Abstract: An electric motor assembly, mud pulser and a method for transmitting data. The electric motor assembly includes an electric motor having a rotor and a stator that includes one or more windings; one or more sensors on the stator and configured to determine an angular position of the rotor; and a motor control circuitry configured to control a commutation of the electric motor based on signals received from the one or more sensors. The motor control circuitry is configured to determine a total angular rotation of the rotor based on a back emf voltage of the one or more windings and independent of the signals from the one or more sensors.

Abstract: An apparatus for creating pressure pulses in the fluid of a bore hole is described. The preferred embodiment takes the form of a mud pulser apparatus having a signalling valve controlled by a variable pilot valve. The forces on the signalling valve are balanced and controlled by the flow of mud through the variable orifice of the pilot valve. The arrangement is such as to act like a hydraulic amplifier, and results in the signalling valve being compensated for variable flow rates. In the preferred embodiment, the pilot valve has rotary vanes that allow it to be self-cleaning.

Abstract: An electric motor assembly, mud pulser and a method for transmitting data. The electric motor assembly includes an electric motor having a rotor and a stator that includes one or more windings; one or more sensors on the stator and configured to determine an angular position of the rotor; and a motor control circuitry configured to control a commutation of the electric motor based on signals received from the one or more sensors. The motor control circuitry is configured to determine a total angular rotation of the rotor based on a back emf voltage of the one or more windings and independent of the signals from the one or more sensors.

Abstract: A differential pressure sensor has a magnetized piston free to move in a cylinder. Magnetic endcaps seal the ends of the cylinder, forming chambers on either side of the piston. The moveable magnetic piston is constrained by the opposing magnetic fields of the endcaps. The piston is covered with magnetic ferrofluid, providing a low friction gas-tight seal around the piston. The cylinder has two pressure input lines, one being connected to the chamber on either side of the piston. The relative pressures of the input lines cause the piston to move to a position of equilibrium within the cylinder, with the magnetic fields of the endcaps holding the piston in place against the pressure. A magnetic field angle sensor detects flux lines on the outside of the cylinder, and the reading is correlated with the pressure differential between the two input lines.

Abstract: Apparatuses, methods for manufacturing an apparatus and methods for measuring a fluid resistivity are provided. An apparatus for measuring a fluid resistivity includes a fluid column defining structure, two current injecting electrodes, voltage measurement electrodes, and two additional electrodes. The fluid column defining structure is configured to allow a fluid, whose resistivity is to be measured, to fill a fluid column inside the fluid column defining structure. The two current injecting electrodes are configured to inject a known current into the fluid column. The voltage measurement electrodes are configured to measure a voltage across a measurement column included in the fluid column. The two additional electrodes disposed inside the fluid column defining structure, outside of the positions of the two current injecting electrodes in the longitudinal direction are electrically connected to each other.

Abstract: A neutron porosity measurement device uses semiconductor detectors located at different distances from a cavity configured to accommodate a neutron source. Each of the semiconductor detectors includes (i) a semiconductor substrate doped to form a pn junction, and having microstructures of neutron reactive material formed to extend from a first surface inside the semiconductor substrate, and (ii) electrodes, one of which is in contact with the first surface of the semiconductor substrate and another one of which is in contact with a second surface of the semiconductor substrate, the second surface being opposite to the first surface. The electrodes are configured to acquire an electrical signal occurring when a neutron is captured inside the semiconductor substrate.

Abstract: Refractive index tools and method. A refractive index tool includes a wave source configured to generate a wave; a transparent rod configured to receive the wave from the wave source; and a wave detector configured to receive the wave from the transparent rod. The wave source is provided at a first end of the transparent rod and the wave detector is provided at the first end or a second end of the transparent rod so that the wave emitted by the wave source travels through the transparent rod and experiences total internal refraction prior to arriving at the wave detector.

Abstract: A seal ring assembly for a well drilling tool that takes the place of conventional O-rings that are prone to costly downhole failures. In a first embodiment the seal ring assembly is configured with a convex adapter seal ring at one end, a concave adapter seal ring at the other end, and a number of V-shaped component seal rings packed in between the convex and concave adapter seal rings and positioned in the space between a drill collar mandrel and a pressure cylinder of the well drilling tool. In a second embodiment the seal ring assembly is configured with a number of X-shaped component seal rings, each of which is fitted with two O-rings. The seal ring assemblies are able to flex when operating in a bent drill hole so as to maintain seal integrity and prevent fluids from passing through to the electronics region of the well drilling tool.

Abstract: Devices and methods to generate a mono-directional ultrasonic wave are provided. An ultrasonic sensor configured to emit a substantially mono-directional ultrasonic wave includes a first piezoelectric element and a second piezoelectric element. The first piezoelectric element is configured to generate a first ultrasonic wave propagating in a first direction and a second ultrasonic wave propagating in a second direction which is different from the first direction. The second piezoelectric element is located and configured to absorb the second ultrasonic wave, and is configured to convert an energy of the absorbed second ultrasonic wave into an electrical energy.

