Study On Plugging Mechamism Of54Region Reservoir In Yuancheng Oilfield

Low permeability reservoir has narrow pore throat and low permeability, it is morevulnerable to suffer damage in the development. Study on the mechanism of reservoir damagedeeply, can provide the theoretical basis for the scientific development of low permeabilityoilfield. X-ray diffraction (XRD), scanning electron microscopy (SEM) were first introduced inthis paper, the casting thin sections and other technical means were used to analyze reservoircore, it is concluded that the main clay mineral is kaolinite, the layer and chlorite, potentiallyvelocity sensitivity, water sensitivity and acid sensitivity damage is existed in the study reservoirarea. Combined with the indoor flow sensitivity experiments to determine the acid sensitivity asmajor potential damage factors in the study area; Reservoir is holes, low permeability reservoir,which has complex pore structure, give priority to with sheet and tube bundle throat, jamin effectcaused in the development. Secondly, the study area reservoir fluid and injected water assayanalysis results show that the formation water and injected water barium strontium ions, calciumions as the main scale into cationic, calcium carbonate scaling trend is serious. Finally, water andformation water static compatibility experiment, dynamic core damage experiments, core scalingdepth test and evaluation of scale inhibitors experiment through injection wells plugging,indicating that the study area mainly due to the compatibility of injected water with formationwater and scale inhibitor effect is not ideal, and oil wells were blocked with calcium carbonateand organic matter.According to the plugging mechanism in the study area, electrical pulses in combinationwith deep acidification were adopted to injection wells, and refracturing were adopted to oilwells, the acidification fluid system with main acid as fluoboric acidification:pretageacidification (12%CH3COOH)+main body acidification (8%HBF4+11%HCl). At the same time,by the evaluation of current research on scale inhibitor ZG-558and four kinds of scale inhibitor,scale inhibitor SIB is selected, the effect best density is60ppm. Field test results show that themeasure efficiency up to100%, and to be able to effectively discharge reservoir restriction.