Assuming the specifications of the Eastern Siberia geological section, mineralized drilling fluids with polymers apply for the drilling of oil and gas wells. Efficiency of filtration control polymers in drilling mud composition depends on their chemical nature, molecular structure and physicochemical interactions between the mud components and the rocks and formation fluids, especially highly mineralized formation water. As a result of such interactions drilling fluid characteristics may get significantly worse, which usually leads to various complications in drilling process and decreases bottomhole formation zone permeability while exposing. The method of polymers efficiency and quality estimation was developed and tested out. It can be used to select the best polymer among similar types, study processes occurring to polymer during drilling and optimize polymer composition in drilling fluids applied in the geological conditions of the Eastern Siberia. The method is based on intrinsic viscosity measurements for polymers in various solvents. The research of polyelectrolyte effect on polymers of similar type with different degrees of polymerization and substitution was carried out. Modeling of interactions between polymers in drilling fluid and salts in formation water was made with applied CMC and modified starch. The reasons why obtaining exact mud characteristics could be complicated and the way characteristics change after physicochemical interactions are determined. Comparative assessment of CMC and modified starch stability in specific conditions is given. It was concluded that developed method is promising.
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