Experimental methods,including mercury pressure,nuclear magnetic resonance(NMR)and core(wateroil)displacement,are used to examine the effects of high-multiple water injection(i.e.water injection with high injected por...Experimental methods,including mercury pressure,nuclear magnetic resonance(NMR)and core(wateroil)displacement,are used to examine the effects of high-multiple water injection(i.e.water injection with high injected pore volume)on rock properties,pore structure and oil displacement efficiency of an oilfield in the western South China Sea.The results show an increase in the permeability of rocks along with particle migration,an increase in the pore volume and the average pore throat radius,and enhanced heterogeneity after high-multiple water injection.Compared with normal water injection methods,a high-multiple water injection is more effective in improving the oil displacement efficiency.The degree of recovery increases faster in the early stage due to the expansion of the swept area,and the transition from oil-wet to water-wet.The degree of recovery increases less in the late stage due to various factors,including the enhancement of heterogeneity in the rocks.Considering both the economic aspect and the production limit of water flooding,it is recommended to adopt other technologies to further enhance oil recovery after 300 PV water injection.展开更多
Pore volume of Cumulative water injection is one of the factors for evaluating water flood effect in a water flood oil field.In previous study,there were limited lab studies for evaluating oil displacement efficiency....Pore volume of Cumulative water injection is one of the factors for evaluating water flood effect in a water flood oil field.In previous study,there were limited lab studies for evaluating oil displacement efficiency.A method to characterize the distribution of pore volume of cumulative water injection is proposed in this paper,and it is verified by a five-spot water flooding streamline simulation model.The logarithmic relation between pore volume of cumulative water injection and water saturation is established by regression.An inflection point and limit point of cumulative water injection pore volume are identified.Current simulation model indicates inflection point appears after 2e5 pore volume(PV)injection,and limit point appears after 15e25 PV injection.Both inflection and limit point vary in different regions of reservoir.展开更多
文摘Experimental methods,including mercury pressure,nuclear magnetic resonance(NMR)and core(wateroil)displacement,are used to examine the effects of high-multiple water injection(i.e.water injection with high injected pore volume)on rock properties,pore structure and oil displacement efficiency of an oilfield in the western South China Sea.The results show an increase in the permeability of rocks along with particle migration,an increase in the pore volume and the average pore throat radius,and enhanced heterogeneity after high-multiple water injection.Compared with normal water injection methods,a high-multiple water injection is more effective in improving the oil displacement efficiency.The degree of recovery increases faster in the early stage due to the expansion of the swept area,and the transition from oil-wet to water-wet.The degree of recovery increases less in the late stage due to various factors,including the enhancement of heterogeneity in the rocks.Considering both the economic aspect and the production limit of water flooding,it is recommended to adopt other technologies to further enhance oil recovery after 300 PV water injection.
基金This work was financially supported by the National Basic Research Program of China(973)Program,‘study on water injection in fracture-cave carbonate reservoir’(2011CB201000).
文摘Pore volume of Cumulative water injection is one of the factors for evaluating water flood effect in a water flood oil field.In previous study,there were limited lab studies for evaluating oil displacement efficiency.A method to characterize the distribution of pore volume of cumulative water injection is proposed in this paper,and it is verified by a five-spot water flooding streamline simulation model.The logarithmic relation between pore volume of cumulative water injection and water saturation is established by regression.An inflection point and limit point of cumulative water injection pore volume are identified.Current simulation model indicates inflection point appears after 2e5 pore volume(PV)injection,and limit point appears after 15e25 PV injection.Both inflection and limit point vary in different regions of reservoir.
