Abstract: A device can include a housing; external electrodes; circuitry disposed in the housing where the circuitry converts analog signals sensed by the external electrodes to digital signals. Various other apparatuses, systems, methods, etc., are also disclosed.

Abstract: Systems and methods for deploying and using a controlled-frequency downhole seismic source are provided. A downhole seismic source may be placed into a borehole in a geological formation and coupled rigidly to the geological formation via an edge of the borehole. A controlled-frequency seismic signal may be generated sufficient to enable a seismic measurement of the geological formation.

Abstract: The present disclosure relates to increasing the output power of a clamped seismic or acoustic source disposed in a wellbore without damaging the borehole/casing/cement. One or more sources are provided and carried on a conveyance mechanism. The conveyance mechanism may be a wireline, a coiled tubing, or a drill pipe. The one or more sources are run into and/or out of the wellbore and temporarily disposed at various locations within the wellbore. The one or more sources are temporarily clamped to the wellbore at the various locations using distributed clamping, and a source signal is generated by the distributed clamped source. The distributed clamping device may have multiple clamping mechanisms along an increased length of the source or a continuous clamping mechanism along an increased length of the source.

Abstract: Systems and methods for deploying and using a controlled-frequency downhole seismic source are provided. A downhole seismic source may be placed into a borehole in a geological formation and coupled rigidly to the geological formation via an edge of the borehole. A controlled-frequency seismic signal may be generated sufficient to enable a seismic measurement of the geological formation.

Abstract: A seismic generation system may include an electrical source, a conductor coupled to the electrical source and to be positioned in a wellbore in a subterranean formation with a casing therein, and a seismic generation source assembly to be positioned in the wellbore and coupled to the conductor. The seismic generation source assembly may include a source element having a sealed housing, an armature within the sealed housing, source electromagnets coupled to the armature, and electromagnetic clamps coupled to the armature, each electromagnetic clamp having opposite magnetic poles. The sealed housing may include respective ferromagnetic portions adjacent the opposite magnetic poles of each electromagnetic clamp, and non-ferromagnetic portions between the opposite magnetic poles of each electromagnetic clamp.

Abstract: A device can include a housing; external electrodes; circuitry disposed in the housing where the circuitry converts analog signals sensed by the external electrodes to digital signals. Various other apparatuses, systems, methods, etc., are also disclosed.

Abstract: A seismic generation system may include an electrical source, a conductor coupled to the electrical source and to be positioned in a wellbore in a subterranean formation with a casing therein, and a seismic generation source assembly to be positioned in the wellbore and coupled to the conductor. The seismic generation source assembly may include a source element having a sealed housing, an armature within the sealed housing, source electromagnets coupled to the armature, and electromagnetic clamps coupled to the armature, each electromagnetic clamp having opposite magnetic poles. The sealed housing may include respective ferromagnetic portions adjacent the opposite magnetic poles of each electromagnetic clamp, and non-ferromagnetic portions between the opposite magnetic poles of each electromagnetic clamp.

Abstract: The present disclosure relates to increasing the output power of a clamped seismic or acoustic source disposed in a wellbore without damaging the borehole/casing/cement. One or more sources are provided and carried on a conveyance mechanism. The conveyance mechanism may be a wireline, a coiled tubing, or a drill pipe. The one or more sources are run into and/or out of the wellbore and temporarily disposed at various locations within the wellbore. The one or more sources are temporarily clamped to the wellbore at the various locations using distributed clamping, and a source signal is generated by the distributed clamped source. The distributed clamping device may have multiple clamping mechanisms along an increased length of the source or a continuous clamping mechanism along an increased length of the source.

Abstract: The present disclosure relates to making seismic measurements using a seismic source disposed in a wellbore. One or more seismic sources are provided and carried on a conveyance mechanism. One or more seismic receivers are provided and placed on or near the earth's surface, in the same wellbore as the seismic sources, or in another wellbore. The one or more seismic sources are run into and/or out of the wellbore using a controller or sequencer. The one or more seismic sources are positioned, manually or automatically, at one or more locations in the wellbore, using a set of computer-controlled instructions. Seismic measurements are made at the one or more locations by activating the one or more seismic sources and detecting a seismic source signal using the seismic receivers. The receivers may be carried on a conveyance mechanism and their position controlled, manually or automatically, using the set of computer-controlled instructions.

Abstract: A compensated ensemble crystal oscillator clock system. The clock system includes preferably four quad compensated clocks, a compensated temperature sensor, and software for processing and correcting system response. Physical fabrication of elements of the quad compensated clocks, the compensated temperature sensor and cooperating software minimized drift in frequency of the oscillator clock system in harsh borehole environments encountered while drilling a borehole. The clock system exhibits a frequency stability of 2.8×10?9 or less over a temperature range of from 0° C. to 185° C. The compensated ensemble crystal oscillator clock system is particularly applicable to seismic-while-drilling operations wherein precise downhole measurements of time are required typically over a period of days.

Abstract: A vibration source (10) includes an armature bar (12) having a major length dimension, and a driver (20A) positioned about the armature bar. The driver (20A) is movably coupled to the armature bar (12), and includes an electromagnet (40). During operation the electromagnet (40) is activated such that the driver (20A) moves with respect to the armature bar (12) and a vibratory signal is generated in the armature bar. A described method for generating a vibratory signal in an object includes positioning the vibration source (10) in an opening of the object, coupling the armature bar (12) to a surface of the object within the opening, and activating the electromagnet (40) of the driver (20A) such that the driver moves with respect to the armature bar (12) and a vibratory signal is generated in the armature bar and the object.

