Evaluation And Optimization Of Improving The Production Capacity Of Compact Reservoirs By Using Degradable Fiber Mixed Fracturing

Kelameili gas field in Xinjiang oilfield is the main condensate oil and gas resource enrichment area in Junggar basin of China.Reservoirs in this area belong to low porosity,low permeability and tight gas reservoirs.They are generally characterized by high stress(about45MPa),normal reservoir pressure(about 33MPa)and normal reservoir temperature(60-65℃).At present,hydraulic fracturing is mainly used to modify low porosity and low permeability reservoirs.By producing long and high fractures,the oil and gas generation rate is maximized.However,in the process of fracturing,the excessive settlement of proppant will hinder the proppant migration in the fracture,restrict the size of proppant fracture and the production efficiency of oil and gas wells.This problem is more serious in thick formations requiring high fractures.In deep reservoirs with high sealing stress,conventional Guanidine gum fracturing fluid,polymer fracturing fluid,sliding water fracturing fluid and other fracturing fluid systems have their own limitations,and adding degradable fibers can solve these problems to a certain extent.A systematic screening and evaluation program was developed to quantify the experimental evaluation system of degradable fibers in suspension proppants and to improve the fracture conductivity by carrying out fiber degradation test,dynamic and static proppant settling test,hole flow test and fracture conductivity test.The above experimental evaluation results show that adding fibers in fracturing fluid can significantly improve the suspensibility of sand-carrying fluid,double the efficiency of proppant laying,and not block the hole in the wellbore;the degradation of fibers will not leave residual material which can destroy the conductivity,and can reduce the residual content of fracturing gel breaking fluid;and the degradation of fibers will not lead to the closure of support cracks under high closure stress.A degradable fiber KL-A suitable for fracturing operation in Kelamei gas field was screened out.The average length of the fiber is 6 mm,the concentration in fracturing fluid is 1.7kg/m~3,and the ratio of fiber to proppant is 0.43%.Finally,two Wells Well-1 and Well-2 in kelameili gas field were selected for fracturing contrast test.In Well-2,fiber was added throughout the sand-carrying stage.After the pressure of two Wells in tubing pressure under different sizes of needle valve and gas production rate were compared,and the use of fiber is not Well-2 Wells using fiber Well-1 Well production increase significantly and tubing pressure,pressure three months after the Well-1 Well and Well-2 Well production is respectively 1960 x 10~3 m~3,2380 x 10~3 m~3 and fiber sand fracturing can significantly improve the crack in pave setting situation of proppant,improved fracture diverting capacity,increasing the fracturing effect of oil increase.