Abstract: A differential pressure sensor has a magnetized piston free to move in a cylinder. Magnetic endcaps seal the ends of the cylinder, forming chambers on either side of the piston. The moveable magnetic piston is constrained by the opposing magnetic fields of the endcaps. The piston is covered with magnetic ferrofluid, providing a low friction gas-tight seal around the piston. The cylinder has two pressure input lines, one being connected to the chamber on either side of the piston. The relative pressures of the input lines cause the piston to move to a position of equilibrium within the cylinder, with the magnetic fields of the endcaps holding the piston in place against the pressure. A magnetic field angle sensor detects flux lines on the outside of the cylinder, and the reading is correlated with the pressure differential between the two input lines.

Abstract: Flowmeters and methods of measuring a fluid flow or manufacturing flowmeters are presented. A flowmeter has a tool body and one or more spinner arms configured to extend with a first end away from the tool body and a second end joined to the tool body, when deployed to measure a fluid flow. Each spinner arm includes a helical blade configured to rotate due to a fluid flowing substantially parallel to a longitudinal axis of the tool body, around a rotation axis between the first end and the second end.

Abstract: A neutron porosity measurement device uses semiconductor detectors located at different distances from a cavity configured to accommodate a neutron source. Each of the semiconductor detectors includes (i) a semiconductor substrate doped to form a pn junction, and having microstructures of neutron reactive material formed to extend from a first surface inside the semiconductor substrate, and (ii) electrodes, one of which is in contact with the first surface of the semiconductor substrate and another one of which is in contact with a second surface of the semiconductor substrate, the second surface being opposite to the first surface. The electrodes are configured to acquire an electrical signal occurring when a neutron is captured inside the semiconductor substrate.

Abstract: Drill pipe segments, communication systems, and methods of manufacturing pipe segments usable for communicating data wirelessly between sensors and tools placed in an oil and/or gas well are provided. Communication specks are applied on at least one of an outer surface or an inner surface of the pipe segments or coil tubing.

Abstract: Refractive index tools and method. A refractive index tool includes a wave source configured to generate a wave; a transparent rod configured to receive the wave from the wave source; and a wave detector configured to receive the wave from the transparent rod. The wave source is provided at a first end of the transparent rod and the wave detector is provided at the first end or a second end of the transparent rod so that the wave emitted by the wave source travels through the transparent rod and experiences total internal refraction prior to arriving at the wave detector.

Abstract: A rotary steerable tool (2) for use in a downhole drilling apparatus for adjusting the direction of drilling is disclosed. The tool comprises a tubular outer housing (20) and a row of steering pushers (24) slidably mounted to the housing for movement between an extended position, in which the steering pusher engages a wall of a borehole formed by the drilling apparatus, and a withdrawn position, in which the steering pushers do not engage the wall of the borehole. A tubular sleeve (4) is mounted inside the housing (20) to transmit rotary drive to a drilling bit. A pressure chamber (22) defined between the sleeve (4) and the housing (20) communicates with the steering pushers (24) to move the steering pushers (24) to the extended position.

Abstract: A centralizer for use in oil well wireline toolstrings comprising a central mounting rod and floating spring mechanisms between which a number of jointed centralizer arms are connected. The jointed centralizer arms have a section with a concave profile disposed near to their pivot points so that a closing force acting on the arms acts at a greater distance from the pivot, thereby increasing the closing moment and making the centralizer easier to draw into a borehole with a narrow cross-section. The floating spring mechanisms also have a linkage to the presser plate of the spring such that an axial force pulling the centralizer apparatus into a borehole is transferred directly into a force on the spring, thereby reducing the opening moment the springs exert on the centralizer arms.

Abstract: A shock absorbing tool for use in pipelines and oil wells, particularly in combination with perforation guns comprises a central mass supported on two springs between the end terminal members. The shock wave is absorbed in the free oscillation of the mass. The mass is constituted by a piston assembly. A steel rope permits the shock absorbing tool to be maneuvered within the bore hole without damage to the springs.

Abstract: A wireline logging sonde for sensing fluid properties in a bore hole. The sonde has a main body and a plurality of sensor capsules mounted peripherally to the main body on fingers. A sensor element is located in each sensor capsule. The sensor elements receive power by inductive coupling from the main body and transmit data signals at radio frequencies back to the main body.

Abstract: A tubular cutting tool includes two or more sets of electrically actuated retractable anchoring legs mounted at longitudinally spaced apart locations and an electrically driven rotary cutting head with a retractable cutting blade. The anchoring legs can be arranged such that they are capable of compensating for variations in the internal radii of the tubular to be cut, thereby ensuring that the cutting tool is clamped rigidly in position.

Abstract: A fluid density measurement device includes a float (12) and a weight (14), each mounted on links (16) for essentially vertical movement. A crank (22) is mounted above the float and weight and is connected to them,by a float link (24) and a counterweight link (28) to convert the forces from the float and the forces from the weight to rotational forces on the crank acting in opposite directions. The position adopted by the crank will be dependent upon the density of the fluid in which the instrument is immersed. The links (16) are arranged so that a good approximation to straight line motion is obtained at the centre of the float and the weight.