METHOD FOR HORIZONTAL WELL GEOSTEERING IN BLACK SHALE OIL-BEARING FORMATIONS Russian patent published in 2019 - IPC E21B47/00 E21B49/00 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil geology and is used to guide horizontal bores of wells in black-shale oil formations, in conditions of thin-layered section and low-power (first meters) of its productive part. Method for horizontal navigation of a horizontal wellbore in black-shale oil-bearing formations involves x-ray-fluorescent study of rock sludge during drilling, base data for geosteering are used are results of studying drill cuttings sludge, and an auxiliary method is gamma-ray logging during drilling, wherein the rock slurry is collected at frequency of 2–8 meters under the direct control of the geologist and with accurate reference on the depth of penetration by calculating the station of geological and technological studies, each obtained sample of slurry is promptly prepared for studies, then by means of X-ray fluorescent analyzer its elementary composition is studied, wherein data on composition of rock are corrected for distortion of result under effect of drilling fluid due to input of corresponding corrections on elements included in composition of solution, in binocular microscope petrographic characteristics of rock are described, results of slurry analysis are presented during drilling in continuous operating mode, composition of rock is compared with gamma-ray logging data, numerically and graphically compared to previously studied support cut, making conclusions on current position of drilling bit in section and its trajectory, as a result of which, if necessary, correcting direction of drilling horizontal hole relative to target section of cut.

EFFECT: high accuracy of placing horizontal boreholes in the target horizon.

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