A communication unit is situated in or on a casing collar. The casing collar has two threaded ends for joining casing joints to construct a well casing, and a communication unit is disposed in or on a central region of the tube between the two threaded ends. In an example, the communication unit has a transmitter for transmitting sensor data uphole from a sensor sensing a well bore condition. For example, the communication unit has a receiver for receiving sensor data from Micro-Electro-Mechanical Systems (MEMS) sensors, a transceiver for interrogating RFID tags, an acoustic transceiver for sensing wellbore conditions, a pressure sensor, a temperature sensor, and batteries for powering the communication unit.

A drilling system, assembly, and method may help optimize drilling in a system that involves more than one rotary tool that engages the formation. A rotary tool may be a rotary cutting tool, such as a drill bit or reamer, or some other rotary tool (e.g. stabilizer or rotary steerable tool) that has the potential to drag on the wall of the hole being drilled and take energy away from cutting. In an example, a wellbore or portion thereof is formed by rotating a first rotary cutting tool having a first cutting structure in engagement with one portion of the formation together with a second rotary cutting tool having a second cutting structure in engagement with another portion of the formation. Forces are obtained above and below the second cutting structure. One or more drilling parameter or drill bit design parameter are adjusted in relation to a force differential between the forces above and below the second cutting structure.

A drill-pipe communication assembly includes a first drill pipe segment. A conductor extends at least partially along a length of the first drill pipe segment. An antenna is electrically coupled to the first drill pipe segment. The antenna facilitates wireless transmission of signals from the first drill pipe segment to an adjacent second drill pipe segment.

A drill-pipe communication assembly includes a first drill pipe segment. A conductor extends at least partially along a length of the first drill pipe segment. An antenna is electrically coupled to the first drill pipe segment. The antenna facilitates wireless transmission of signals from the first drill pipe segment to an adjacent second drill pipe segment.

Methods, systems and devices for evaluating an earth formation, including an electromagnetic (EM) well logging apparatus for investigating a formation from a fluid-filled borehole intersecting the formation. Apparatus include a carrier body having a pocket formed in an outer surface, the pocket being defined by a plurality of walls and a bottom; a pad configured to emit EM energy, the pad having an outer face, a plurality of sides complementary to the plurality of walls, and an inner face positioned adjacent to the bottom, wherein the pad is movably disposed in the pocket such that a gap separates at least one wall of the plurality of walls and at least one side of the plurality of sides; and at least one electrically conductive member forming an electrical connection between the carrier body and the pad and covering the gap. The pad may be slideably disposed in the pocket.

A system includes a first instrumented bridge plug positionable in a downhole wellbore environment. The first instrumented bridge plug includes an acoustic source for transmitting an acoustic signal. The system also includes a second instrumented bridge plug positionable in the downhole wellbore environment. The second instrumented bridge plug includes an acoustic sensor for receiving a reflected acoustic signal originating from the acoustic signal. The reflected acoustic signal being usable to interpret wellbore formation characteristics of the downhole wellbore environment.

An apparatus can include a downhole tool having a fluid outlet connectable to a fluid inlet to define a flow path via a hollow interior of the tool, and a valve member capable of opening and constricting or closing the flow path. The apparatus further includes pipe within which a part of the tool is located, the tool being sealed with an interior of the pipe, preventing fluid flow in the pipe via the part of the tool. The pipe includes an openable valve for permitting flow of fluid from the pipe interior via another flow path interconnecting the pipe interior and outside. The valve is normally closed. When the valve member constricts or closes the first flow path, fluid pressure in the pipe increases to cause opening of the valve and venting of pressurized fluid from within the pipe to the outside via the second flow path.

Slotted dipole antennas for use in an antenna system on a drill collar segment is presented. Dipoles may be placed in slots on the drill collar segment. A dipole consists of a ferrite rod with electric wires placed above and below the ferrite rod. Wires may be connected such that wire current forms a loop around the ferrite rod. When a group of slots are used for an antenna, wire holes are constructed between slots. Effectively a single wire may be used to go above all ferrite rods in the group and then turn to go below all the ferrite rods. Two wire segments are in a wire hole connecting two adjacent slots. Currents in the two segments are the same in magnitudes and flow in opposite directions. There is no net current in wires in a wire hole.

A down-hole tool includes at least one wall. The at least one wall may include a plurality of joined substantially parallel layers of material, a plurality of pockets defined within the at least one wall, each pocket of the plurality of pockets including a plurality of openings formed in consecutive layers of the plurality of joined substantially parallel layers of material, and a plurality of recesses defined within the at least one wall and between layers of the plurality of joined substantially parallel layers of material, the plurality of recesses defining at least one conduit. The down-hole tool also includes at least one electronic component disposed within a pocket of the plurality of pockets and at least one electrical connection disposed within the at least one conduit.

A down-hole tool includes at least one wall. The at least one wall may include a plurality of joined substantially parallel layers of material, a plurality of pockets defined within the at least one wall, each pocket of the plurality of pockets including a plurality of openings formed in consecutive layers of the plurality of joined substantially parallel layers of material, and a plurality of recesses defined within the at least one wall and between layers of the plurality of joined substantially parallel layers of material, the plurality of recesses defining at least one conduit. The down-hole tool also includes at least one electronic component disposed within a pocket of the plurality of pockets and at least one electrical connection disposed within the at least one conduit.