Effect Of Fracturing Fluid Loss Property On Oil Increase And Mechanism Of Action

Fracturing construction is a way of increasing production of oil well and injection of water well,also,it is a kind of reservoir completion method of low permeability reservoir,which has a wide application prospect.Currently,most commonly used fracturing fluids are guanidine gum fracturing fluid,but due to the source and price factors of guanidine gum,polymer fracturing fluid has been applied to oilfield fracturing construction.The fracturing operation of polymer fracturing fluid has been done in 26 wells in Daqing Oilfield.Compared with the nearby guanidine gum fracturing hydraulic fracturing wells,polymer fracturing wells lag behind for a month,but the cumulative oil consumption is larger,and it can achieve good technical and economic effects.In order to further understand the mechanism of polymer fracturing,optimize the construction parameters of polymer fracturing fluid and improve the economic effect of fracturing technology,this paper,taking the reservoir geology and fluid of Daqing Oilfield as the research object,carried out experimental studies on displacement efficiency of polymer and guanidine gum fracturing fluid and its influencing factors?physical simulation of filtration distance of polymer fracturing fluid and its influencing factors and the improvement of oil recovery by polymer fracturing and its influencing factors.The results show that when the core permeability limit is less than that of the reservoir permeability,the molecular structure of polymer is less affected by shear action when it migrates in porous media.At this time,the viscosity of the polymer solution increases with the increase of the polymer concentration,and the oil displacement efficiency increases.In addition,the addition of a proper amount of surfactant in the polymer solution is beneficial to the improvement of oil displacement efficiency.Compared with the polymer gel,the simple polymer solution has a low viscosity,but its injectivity is better and the oil displacement efficiency is higher.Under the condition of the same core permeability,with the increase of the filtration pressure difference,the filtration rate of fracturing fluid increases,the filtration loss increases and the filtration distance increases.Under the condition of the constant filtration pressure difference,the filtration loss of the fracturing fluid increases with the increase of core permeability.The filter loss capacity of the five types of fracturing fluid is: slick water > polymer solution(formula 1)> polymer solution(formula 2)>GRF associating polymer solution > polymer gel(formula 1).