Abstract: Various embodiments of an improved downhole disconnect tool are provided, some of which may include a first housing releasably connected to a second housing, a first piston releasably connected to the first housing, and a second piston releasably connected to the second housing. Various fluid communication ports and ball seats may be provided in various combinations in the first and second pistons and in the second housing to enable remote control of the tool by circulating one or more balls into engagement with one or more of the ball seats to disconnect the first housing from the second housing, and thereby disconnect any structures connected to the first and second housings, respectively. Other features and aspects of the invention are also provided.

Abstract: A substantially constant force actuator that is applicable to centralizers, anchors and tractors for use in wells and is applicable to lifting devices such as jacks and load supporting devices. One or more sets of linkage arms are angularly movable by the force of one or more force transmitting members from a minimum angle with the force transmitting members at maximum spacing to a maximum angle with the force transmitting members at minimum spacing to impart a substantially constant force to an object or surface, with the direction of the force being substantially perpendicular to the direction of relative linear movement of the force transmitting members. With the linkage arms at their minimum angles, movement control elements on at least one of the force transmitting members react with guide surfaces of the linkage arms to achieve angular linkage movement and to develop a substantially constant force during angular linkage movement.

Abstract: A gravel packing system for re-entry of a screen assembly by a completion tool having an inflate packer as an isolation barrier for minimizing the necessary height of the gravel pack within the casing and thus maximizing the production interval of a well to permit a higher rate of production. The invention assures re-entry of tools to a gravel pack screen assembly for well completion following a gravel pack operation. A guiding and anchoring tool is run through a casing restriction and/or well tubing to a desired position below the restriction and/or tubing and within the casing and is actuated for anchoring. Guide fingers are formed downhole into a tool guiding configuration and the tool is left anchored within the well casing. Subsequently, a well completion tool is and guided into and latched within the guiding and anchoring tool and the inflate packer is set to enable optimum well production.

Abstract: An apparatus, system, and method useful for discouraging the extrusion of at least one deformable member of a device into a space adjacent to the deformable member when the device is disposed within a borehole and the deformable member extends from the device to the borehole wall involves at least one expandable member disposed upon the device. The expandable member is expandable into the annulus to reduce the width thereof and retractable therefrom to allow movement of the device within and out of the borehole and redeployment of the expandable member. The apparatus, system, and method are particularly suited for limiting the extrusion of packer elements.

Abstract: An apparatus and method for opposing pressure-induced forces acting on a mandrel of a downhole tool. The apparatus and method are particularly suited for use with a packer and include a piston engageable with the mandrel. Forces placed upon the piston by pressure communicated from the tubing bore are transferred to the mandrel.

Abstract: A down-hole tool includes a first and second portion that are moveable relative to one another, but are electrically coupled together. A rigid tube formed into a helical coil extends between the first and second portions. The helical coil is expandable and compressible in response to movement between the first and second portions. A conductor is positioned within the helically wound tube and is adapted to pass electrical signals between the first and second portions.

Abstract: The method and apparatus of the invention determines earth formation resistivity at extended depths into the formation by the use of telemetry transmission signals to measure the formation resistivity. The telemetry transmission signals carry measurement data from downhole sensors through the formation to an uphole receiver. The signal transmission is by means of induction telemetry. At the receiver, the signal is demodulated to obtain the transmitted measurement data. During the detection of the signal at the receiver, the signal amplitude is also extracted and is used to determine the formation resistivity. In addition, changes in the signal amplitude are also used to indicate formation boundaries for determining well location during directional drilling.

Abstract: An actively controlled rotary steerable drilling system for directional drilling of wells, the system having a rotary drive component rotatable within a tubular sliding tool collar that incorporates elastic anti-rotation members to maintain a coupled relation with the borehole wall during drilling. An offsetting mandrel is supported within the tool collar by a knuckle joint for pivotal movement and for rotation relative to the tool collar and has a lower end extending from the tool collar and supporting a drill bit. To achieve controlled steering of the rotating drill bit, orientation of the tool collar is sensed and the offsetting mandrel is maintained geostationary and selectively axially inclined relative to the tool collar by orienting it about the knuckle joint.

Abstract: When drilling a borehole for an oil well it is desirable to know when fluid is passing through the walls of the borehole between the borehole itself and the formation through which the borehole is passing. It has now been discovered that useful information about the influx or efflux of fluid can be gained by observing the pressure within the borehole in the region of the drilling bit, this observation being carried out not when the drill is actually operating but when it is still (and the pipe string to which it is mounted is also still) and the drilling fluid is not being pumped; the basis for this is that the drilling fluid is thixotropic, and when not disturbed will form a gel which is capable of quite accurately transmitting the force created by moving fluids at the interface between the borehole and the earth formation being drilled through--that is inflowing or outflowing fluids--displacing the drilling fluid along the borehole, and with an efficiency far greater than previously recognized.

Abstract: The invention concerns a method of and apparatus for measuring the flow rate of a continuous phase in a flowing multiphase fluid. It includes the steps of measuring a velocity of the fluid with a thermal anemometer at a location in the flow and simultaneously measuring the passage of a discontinuous phase at the same location with a local probe system capable of measuring the passage of a discontinuous phase, and then using the measurement of the discontinuous phase to correct the measurement of the continuous phase so as to derive the flow rate thereof.

Abstract: A method of determining fluid influx or loss from a well being drilled from a floating vessel and using a drilling fluid, the method comprising monitoring the flow of fluid from the well to obtain a varying signal indicative of the variation in flow from the well, monitoring the heave motion of the vessel to obtain a varying signal indicative of said motion, using the signal indicative of the heave motion to calculate the expected variation in fluid flow from the well due to said motion, using said calculated flow to correct the varying flow signal to compensate for any flow component due to heave motion and monitoring the compensated signal for an indication of fluid influx or loss from the well.

Abstract: A disclosed embodiment utilizes one or more toroidal coil antennas mounted, in an insulating medium, on a drill collar to induce currents which travel in a path that includes the drill collar and earth formations around the drill collar. At least one array of electrodes is provided on at least one stabilizer blade of the drill collar and is utilized to detect currents transmitted by toroidal coil antennas which return via the formations to the electrodes laterally; that is, approximately normal to the axis of the drill collar. Signal traces are obtained from measurements taken at respective ones of the transducers, and a dip characteristic of the formations is determined from the signal traces and from signals representing the rotational orientation of the drill collar.