Abstract: A method involves mixing metallic particles and a liquefied polymer to form a mixture, placing the mixture within a mold, placing a magnet in the vicinity of the mixture within the mold, thereby causing the metallic particles to position themselves in a self-assembly formation within the mixture in response to a magnetic field generated by the magnet, and solidifying the liquefied polymer, such that a polymer matrix is formed. The metallic particles are distributed and secured in the self-assembly formation throughout the polymer matrix, thereby forming a ballast for an untethered downhole tool configured to be lowered into a well formed in a subterranean formation. The polymer matrix is configured to dissolve in response to being exposed to downhole fluid within the well at specified downhole conditions.

Abstract: Untethered, downhole robots are described. In some cases, the downhole robots are configured to have a density within + or ?20% of wellbore fluid in which it will be operating. In some cases, the downhole robots a controller capable of discerning deviation of the wellbore from vertical and, in response, control a buoyancy system to change longitudinal distribution of the weight of the robot, wherein the magnitude of the change in the longitudinal distribution of the weight suffices to reorient the robot.

Abstract: In one implementation, a downhole robot includes a housing, electrically-powered equipment configured to perform operations of the downhole robot, a power source disposed inside the housing, the power source coupled by a current flow path to provide electrical current to power to the electrically-powered equipment, and a resettable latch disposed inside the housing. The resettable latch is configured to either interrupt flow of electrical along the current flow path or allow current to flow along the current flow path in response to a signal that wirelessly penetrates the housing.

Abstract: An untethered downhole tool includes a housing and a propeller. The housing is configured to house a logging tool and a power supply. The housing defines a longitudinal axis. The propeller includes a propeller blade. The propeller is coupled to the power supply for receiving power from the power supply to rotate. The propeller is positioned at an end of the housing such that the axis of rotation of the propeller is substantially parallel and/or inline with the longitudinal axis of the housing for the untethered downhole tool to traverse a well.

Abstract: In an implementation, a downhole robot for oil wells includes a pressure housing enclosing an internal gas-filled or vacuum-filled volume and at least one propulsion unit coupled to an end of the pressure housing. The downhole robot includes at least one centralization element. At least one sensor measures properties of interest with respect to the downhole robot and for an environment outside of the downhole robot. The downhole robot also includes a buoyancy system, an electrical power supply, an anchoring system, and a power system configured for non-contact operation.

Abstract: A method for locating a downhole tool in a wellbore involves obtaining, by the downhole tool, a pressure measurement in the wellbore, generating a first depth estimate based on the pressure measurement, and anticipating a passing of the downhole tool by a collar, based on the first depth estimate and a known depth of the collar. The method further involves, based on the anticipating of the passing of the downhole tool by the collar, performing, by the downhole tool, a collar detection, and based on the collar detection resulting in a detection of the collar: generating an updated depth estimate, and reporting the updated depth estimate.

Abstract: A wellhead attachment can be used to deploy an untethered downhole tool into a well. The wellhead attachment includes a housing, a relief valve, a mounting flange, and a gate valve. The housing is configured to house the untethered downhole tool. The relief valve is in fluid communication with the housing and located at a first end of the wellhead attachment. The mounting flange is located at a second end of the wellhead attachment. The mounting flange is configured to couple to a tree of the well. The gate valve is coupled to the housing and the mounting flange. The gate valve is positioned between the housing and the mounting flange. The housing is positioned between the relief valve and the gate valve.

Abstract: An electric submersible pump (ESP) including: a switched reluctance motor (SRM) including stator coils. The number of the stator coils is a multiple of three, surface electronics that drive the SRM, a cable that connects the SRM to the surface electronics. The cable includes conductors in a number equal to the number of the stator coils, each cable includes a push-pull driver that connects the cable to a ground, a DC voltage different from the ground, or disconnects the cable.

Abstract: A system and method for using a Distributed Acoustic Sensor (DAS) system to receive signals transmitted from remote autonomous sensors and to locate the autonomous sensors are disclosed. The method includes installing a DAS system in a borehole consisting of at least one fiber-optic cable connected to at least one corresponding interrogator, deploying at least one autonomous sensor and conducting at least one measurement. The methods also include encoding the at least one measurement in at least one encoded acoustic signal, transmitting the at least one encoded acoustic signal to the at least one fiber-optic cable, and detecting the at least one encoded acoustic signal with the DAS system. Furthermore, the methods include recording the at least one encoded acoustic signal received by the DAS system at a surface location and processing the at least one encoded acoustic signal with a processing unit to decode and obtain the at least one measurement.

Abstract: An apparatus includes a ballast that is configured to couple to an untethered downhole tool. The ballast includes a composite material. The composite material includes a first portion and a second portion. The first portion includes metallic particles. The first portion is configured to, while the ballast is coupled to the untethered downhole tool, provide weight to the untethered downhole tool to lower the untethered downhole tool into a well formed in a subterranean formation. The second portion includes a polymer matrix. The metallic particles of the first portion are distributed throughout the polymer matrix of the second portion. The second portion is configured to dissolve in response to being exposed to downhole fluid within the well at specified downhole conditions, thereby releasing the metallic particles of the first portions from the polymer matrix that has dissolved.

Abstract: Embodiments of the invention provide an untethered apparatus for measuring properties along a subterranean well. According to at least one embodiment, the untethered apparatus includes a housing, and one or more sensors configured to measure data along the subterranean well. The data includes one or more physical, chemical, geological or structural properties in the subterranean well. The untethered apparatus further includes a processor configured to control the one or more sensors measuring the data and to store the measured data, and a transmitter configured to transmit the measured data to a receiver arranged external to the subterranean well. Further, the untethered apparatus includes a controller configured to control the buoyancy or the drag of the untethered apparatus to control a position of the untethered apparatus in the subterranean well. The processor includes instructions defining measurement parameters for the one or more sensors of the untethered apparatus within the subterranean well.

