The Research On Trapezoid Protection Technology For Low Permeability Water Injection Reservior

All operation links during petroleum exploration and development may cause different degree of reservoir damage, needs take measures to protect reservoir.The main characteristics of low and ultra-low permeability reservoir are as follows: bad reservoir physical property, low permeability, narrow channel which oil and water pass by, high sensitivity, etc.Thus it is easier to be damaged. Furthermore during the injection in low and ultra-low permeability reservoir , there are many widely existing bad phenomena such as: fast-increasing water injection pressure, high water injection pressure, high filtrational resistance, fast energy consumption and long-term insufficient injection. Finding an effective and economic solution to the formation damage during injection has become the mayor task for every oilfield.On the base of the research of reservoir protection technology at home and abroad and the present injection situation of the low and ultra-low permeability reservior,we summarize and study deeply the formation damage mechanisms of low and ultra-low permeability water injection reservior, also find out the main damage factors during water injection by experiment.Finally we screen out and develp trapezoid protection treating agents suitable to low and ultra-low permeability water injection reservior.The agents are superior to similar treatment agents in compatibility, anti-swelling property and scale inhibition performance by performance evaluation.The trapezoid protection technology for low and ultra-low permeability water injection reservior we established applid preliminarily in Shengli and Changqing Oilfield,and its success rate was 100%,the increasing rate of injection pressure decreased by more than 50%, the period of validity extended to two times more than ever, the new technolgy has obvious effect in decompression and augmented injection,it supply the energy of low and ultra-low permeability reservior.