Research And Application Of Temporary-Plug-Acid Technology

The article researches the enhanced-recovery technique of temporary-plugging-acidiifcation in view of heterogeneous reservoir in Xing he block. By means of laboratoryexpeirment, performance of temporary addictive is evaluated, acid system and temporaryplugging additive that suit to An sai ifeld is selected, temporary-plugging-acidiifcationprocess-system are consummated，and then prepare to put in to practice in scale.An Sai oilfield which lie in Chang6reservoir, is located in east part of Shan Bei back-fall,which is one of most favorable oil-abundance area.Yanchang6and Chang2are mainproduction-layers, Chang6is more. Physical characteirstics in An sai oilifeld is awful, An saioilfield is low-porosity, ultra-low permeability low saturation, low pressure, low temperatureand production lithologic hydrocarbon reservoir. Atfer drilling well can produce crude oil,recently，a seires of problems appear atfer acidification in oil well，including precipitousascend of water-percentage while oil production increases. The characteirstic indicatespermeable capability of reservoir. It is necessary to adopt measure of plug-removal-tcchnology,while formation energy is ample and condition is favorable.By expeirment and analysis main reason of reservoir，plug is found (as far as Chang6isconcerned, some measures must be adopted to avoid second pollution of reservoir about theproblems of acid-sensitivity,water-sensitivity and so on). It is very necessary that a set ofeffective and synthetic technologic measures is researched, which effectively plug highwater-yield layer and relieve the pollution of low permeable ones. In the same well, it hasextremely important realistic signiifcance that organically combining water-plugging andacidizing and using synergistic action of two processes control high permeability water-bloodlayer and release potential of production in low-permeability ones.