Application Of Micro Visualization In The Study Of Residual Oil Occurrence In ASP Flooding

ASP flooding technology can greatly improve the recovery rate of crude oil,but its flooding efficiency is still influenced by several factors.Besides geological conditions directly,there are some other problems should be further understood:complex chemical reaction between alkali and reservoir rocks or fluids,changes in pore structure and physical properties caused by mineral dissolution and particle transportion,whether scaling occurs inside the reservoir and whether the scaling reduce injectivity and productivity of reservoir,and distribution characteritics of residual oil after ASP flooding.In this paper,through the researching of the characteristics of DQYT A block reservoir and a large number of relevant documents in China and abroad,and based on reservoir geology,oil layer physics,mineralogy,oilfield chemistry,geochemistry and other knowledges,finished the ASP flooding experiment of normal core samples and the micro displacement experiment of the core samples before and after the ASP flooding.The 6 cores after water flooding in the A block reservior and another 6 cores after the ASP flooding were detected by the visualization test.The nuclear magnetic resonance oil saturation was detected,the laser confocal was observated,the fluorescence microscope was detected,the casting thin film was detected,and the electrical probe detection analysis were carried out.the following results have been achieved through experimental comparative analyses:(1)Creating the matching technology for supporting on the core analysis after the ASP flooding.Scaling characteristic and remaining oil based on advanced large-scale equipments such as laser confocal,electron probe and casting body image analysis Characteristics of the multi-parameter integrated quantitative analysis technology to effectively solve the micro-residual oil quantitative characterization,scaling can not be determined and other problems,to carry out comparative analysis composite flooding provides a reliable technical means.(2)The characteristics of reservoir physical properties during ASP flooding are revealed.The obvious dissolution and the recrystallization of the skeleton minerals were confirmed after the composite flooding.The characteristics of clay mineral reduction and pore structure change were clearly identified,and the formation mechanism of scale formation inside of the reservoir was explained thoroughly.(3)The remaining oil distribution features based on coring Wells after clarified the compound flooding has been clarified.The different displacement way under the condition of residual oil occurrence morphology variation characteristics have been microscopic quantitative contrast described,confirming that the compound flooding can greatly improve the efficiency of oil displacement,it can be used as a potential in residual oil type object.after the ASP flooding.