Slickline and Wireline Intervention

 Wireline Defined

Wireline is a method of conveying specialized strings of tools and associated specialty tools into and out of a well. The tool string is attached to a single or multi- strand wire.

The three types of wireline used are: 
  • Braided non-electric
  • Braided electric.
Wireline units come in a wide variety of designs and configurations. Pictured here are two skid mounted units which can be fitted out with slickline, braided line, or electric line. This design is commonly seen on offshore locations but can be mounted to a flatbed for land operations. The wireline truck pictured below is the unit more commonly used on land locations.

Skid mounted units can be used on both land and offshore locations. They can be fitted out with slickline and braided line,This truck mounted unit is equipped with a crane and can also be fitted out with slickline and braided line.

The truck mounted unit can carry both slickline and braided line. The gin pole rig-up, although no longer used offshore, can still be seen on land locations.

The iconic offshore slickline unit – the sidewinder, is usually powered by a 50hp diesel engine, a 3-speed transmission, contains a spool of wire and a counter head.

The design of these units varies with the imagination of the designer and fabricator. The main benefit of the unit is its diminutive size, low weight, and available power. While esthetics and comfort aren’t the main design criteria, it is definitely a unit that can get the work done, just about anywhere.

Sheave – may be a separate component or an integral part of the stuffing box; is bearing- loaded and guides the wire into the stuffing box; in some cases the sheave is an integral part of the stuffing box.
Stuffing Box – seals around the wire and contains wellbore pressure and fluids
Head Catcher – uses internal dogs to latch the rope socket when the tool string is pulled from the hole; designed to prevent the wire from being pulled out of the rope socket

Chemical Injection Sub – provides a means of injecting chemicals such as anti-freezing fluids, etc.
Lubricator – serves as a means of deploying the tools string – much like the riser in a coiled tubing rig-
Bleed Off Valve – bleeds fluids and pressure from the lubricator allowing the lower union of the lubricator to be “broken” and the tool string lowered for service, tool replacement, etc.

Quick Test Sub – provides a means of testing the lubricator union prior to the tool string being run back into the hole:
  • Tool Trap – is manually or hydraulically operated to close after the tool string passes the trap into the lubricator – catches the tool string in the event the wire is accidentally pulled out of the rope socket
Hydraulic BOP – one or more hydraulically operated blowout preventers (wireline valve) used to seal around the wire, cut the wire, or close when there is no wire in the hole
Pump-In Sub – provides a means and connection to pump into the well is desired
Adapter Flange/Swedge – a connection which allows the surface equipment rig-up to be connected to the tree

Basic Description
  • Used in slickline operations to confine well fluids and gases to a well
  • The stuffing box wipes the wire clean
  • It is available in manual and hydraulic configurations
  • Available in pressure ratings of up to 15,000 PSI and sizes up to 7”
Steps to take if stuffing box is not working
For the manual stuffing box, an indication of “time to repack” is given by the packing nut. If the packing nut is screwed fully down, the packing needs to be replaced. Packing may also need to be replaced if tightening the packing nut does not stop the leaking.

Slick Line – Manual Stuffing Box

The function of the stuffing box is to allow entry of the wire into the wellbore while sealing around the diameter of the wireline and preventing the escape of wellbore fluids.
Sheaves are available for wireline sizes of .072” to .125” diameters, and with working pressures up to 15,000 psi.

The plunger (blowout plug) prevents well flow when wireline is pulled out of rope socket or if the line breaks and is blown out of the hole.

One main safety advantage of this type
over the manual stuffing box is that no one is required to climb the lubricator or be hoisted in order to manually tighten the stuffing box while it is under pressure.


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