Abstract: A downhole apparatus comprises a casing string with a frangible disk positioned therein. A flow barrier is connected in the casing string and spaced downwardly from the frangible disk. The frangible disk and the flow barrier define a buoyancy chamber. The sliding sleeve will impact and shatter the frangible disk into a plurality of pieces that will pass downwardly in the casing after the casing has been lowered to a desired depth.

Abstract: The disclosed embodiments include pressure-activated firing heads, perforating gun assemblies, and methods to set off a downhole explosion. A pressure-activated firing head includes a first chamber and a second chamber having an energy storage element disposed within the second chamber. The pressure-activated firing head also includes a port fluidly connecting the first chamber and the second chamber. The pressure-activated firing head further includes a flow restrictor that restricts fluid flow from the second chamber to the first chamber. The pressure-activated firing head further includes a firing pin shiftable from a first position to a second position to strike an initiator. The pressure-activated firing head further includes a shear pin that holds the firing pin in the first position and configured to shear in response to a threshold pressure applied to the shear pin to release the firing pin from the first position.

Abstract: A system for gathering downhole measurements includes a drill bit, at least one nozzle receptacle located on the drill bit, and a sensor system. The sensor system has a sensor housing, a flow path extending through the sensor housing, wherein the flow path allows fluid to flow through the sensor housing, and an internal cavity provided within the sensor housing separate from the flow path. The internal cavity contains components that include at least one sensor for gathering data about drill bit conditions and downhole conditions, a powering unit, a printed circuit board, and an electrical conductor, wherein the sensor housing is installed in the at least one nozzle receptacle.

Abstract: 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.

Abstract: A method of sampling a fluid from a rock formation includes deploying a downhole sampling tool to a target zone within a wellbore of the rock formation, with the downhole sampling tool being coupled to a downhole end of a drill pipe. The method further includes rotating the drill pipe within the wellbore while maintaining a body of the downhole sampling tool in a stationary angular position and while collecting samples of the fluid from the rock formation at the downhole sampling tool.

Abstract: Disclosed is a method for determining three-dimensional in-situ stress based on displacement measurement of borehole wall, including the following steps: selecting a testing borehole section for in-situ stress testing; arranging 6-9 measurement points in the testing borehole section; using a coring drill to perform a radial cut around the displacement measurement device to relieve the stress at the measurement point; cutting off the drilled core by the coring drill; recovering the sidewall coring device and removing the cores, and then measuring the elastic deformation parameters of each core; The beneficial effect of the technical scheme proposed in this disclosure is: the method provided by this disclosure overcomes the disadvantage that the measurement can only be performed at the bottom of a borehole and thus it has a wider application range.

Abstract: An apparatus for cutting into a subterranean formation includes a body and multiple cutting blades distributed around a circumference of the body. The cutting blades are configured to cut into the subterranean formation in response to being rotated. Each cutting blade includes a ball embedded in the respective cutting blade. At least a portion of the ball protrudes towards the subterranean formation from the respective cutting blade in which the ball is embedded. Each ball is configured to roll against the subterranean formation to reduce friction while the cutting blades are rotating.

Abstract: A stochastic control method includes determining a property of a solid present in a drilling fluid circulating within a mud circulation system and identifying a mud circulation model that dictates operation of the mud circulation system. The mud circulation model is based on one or more models of one or more uncertainties encountered during a wellbore drilling operation. The method further includes determining an accuracy of the mud circulation model based on a difference between the determined property of the solid present in the drilling fluid and a solid property of the drilling fluid as provided by the mud circulation model, and programming a controller of the mud circulation system based on the mud circulation model to modify operation of the mud circulation system.

Abstract: Apparatuses and methods measuring properties of drilling fluids in which the drilling fluid is contained in a structure, and a measuring device and a processor are used to measure the properties. The measuring device is immersed within the drilling fluid. The measuring device can comprise a shell defining a chamber, a weight adapted to cause the measuring device to sink through the drilling fluid, a transmitter and at least one sensor adapted to measure a property of the drilling fluid. The transmitter is adapted to transmit data representing the property to the processor.

Abstract: A diagnostic coating is applied to the surface of a wellbore service tool. The diagnostic coating has one or more constituents that undergoes an optically-detectable physical change responsive to changing values of one or more downhole parameters. After exposing the diagnostic coating of the service tool to the downhole environment, the tool may be retrieved from the wellbore and inspected to detect any physical change indicative of the service tool having been exposed to elevated values of the one or more downhole parameters.

Abstract: A system includes a bottom hole assembly and a core sampling tool. The bottom hole assembly includes a housing and a drill bit coupled to the housing. The core sampling tool includes a first compartment positioned within the housing, the first compartment including a motor; a second compartment positioned within the housing and radially spaced apart from the first compartment, the second compartment including a coring bit; and a flexible drilling shaft extending between and coupled to the motor and the coring bit.

