A drill bit for drilling a subterranean formation. The drill bit includes a drill bit body, at least one cutting element disposed on the drill bit body, and an optical sensor disposed on the drill bit body and configured to generate an environmental parameter measurement while drilling the subterranean formation. The optical sensor includes a fiber bragg grating embedded in an optical fiber that passes through a first channel in the drill bit body and a second channel in the drill string to couple to a surface logging station for analyzing the environmental parameter measurement, where the environmental parameter measurement represents at least a downhole chemical composition measured by the fiber bragg grating, and an analysis result of the surface logging station is presented to a user to facilitate a drilling operation.

A drill bit for drilling a subterranean formation. The drill bit includes a drill bit body, at least one cutting element disposed on the drill bit body, and an optical sensor disposed on the drill bit body and configured to generate an environmental parameter measurement while drilling the subterranean formation. The optical sensor includes a fiber bragg grating embedded in an optical fiber that passes through a first channel in the drill bit body and a second channel in the drill string to couple to a surface logging station for analyzing the environmental parameter measurement, where the environmental parameter measurement represents at least a downhole chemical composition measured by the fiber bragg grating, and an analysis result of the surface logging station is presented to a user to facilitate a drilling operation.

A wellbore logging device incorporating selected electronic sensors and a power source is sealingly and removably embeddable within an instrumentation recess formed in a new or existing downhole equipment component such as a downhole tool or other component of a bottomhole assembly (BHA) in a tubular string such as a drill string. The logging device may be a modular device comprising an electronics module incorporating the electronic components, and a power module incorporating one or more energy cells. The electronics module and power module are engageable to form the logging device for insertion into an instrumentation recess, and to enable energization of the sensors and data transfer between the modules. In alternative embodiments, the logging device is a unitary device incorporating both the electronic components and the energy cells.

A wellbore logging device incorporating selected electronic sensors and a power source is sealingly and removably embeddable within an instrumentation recess formed in a new or existing downhole equipment component such as a downhole tool or other component of a bottomhole assembly (BHA) in a tubular string such as a drill string. The logging device may be a modular device comprising an electronics module incorporating the electronic components, and a power module incorporating one or more energy cells. The electronics module and power module are engageable to form the logging device for insertion into an instrumentation recess, and to enable energization of the sensors and data transfer between the modules. In alternative embodiments, the logging device is a unitary device incorporating both the electronic components and the energy cells.

A retrievable whipstock assembly for a wellbore includes a whipstock including a longitudinal body and an anchor connection, a deflection surface provided on the longitudinal body with a first engagement element, and a drilling assembly including a drill housing and a second engagement element. The second engagement element is selectively extendible between a recessed position and an extended position. In the extended position the second engagement element is engageable with the first engagement element.

A method that includes deploying a casing with a multi-electrode configuration over a dielectric layer in a downhole environment. The method also includes collecting electromagnetic (EM) measurements using the multi-electrode configuration, and processing the EM measurements to obtain a characterization of fluids in an annulus between the casing and a borehole wall. A related system includes a casing deployed downhole, the casing having a multi-electrode configuration and a dielectric layer between the casing and the multi-electrode configuration. The system also includes a controller for directing collection of EM measurements using the multi-electrode configuration, and a processor that processes the EM measurements to obtain a characterization of fluids in an annulus between the casing and a borehole wall.

The downhole tool may include an electrical power source, a positive and a negative electrode, and at least one sensor. The positive and negative electrodes may be configured to generate an electric field between the positive and the negative electrode with an electrical charge from the electrical power source and discharge the electric charge through a downhole formation. The at least one sensor may be configured to detect quantum particles dislocated by at least one of the electric field and the discharged electrical charge to determine downhole information from at least one of a travel time of the quantum particles, a composition of the quantum particles, a quantity of the quantum particles, and a charge of the quantum particles.

A housing defines a through passage along its length and is configured to support a group of electrical isolators surrounding the through passage to form an electrically isolating break in a drill string such that each isolator of the group of isolators is subject to no more than a compressive force responsive to extension and retraction of the drill string. The housing defines a housing cavity to receive an electronics package having a signal port and is configured for electrical connection of the signal port across the electrically isolating break. A housing lid can cooperate with a main housing body to define elongated slots for purposes of enhancing the emanation of a locating signal. A housing arrangement can support electrical connections from an electronics package to bridge an electrically isolating gap.

A housing defines a through passage along its length and is configured to support a group of electrical isolators surrounding the through passage to form an electrically isolating break in a drill string such that each isolator of the group of isolators is subject to no more than a compressive force responsive to extension and retraction of the drill string. The housing defines a housing cavity to receive an electronics package having a signal port and is configured for electrical connection of the signal port across the electrically isolating break. A housing lid can cooperate with a main housing body to define elongated slots for purposes of enhancing the emanation of a locating signal. A housing arrangement can support electrical connections from an electronics package to bridge an electrically isolating gap.

A drill head assembly may include a sonde housing and a drill bit. Two or more alignment posts protruding from the steering face of the sonde housing may mate with holes on the underside of a Horizontal Directional Drilling (HDD) drill bit and are used to align the drill bit and transfer much of the forces from the drill bit to the sonde housing. The alignment posts reduce the load on the drill bit mounting bolts and help prevent these bolts from breaking while drilling in difficult ground conditions.