Abstract: The subject technology relates to an in-line amplifier assembly for distributed sensing system. The subject technology includes deploying a distributed sensing tool into a wellbore, and logging the wellbore using the distributed sensing tool. The distributed sensing tool includes a first optical amplifier and a first optical filter coupled to a first single-mode optical fiber. The first optical amplifier is coupled to a first single-mode circulator for amplifying a single-mode optical signal, and the first optical filter is coupled to the first optical amplifier for filtering the amplified single-mode optical signal. The first single-mode circulator is coupleable to an interrogator for routing the single-mode optical signal to a second single-mode optical fiber and routing a reflective optical signal from a second single-mode optical fiber to the interrogator. The reflective optical signal may traverse a second optical amplifier and a second optical fiber between the first and second single-mode circulators.

Abstract: Fluid allocation in a well can be determined with a distributed temperature sensing system using data from a distributed acoustic sensing system. Flow data indicating a flow rate of a fluid through a perforation in a well based on an acoustic signal generated during a hydraulic fracturing operation in the well can be received. Warm-back data indicating an increase in temperature at the perforation can be received. A fluid allocation model can be generated based on the flow data and the warm-back data. The fluid allocation model can represent positions of the fluid in fractures formed in a subterranean formation of the well.

Abstract: The subject technology relates to distributed sensing interrogation using single-mode fiber for multi-mode fiber interrogation. The subject technology includes deploying a distributed sensing tool into a wellbore, and logging the wellbore using the distributed sensing tool. The distributed sensing tool includes an optical amplifier and an optical filter coupled to a single-mode optical fiber and a multi-mode optical fiber. The optical amplifier is coupled to a single-mode circulator for amplifying a single-mode optical signal, and the optical filter is coupled to the optical amplifier for filtering the amplified single-mode optical signal. The single-mode circulator is coupleable to an interrogator for routing the single-mode optical signal to the multi-mode optical fiber and routing a reflective optical signal from the multi-mode optical fiber to the interrogator.

Abstract: Screen-outs can be detected from acoustical signals in a wellbore. Data based on an acoustic signal generated during a hydraulic fracturing operation in a wellbore formed through a subterranean formation can be received. An expected total flow rate of fluid being injected into the wellbore can be determined based on the data. An actual total flow rate of the fluid being injected into the wellbore can be determined. A screen-out that occurred can be identified by comparing the expected total flow rate and the actual total flow rate.

Abstract: Various embodiments include methods and apparatus structured to increase efficiencies of a drilling operation. These efficiencies may be realized with a fiber cable located in a wellbore at a well site, where the fiber cable can include an optical fiber disposed as a single handed helix in the fiber cable, where the optical fiber is disposed in the cable without having helix hand reversal. Construction of such fiber cables may include applying a twist to the optical fiber during insertion of the optical fiber into the fiber cable in a tubing process in which control of an amount of the twist to form a portion of the optical fiber can control excess fiber length in the tube. Additional apparatus, systems, and methods can be implemented in a variety of applications.

Abstract: Disclosed is a fiber optic interrogation system unit with one or more controllable laser sources that are electrically tuned to fit the laser source requirements for different sensing principles. Such an interrogation unit would employ a designed optical configuration at the distal end of the optical fiber to enable DAS, DTS and stimulated Brillouin DSS to operate on the same optical fiber. It would provide a single fiber optic interrogation system with integrated DTS, DAS and DSS systems that is cost effective and simple in design.

Abstract: A hybrid fiber optic assembly and system for use in a well, where the system includes a hybrid fiber optic cable with at least a first transmission region and at least a first sensory region as well as an interrogator system coupled to the hybrid fiber optic cable. The hybrid fiber optic cable can have a plurality of transmission regions and sensory regions, as well as transition regions in between and coupling individual pairs of transmission regions and sensory regions.

Abstract: A cable introduction assembly that can include: a spool assembly including a spool having a first axis, the spool configured to retain a cable wound around the first axis in an undeployed mode; and a spool mount assembly configured to retain the spool and introduce the cable in a deployed mode into a conduit configured for a downhole environment, the conduit having a proximal end and a distal end, the cable in the deployed mode extending from the proximal end towards the distal end, wherein the spool assembly is configured to provide a handedness to the cable in the deployed mode.

Abstract: Various embodiments disclosed relate to a composite mandrel. In various embodiments, the present invention provides a method of forming a composite mandrel for use in a subterranean formation. The method can include securing an elongated mold to at least a portion of an exterior surface of a rigid tubular to form a cavity between the mold and the exterior surface of the rigid tubular. The elongated mold can include a recessed portion. The cavity can extend longitudinally along the tubular. The method can include filling the cavity with a curable resin composition. The method can also include curing the resin to provide a cured resin including a utility recess corresponding to the recessed portion. Curing the curable resin composition can form the composite mandrel including the tubular and the cured resin.

