An apparatus and method for preparing a casing of a subterranean well and injecting a sealing mixture therein. The apparatus comprises an elongate body extending between top and bottom ends connectable to a wireline at the top and having a plurality of nozzles extending therethrough proximate to the bottom. A plurality of scrapers within the body each have a first retracted position and a second radially extended position engageable with the casing. A cavity is operable to contain the sealing mixture and a piston is movable therein so to eject the sealing mixture through the nozzles. The method comprises positioning the body in the well at a location to be sealed, extending the scrapers to engage with the casing, displacing the body so to scrape against the casing and retracting the scrapers. The piston is displaced so to eject the sealing mixture through the nozzles.

A scale impeding arrangement including a movable member, having a sole purpose of impeding accumulation of scale, in fluid contact with a flow passage, and a movement activator operably connected to the movable member to change elastic energy of the moveable member.

A diffuser assembly is provided which includes an upper mounting member mountable within a conduit and having an fluid inlet port, and a lower section having a diffuser screen. A plurality of radially oriented cutters are removably attached to the diffuser screen, and the cutters may extend internal or external to the diffuser screen. A first set of cutters is mounted at a first selected height along the central axis of the diffuser screen, and wherein a second set of cutters is mounted at a second selected height along the central axis of the diffuser screen. The diffuser assembly may be positioned in different locations, including within a downhole carrier sub inside a well bore, within a drill pipe at the rig floor, or within a conduit in fluid communication between a mixing tank and a pump.

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.

The method of providing a latch which is capable of passing a relatively short radius bend in a pipeline and then engaging a fishing neck on a service tool in a pipeline, and after the latch has engaged the service tool having the ability to pass the combination back through the relatively short radius bend in the pipeline.

A downhole cleaning apparatus (10) comprising a tubular body (12). The tubular body (12) comprises comprising a plurality of openings (20) therethrough. Each opening (20) defines at least part of a helix extending longitudinally and circumferentially about the tubular body (12). The downhole cleaning apparatus (10) also includes a plurality of cleaning elements (22). Each cleaning element (22) is configured to extend through an opening (20) and to extend outwards from an outer surface of the tubular body (12). The cleaning elements (22) are distributed about the tubular body (12) and each cleaning element (22) defines at least part of a helix extending longitudinally and circumferentially about the tubular body. The openings (20) and the cleaning elements (22) are grouped to define a plurality of substantially continuous helical paths (18). Each helical path (18) extends substantially end to end of the tubular body and the helical paths (18) are distributed relative to each other to define a cleaning surface of at least 360 degrees.

A wiper dart can be used in an oil and gas operation. The wiper dart can have at least two different outer diameters. A first outer diameter can be less than a second outer diameter and used to wipe the insides of tool joints of a tubing string. The second outer diameter can be used to wipe the insides of pipe sections of the tubing string that have a larger inner diameter than the tool joints. The single, bi-diameter wiper cup can be used in lieu of two or more current, conical-shaped wiper cups to accomplish the same functionality. The wiper cup can include a protruding ring located circumferentially around the wiper cup at the first outer diameter. A plurality of buttons or splines can be spaced apart around the wiper cup at the second outer diameter.

A wiper dart can be used in an oil and gas operation. The wiper dart can have at least two different outer diameters. A first outer diameter can be less than a second outer diameter and used to wipe the insides of tool joints of a tubing string. The second outer diameter can be used to wipe the insides of pipe sections of the tubing string that have a larger inner diameter than the tool joints. The single, bi-diameter wiper cup can be used in lieu of two or more current, conical-shaped wiper cups to accomplish the same functionality. The wiper cup can include a protruding ring located circumferentially around the wiper cup at the first outer diameter. A plurality of buttons or splines can be spaced apart around the wiper cup at the second outer diameter.

A coupling connects an inner string to a lower end of a bore-lining tubing, such as a liner. The coupling includes a catcher and may be provided in combination with at least one member for translating through the inner string and landing in the catcher. The member may be an occluding member, such as a ball for occluding a flow passage through the coupling.