POLYMER-CLAY FLUID FOR DRILLING WELL IN PERMAFROST ROCK Russian patent published in 2006 - IPC C09K8/08 

FIELD: petroleum and gaseous industry.

SUBSTANCE: invention relates to drilling oil and gaseous wells, in particular, to polymer-clay fluids for drilling used under conditions of permafrost rocks. Proposed polymer-clay fluid shows the improved pseudoplastic properties providing enhancing retaining and transporting capacity and treatment degree of the well walls, diminished filtration due to high rate in formation of low-penetrable filtration crust preventing the well pollution and promoting to retention of its collector properties, reduced rate of warming up of permafrost rocks that prevents formation of caverns and destruction of the well walls and as result provides prolonged retention of the well trunk in the stable state. Polymer-clay fluid for wells drilling in permafrost rocks doesn't freeze at negative temperatures and comprises clay, stabilizing agent as a mixture of polysaccharide reagent and structure-forming agent, hydrocarbon antifreeze and water. As a polysaccharide reagent the polymer-clay fluid comprises Acinetobacter sp. biopolymer, and as a structure-forming agent it comprises condensed sulfite-alcohol distillery grains in the following ratio of components, wt.-%: clay, 6-8; condensed sulfite-alcohol distillery grains, 4-6; Acinetobacter sp. biopolymer, 2-4; hydrocarbon antifreeze, 7-19, and water, the balance, wherein the ratio of Acinetobacter sp. biopolymer and condensed sulfite-alcohol distillery grain = 1:(1-3) mas. p., respectively. As hydrocarbon antifreeze, polymer-clay fluid comprises carbamide or glycerol. Invention provides enhancing effectiveness in drilling of wells in permafrost rocks.

EFFECT: improved properties of polymer-clay fluid.

2 cl, 15 ex