Abstract: A sensory assembly and system can be used in a wellbore to detect and characterize the earth strata and formations around the wellbore, where a signal emitting sensory tool is part of a tool string deployed in the wellbore, and where weighted fiber optic cable is deployed in an extended position below the signal emitting sensory tool. The fiber optic cable is also part of wire-line, slickline, or coiled tubing injector head connected to the signal emitting sensory tool, thereby providing fiber optic cable both above and below the signal emitting sensory tool in position to collect backscatter signals from earth strata and formations around the wellbore. The collection of backscatter signals, particularly from below the signal emitting sensory tool, allows for more precise characterization of formations and fractures within the earth strata.

Abstract: A system for continuous determination of annulus pressure in subsurface wells comprises one or more electro acoustic technology sensor assemblies permanently installed in each annulus surrounding a subsurface well; and a fiber optic cable in close proximity to the electro acoustic technology sensor assemblies and in communication with a surface distributed acoustic fiber optic interrogator.

Abstract: A wellbore distributed acoustic sensing system can include a mode scrambler and a multimode circulator. The mode scrambler can be coupled to a multimode optical fiber for outputting to the multimode optical fiber a multimode optical signal generated from a single-mode optical signal. The multimode circulator can be coupled to the multimode optical fiber for routing the multimode optical signal to a distributed acoustic sensing optical fiber positioned downhole in the wellbore. The multimode circulator can further be communicatively coupled to an optical receiver for routing a backscattered multimode optical signal received from the distributed acoustic sensing optical fiber to the optical receiver.

Abstract: A hybrid fiber optic assembly and system for use in a well, where the system includes a hybrid fiber optic cable with at least a first transmission region and at least a first sensory region as well as an interrogator system coupled to the hybrid fiber optic cable.

Abstract: Various embodiments disclosed relate to a composite mandrel. In various embodiments, the present invention provides a method of forming a composite mandrel for use in a subterranean formation. The method can include securing an elongated mold to at least a portion of an exterior surface of a rigid tubular to form a cavity between the mold and the exterior surface of the rigid tubular. The elongated mold can include a recessed portion. The cavity can extend longitudinally along the tubular. The method can include filling the cavity with a curable resin composition. The method can also include curing the resin to provide a cured resin including a utility recess corresponding to the recessed portion. Curing the curable resin composition can form the composite mandrel including the tubular and the cured resin.

Abstract: Systems and methods for correcting chromatic dispersion in a remote distributed sensing application are disclosed. A remote distributed sensing system includes an interrogation subsystem configured to transmit an optical pulse and receive a reflection from the optical pulse. The remote distributed sensing system also includes a transit optical fiber coupled to the interrogation subsystem and having chromatic dispersion of a first slope at a frequency of the optical pulse, and an optical fiber under test being located in a remote location apart from the interrogation subsystem. The remote distributed sensing system additionally includes a chromatic dispersion compensator coupled in-line with at least one of the transit optical fiber and the optical fiber under test to adjust chromatic dispersion on the optical pulse in a direction of a second slope having an opposite sign from the first slope.

Abstract: A sensory assembly and system can be used in a wellbore to detect and characterize the earth strata and formations around the wellbore, where a signal emitting sensory tool is part of a tool string deployed in the wellbore, and where weighted fiber optic cable is deployed in an extended position below the signal emitting sensory tool. The fiber optic cable is also part of wire-line, slickline, or coiled tubing injector head connected to the signal emitting sensory tool, thereby providing fiber optic cable both above and below the signal emitting sensory tool in position to collect backscatter signals from earth strata and formations around the wellbore. The collection of backscatter signals, particularly from below the signal emitting sensory tool, allows for more precise characterization of formations and fractures within the earth strata.

Abstract: An example device in accordance with an aspect of the present disclosure includes a splice housing body comprising a raceway within which optical fibers and electrical cables can be positioned, at least one port through the splice housing body to which a pressure fitting for optical fiber or electrical cable can be mounted, a base to which the splice housing body may be removably attached, and a port in one of the splice housing body or base for inserting fluid in the splice housing body.

Abstract: An example device in accordance with an aspect of the present disclosure includes a splice housing body comprising a raceway within which optical fibers can be positioned, at least one port through the splice housing body to which a pressure fitting for optical fiber can be mounted, a base to which the splice housing body may be removably attached, and a port in one of the splice housing body or base for inserting fluid in the splice housing body.

Abstract: A method and device for relieving thermal stresses on the optical fibers in fiber optic splice housings used in hostile thermal environments.

Abstract: A method and device for relieving thermal stresses on the optical fibers in fiber optic splice housings used in hostile thermal environments.