Mesoscopic Representation Of Sandstone Before And After ASP Flooding By Using AFM

Each block has been into extra high water-bearing period in succession, some blocks have more than 98% moisture content of produced liquid.Tertiary oil recovery technology has increasingly great use in order to improve the recovery of the existing oil fields. Chemical flooding is the main method in the period of tertiary oil recovery, and which has influence on the feature of microscopic pore structure in reservoir. The study on the changes of the microscopic pore structure in oil recovery can get information about the chemical reagent’s adsorption in the pore surface and the rock wettability, then we can give the objective judgement on the oil displacement efficiency, therefore, detailed research on the changes of microscopic pore structure in pre and post oil recovery has important significance on effective tertiary oil recovery.On the base the fully research about the methods of chemical flooding and the reservoir microscopic pore structure at home and abroad, We get four cored wells in Daqing, which are the N5-4-J725 before the ASP and the N5-2-GP30 after the ASP in fifth part of the south of oil extraction’s second factory, the others are the X2-1-J29 before the ASP and X2-10-J3E7 after the ASP in the middle of the second part of Xing Shugang area of the oil extraction’s fourth factory. During the research we use the methods of capillary pressure curve, thin section method, scanning electron microscope, scanning common focusing microscope, the atom force microscope(AFM), x-ray diffraction, scanning probe microscopy are used in the study of the change law of microscopic pore structure after the alkaline surfactant-polymer flooding. The result shows that the method of capillary pressure curve can obtain macroscopic data,the scanning electron microscope can get the micro-data,the scanning common focusing microscope gives the relationship between the remaining oil and the rock pores,the AFM gives the true data of pore throat distribution the lx-ray diffraction, scanning probe microscopy can supply the composition change of interesting part,all the methods construct the systems in the representation of sandstone before and after ASP.By the analysis of the particle migration, rock dissolution, the interaction of alkali and fluid, the function on the microscopic pore structure by the silicate formation and polymerization, we carry the research on the rock and sediment composition. The conclusion is that the particle migration, particle surface dissolution and the sediment formation are the main reasons on the rock microscopic pore structure, then we develop the study on the influence about displacement time, the injection well distances and other factors in the course of alkali ternary composited flooding. The results have important significance to establish the evaluation system of reservoir pore structure, which can be applied into the petroleum exploration and development and tertiary oil recovery.