REAGENT MODIFIED STARCH FOR DRILLING AND METHOD THEREOF Russian patent published in 2016 - IPC C09K8/35 

FIELD: oil and gas industry.

SUBSTANCE: group of inventions relates to drilling of oil and gas wells. Process for producing a modified starch reactant drilling, comprising treating starch containing raw material, reagent prepared by single- or multiple-component extrusion processing of starch with/without additional components at 100-200 °C (most preferred temperature of 110-150 °C), screw speed of 50-100 rev/min, die diameter - 1-6 mm, followed by crushing and sieving or reagent is prepared by mixing extrudates are made with above various modes extrusion process, with each other or with native starch, and / or with the addition of 1-5 wt % dextrin or mixture of dextrins selected from the group consisting maltodextrine and / or eritrodekstrin and/or ahroodekstrin and/or maltodextrin. Reagents modified starches for drilling comprising starchy component obtained by above method and is homogeneous powdery material with particle size of 0.67 mm, 10-12 % humidity, completely soluble in fresh water at 20°C, a dynamic viscosity of a 5 % aqueous solution of reagent is not less than 10 Pa·c (600 rev / min OFITE) and hydrogen ion concentration in solution of at least 6 pH-units, providing filtering model salt-slurry (0.1 MPa) with reagent concentration of 5-15 kg/m³ no more than 5-8 cm³/30 min and conditional viscosity of this solution with concentration of reactant of 15 kg/m³ not more than 50 seconds.

EFFECT: technical result - high technological characteristics of reagent for drilling, high efficiency and cost-effectiveness of its receipt.

2 cl, 1 dwg, 2 tbl, 5 ex