POLYMER-BASED DRILLING MUD FOR WELL CONSTRUCTION Russian patent published in 2016 - IPC C09K8/08 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to drilling oil and gas wells, specifically to clayless biopolymer drilling mud, used for drilling producing reservoirs of horizontal wells and wells with large angle of deviation, represented by carbonate and terrigenous (sandstones) reservoirs, as well as for recovery wells by drilling sidetracking in different hydrogeological conditions. Polymer-based drilling mud for well construction contains, wt%: xanthane type biopolymer grade xanthan gum FCC IV 0.15-0.22; modified starch grade MK-F1 or MK-B 1.8-2.5; sodium carbonate and/or caustic soda 0.1-0.2; calcium carbonate 3-10; potassium chloride or potassium carbonate, sodium formate, or sodium chloride 3-23; surfactant OP-10 0.1-0.2; water - balance.

EFFECT: maintaining filtration-capacitance properties of productive reservoirs, reduction of reservoir energy consumption for movement of fluids using biodegradable polymers and easily removable sealants.

1 cl, 3 tbl, 1 ex