DRILLING MUD-STABILIZING REAGENT AND DRILLING MUD CONCENTRATE Russian patent published in 2004 - IPC

FIELD: oil and gas production.

SUBSTANCE: invention relates to production of chemicals for treating drilling fluids with various degree of mineralization intended for boring deep and ultradeep oil and gas production wells. Stabilizing reagent is prepared by heat treatment (90-110^оС) of lignosulfonates, tall pitch, and carboxymethylcellulose at stirring and controlled removal of water vapors resulting in polymer composition in the form of stable aqueous suspension with viscosity 4000-7000 cPs. Suspension comprises water-soluble phase including low-substituted cellulose ethers and alkali metal carboxymethylcellulose salt and water-insoluble phase including polysubstituted cellulose ethers. Reagent has following proportions of ingredients, wt %: lignosulfonates 15-18, tall pitch 54-58, alkali 8-18, carboxymethylcellulose 18-20, and water - the balance. Aqueous alkali solution has pH value 9.5-11. Drilling mud concentrate represents powderlike mixture of filler, in particular mud powder or chalk, and milled drilling mud-stabilizing reagent solidified on cooling, said powderlike mixture being composed of water-soluble and water-insoluble constituents at their weight ratio (6,5-21.5):(78.5-93.5), respectively. Invention improves and imparts reproducibility to structural and mechanical characteristics of reagent providing increased values of static shear stress and lowered drilling mud filtration level accompanied by lower reagent consumption and retained heat resistance upon salt effects up to 180^оС.

EFFECT: improved performance characteristics of drilling mud and increased efficiency of inexpensive water-dispersible drilling mud concentrate.

8 cl