Disclosed herein are various embodiments of methods and systems for drilling a wellbore into an oil or gas production zone to prevent formation damage in the reservoir using underbalanced or near-balanced drilling techniques, wherein a jet pump drilling assembly is used to create a vacuum around the drill bit. The design of this jet pump drilling assembly prevents the flow of all drilling/power fluid from entering a drill bit Only fluids from the reservoir are allowed to enter the drill bit. The assembly includes a barrier to ensure that no drilling/power fluid discharged from the jet pump located above the drill bit can flow back around to the jet pump jet pump suction ports located in the drill bit thus preventing any drilling/power fluid from ever contacting the drill bit.

A shifting tool for use in a wellbore includes a tubular housing having a bore formed therethrough; a tubular mandrel disposed in the housing and longitudinally movable relative thereto; and an engagement member moveable relative to the housing between an extended position, a released position, and a retracted position, wherein: the engagement member is movable from the retracted position to the extended position in response to movement of the mandrel relative to the housing, and the engagement member is further movable from the extended position to the released position in response to movement of the mandrel relative to the housing.

Systems and processes for subsea marine managed pressure operations. One system includes a modified riser joint configured to fluidly connect inline with one or more riser joints. The modified riser joint and the one or more riser joints are connected to form a riser connecting a floating vessel with a wellhead. The system further includes a subsea pressure management sub-system configured to be operatively and fluidly connected to the modified riser joint at a subsea location.

A closed-loop hydraulic drilling system generates choke characteristic curves or data that more accurately reflects the relationship between the commanded choke valve position and the resulting pressure drop across the choke valve for a given flow rate and fluid density. The choke characteristic curves may be generated through a calibration procedure and then used during normal operations to more accurately monitor return flow and manage wellbore pressure. The specific gravity of an injected calibration fluid and pressure drop across the choke valve may be determined and correlated to the current choke valve position to reflect the choke characteristic curve in situ, thereby providing for more precise control of wellbore pressure and enabling condition monitoring of the choke valve. In addition, an improved closed-loop hydraulic drilling system does not require a flow meter, enabling the adoption of MPD systems in low-specification and economically constrained applications.

A method for determining the permeability of a fractured zone in the subsoil, wherein at least one well is being drilled and at least said fractured zone is encountered, includes: detecting at least one value of a characteristic quantity associated with said well; retrieving from a memory a mathematical model descriptive of said characteristic quantity and dependent on at least the permeability of said fractured zone; activating a processor for: obtaining at least one calculated value of said characteristic quantity by means of said mathematical model; comparing said calculated value with said detected value; calculating a permeability value of said fractured zone as a function of said comparison; generating an output signal representative of said permeability value. Also described is an apparatus for determining the permeability of a fractured zone in the subsoil.

A closed-loop hydraulic drilling system generates choke characteristic curves or data that more accurately reflects the relationship between the commanded choke valve position and the resulting pressure drop across the choke valve for a given flow rate and fluid density. The choke characteristic curves may be generated through a calibration procedure and then used during normal operations to more accurately monitor return flow and manage wellbore pressure. The specific gravity of an injected calibration fluid and pressure drop across the choke valve may be determined and correlated to the current choke valve position to reflect the choke characteristic curve in situ, thereby providing for more precise control of wellbore pressure and enabling condition monitoring of the choke valve. In addition, an improved closed-loop hydraulic drilling system does not require a flow meter, enabling the adoption of MPD systems in low-specification and economically constrained applications.

A closed-loop hydraulic drilling system generates choke characteristic curves or data that more accurately reflects the relationship between the commanded choke valve position and the resulting pressure drop across the choke valve for a given flow rate and fluid density. The choke characteristic curves may be generated through a calibration procedure and then used during normal operations to more accurately monitor return flow and manage wellbore pressure. The specific gravity of an injected calibration fluid and pressure drop across the choke valve may be determined and correlated to the current choke valve position to reflect the choke characteristic curve in situ, thereby providing for more precise control of wellbore pressure and enabling condition monitoring of the choke valve. In addition, an improved closed-loop hydraulic drilling system does not require a flow meter, enabling the adoption of MPD systems in low-specification and economically constrained applications.

A natural gas hydrate solid-state fluidization mining method and system under an underbalanced positive circulation condition, used for performing solid-state fluidization mining on a non-rock-forming weak-cementation natural gas hydrate layer in the ocean. Equipment includes a ground equipment system and an underwater equipment system. The construction procedure has an earlier-stage construction process, underbalanced hydrate solid-state fluidization mining construction process and silt backfilling process. Natural gas hydrates in the seafloor are mined through an underbalanced positive circulation method.

A fast-acting managed pressure drilling rig is disclosed. A main valve configured as an alternative for a conventional rotating control device is provided to control drilling of a wellbore. A second valve is configured to trap pressure in the wellbore. A choke valve maintains well bottomhole pressure within specified limits by trapping pressure or by releasing trapped pressure within the wellbore. A pressure relief choke is configured to provide fine pressure stability control within the well and to act as a pressure relief valve in response to wellbore overpressure. A controller is configured with at least one processor to affect operation of the main valve, the second ratio valve, the choke valve, and the pressure relief choke in response to information received by the controller representing operation of the managed pressure drilling rig.

A drilling choke is controlled in a controlled pressure system. Pressure and position of the drilling choke are monitored. An adjustment to the position of the choke is determined based on the monitored pressure to control the drilling pressures. An actuation is produced of an actuator operably coupled to the choke to implement the determined adjustment. Rather than directly transferring, the actuation of the actuator is transferred with a transfer mechanism to motion of the choke in a non-linear relationship relative to the position of the choke. Generally, motion of the choke's internal trim (e.g., gate, ball, flapper, disc, etc.) is made quicker when near a fully opened position and is made slower when near a fully closed position. This reduces the need for strict precision for the motion. In the end, the monitored pressure is altered in response to the implemented choke adjustment.