effectiveness. G3-type(intermediate) reservoirs propose to use the horizontal wells in exploitation. G4-type(bad grade) reservoirs mainly through gas injection method to improve the development effect.