METHOD OF PREPARING HYDROPHOBIC EMULSION DRILLING MUD BY PHASE INVERSION TECHNIQUE FOR DRILLING LOW-ANGLE AND HORIZONTAL WELLS Russian patent published in 2013 - IPC C09K8/36 

FIELD: chemistry.

SUBSTANCE: invention relates to drilling oil and gas wells. Method of preparing hydrophobic emulsion drilling mud by phase inversion technique for drilling low-angle and horizontal wells involves using two types of drilling mud - hydrocarbon-based and a water-based drilling mud, and mixing said drilling mud with each other by adding the water-based drilling mud to the hydrocarbon-based drilling mud; the water-based drilling mud is added to the hydrocarbon-based drilling mud first in amount of 30-40% of the total volume while stirring until the appearance of features indicating formation of an inverted emulsion with resistivity of at least 6 ohm∙meter and electrical stability of at least 10 V, and then adding the remaining portion of drilling mud, with the following ratio of said types of drilling mud, vol. %: hydrocarbon-based drilling mud 23.85-30.0, water-based drilling mud - the balance; the hydrocarbon-based drilling mud used is a mixture of a hydrocarbon liquid with an inverted emulsion emulsifier, the active primary material of which is a nonionic surfactant based on polyglycol ethers of fatty acids or alcohols with a hydrophilic-lipophilic balance of not more than 10, with the volume ratio of the hydrocarbon liquid to said emulsifier of (7.3-20):1, respectively, and the water-based drilling mud used is polymer-emulsion drilling mud which contains a polymer, an alkaline surface-active emulsifier - oil-in-water emulsion stabiliser, a hydrocarbon phase and mineralised water. The invention is developed in subclaims.

EFFECT: simple method, low consumption of hydrocarbon liquid and emulsifier, improved structural and rheological properties and high inhibiting capacity of the drilling mud.

6 cl, 2 ex, 1 tbl