A downhole sealant injection system includes a first casing configured to be positioned in a wellbore and a second casing configured to be positioned in the wellbore within the first casing. Cement at least partially fills an annulus between the interior of the first casing and the exterior of the second casing. A first sealant injection tool is configured to be attached to the exterior of the second casing, and is positioned at a downhole location and within an annulus between the interior of the first casing and the exterior of the second casing. The sealant injection tool includes a plurality of nozzles configured to inject sealant into voids within the cement in the annulus between the interior of the first casing and the exterior of the second casing.

A drilling system includes a drill string for connecting with a drill bit for drilling a borehole, a fixed stabilizer fixed on the drill string, and an active stabilizer including a body and actuators connecting the body and the drill string. The actuators are capable of driving the drill string away from a center of the borehole with a displacement. The body has an outer surface for contacting a wall of the borehole, an inner surface facing the drill string, and at least one guiding portion projecting from the inner surface and each defining at least one groove. The drill string includes at least one sliding portion slidable within the at least one groove respectively to constrain movement between the drill string and the active stabilizer along an axial direction of the drill string and guide movement between the drill string and the active stabilizer perpendicular to the axial direction.

A shaft enlargement arrangement for a boring system is provided, the shaft enlargement arrangement comprising a hollow column proximate a lower end of the boring system; a first cutter head that is rotatably fitted to the hollow column, with first drive means being provided to rotate the first cutter head relative to the hollow column so as to bore downwardly a hole having a diameter corresponding substantially to the diameter of the first cutter head; and a boring head arrangement fitted to an operatively lower end of the column, the boring head arrangement terminating in a second cutter head to bore a leading hole as the boring system proceeds to bore downwardly. In an embodiment, the first cutter head comprises a support body carrying a winged arrangement, the support body being rotatably fitted to the column, the winged arrangement comprising a plurality of wings extending from the support body, each wing being fitted with, or comprising, a plurality of first cutter elements.

The invention provides a downhole borehole traction apparatus (10) and method of use. The apparatus comprises a body comprising a borehole engaging section wherein the borehole engaging section comprises an outer surface comprising at least one thread. The at least one thread comprises a crest surface (32), a leading surface (30), and a trailing surface (28) having a curvilinear shape. The at least one thread has a low pressure generation means comprising one or more formations.

A modular anti-rotation device for preventing rotation with respect to the central axis of a drilling tool in a borehole and for producing a notch in a borehole surface. The anti-rotation device includes an upper fixture portion and a lower fixture portion in axial alignment. The upper fixture portion and the lower fixture portion are connected by yoke assemblies. Each yoke assembly is connected to the fixture portion and fixture portion at one end, and forming an articulated joint of the upper yoke assembly and the lower yoke assembly at a distal end opposite the first end. A roller is connected at each joint, connecting the upper and lower yoke assemblies. The rollers engage vertically with a borehole surface, the rollers travelling axially, as a drill shaft penetrates into the borehole, the rollers simultaneously preventing radial movement of the anti-rotation device and prevent rotation with respect to the central axis of the borehole.

A system for securing a downhole tool to a housing includes a plurality of linear wave springs placed around a chassis. The linear wave strings have an unstressed height that is less than or equal to an annular gap. This reduces the insertion force required to insert the chassis into the housing. The linear wave springs are compressed to increase the amount of radial force applied to the chassis and the housing.

A drill pipe mountable wellbore cleaning tool apparatus includes a support sleeve that is mounted to a drill pipe joint in between the connector end portions of the drill pipe joint. Centralizers are attached to the opposing ends of the support sleeve and the support sleeve carries one or more debris cleaning tools in between the centralizers. At least one locking clamp is attached to the cylindrical portion next to a said centralizer, and prevents the support sleeve from moving longitudinally along the drill pipe joint.

A running tool coupled to a running string and for operational use in a well casing. The running tool having a collapsed and expanded state, a tubular positioned around the centralizer to hold the centralizer in the collapsed state, a release assembly maneuverable to release the tubular causing the centralizer to enter into an expanded state, and a cleaning device for cleaning walls of the well casing. The cleaning device includes at least one of a scraper, magnet, brush, and a high flow rate circulation valve for channeling fluid from the running string into the well casing. The centralizer functions as a stabilizer in the expanded state protecting the running tool during operation.

A method may comprise forming a data matrix, extracting chromatographs of a mud filtrate and a formation fluid, extracting concentration profiles of the mud filtrate and the formation fluid, and decomposing a data set on an information handling machine using a bilinear model. A system may comprise a downhole fluid sampling tool and an information handling tool. The downhole fluid sampling tool may comprise one or more multi-chamber sections, one or more fluid module sections, one or more gas chromatographers, wherein the one or more gas chromatographers are disposed in the one or more fluid module sections, and an information handling system.

Centralizers for stabilizing production tubing within a well may include a mandrel for securing within a section of production tubing and having a gland mounting surface; a gland mounted to the gland mounting surface of the mandrel, and having a cylindrical body and two or more lobes extending radially outward from the cylindrical body and comprised of an abrasion resistant material. Downhole assemblies may include a production string receivable within a cased well; a tubing anchor catcher positioned within the production string; a downhole pump coupled to the production string and located axially below the tubing anchor catcher; and a centralizer coupled to the production string.