METHOD FOR PREPARING DRILLING SOLUTION ON HYDROCARBON BASE FOR WELLS DRILLING WITH ABNORMALLY LOW FORMATION PRESSURE Russian patent published in 2017 - IPC C09K8/38 

FIELD: mining engineering.

SUBSTANCE: method for preparing a hydrocarbon-based drilling fluid for wells drilling with abnormally low formation pressure comprises: mixing gel agent with the hydrocarbon fluid at 600-1500 rpm to obtain emulsion composition, adding aphron forming surfactant-surface active agent to this emulsion composition, dispersing of the obtained mixture, introduction of the facilitating additive in a two-stage stirring mode: 600-1500 rpm for 10-30 minutes in the first stage and subsequent dispersion of the obtained solution with the rotational speed of 1500-2500 rev/min for 15-60 minutes in the second stage, while a highly dispersive amorphous silica dioxide, or an aqueous solution of a mixture of saponified fatty acids or thereof mixture with the following ratio of components, vol. %: said gel forming 1-10; aphron-forming surfactant 2-10; facilitating additive 0.1-15; hydrocarbon liquid 65.0-96.9.

EFFECT: production of lightweight solution with high density having low gas content and low rheological properties which enables to use the resulting drilling solution in open circulation system without the use of additional collar sealing equipment, as well as systems and methods for defoaming during circulation, reduction of hydraulic load on formations woth abnormally low formation ALFP and reduction of drilling solution losses during process operations.

9 cl, 3 tbl