A downhole well system can use a fiber optic cable that can be positioned downhole along a length of a wellbore. The well system may include a top plug, a bottom plug, or both that are used to contain a cement slurry during a cementing operation. The movement of the top plug and bottom plug may cause acoustic noise along the downhole portion of the casing. A reflectometer may detect the acoustic noise from strain in the fiber optic cable and determine a location of the top plug or bottom plug downhole.

An assembly for hanging a tubular string includes a packoff (56) having a fastener and a seal for engaging an inner surface of the tubular string and a setting tool. The setting tool includes: a debris cap (84) for engaging an upper end of the tubular string, thereby forming a buffer chamber between the debris cap (84) and the packoff (56); a mandrel (66) having a port formed through a wall thereof; a piston (71): disposed along the mandrel, having an upper face in fluid communication with the port, and operable to stroke the debris cap relative to the mandrel, thereby setting a hanger of the tubular string; an actuator sleeve (71) extending along the mandrel and connected to the piston; a packer actuator (62) including a housing connected to the debris cap above the buffer chamber and a fastener for engaging a profile of the actuator sleeve; and a latch releasably connecting the housing to the mandrel.

A method for operation in wellbore, the method comprises: pumping a fluid barrier into a wellbore through a tubular, the fluid barrier being operable to separate a cement slurry from a second fluid; the fluid barrier comprising a polyurethane member derived from a polyurethane forming composition comprising a para-phenylene diisocyanate terminated polycarbonate prepolymer and an aromatic diol

A tool for launching wiper plugs into a casing string in a gas or oil well during cementing operations employs a collet-like mechanism carrying radially-movable jaws arranged to retain a plug in a fluid flow path when the tool is in a closed position, and to release the plug into the fluid flow path when the tool is in an open position. Selection of the desired operational position of the plug launcher (i.e., open or closed) is effected by actuation of an axially-movable sliding sleeve. Alternative means for actuating the sliding sleeve include rotary actuation about the tool's longitudinal axis, rotary actuation about a radial axis generally normal to the longitudinal axis, rotary actuation about a generally tangent axis, and pneumatic or hydraulic actuation. The tool may be adapted to carry multiple wiper plugs for sequential launching into a casing string.

A method for casing a subsea wellbore includes running a tieback casing string into the subsea wellbore using a workstring including first, second, and third wiper plugs. The method further includes: launching a first release plug or tag into the workstring; pumping cement slurry into the workstring, thereby driving the first release plug or tag along the workstring; after pumping the cement slurry, launching a second release plug or tag into the workstring; and pumping chaser fluid into the workstring, thereby driving the release plugs or tags and cement slurry through the workstring. The release plugs or tags engage and release the respective wiper plugs from the workstring. The first wiper plug or release plug ruptures, thereby allowing the cement slurry to flow therethrough. The method further includes: stabbing the tieback casing string into a liner string; and retrieving the workstring, the workstring still including the third wiper plug.

A wiper dart includes one or more wiper elements disposed about a mandrel, each wiper element comprising a wiper cup that extends radially outward and rearwardly relative to the mandrel, and a nose assembly coupled to the mandrel. A drive element is disposed about the mandrel and includes a shoe and a cup coupled to the shoe. The cup extends radially outward and rearwardly from the shoe and exhibits a maximum diameter less than or equal to a maximum diameter of the one or more wiper elements, and the shoe provides at least one of axial and radial support to the cup.

A top latch-in plug includes a housing having a bore and a transitionable seal. The transitionable seal seals the bore of the housing when in a first configuration, and the transitionable seal unseals the bore when in a second configuration. The transitionable seal is triggerable to transition from the first configuration to the second configuration. A casing floatation system includes a casing having a pre-load collar and a landing collar; and a lower bottom latch-in plug. The lower bottom latch in plug includes a catch mechanism compatible with the pre-load collar; and a landing mechanism compatible with the landing collar.

A delayed fin deployment wiper plug has a tubular body, which has a closed top and a piston therein. The piston is supported at one or more locations inside the tubular body by one or more sets of shear pins or spring clips or some equivalent device. The piston is connected to or abutted to a sleeve that covers an upper portion of the tubular body, containing therein one or more sets of deployable fins that are not exposed for use unless the piston is activated and raises the sleeve.

Provided in one aspect is a new tool and methodology to work, in a single-trip system, and create conduits through the casing or tubing to access the annuli, circulate out the annuli contents, accurately deliver the cement required to create the subsequent barrier. The tool and system provided by this aspect provide a cost effective way of plugging an oil and gas well in a single trip without the need to remove in-place production casing.

An improved method and apparatus for dropping a ball, plug or dart during oil and gas well operations (e.g., cementing operations) employs a specially configured tool body assembly having valving members (e.g., safety or kelly values) and valving members holding plugs, balls, or darts to be dropped. In one embodiment, the ball(s), dart(s) or plug(s) are contained in a sliding sleeve that shifts position responsive to valve rotation. An optional indicator indicates to a user or operator that a ball or plug has passed a selected one of the valving members. A transmitter (or transceiver) provides an ability to generate a wireless signal that is received by receivers (or transceivers) on the tool body assembly. Each receiver (or transceiver) controls an electrical actuator that engages a valving member or the indicator. Wireless signals can be used to open or close a valve or to reset a tripped indicator.