Study On Damage Mechanism Of High Molecular Polymer Fracturing Fluid To Yuanping1 Tight Oil Reservoir

Yuanping1 is tight oil reservoir and need to take fracturing measure to be able to achieving economic capacity.The fracturing fluid as an important part in fracturing have a good ability of getting conductance crack besides the main sources of bring damage to the stratum.So,effective evaluation of the fracturing fluid performance,analysis the main reasons of damage and research the chief damage mechanism have a great significance to optimize the formula of fracturing fluid and develop tight oil.The geological characteristics of the reservoir of Yuanping 1 were studied by XRD and thin slice identification experiments.The formulation was optimized by testing the properties of the polymer polymer fracturing fluid and the optimization of the additives.The damage mechanism was studied by core flooding experiments,CT scanning experiments and SEM.The low damage fracturing fluid system was evaluated.The experimental results show that: the whole rock mineral of Yuanping 1reservoir is mainly quartz,the average clay content is 30.15%,the interstitial is mainly calcite;the fracturing fluid formula is optimally 0.2%?0.25% high polymer+0.3 %helper+1.2% stabilizer+0.05%?0.08% breaker,cross-linking ratio 50:1,polymer fracturing fluid breakage rate reached 18.65%,optimized polymer fracturing fluid to core The damage is only 10.68%,and the permeability varies little with the increase of the boring time,and is stable at about 21%.The experimental results show: The reservoir of Yuanping1 is a typical ultra-low porosity and ultra-low permeability reservoir,showing compact characteristics and strong heterogeneity;reservoir damage mainly comes from particle pairs in polymer breaker.The blockage of the pores and pores of the reservoir are related to the size and content of the particles,and the well does not promote the degradation of the particles or the particle size,so reservoir damage has not improved significantly.