METHOD OF PREPARING INVERT-EMULSION DRILLING MUD Russian patent published in 2012 - IPC C09K8/36 

FIELD: chemistry.

SUBSTANCE: invention relates to well construction, particularly to methods of preparing hydrocarbon drilling mud, which is an invert emulsion and is used for flushing when drilling oil and gas wells with a strongly crooked hole, long distance wells and horizontal wells. In the method of preparing invert-emulsion drilling mud by mixing a hydrocarbon medium, an aqueous phase, an emulsifier and a complex reagent, the hydrocarbon medium and the emulsifier are mixed first, followed by addition of the complex reagent - mixture of synthetic latex and oxal, taken in volume ratio of 1:(0.1-5). The aqueous phase is then added to said components and the mixture is dispersed, wherein components are taken in the following ratio, wt %: hydrocarbon medium 30.0-80.0; emulsifier 1.0-4.0; said complex reagent 1.5-10.0; aqueous phase 6.0-67.5. The invention is developed in subclaims.

EFFECT: high dynamic and static shearing stress, low plastic viscosity, stability of the emulsion while maintaining stability of these parameters during temperature drop at the mouth and at the bottom.

7 cl, 2 ex, 2 tbl