A tool is used to inject a rapidly solidifying sealant into and across highly fractured oil and gas wellbore formations when a significant loss circulation zone or event is encountered. A system including the tool allows for application of the sealant to the formation without requiring removal of the drill string from the hole. The tool may have operatively associate with containers storing sealant and or sealant components that are provided downhole from the surface via wireline or the like.

A downhole tool, for selectively reaming a wellbore or stabilizing drill string components within a wellbore, includes an elongate tool body adapted to receive reamer cartridges or stabilizer cartridges depending on the function desired. The reamer cartridges are radially insertable into corresponding pockets in the tool body, with each reamer cartridge having a reamer insert with an array of cutting elements. The reamer insert is disposed within a bushing and is rotatable relative thereto, about a rotational axis transverse to the longitudinal axis of the tool. However, the rotational axis is offset from the tool body axis, resulting in eccentric contact of the cutting elements with the wall of the wellbore, which in turn imparts rotation to the reamer insert when the tool is being moved axially through a wellbore without rotation. When the tool is to be used for stabilization, the reamer cartridges can be removed and replaced with stabilizer cartridges having stabilizer inserts with hard-faced stabilizer cones.

A casing centralizer comprising a cylindrical base and a plurality of blades extending from the cylindrical base. The plurality of blades and the cylindrical base are compression molded as a single piece from a mineral filled, glass and specialty fiber reinforced polyester molding compound.

An inductive coupler includes a first transceiver electrically coupled to a first coil through a first tuning circuit. The inductive coupler may also include a second transceiver electrically coupled to a second coil through a second tuning circuit, where the second coil is positioned substantially concentric with the first coil.

Methods of configuring a surface of a component exposed to fluid flow are disclosed. A first method includes forming a plurality of protrusions on a surface, the plurality of protrusions separated by a plurality of channels, and depositing a coating on the surface to increase a coefficient of friction of the surface, the coating formed of a diamond-like carbon and having a wrinkled texture. A second method includes forming a plurality of protrusions on a surface, the plurality of protrusions separated by a plurality of channels, and forming a plurality of nanotubes on the surface.

Methods and systems for logging a wellbore having a casing are described. Acoustic energy, typically ultrasonic acoustic energy, is used to stimulate reverberation of the casing at a harmonic (for example, the second or third harmonic) of the resonance frequency of the casing. One or more acoustic sensors are used to measure acoustic signals generated by the casing reverberation. Parameters of the casing are calculated based on the measured acoustic signals adjusted by an adjustment factor determined by the particular harmonic. The use of harmonics instead of the fundamental resonance frequency allows wellbores with casings having walls thicker than 0.625 inches to be logged.

A centralizer for stabilizing fluid flow through a hollow shaft has a body with an axis, an outer surface and a circumference. Fins extend from the outer surface and include a first pair of fins that are axially aligned with each other and circumferentially spaced from each other. A second pair of fins are axially spaced a first distance from the first pair of fins. The second pair of fins are axially aligned with each other and circumferentially spaced from each other. The first and second pairs of fins are circumferentially offset from each other.

A centralizer for downhole OCTG having a storage space capable of housing downhole electronics and other down-hole devices, compositions and elements is disclosed. The storage space is located within an inner cavity formed in one or more of the blades making up the centralizer. A capsule is provided for protecting the contents of the items being stored within the inner cavity. The capsule may be hermetically sealed to protect the contents from the damaging effects of downhole fluids. Ports may be provided within the capsule to allow downhole electronics to be connected to sensors and other devices and components residing outside of the capsule.

In some embodiments, an apparatus and a system may include a tubular member; at least two interchangeable blades attached to the tubular member, the blades extendible radially outward to an extended position and retractable radially inward to a retracted position, wherein an outer surface of the blades is disposed at or below an outer surface of the tubular member when the blades are in the retracted position; and a plurality of sensors attached to the blades, the sensors to engage a circumferential portion of a borehole wall along the outer surface of the blades in an azimuthal direction when the blades are disposed downhole in the extended position, and to refrain from engaging the borehole wall when the blades are disposed downhole in the retracted position. Additional apparatus and systems, as well as methods, are disclosed.

A downhole tubing rotator that has a housing configured into a production tubing string in a well in a reservoir, the housing being generally cylindrical with a hollow center and containing a two pole, three phase induction squirrel cage motor operatively connected to a tubing rotator configured to clamp onto a production tubing joint and rotate one or more production tubing joints (but not an entire production tubing string) when the motor is activated. An armor-protected insulated power and control cable connects the motor to a control box positioned at a surface of a reservoir and various sensors provide feedback for the unit. Methods of using this tool are also provided.