Experimental Study On Adaptability Of Heavy Oil Polymer Flooding In Yudong Block Of Lukeqin

Our country is a powerful nation in oil consumption,and huge oil demand makes our oil more and more dependent on foreign oil year after year,what's worse,by the end of 2015 the interdependency has reached to 60%,while China is abundant in heavy oil resource which has a lower oil recovery,thus increasing the intensity of heavy oil development and improving heavy oil recovery have become a prerequisite to ensure the rapid development of China's economy.LUKEQIN reservoir is a heavy oil reservoir which has hundreds million ton of oil.Studies show that District Yudong reservoir has deeply buried reservoirs,high oil viscosity,high salinity formation water,calcium and magnesium content,low permeability formations,heterogeneity,and other characteristics that used waterflooding development in the early stage.The current recovery factor only reaches' 4.47%,but the water cut rate runs up to70%.With waterflooding contradictions gradually increasing,we'are urgently supposed to change the development mode to improve well productivity for guaranteeing the normal oil production.Polymer flooding technology is taken under considerration for its simple process,easy operation and mature technology.Through the investigation,we found that there are no similar precedent in the specific heavy oil reservoir in China and foreign countries.Therefore,polymer flooding adaptability study should be carried out in order to evaluate whether the polymer flooding could improve the oil recovery efficiency in the heavy oil reservoir.This paper is mainly based on the characteristics of the Yudong reservoir which seclects AP-P8 hydrophobic association polymer to study on the increasing viscosity of polymer solution in consideration of reservoir temperature and salinity of injected water under ground.This paper studies injection capacity and mobility control ability of polymer solution under the consideration of formation permeability.The text studies on oil displacement ability of polymer solution under different oil and water viscosity ratio by changing the viscosity of polymer solution which is to change the oil-water viscosity ratio.In addition,it is important to seclect optimal injection concentration of polymer solution by laboratory experiments and study on the ability of the polymer solution to enhance oil recovery of crude oil with different viscosity under reservor conditions.In this paper,the injection parameters were optimized by changing the injection quantity and injection time of the polymer solution and the displacement effection of polymer solution under different permeability was studied through homogeneous core displacement experiment.Finally,the text studys the effect of heterogeneity on polymer solution flooding by changing the permeability variation coefficient to carry out heterogeneous core flooding experiment.the result of experiments show that,in the condition of reserivoir temperature and injecting water salinity,AP-P8 polymer solution can have superior viscosified effection,and in the situation of strtum permeability,AP-P8 polymer solution will bulid high resistance factor and high residual resistance factor with a well injection ability.When control the injected concentration of AP-P8 polymer solution with 2750mg/L and the injected amount with 0.4PV,the earlier carry out polymer flooding,the higher substantially of enhanced oil recovery we will gain.When the permeability variation coefficient is 0.89 convert watering flooding to polymer flooding with the water cut is 70%at the stage of water flooding,the ultimate recovery ratio is 43.17%and the recovery ratio of polymer flooding is 15.96%higher than water flooding,which indicates that hydrophobic associated polymer of AP-P8 can get a preferable flexibility in the reservoir condition of District Yudong.