An underbalanced drilling system is provided. A bottomhole assembly includes a drill bit drilling a wellbore in a formation underbalanced. The bottomhole assembly includes a telemetry sub. A telemetry component transmits signals in real-time between the telemetry sub of the bottomhole assembly and a controller on the surface. A drill string is coupled with the bottomhole assembly, and the drill string includes a plurality of drill collars. The drill collars form a channel through which drilling fluid flows from the surface to the bottomhole assembly. The drill string is inserted into the wellbore by a hydraulic work over unit. A continuous circulation component provides continuous circulation of the drilling fluid while a new drill collar is coupled to the drill string. The continuous circulation component substantially maintains a wellbore density at a predetermined density.

An underbalanced drilling system is provided. A bottomhole assembly includes a drill bit drilling a wellbore in a formation underbalanced. The bottomhole assembly includes a telemetry sub. A telemetry component transmits signals in real-time between the telemetry sub of the bottomhole assembly and a controller on the surface. A drill string is coupled with the bottomhole assembly, and the drill string includes a plurality of drill collars. The drill collars form a channel through which drilling fluid flows from the surface to the bottomhole assembly. The drill string is inserted into the wellbore by a hydraulic work over unit. A continuous circulation component provides continuous circulation of the drilling fluid while a new drill collar is coupled to the drill string. The continuous circulation component substantially maintains a wellbore density at a predetermined density.

A pulser for generating pressure pulses propagating through a column of drilling fluid in the drill string to the surface during drilling. The pulser may include a screen in the surface of a tubular housing to permit mud from the mud stream to enter into the pulser; an adjustable servo valve configured to receive the mud and including a removable servo poppet and a removable servo orifice member positioned in the tubular housing, wherein the adjustable servo valve is configured to allow the removable servo poppet and the removable servo orifice member to be replaced by another removable servo poppet and another removable servo orifice member to alter an inner diameter of an orifice of the adjustable servo valve to accommodate drilling conditions to increase a performance of the pulser generating pressure pulses for the mud stream returning to the surface.

An electro-acoustic transducer includes a tubular body extending a longitudinal direction and having two end portions, opposing each other longitudinally, and internally having a first chamber, sending with the first end portion and a second chamber, on one side adjacent to and in fluidic communication with the first chamber and on the other side ending with the second end portion. The first end portion is closed towards the outside by a membrane applied to the tubular body. The second end portion has openings that put it in fluidic communication to the outside of the tubular body. The first chamber containing electrical windings arranged in succession to each other in the longitudinal direction. The second chamber is filled with a liquid. A movable element is housed in the first chamber and has a permanent magnets packaged and arranged one above the other, with the magnetization alternating and separated.

An electro-acoustic transducer includes a tubular body extending a longitudinal direction and having two end portions, opposing each other longitudinally, and internally having a first chamber, sending with the first end portion and a second chamber, on one side adjacent to and in fluidic communication with the first chamber and on the other side ending with the second end portion. The first end portion is closed towards the outside by a membrane applied to the tubular body. The second end portion has openings that put it in fluidic communication to the outside of the tubular body. The first chamber containing electrical windings arranged in succession to each other in the longitudinal direction. The second chamber is filled with a liquid. A movable element is housed in the first chamber and has a permanent magnets packaged and arranged one above the other, with the magnetization alternating and separated.

An apparatus for generating pressure variances in a flowing fluid includes a first member having a body and a second member. The second member is displaceable about a rotational axis to at least partially block fluid flow through one or more channels in the first member and at least partially reduce the blockage of this fluid flow. The second member has a hub and at least one section extending axially and radially from the hub relative to the rotational axis of the second member. A related method includes guiding fluid across the first member using the channel(s); selectively blocking the fluid flow through the channel(s) using at least one section of a second member; and moving the second member using an actuator to reduce the blockage of the flow of fluid through the channel(s).

The present invention relates to a downhole inflow production restriction device for mounting in an opening in a well tubular metal structure arranged in a wellbore, the downhole inflow production restriction device comprising a device opening, and a brine dissolvable element configured to prevent flow from within the well tubular metal structure through the device opening to an outside of the well tubular metal structure before being at least partly dissolved in brine, wherein the brine dissolvable element is at least partly made of a magnesium alloy. The present invention also relates to a downhole completion system and to a completion method.

The present invention relates to a downhole inflow production restriction device for mounting in an opening in a well tubular metal structure arranged in a wellbore, the downhole inflow production restriction device comprising a device opening, and a brine dissolvable element configured to prevent flow from within the well tubular metal structure through the device opening to an outside of the well tubular metal structure before being at least partly dissolved in brine, wherein the brine dissolvable element is at least partly made of a magnesium alloy. The present invention also relates to a downhole completion system and to a completion method.

A method for geosteering while drilling a well in a subterranean formation using a downhole assembly having a toolface comprises measuring at least one motion-related downhole parameter relative to the toolface angle so as to generate azimuthally-associated data, using the azimuthally-associated data to assess formation anisotropy, and using the anisotropy assessment to manually or automatically steer a well while drilling the well. The motion-related downhole parameter may relate to motion of an asymmetric bit or bent housing or bent housing section. The downhole parameter may be selected from the group consisting of angular velocity, angular acceleration, tangential acceleration, radial acceleration, axial acceleration, cross-axial acceleration, total acceleration, high-frequency torsional oscillation (HFTO) severity, band-pass-filtered root-mean-square (RMS) acceleration, band-pass-filtered peak acceleration and the azimuthally-associated data may comprise azimuthally-associated measurements of any of the motion-related parameters and/or azimuthally-associated calculations of compressive strength, Young's modulus, Poisson's ratio, stress, and fracture measurement.

A method for geosteering while drilling a well in a subterranean formation using a downhole assembly having a toolface comprises measuring at least one motion-related downhole parameter relative to the toolface angle so as to generate azimuthally-associated data, using the azimuthally-associated data to assess formation anisotropy, and using the anisotropy assessment to manually or automatically steer a well while drilling the well. The motion-related downhole parameter may relate to motion of an asymmetric bit or bent housing or bent housing section. The downhole parameter may be selected from the group consisting of angular velocity, angular acceleration, tangential acceleration, radial acceleration, axial acceleration, cross-axial acceleration, total acceleration, high-frequency torsional oscillation (HFTO) severity, band-pass-filtered root-mean-square (RMS) acceleration, band-pass-filtered peak acceleration and the azimuthally-associated data may comprise azimuthally-associated measurements of any of the motion-related parameters and/or azimuthally-associated calculations of compressive strength, Young's modulus, Poisson's ratio, stress, and fracture measurement.