CLAYLESS DRILLING MUD FOR PRODUCTIVE STRATUM OPENING Russian patent published in 2002 - IPC

FIELD: oilwell and gashole drilling. SUBSTANCE: clayless drilling mud used for productive strata opening has starch, biopolymer, carbonate weighting compound, alcohol, surface-active substance and water. Drilling mud has polyglycol as an alcohol, hydrophobizing surface-active substance PKD-515 as a surface-active substance and reagent DSB-4TT which is a product of condensation of monoethanolamine and crude tall oils in mixture with kerosene, monoethanolamine and flotation reagent oxal as an additional lubricating addition taken in the following ratio of components, wt.-%: starch, 1.0-1.5; biopolymer, 0.2-0.3; carbonate weighting compound, 5- 10; polyglycol, 3-5; indicated surface-active substance, 1.5-2.0; indicated lubricating addition, 0.5-1.0 and water, the balance. EFFECT: increased recovery coefficient of initial permeability of productive stratum. 4 tbl