METHOD FOR CONSTRUCTING A WELL WITH AN EXTENDED HORIZONTAL OR INCLINED SECTION IN UNSTABLE ROCKS Russian patent published in 2022 - IPC E21B7/04 E21B33/10 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil and gas industry, in particular to methods for the initial opening of the reservoir by wells with an extended (1000 m or more) horizontal or inclined section passing in the zones of complications. A method for constructing a well with an extended horizontal or inclined section in unstable rocks includes construction in unstable rocks, in which zones of complications are preliminarily determined, wells with a wellhead vertical section and a horizontal or inclined section with the end entering the productive formation. The zones of complications of unstable rocks are covered with a string of pipes, followed by deepening of the well with a bit of a smaller diameter and final fixing by cementing with a production casing string. A well changes from a vertical to a horizontal or deviated section when the well is drilled. The zones of complications are sequentially opened using drilling fluids with a density of 1.30-1.40 g/cm³, followed by successive fastening from the mouth with a pipe string in the form of casing pipes of successively decreasing diameter, with cementing the annulus. The entire horizontal and/or inclined section in the zones of complications is covered with an intermediate casing string, equipped every 10-50 m with rigid longitudinal centralizers, the circumscribed circle diameter of which is 3-20 mm less than the diameter of the drilled hole.

EFFECT: expanding functionality of well construction due to drilling in extended zones of complications with a horizontal or inclined section.

1 cl, 2 dwg