Evaluation Of Imbibition And Displacement Potential Of Tight Oil In Jilin

Large-scale fracturing is one of the efficient development of tight oil technology,during the process of fracturing,large-scale of fracturing fluid will remain in the reservoir as result of the particularity of tight oil reservoir.On the one hand,water is detained in the reservoir which causes damage to the reservior,on the other hand,fracturing fluid will be absorbed into the reservoir under the action of capillary force and osmotic pressure,and displace the oil and gas,so as to improve oil production.Therefore,understanding the interaction of fracturing fluid and reservoir,evaluating the potential of water imbibition and the displacement of tight oil,has the vital significance to improve the efficiency of oil well production.This paper is based on Quansi segment reservoir in Qianan area in Jilin,understanding the basic physical characteristics by analyzing the physical properties;using microscopic analysis methods such as SEM and CT to understand its microscopic pore structure;carrying out a spontaneous imbibition and displacement experiment by using different fluids such as distilled water,salt solution of different salinity and slick water liquid.Comparing Q-1,Q-2,C-1 and C-2,we study the mechanism of imbibition and oil displacement.At last,this paper evaluated the potential of imbibition and oil displacement.The study find that pore structure characteristics,wettability and the clay minerals have important effect on the displacement of fracturing fluid;capillary force and osmotic pressure are the important mechanism of imbibition and displacement of fracturing fluid.The imbibition segement is mainly influenced by the capillary force and osmotic pressure,the diffision section is mainly influenced by the clay minerals and concentration difference.C-1 well has the greatest potential of imbibition and displacement,while C-2 and Q-1 wells have the same potential,they are both fit for shutting in.Q-2 well has the minimum potential of imbibition and displacement and is suggested to be fast flowing back.The research will be of great significance to the efficient development and production of the tight oil reservoir in Jilin.