In the middle and later stages of development,Bohai P oilfield experienced changes in the internal structure of the formation due to long-term water injection,exacerbating the dominant channels within the reservoir.However,there is a lack of systematic understanding of the changes in reservoir physical properties after water flooding and acidification measures.Therefore,reservoir water sensitivity/salt sensitivity experiments and acid sensitivity/alkali sensitivity experiments were conducted based on on-site actual rock cores to obtain the changes in physical properties of the reservoir when exposed to fluids with different mineralization degrees.The results showed that the degree of water/salt sensitivity damage in Bohai P oilfield was moderate-weak to moderate-strong,with the mineralization degree of the fluid entering the well>20000 mg·L-1.To prevent particle migration of clay,clay stabilizers could be appropriately added in the early stage of water injection;the acid sensitivity damage rate ranged from 11.0% to 49.1%,and the degree of damage was weak to moderate-weak;the alkali sensitivity damage rate ranged from 25.2% to 69.1%,and the degree of damage was weak to medium-weak.The critical pH of the fluid entering the well was 8.5.After acidizing the oil well,try to avoid high-pressure differential production in the initial stage of production,reduce the blockage of movable particles on the reservoir pore throat,and improve the acidizing validity period.The research results can provide theoretical guidance for adjusting the development policy of Bohai P oilfield and improving the degree of reserve utilization.
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