The Experimental Research On High Temperature And High Pressure Imbibition (Extraction) For Tight Core

In recent years,the proportion of low permeability and tight oil and gas resources in newly proved oil and gas reserves has increased significantly.With the increasing demand for energy,low permeability tight oil reservoir has gradually become a hot spot for development.In this thesis,the physical properties of reservoirs and fluids are evaluated and physical simulation experiments of high-temperature and high-pressure imbibition and extraction are carried out to provide theoretical basis and technical support for the efficient development of tight reservoirs in the target block M,Ordos Basin.In this thesis,a visible high temperature and high pressure imbibition(extraction)equipment is used to carry out the imbibition and extraction experiments.The relationship between imbibition recovery and imbibition time,experiment pressure and permeability is investigated.The optimum concentrations of the three surfactants are selected through the IFT,and the EOR effects of the three surfactants are compared.The extraction effects of carbon dioxide,methane and nitrogen gas are studied,and the influences of the fracture quantity and experiment pressure on the extraction recovery of supercritical carbon dioxide are investigated.According to imbibition rate,imbibition recovery can be divided into rapid imbibition stage,slow imbibition stage and imbibition balance stage.Pressure can increase the imbibition rate of the rapid imbibition stage.The imbibition recovery has a logarithmic relationship with permeability.Considering the EOR effect,migration loss and economic factors comprehensively,the surfactant No.I is selected as the best one and the concentration is 0.15 wt.%.Gas extraction experiment results show that carbon dioxide is better than methane and nitrogen.NMR and mass methods both prove that the existence of fractures can greatly improve the carbon dioxide extraction recovery.The increase of experiment pressure can improve the extraction effect of supercritical carbon dioxide to a certain extent.