Research On The Relationship Between The Change Of The Pore And The Flow Of The Fluid In The Oil Reservior

Petroleum is very important substance of energy source, and is a lot of mining. So it is avery key question how to improve oil recovery. The change of pore structure has importantinfluence to micro fluid dynamics in the oil reservoir, this effect is closely related to thechange of oil recovery factor.For describing the form characteristics of the core accurately and quantificationally, theoriginal rock micro structure is characterized by Atomic Force Microscopy on nano-microscale. For acquiring binary image, the captured core photos are processed by Image-Pro Plus.Import binary image into COMSOL Multiphysics through AutoCAD to acquire the effect ruleof the tiny changes of pore diameter to micro fluid velocity and pressure. Interrelated analysesconclude that there is not a proportion relationship between micro fluid velocity and pressureand the size of the pore diameter in oil reservoir core. At the same time, coordinated variationof other porosity will influence micro fluid velocity. With the increment of the pore diameter,the micro fluid velocity increases consequently somewhere in the core. With the increment ofthe pore diameter in other place, the micro fluid velocity and pressure are affected apparentlyin this place. With the increment of the pore diameter in a similar position, the micro fluidvelocity decreases but pressure increases in this place. The micro fluid chooses the path whicheasily to pass, and the wave trough of the image of the rate correspond the wave crest of theimage of the pressure. If the increment of the pore diameter in the exit position, the microfluid velocity increases and pressure decreases in this place, and the wave crest of the imageof the rate corresponds the wave trough of the image of the pressure.Further analysis showed that there is a threshold point of pore size. With the variation ofpore diameter, the change regularities of micro fluid velocity and pressure are very differenton both sides of the threshold point. These conclusions are very useful to certain secondarypore or the change of secondary pore qualitatively and quantificationally for enhancingtertiary oil recovery efficiency.