This disclosure provides an agitator system that includes an agitator assembly of concentric power-sections, (one power-section inside another power-section both of which comprise stators and rotors). The agitator system includes a controller configured to control a valve assembly of the agitator assembly to selectively open and close the valve assembly to allow fluid to selectively flow between the power-sections of the agitator assembly that generates pressure fluctuations or pressure pluses in the fluid pressure, which increases the speed of the rotor or rotors, and thus, the vibrational frequency of the agitator. The controller can be used to increase the vibrational frequency of the agitator assembly when necessary to prevent the drill string from becoming lodged in a wellbore.

A first aspect of the invention provides a gas or oil well tubing having an annular packer mounted thereon, wherein the annular packer is formed from an eutectic alloy. By prefabricating the annular packer on the tubing it can be placed in situ from the outset and thus can be active by melting at any time to form a eutectic seal quickly and easily. An annular packer with by-pass conduits is also provided to enable cement to be pumped past the annular packer when it is in situ. The annular packer is further provided with conduit clearance means to clear cement from within the conduits.

Techniques for axial vibration control of wireline tools and cables during logging operations. In undesirable cases the axial vibrations may lead to or exasperate the stick-slip problems of the logging tool. Control systems and strategies to minimize vibrations and techniques for identifying and inhibiting the sticking of the cable. A system includes a surface actuator and a sensor. The actuator generates an axial wave on the wireline cable which travels down the cable. If there is sticking of the cable, a reflection can also occur at the location of sticking. This shift in the transmission of the wave on the wireline cable is used to identify the onset and/or presence of sticking.

An assembly for retrieving piping from a well may include a cylindrical housing having a central aperture extending through the cylindrical housing along a central axis thereof. The assembly may include a retrieving device. The retrieving device may include a first securing mechanism having a first cylindrical profile and a first diameter, the first securing mechanism may be configured to axially secure a first type of piping comprising a first outer diameter. The retrieving device may include a second securing mechanism having a second cylindrical profile and a second diameter, the second diameter may be larger than the first diameter and the second. securing mechanism may be configured to axially secure a second type of piping comprising a second outer diameter.

A vibratory tool for use in a tubular string to prevent sticking or to release a stuck string features a fluid operated dart valve working in conjunction with an impact sleeve to deliver continuous axial jarring blows in opposed directions as long as flow is maintained. Movement of one of those components axially in opposed directions opens and closes access to opposed lateral ports so that a lateral vibration is also established as flow cyclically occurs and stops sequentially at opposed lateral outlets.

An apparatus for detecting over-torquing or un-torquing of a threaded connection between components in a borehole penetrating the earth includes: a string of components coupled in series by a threaded connection; a transmission line attached to each component; a signal coupler in communication with the transmission line and disposed on each component at each threaded connection, the signal coupler being configured to transmit the signal to an adjacent signal coupler on an adjacent coupled component in order to transmit a signal along the transmission line attached to the adjacent coupled component; a receiver configured to receive the signal; and a processor in communication with the receiver and configured to: (i) determine a difference between a characteristic of the signal and the characteristic of a reference signal and (ii) transmit an alert signal signifying that the threaded connection is over-torquing or un-torquing in response to the difference exceeding a threshold value.

Disclosed combination impact tool generates optimized linear hammering and vibrational impacts. Flow of pressurized fluid through an upper section of the tool generates linear hammering impacts, and flow of pressurized fluid through a lower section of the tool generates vibrational impacts. Flow of pressurized fluid through the lower section induces an eccentric arm to rotate and cause vibrational impacts. While frequency of hammering impacts can be controlled by varying pressure of the fluid flowing through the upper section, the frequency and amplitude of vibrational impacts can be controlled by varying weight of the eccentric arm and by varying pressure of the fluid flowing through lower section. Disclosed tool is particularly useful in drilling in shale and in fishing operations in a well-bore.

A junk catching device (1) for catching junk traveling into a well. The device comprises an outer housing (10) comprising an upper end (10a) and a lower end (10b), a bore (11) provided inside the housing (10), a receiving device (20) provided in the upper end (10a) of the housing (10). The receiving device (20) comprises a receiving opening (21) providing an opening into the bore (11) and a junk guiding device (22) for guiding junk into the bore (11) via the receiving opening (21). The junk guiding device (22) is configured to be provided in a run state, in which the outer diameter of a guiding section (22A) of the junk guiding device (22) is less than or equal to the outer diameter of the housing (10), and in a set state, in which the outer diameter of the guiding section (22A) of the junk guiding device (22) is larger than the outer diameter of the housing (10).

A synthetic acid composition for use in oil industry activities, said composition comprising: urea and hydrogen chloride in a molar ratio of not less than 0.1:1; and a metal iodide or iodate. Optionally, a phosphonic acid derivative may be added.

Terpene-based spotting fluid compositions and processes for freeing differentially stuck pipe are provided. A spotting fluid composition includes a terpene and an acid, such that the acid initiates an exothermic polymerization reaction of the terpene. Another spotting fluid composition includes an invert emulsion having a terpene external phase and a non-miscible organic hygroscopic fluid internal phase. The terpene emulsion spotting fluid composition may be introduced downhole in the vicinity of a portion of a differentially stuck pipe such that the spotting fluid composition contacts a filter cake surrounding the portion of the differentially stuck pipe. An acid may be introduced downhole in the vicinity of a portion of a differentially stuck pipe such that the acid initiates an exothermic polymerization reaction of the terpene of the terpene emulsion spotting fluid composition.