Study And Application Of Water Based Fracturing Fluid System For Low Permeability Reservoir In Jidong Oilfield

Fracturing is an effective technique for increasing oil production in oilfield,and fracturing fluid system is the key and key to decide the effect of fracturing.The complex fault block reservoirs in Jidong Oilfield are mainly composed of fine sandstone with poor natural permeability and belong to ultra-low permeability reservoirs.In the traditional use of guar gum fracturing fluid,the injected polymer only 35-40% can be flowback,and stay in the residual polymer crack or invaded formation cause secondary damage to the reservoir permeability.The fracturing stimulation measures fail to achieve the expected goal.High efficiency,low damage and targeted clean fracturing fluid have become the primary problems in the study of fracturing fluid system at present.In this paper,the production process and production conditions of crosslinking agent and assistant were optimized.A novel cationic gemini swelling inhibitor with small molecular weight and a new anti milk additive agent formulated with various surfactants are developed for low permeability reservoirs.Finally,a set of JRYL-1 fracturing system which can meet the reservoir temperature from 90 to 120 degrees is obtained,which is suitable for 403X1 fault block formation in Nanpu of Jidong oilfield.Through the test,the new anti milk additive helps to reduce the retention rate of fracturing fluid from 40% of monomer to 50% after compounding,which is much higher than 16.7% of the existing cleanup additive.The new anti milk additive can reduce the interfacial tension of fractured fracturing fluid to 0.29-0.34mN/m,and the recovery rate of permeability is 83.4%,which is higher than the recovery value of the existing cleanup additive by 72.2%.It effectively reduces the damage of broken fluid to core.By the end of 2015,JRYL-1 had been used 120 well-times in Jidong Oilfield.The construction process has been carried out smoothly and finished with high quality.The production of the oil well has been improved and the economic benefits have been brought to the oilfield.This fully demonstrates the excellent performance and reliability of JRYL-1 fracturing system.