| At present,with the further shortage of global energy resources,various oil fields generally enter the tertiary oil recovery stage.At this time,the potential for exploitation of low-permeability oil reservoirs has received increasing attention.Therefore,how to improve the recovery of low-permeability reservoirs is becoming The important objective of the oilfield's tertiary recovery stage.The development of conventional low-permeability reservoirs is mainly based on water injection development,with low efficiency,high injection requirements,and poor displacement.In recent years,gas injection and foam flooding have been widely used to extract low-permeability reservoirs and improve oil recovery in low-permeability oil fields.In this paper,the Y oilfield Z block suitable for CO2-foam flooding is selected as the research target,focusing on the introduction and introduction of the carbon dioxide-foam flooding technology mechanism,based on the reservoir characteristics,based on the foam volume,half-life,and integrated bubble capacity.An important index is to select two foaming agents that are suitable for the characteristics of the block,a foam stabilizer,and through the internal flooding experiment,adjustability is added to the stable adhesion agent,and the most advanced species has obtained the optimal injection system formulation.The two formulations were: 1)CO2+0.4%FPJ1+0.03%WPY111+150mg/LLN;2)CO2+0.4%FPY03+0.03%WPY111+150mg/LLN.On this basis,using the laboratory experiment method,the performance of the preferred system formulation was evaluated.Under the four temperature gradient experiments,the recovery of carbon dioxide-foam system showed a downward trend with increasing temperature.The recovery factor of FPJ1 was the highest at 45°C,while the recovery factor of FPY03 was the highest at 25°C.The ability of both carbon dioxide-foam systems to enhance oil recovery increases by more than 20%.Overall,the flooding effect of FPJ1 is higher than that of FPY03,but FPY03 is more economical. |
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