低渗透油藏注入水损害储层主控因素研究.

Aiming at the water injection development problems of low permeability reservoir in Nanpu oilfield, such as increasing pressure of water injection wells, decreasing water absorption index and decreasing liquid production of production wells, the natural core and injected water of low permeability reservoir in Nanpu 13-52 well are studied to evaluate the damage degree of reservoir permeability caused by factors such as reservoir sensitivity, water injection scaling and solid particles blockage. Sensitivity damage experiments show that the degree of reservoir water sensitivity damage is moderately strong; the variation of ion content of injected water at normal temperature and formation temperature indicates that the injected water is extremely unstable and there is a large amount of scale precipitation under the formation temperature ; the permeability damage rate increased linearly with the increase of solid content and median particle size in injected water, and the permeability damage rate of injected water due to solid particle blockage reached 64.84%. According to the comprehensive study, reservoir water sensitivity, scale formation of injected water and solid particle blockage are the main reasons for water injection difficulties in low-permeability reservoirs in Jidong oilfield. and solid phase particle blockage is the main factor of injection water damaging low permeability reservoirs. [ABSTRACT FROM AUTHOR]