In the early 1900s, slickline was introduced as a means of conveying tools into a production oil well for the purpose of well intervention – a process for controlling production elements in an open-hole or cased-hole oil well, but also used to measure the depth of a well. Early slickline was predominantly low-grade carbon steel wires, but the use of a single wire for this application allowed for greater pressure control during the intervention.
Slickline as briefly mentioned above is used to place and recover wellbore equipment, such as plugs, gauges, and valves. These are single non-electrical wires lowered into oil and gas wells from the surface. They can also be used to adjust valves and sleeves located downhole, as well as repair tubing within the wellbore. Wrapped around a winch drum on the back of a truck, the slickline is hydraulically raised and lowered into the well to carry these various operations. This calls for a very high-quality wire (defect-free) and with a high break load so it can operate heavy equipment.
Sour service slickline was introduced in reaction to the change in conditions found in some oil-producing regions, where an element of sour service was encountered such as H2S or CO2 in wet wells. These elements created acidic environments that were detrimental to the carbon steel slicklines that had previously been the mainstay of well intervention. As a result, some manufacturers started to produce stainless steel slicklines to counter this development.
Many decades ago, the Supa alloy slickline brand was at the forefront of sour service slickline development, with duplex and super austenitic grade alloys, allowing intervention services in the most hostile of well conditions. The technical leadership of Supa Slicklines was solidified through established certification credentials and close industry links to oil recovery and well intervention companies operating in the North Sea and further afield. After many years of proven performance in global oil production, and several changes in ownership, Supa Slicklines is now part of Central Wire, the world’s leading manufacturer of austenitic/super austenitic and duplex slicklines.
With the technical knowledge of our production teams and the applications knowledge of our global partners, CWI GD™ – SUPA® Slicklines offer the highest quality standards in slickline production. As a result, CWI is now the “go-to” manufacturer for well intervention products around the world.
Today, CWI produces a range of slicklines that cover all sour well conditions. These include GD316 Stainless / GD 22 Duplex (Supa 40) / GD31 (Supa 75) and occasionally GD50 (Mp35). With well depths increasing all the time, lengths supplied start at 15,000 feet with standard diameters ranging from 0.082″ to 0.160″, depending upon the operation performed. All our lines are available for use in offshore or onshore applications. These are often demanding environments that require a very haute qualité wire. The processes we have in place and the level of NDT testing and inspection that we carry out has secured CWI‘s position as the world’s leading manufacturer of slicklines.
Wireline (which is different from slickline) is an electrical cable that transmits data about the well. Consisting of single strands or multiple strands, the wireline is used for both well intervention and to provide telemetry about the well conditions. While CWI does not produce wirelines, we do supply the raw materials to companies that do.
CWI produces and supplies single wires to companies that produce heavy-duty stranded cables. Typically, these are 3/16″ – 5/16″ – 7/32″ in construction. These cables are often required to perform heavy-duty operations and are also used when a slickline has failed, snapped, and has dropped down into the well. This operation is known as fishing. Even though CWI produces a lot of single-end strand wires for the cable industries – they are not used to fish out CWI slicklines (as our slicklines are designed to outperform the ones that do fail).
Offshore (sea-based) units on ships or rigs are generally skid-mounted units and can be moved from location to location. Onshore (land-based) operations mainly use slickline trucks – with the winch unit mounted on the back. These can be driven to wherever they are needed. CWI makes weld-free austenitic, super austenitic, and duplex stainless steel slickline for onshore and offshore applications.