Optimization of drilling fluid formulations

The article presents a decomposition of the problem of selecting formulations for drilling fluids, which includes the formalization of requirements for their composition and properties, the construction of a set of acceptable formulations and the justification of a subset of equivalent formulations by component composition, selection of the optimal component composition and content of chemical reagents, as well as the composition and concentration of surfactants. The model was built using expert procedures and the results of multifactorial experimental studies on the effect of chemical reagents on the properties of drilling fluids. The formalization of the content of the formulation components was performed based on a decision-making model with a flexible selection of the optimality criterion from several classes, which reflects the functional features of the use of technological fluids in the relevant mining and geological conditions. Fragments of the model for selecting the formulation of the Biocar-TF drilling mud for drilling within the interval of 5752−6572 m of well 43 Semyrenky at temperatures up to 160°С are described. To ensure high initial quality of the opening to productive horizons and prevent possible complications, an additive criterion based on HTHP filtration loss and mud cake permeability was used. Fragments of the results of the selection of killing fluid formulations for well 526 of the Bugrivativske oil field are presented according to the criteria of the cost per unit volume, surface tension at the interface between the killing fluid filtrate and oil, and the cutting carrying index. The feasibility of using technological fluid formulations of according to various optimality criteria is illustrated.