Study on formation damage with water flooding for ultra-low permeability reservoir in Xinjiang Oilfield

Because of the special characteristics of pore throat, the suspended solids content and the scaling tendency of foreign fluids are strictly limited with water flooding for ultra-low permeability reservoir. How to reduce the degree of formation damage with water flooding to protect pore throat, that will be the critical to efficient development of ultra-low permeability reservoir. Taking a block of Xinjiang Oilfield as an example, by analyzing the reservoir sensitivities and scaling tendency, this paper defined the damage factors of formation with water flooding. The result shows that the reservoir exhibits medium to strong water sensitivity, serious salt sensibility and medium to strong alkali sensitivity, the scale is serious for oilfield injection water, injected water will produce insoluble that will damage the water injection pipeline and reservoir pore throat. Thus, in the water flooding development process of ultra-low permeability reservoir, we need to not only focus on reservoir protection, but also limit the quality of injected water so as to effectively protect reservoirs and lay the foundation for long-term efficient development.