FIELD: oil and gas production.
SUBSTANCE: retrievable instrument for control over direction of drilling through underground formation consists of first instrument unit (406) and sloping aerial (410) attached to first instrument unit (406). Also the instrument consists of second instrument unit (422) secured to first instrument unit (406) and sloped aerial (426) attached to second instrument unit (422). First instrument unit (406) is attached to second instrument unit (422) so, that aerials (410, 426) are sloped in specified directions. Sloped aerials (410, 426) correspond to emitting aerials or receiving aerials. Each instrument unit corresponds to a tubular cylinder with lengthwise axis passing along length of the cylinder, also the tubular cylinder has two ends each equipped with a rotary fastener. The instrument units are coupled by means of their rotary fasteners. The rotary fasteners can be made as a screw devise, a device of a press fit or they can be welded.
EFFECT: modular instrument unit facilitates detection of approaching bed boundaries and avoiding this approach during drilling boreholes.
16 cl, 23 dwg
