The paper presents the results of an integrated approach to prediction of precipitation of solid materials (precipitates) in the near-wellbore region of producing formation to select optimal technological solutions for removal of such materials and improvement of the injectivity of injection wells in terrigenous reservoirs of TATNEFT PJSC fields. Injectivity reduction is commonly known to interfere with routine production operations. Hence it is imperative that adequate injectivity be maintained throughout the entire field development period. Efficiency of bottomhole treatment depends largely on the design; particularly, the composition and volume of preflush, main treatment acid and overflush, and various quality-improvement additives. An adequate design shall be based on direct causes of permeability impairment in a particular well. This necessitates qualitative assessment of formation damage. The authors analyzed the composition of water injected in TATNEFT PJSC fields and the content of precipitating components. The analysis revealed the necessity to predict corrosion products and inorganic salts: calcite, barite and gypsum. Characteristics of suspended solids in injected water are summarized, the effects of dispersed phase particle size on water flow through porous media are considered. The existing methods for prediction of scaling and asphaltene-resin-paraffin deposition are described, together with corrosion processes during injection well operation in terrigenous reservoirs. Literature survey of precipitates invasion depth is presented. The authors propose way forward to improve NORSOK M-506 corrosion rate and Oddo-Tomson scaling prediction methods for development of an expert system aimed at selection of bottomhole treatment technology to increase injectivity of injection wells in terrigenous reservoirs. Method for evaluation of depth of invasion of formation damage based on core flood experimental data was developed and implemented.
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