| GanGuYi Chang 6 reservoir is typical low Permeability,low porosity reservoir.The exploitation relies mainly on natural energy in initial field development.Currently injection wells into conventional injection wells and conversion production wells.Large differences in the two types of injection wells,conversion production wells is characterized by low water pressure,water channeling serious,small formation pressure,low water efficiency.In the process of water flooding,the conventional water injection rate declined fast,with high water injection pressure,slow effect,injection-production imbalance as well as,low degree of developed producing reservoirs,which seriously affected the oilfield development.In order to improve the effects of water flooding,we study the sensitivity of Chang 6reservoir and formation damage factors caused by water injection,find out what influence water flooding efficiency and put forward solutions,provide the basis for oilfield water flooding.At first we analysis the reservoir lithology and physical property characteristics by all kinds of means;then we study the reasons of GanGuYi Chang 6 reservoir damage and damage degree through core flow experiments compatibility experiments and fouling prediction methods;finally we analysis and evaluate what influence conventional injection wells and conversion production wells efficiency through indoor simulation experiments,and put forward a method to improve the efficiency of water injection.The results are as below:(1)Ganguyi Chang 6 reservoir mainly intergranular pore pore combination types are mainly intergranular pore-dissolved pores,pore throat distribution has a strong heterogeneity,with an average porosity of 8.73 percent,with an average permeability of 0.46×10-3?m2,average pore throat radius of 1.48?0.02?m,low porosity-ultra-low permeability reservoir.(2)In GanGuYi Chang 6 reservoir,the velocity sensitivity is weak,the water sensitivity is medium weak,the acid sensitivity is strong,the base sensitivity is medium weak and the stress sensitivity is weak.(3)The formation damage scale types are mainly calcium sulfate scale in GanGuYi Chang6 reservoir.Preferred test out weak gel plugging agent plugging cracks rate reached more than 98%.(4)We study the factors that influence efficiency of conversion oil production wells,put forward a method to improve water flooding efficiency by reducing the fracturing fracture flow conductivity.(5)To solve low efficiency of high pressure water injection well in GanGuYi Chang6 reservoir,we select a suitable injection agent,and put forward a new method of plug removal in the bottom of injection well. |
PDF Full Text Request