Abstract: A wellbore assembly including a cable disposed within a wellbore and a fishing jar assembly coupled to the cable. The fishing jar assembly includes a housing assembly, a mandrel assembly, a fishing assembly, and an actuator. The housing assembly has an inwardly projecting shoulder defining an anvil surface and a hydraulic fluid chamber housing hydraulic fluid. The mandrel is movable along a central axis of the housing assembly and has an outwardly projecting shoulder that defines a hammering surface to strike the anvil surface. The mandrel assembly defines a piston disposed within the hydraulic fluid chamber. The fishing assembly engages a component stuck within the wellbore. The actuator moves the piston of the mandrel assembly along the longitudinal axis to pressurize the hydraulic fluid until the hydraulic fluid bleeds past a fluid port allowing the mandrel assembly to trip to strike the anvil surface with the hammering surface.

Abstract: A tie-back string and a method of coupling the tie-back string to a casing is disclosed. The tie-back string is disposed within the casing. The tie-back string includes an anchor and an actuator section. The actuator section including a sleeve that forms a first chamber and a setting piston that forms a second chamber. A pressure differential is created between the first chamber and the second chamber to move the setting piston to engage the anchor of the tie-back string.

Abstract: A counter including a housing disposed about a tubular creating a space therebetween, a piston disposed in the space and responsive to pressure up events in the tubular to compress a transfer chamber, a supply chamber fluidly attached to the transfer chamber; a trigger chamber fluidly attached to the transfer chamber wherein sequential pressure events cause the piston to move fluid from the supply chamber to the trigger chamber. A counter including a fluid incrementing configuration, an activation member in fluid force communication with the fluid incrementing configuration, the activation member having a first position where a fluid port is blocked and a second position where the fluid port is unblocked, the fluid port being fluid pressure connected to a tool to be actuated when the activation member is in the second position.

Abstract: A rotary steerable tool for directional drilling includes a tool body including a flowbore for flowing pressurized fluid therethrough and a plurality of extendable members movably coupled to the tool body for selectively engaging a borehole wall, each extendable member including a piston for moving the extendable member to an extended position. The tool further includes a pressurized fluid supply flow path to provide fluid pressure from the flowbore to the pistons, and a plurality of linear actuators, each independently actuatable to control fluid pressure from the pressurized fluid supply flow path to a respective piston.

Abstract: An electrical connector apparatus for use in a downhole tool comprising a housing, a contact screw within outer threads and inner threads, a contact plunger within the inner bore of the housing and a second cylinder protruding from the first cylinder. The contact spring is located between the contact plunger and the contact screw and pre-loads the contact plunger within the housing.

Abstract: A suspended fluid sampling and monitoring system includes a BOP, the BOP attached to a wellhead. The BOP is positioned above a wellbore. The suspended fluid sampling and monitoring system further includes a TEC, the TEC connected to a sensor package. The TEC and sensor package extend through the BOP into the wellbore. The suspended fluid sampling and monitoring system also includes a fluid sample line, the fluid sample line extending through the BOP into the wellbore. The suspended fluid sampling and monitoring system also includes a fluid sample intake and filtration device, the fluid sample intake and filtration device mechanically coupled to the fluid sample line within the wellbore.

Abstract: The disclosure relates to the field of geotechnical engineering investigation in the civil engineering field. A portable in-situ gas pressure measuring device for a shallow gas-bearing stratum and a measuring method thereof are provided, the device includes a static cone penetrometer, a pressure-sensor control system, a static cone penetration rod and a probe. The static cone penetrometer is connected with the static cone penetration rod, the static cone penetration rod is connected with the probe; the probe is connected with the pressure-sensor control system. The portable in-situ pressure measuring device for a shallow gas-bearing stratum has simple structure and clear principle and is conveniently assembled and disassembled and easy to popularize and provides a measuring method.

Abstract: A method for drilling a wellbore through a subterranean formation includes rotating a drill string in the subterranean wellbore to drill. The drill string includes a rotary steerable tool or a steerable drill bit including a plurality of pads configured to extend radially outward from a tool body and engage a wall of the wellbore. Radial displacements of at least one of the pads are measured while rotating (e.g., drilling). A formation index is computed while drilling by processing the measured radial displacements, where the formation index is indicative of a strength or hardness of the subterranean formation.

Abstract: A ground drilling device with a percussion piston for drilling into the soil, comprising at least one housing section for the percussion piston, wherein an insert is arranged in the housing between the drilling head tip and the percussion piston such that the insert transmits at least a portion of the energy of the percussion piston to the housing, and the insert is held in the housing by means of a shrinking adhesion connection.