Abstract: An apparatus for rotating an instrument in a wellbore includes a non magnetic housing configured to traverse the interior of the wellbore. The housing has an external diameter smaller than an internal diameter of a casing disposed in the wellbore. A plurality of electromagnets is arranged circumferentially about the interior of the housing and is configured to induce magnetic flux through a wall of the housing when actuated. A controller configured to sequentially rotationally actuate the electromagnets. A method for rotating a wellbore instrument in a wellbore includes causing parts of an instrument housing to be sequentially rotationally magnetically attracted to a casing disposed in the wellbore. The housing has a smaller external diameter than an internal diameter of the casing. The sequential rotational magnetic attraction is continued as needed.

Abstract: A magnetically clamped wellbore instrument module includes a substantially non-magnetic housing configured to traverse an interior of the wellbore. At least one electromagnet is disposed at a longitudinally spaced apart position along the housing. The at least one electromagnet has a plurality of circumferentially spaced apart contact points that define a diameter greater than a diameter of the housing. The contact points have circumferential spaces therebetween defining a diameter smaller than the diameter defined by the contact points.

Abstract: A magnetically clamped wellbore instrument module includes a substantially non-magnetic housing configured to traverse an interior of the wellbore. At least one electromagnet is disposed at a longitudinally spaced apart position along the housing. The at least one electromagnet has a plurality of circumferentially spaced apart contact points that define a diameter greater than a diameter of the housing. The contact points have circumferential spaces therebetween defining a diameter smaller than the diameter defined by the contact points.

Abstract: A vibration source (10) includes an armature bar (12) having a major length dimension, and a driver (20A) positioned about the armature bar. The driver (20A) is movably coupled to the armature bar (12), and includes an electromagnet (40). During operation the electromagnet (40) is activated such that the driver (20A) moves with respect to the armature bar (12) and a vibratory signal is generated in the armature bar. A described method for generating a vibratory signal in an object includes positioning the vibration source (10) in an opening of the object, coupling the armature bar (12) to a surface of the object within the opening, and activating the electromagnet (40) of the driver (20A) such that the driver moves with respect to the armature bar (12) and a vibratory signal is generated in the armature bar and the object.

Abstract: An apparatus for rotating an instrument in a wellbore includes a non magnetic housing configured to traverse the interior of the wellbore. The housing has an external diameter smaller than an internal diameter of a casing disposed in the wellbore. A plurality of electromagnets is arranged circumferentially about the interior of the housing and is configured to induce magnetic flux through a wall of the housing when actuated. A controller configured to sequentially rotationally actuate the electromagnets. A method for rotating a wellbore instrument in a wellbore includes causing parts of an instrument housing to be sequentially rotationally magnetically attracted to a casing disposed in the wellbore. The housing has a smaller external diameter than an internal diameter of the casing. The sequential rotational magnetic attraction is continued as needed.

Abstract: Methods and apparatus for generating a signal with a signal generator comprising a tool body disposed in a tubular member. A first and second electromagnets are disposed within the tool body such that the second electromagnet is opposite the first electromagnet. A power supply selectively provides electrical current to the first and second electromagnets so as to displace the tubular member and generate a signal in the surrounding formation.

Abstract: Geophysical measurement system employed during the drilling of a well borehole. The system employs a reference clock disposed within equipment at the surface of the earth and a borehole assembly which houses a downhole clock and at least one sensor. The borehole assembly is operationally connected to a drill string, which advances the borehole. At least one synchronization shuttle apparatus containing a shuttle clock is conveyed downhole to the borehole assembly to synchronize the borehole clock with the reference clock. Reference and borehole clock synchronization is maintained at one millisecond or less over a period of days. Outputs from the reference clock and borehole clock and sensor are combined to obtain a measure of a geophysical parameter of interest. Although the measurement system is particularly applicable to seismic-while-drilling measurements, it can be used in a wide variety of clock driven geophysical measurements.

Abstract: A compensated ensemble crystal oscillator clock system. The clock system includes preferably four quad compensated clocks, a compensated temperature sensor, and software for processing and correcting system response. Physical fabrication of elements of the quad compensated clocks, the compensated temperature sensor and cooperating software minimized drift in frequency of the oscillator clock system in harsh borehole environments encountered while drilling a borehole. The clock system exhibits a frequency stability of 2.8×10?9 or less over a temperature range of from 0° C. to 185° C. The compensated ensemble crystal oscillator clock system is particularly applicable to seismic-while-drilling operations wherein precise downhole measurements of time are required typically over a period of days.

Abstract: A compensated ensemble crystal oscillator clock system for use in a well borehohe system. The clock system includes preferably four quad compensated clocks, a compensated temperature sensor, and software for processing and correcting system response. Physical fabrication of elements of the quad compensated clocks, the compensated temperature sensor and cooperating software minimized drift in frequency of the oscillator clock system in harsh borehole environments encountered while drilling a borehole. The clock system exhibits a frequency stability of 2.8×10?9 or less over a temperature range of from 0° C. to 185° C. The compensated ensemble crystal oscillator clock system is particularly applicable to seismic-while-drilling operations wherein precise downhole measurements of time are required typically over a period of days.