DRILLING FLUID MEDIA AND METHODS FOR THEIR USE Russian patent published in 2020 - IPC C09K8/02 C04B28/00 C04B16/04 

FIELD: drilling of wells.

SUBSTANCE: group of inventions relates to drilling methods using drilling fluid compositions. Drilling fluid contains a water source, a clogging agent, a nanocomposite containing a core and shell structure. Core comprises a nanoparticle having an average particle size of about 5 nm to 500 nm. Nanoparticle is selected from silicon dioxide, treated or partially treated pyrogenic silicon dioxide, colloidal silicon dioxide, composite particles of double oxide of silicon and aluminum, or titanium dioxide. Envelopment contains cross-linked polymer containing acrylamide repeating links, repeating units of acrylic acid or its salt, repeating units of 2-acryloylamino-2-methylpropane-1-sulphonic acid or a salt thereof, or combinations thereof.

EFFECT: technical result is prevention of loss of fluid medium in formation by means of aqueous drilling fluids, in which fluid loss control substance practically does not swell in water, retention of water in aqueous drilling mud, temperature of which reaches or exceeds level of 80 °C to 200 °C.

14 cl, 9 tbl, 10 ex, 5 dwg