In the oil and gas industry, the term wireline usually refers to the use of multi-conductor, single conductor or slickline cable, or "wireline", as a conveyance for the acquisition of subsurface petrophysical and geophysical data and the delivery of well construction services such as pipe recovery, perforating, plug setting and well cleaning and fishing. The subsurface geophysical and petrophysical information results in the description and analysis of subsurface geology, reservoir properties and production characteristics.
Associated with this, "wireline logging" is the acquisition and analysis of geophysical and petrophysical data and the provision of related services provided as a function of along-hole depth.
There are four basic types of wireline: multi-conductor, single conductor, slickline and braided line. Other types of wireline include sheathed slickline and fibre-optic lines.
Multi-conductor lines consist of external armor wires wound around a core of typically 4- or 7-conductors. The conductors are bound together in a central core, protected by the outer armor wires. These conductors are used to transmit power to the downhole instrumentation and transmit data (and commands) to and from the surface. Multi-conductor cables are used primarily in open- (and cased-) hole applications. Typically they have diameters from to with suggested working loads from . (Note that wireline diameters and performance characteristics are typically expressed in imperial units.) Multi-conductor cables can be sheathed in smooth polymer coverings but are more commonly open wound cables.
Single-conductor cables are similar in construction to multi-conductor cables but have only one conductor. The diameters are usually much smaller, ranging from to and with suggested working loads of 800 to 7,735 lbf. Because of their size, these cables can be used in pressurized wells making them particularly suited for cased hole logging activities under pressure. They are typically used for well construction activities such as pipe recovery, perforating and plug setting as well as production logging and reservoir production characterization such as production logging, noise logging, pulsed neutron, production fluid sampling and production flow monitoring.
Slickline is a smooth single strand of wireline with diameters ranging form 0.082" to 0.160". Slickline has no conductor (although there are specialized polymer coated slicklines and tubing encapsulated (TEC) slicklines). They are used for light well construction and well maintenance activities as well as memory reliant subsurface data gathering. Slickline work includes mechanical services such a gauge emplacement and recovery, subsurface valve manipulation, well bore cleaning and fishing.
Braided line has mechanical characteristics similar to mono-conductor wireline, and is used for well construction and maintenance tasks such as heavy duty fishing and well bore cleaning work.
Slicklines
Used to place and recover wellbore equipment, such as plugs, gauges and valves, slicklines are single-strand non-electric cables lowered into oil and gas wells from the surface. Slicklines can also be used to adjust valves and sleeves located downhole, as well as repair tubing within the wellbore.
Wrapped around a drum on the back of a truck, the slickline is raised and lowered in the well by reeling in and out the wire hydraulically.
Braided line can contain an inner core of insulated wires which provide power to equipment located at the end of the cable, normally referred to as electric line, and provides a pathway for electrical telemetry for communication between the surface and equipment at the end of the cable.
On the other hand, wirelines are electric cables that transmit data about the well. Consisting of single strands or multi-strands, the wireline is used for both well intervention and formation evaluation operations. In other words, wirelines are useful in gathering data about the well in logging activities, as well as in workover jobs that require data transmittal.