Abstract: A computer-implemented method for automated wellhead monitoring using imaging and computer vision is described. The method includes establishing a baseline for a wellhead using image dimension and perspective calibration. The method also includes constructing at least one computer vision model using images or video from a wellhead database and inputting unseen wellhead images to the trained at least one computer vision model. Additionally, the method includes extracting a wellhead shape and geometric information of the wellhead in the unseen wellhead images and estimating wellhead displacement and growth based on the extracted images.

Abstract: An electric submersible pump (ESP), comprising: an intake that suctions fluids into the ESP, wherein the fluids include a mixture of gas, water, and oil; a discharge that discharges the fluids from the ESP; an acoustic intake transducer that determines the speed of sound in the fluids suctioned into the ESP at the intake; and a first acoustic discharge transducer that determines the speed of sound in the fluids discharged from the ESP, wherein the speed of sound of the fluid at both intake and discharge is used to calculate a gas volume fraction difference of the multiphase fluid mixture across the intake and discharge of the pump, and wherein the gas volume fraction difference is used as feedback to control the ESP.

Abstract: Techniques for determining rheological properties of a fluid include actuating a resonator disposed in a volume that contains a fluid sample to operate the resonator in the fluid sample at a predetermined actuation scheme; measuring at least one characteristic of the resonator based on the operation of the resonator in the fluid sample; comparing the at least one measured characteristic to a rheological model that associates characteristics of the fluid sample to one or more rheological properties; and based on the comparison, determining one or more rheological properties of the fluid sample.

Abstract: Embodiments of the invention provide an untethered apparatus for measuring properties along a subterranean well. According to at least one embodiment, the untethered apparatus includes a housing, and one or more sensors configured to measure data along the subterranean well. The data includes one or more physical, chemical, geological or structural properties in the subterranean well. The untethered apparatus further includes a processor configured to control the one or more sensors measuring the data and to store the measured data, and a transmitter configured to transmit the measured data to a receiver arranged external to the subterranean well. Further, the untethered apparatus includes a controller configured to control the buoyancy or the drag of the untethered apparatus to control a position of the untethered apparatus in the subterranean well. The processor includes instructions defining measurement parameters for the one or more sensors of the untethered apparatus within the subterranean well.

Abstract: This disclosure discusses methods and apparatus for generating vertical seismic profiles of a subsurface formation though deploying an untethered downhole tool into a wellbore, the untethered tool including at least one seismic sensor, a ballast, and a first electromagnet in the untethered downhole tool to attach the untethered downhole tool to a casing of the wellbore at a predetermined depth. The method further includes transmitting a seismic signal into the subsurface formation from a source located above the subsurface formation, receiving the seismic signal with the at least one seismic sensor, deactivating the first electromagnet to release the untethered downhole tool from the casing of the wellbore, releasing the ballast from the untethered downhole tool such that buoyancy effects move the tool uphole, and retrieving the untethered downhole tool from the wellbore.

Abstract: A downhole tool includes a body configured to move in a wellbore formed from a terranean surface to a subterranean formation in a direction downhole of the terranean surface independent of a downhole conveyance attached to the body; one or more sensors positioned in the body, the one or more sensors configured to measure a value associated with at least one of the wellbore or the terranean surface; and at least one mass positioned in the body and configured to adjust an orientation of the body in response to one or more forces acting on the body as the downhole tool moves in the wellbore in the direction downhole of the terranean surface.

Abstract: The present device and technique relates to measuring geological formation permeability, such as by injection/withdrawal of conductivity-permeability doped fluid and measuring the magnetic permeability and/or conductivity of the surrounding formation. Before, during and/or after injection or withdrawal, pluralities of electromagnetic measurements of the radial distribution of magnetic permeability and/or conductivity of the surrounding formation may be made. The rate of change of the radial distribution of magnetic permeability and/or conductivity of the formation is generally directly proportional to the permeability of the surrounding formation. In implementations, magnetic permeability and electrical conductivity can be measured independently in time domain or frequency domain, such that the magnetic permeability mapping is not disturbed by other confounding electromagnetic parameters.

Abstract: An electric submersible pump (ESP), comprising: an intake that suctions fluids into the ESP, wherein the fluids include a mixture of gas, water, and oil; a discharge that discharges the fluids from the ESP; an acoustic intake transducer that determines the speed of sound in the fluids suctioned into the ESP at the intake; and a first acoustic discharge transducer that determines the speed of sound in the fluids discharged from the ESP, wherein the speed of sound of the fluid at both intake and discharge is used to calculate a gas volume fraction difference of the multiphase fluid mixture across the intake and discharge of the pump, and wherein the gas volume fraction difference is used as feedback to control the ESP.

Abstract: A method and a system for collecting data at a fixed point in a wellbore are provided. An exemplary method includes dropping an untethered measurement tool (UMT) in the wellbore, switching a first magnet to drop a ballast from the UMT at a ballast drop condition, switching a second magnet to attach the UMT to a wall of the wellbore at a wall attachment condition. Data is collected in the UMT while the UMT is attached to the wall of the wellbore. The second magnet is switched to release the UMT from the wall of the wellbore at a wall release condition. The UMT is collected from the wellbore and the data is downloaded from the UMT.