Research Of Low-permeability Reservoir Blockage Removal Formula System Of LJ Oilfield

For a long time, drilling, cementing, well completion, fracturing, injection andproduction measures are likely to cause damage to the reservoirs with the LJ blockdevelopment process. High water injection pressure, low oil recovery and such problems arebecoming more and more obvious and urgent. In this paper, the method of X-ray diffractionis used to analysis of LJ block scale components, the blockage type and reason of LJ reservoirare got. Research shows that the reason of formation damage in LJ block reservoir includesreservoir sensitivity, inorganic fouling, organic fouling and acidizing which cause the seconddamage. According to the reservoir damage type and scale components, through the indoorexperiment, the LJ block model plugging agent is developed.By means of XRD analysis of scale sample, components are mainly two categories:carbonate and fluoride. For carbonate kind of block, it is caused by the reason thatcompatibility of the injected water and formation water is not good. It is recommend thatinjection water salinity is added in the field, or anti scaling agent adding carbonate, sulfate. Inthe development process, compatibility on reservoir damage should be avoided. For fluoridescale sample block, it is due to the introduction of acidizing in F+which leads to the formationof two precipitation.According to the analysis of scale composition and the combination with reservoirmineral composition, a blocking system formula of LJ block is developed. The results showthat the scale component LJ blocks are mainly carbonate and fluoride. By using artificial coresimulation on flooding simulation plugging and plugging experiment simulation, the resultsshow that, core plugging rate can reach more than90%, re blockage rate fell below50%.