Research On Reservoir Damage Evaluation And Acidizing Plug Removal Of Xingbei Area

Xingbei area of Daqing Oilfield has developed by water flooding for a long time. Because of the clay mineral, injection water impurities and scale on injection well bottom, reservoir is damaged, which causes apparent injectivity index of injection wells reduce greatly, injection wells is inefficient or invalid. The damage of Xingbei area reservoir seriously affects the normal production of Oilfield. To solve this problem, this paper evaluates the damage of reservoir in Xingbei area, and studies on acidizing plugging removal.In this paper,based on the core data of Xingbei area 4 coring wells in different lithologies and horizon formations, were analyzed by X diffraction and scanning electron microscopy. The composition of rock and clay mineral before and after core washing is measured respectively. Combined with the result of observation of SEM, analyze the change of clay minerals during the water flooding and the effect of clay minerals on the rock pore structure. Measure the change of porosity and permeability before and after water washing. On this basis, carry out the clay damage simulation experiment and the quality of injection water damage simulation experiment. Measure the speed sensitive critical velocity, the speed sensitive degree, water sensitive critical salinity and water sensitive degree in different lithologies. Determine the main factor affecting the water absorption capacity of water injection layer caused by reservoir damage in Xingbei area. Through laboratory experiments, the starting pressure gradient under different confining pressure cores were measured, which is providing the basic data for the related calculation and theoretical analysis. Finally, do test evaluation of different acid relieving clay damage, the injected water impurities damage, ferric hydroxide damage, mud pollution damage, and barite powder damage. Optimize acidification method suitable for different kinds of damage. Summary the main factors that affect the low injection wells in Xingbei area and the corresponding countermeasures. This paper has guiding significance in Xingbei area reservoir comprehensive management.