A method may comprise measuring during a survey operation a gravitational field data using a survey accelerometer and magnetic field data using a survey magnetometer and determining during a drilling operation an azimuth of a wellbore based on the gravitational field data and the magnetic field data obtained during the survey operation. A system may comprise a drilling rig; a pipe string attached to the drilling rig; a bottom hole assembly attached to the pipe string, wherein the bottom hole assembly comprises at least one sensor; a drill bit, wherein the at least one sensor measure a revolutions-per-minute (RPM) of the drill bit; and a computing subsystem.

Slotted dipole antennas for use in an antenna system on a drill collar segment is presented. Dipoles may be placed in slots on the drill collar segment. A dipole consists of a ferrite rod with electric wires placed above and below the ferrite rod. Wires may be connected such that wire current forms a loop around the ferrite rod. When a group of slots are used for an antenna, wire holes are constructed between slots. Effectively a single wire may be used to go above all ferrite rods in the group and then turn to go below all the ferrite rods. Two wire segments are in a wire hole connecting two adjacent slots. Currents in the two segments are the same in magnitudes and flow in opposite directions. There is no net current in wires in a wire hole.

A method for obtaining accuracy gravity coefficients out of three orthogonally oriented accelerometer devices and a thermometer by computing, using a pre-programmed micro-control unit processor, temperature errors, bias error coefficients, sensitivity error coefficients, and orthogonality error coefficients during measurement while drilling operations. Particularly, the method uses voltage data values of the three orthogonally oriented accelerometers to compute said error coefficients which provides for zero-error positioning of the MWD tool during long-term downhole surveying as well as while facing high-shock, vibrations, and high temperatures.

Embodiments herein relate to identifying occurrence of a trigger condition related to an existing physical well. Embodiments further relate to simulating, based on identification of the occurrence of the trigger condition, a plurality of computer-simulated ancillary wells in a vicinity of the existing physical well. Embodiments further relate to determining one or more simulated parameters related to respective ones of the plurality of computer-simulated ancillary wells. Embodiments further relate to determining, based on the one or more simulated parameters, a parameter of a sidetrack well that is to be related to the existing physical well. Embodiments further relate to outputting an indication of the parameter of the sidetrack well. Other embodiments may be described or claimed.

Embodiments herein relate to identifying occurrence of a trigger condition related to an existing physical well. Embodiments further relate to simulating, based on identification of the occurrence of the trigger condition, a plurality of computer-simulated ancillary wells in a vicinity of the existing physical well. Embodiments further relate to determining one or more simulated parameters related to respective ones of the plurality of computer-simulated ancillary wells. Embodiments further relate to determining, based on the one or more simulated parameters, a parameter of a sidetrack well that is to be related to the existing physical well. Embodiments further relate to outputting an indication of the parameter of the sidetrack well. Other embodiments may be described or claimed.

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.

An electromagnetic tool using slotted dipole antennas is presented. The dipoles may be placed in slots on a drill collar. A receiver or transmitter antenna consists of one or more slots. A dipole consists of a ferrite rod with electric wires placed above and below the ferrite. Wires may be connected such that wire current forms a loop around the ferrite rod. When a group of slots are used for an antenna, wire holes are constructed between slots. Effectively a single wire may be used to go above all ferrite rods in the group and then turn to go below all the rods. Two wire segments are in a wire hole connecting two adjacent slots. Currents in the two segments are the same in magnitudes and flow in opposite directions. There is no net current in wires in a wire hole.

Disclosed herein, in one aspect, is a system for determining depth within a borehole. The system can comprise a downhole device comprising at least one inertial sensor, at least one processor, and a memory in communication with the at least one processor. The memory can comprise instructions thereon that, when executed, cause the processor to: receive data from the at least one inertial sensor and store the data from the at least one inertial sensor in the memory with respective correlated time values. The system can further comprise a drill rig comprising at least one depth measurement device. The at least one depth measurement device can comprises a drill string position sensor that is configured to produce a measurement indicative of a length of a portion of a drill string removed from a borehole or a wireline sensor that is configured to determine a length of deployed wireline cable.

Disclosed herein, in one aspect, is a system for determining depth within a borehole. The system can comprise a downhole device comprising at least one inertial sensor, at least one processor, and a memory in communication with the at least one processor. The memory can comprise instructions thereon that, when executed, cause the processor to: receive data from the at least one inertial sensor and store the data from the at least one inertial sensor in the memory with respective correlated time values. The system can further comprise a drill rig comprising at least one depth measurement device. The at least one depth measurement device can comprises a drill string position sensor that is configured to produce a measurement indicative of a length of a portion of a drill string removed from a borehole or a wireline sensor that is configured to determine a length of deployed wireline cable.