How to Choose Oil and Gas Cable for Industrial Projects

Environmental Challenges in Oil and Gas Installations

High Temperature and Thermal Cycling

In refineries, gas processing stations, desert oil fields, etc., temperatures are permanently high. The ambient temperature in some areas, combined with the heat generated by the equipment, can expose cables to temperatures over 90°C, and in some cases over 120°C. Therefore, oil and gas cables must be run at high temperatures for long periods, and the sheath must not harden or crack.

Chemical and Oil Exposure

In oil and gas environments, cables are almost inevitably contacted with crude oil, drilling fluids, solvents, and various chemicals. After prolonged exposure, the sheath may soften, swell, and crack on the surface, which can eventually lead to a loss of insulation. Especially in refineries, where chemical vapors are inherently present in the air, cables can be affected even if they are not directly immersed.

Offshore Saltwater and UV Exposure

The environment on offshore platforms is even more demanding. Long-term salt spray, high air humidity, and high salt content also accompany strong ultraviolet radiation.

Under such conditions, the metal conductor and armor layer of the cable are more likely to be corroded and rusted, and the outer sheath will gradually age and degrade in the long-term humidity and sunlight environment.

Therefore, offshore cables should not just consider water resistance, but salt spray resistance and UV resistance, in order to guarantee long-term stable operation.

Mechanical Stress and Abrasion

Oilfield sites have a lot of heavy equipment in operation. Cables may be dragged, bent, crushed, or fixed to bridges or steel structures. Being under such mechanical stress for a long period of time, the outer sheath of the cable is easy to wear out, and the inner conductor may be damaged due to repeated stress. Therefore, cables used in such environments need to have strong tensile strength and abrasion resistance to preserve structural integrity and a normal power supply.

Hazardous Areas and Explosion Risk

Many oil and gas areas are hazardous zones where flammable gases are present. If a cable suffers insulation damage, loose joints or short circuits, electric arcs or high temperatures can be generated, which can lead to a risk of ignition. Cables used in these areas must therefore comply with the appropriate explosion protection and safety standards and ensure reliable insulation and sheath construction.

Types of Cables Used in the Oil and Gas Industry

Power Cables

In the oil and gas industry, power cables are mainly used for equipment power supply and distribution systems. Depending on system voltage, oil and gas power cables are usually classified as low-voltage (LV), medium-voltage (MV), and high-voltage (HV).

In land-based oilfields, they are mostly used for the power supply of production equipment and internal power distribution; in offshore platforms, power cables are usually connected to the main power system to undertake the core power supply tasks. For example, pumps, compressors, drilling equipment, and various types of large motors.

Instrumentation Cables

Instrumentation cables are used to transmit signals in oil and gas systems for pressure sensors, temperature monitoring, flow control, and remote data acquisition systems.

These signals are typically low voltage but require high signal stability. If the signals are disturbed, the system can experience false alarms, data anomalies, or control delays. For this reason, instrumentation cables are often constructed with a shield to reduce the risk of electromagnetic interference.

In oil and gas projects with a high degree of automation, the number of instrumentation cables is often greater than the number of power cables.

Control Cables

In the oil and gas industry, control cables are used to connect control signals between equipment, and they are usually found in the following systems:

• Oil well head control units
• Valve actuation systems for refineries
• Pump station start/stop control
• Compressor control cabinets
• Emergency shutdown systems (ESD)
• Distributed control systems (DCS)

If there is vibration or dragging on the job site, you also need to consider the sheath and structural strength of the oil and gas control cables to ensure the stability of the control cable work.

VFD Cables

In the oil and gas industry, many pumps and motors are operated via frequency converters for speed regulation. This type of inverter drive system generates strong electromagnetic interference and places higher demands on cable insulation. The use of ordinary power cables under these conditions results in easily disturbed signals, extra voltage stress on the insulation, and even abnormal motor operation.

Therefore, these systems require the use of VFD cables, which are often shielded to minimize the effects of interference on equipment and control systems.

If your oil and gas project utilizes variable frequency drives, the cables can no longer be replaced with ordinary power cables.

Offshore and Marine Cables

Offshore platforms employ different cables than those used in onshore projects. In addition to power and control functions, they are exposed to seawater and salt spray environments. These cables usually have:

• Salt spray corrosion resistance
• UV resistance
• Higher fire rating

In many offshore projects, the cables are also required to meet certain standards, for example, Nordic or classification society standards.

Submersible Pump Cables (ESP Cables)

Inside an oil well, cables need to follow the electric submersible pump down the well. These cables are usually in high-temperature and high-pressure environments. Scenarios for the use of submersible pump cables in the oil and gas industry include:

• Electric submersible pump power supply
• Deep well operation
• Continuous operation for long periods of time

Downhole environments are very costly to maintain, so the stability of these cables is very important.

Portable Power Cables

During construction stages and temporary operations in the oil and gas industry, power supply points often need to be moved along with equipment. Ordinary power cables are prone to damage from frequent dragging and repeated bending, which is why more flexible, abrasion-resistant portable power cables are needed to supply power to mobile generators, temporary pumping stations, and maintenance equipment.

Armoured Cables

In oil and gas projects, with dense bridges and complex steel structures, cables are easily squeezed or subjected to mechanical shock. Armored structures can be used to offer mechanical protection to cables and minimize damage to conductors and insulation due to external forces.

LSZH and Fire-Resistant Cables

In oil and gas installations, the smoke and toxic gases generated in fires can interfere with evacuation and emergency operations, so it is necessary to take into account the burning properties of the cables.

LSZH cables burn with little smoke and low toxicity and are used in areas where a large number of people are present, such as control rooms and module areas. Fire-resistant cables are used in critical circuits such as emergency shutdown systems, fire alarms, and safety lighting to continue system operation during a fire.

Oil and Gas Cable Standards and Certifications

In oil and gas projects, the cables have to meet the relevant industry specifications, or approval of design and ultimate acceptance may be put at risk. For the selection process, you have to find out in advance what kind of standards your project has to comply with. Example:

• IEC Standards:The most basic system of standards in international programs, covering flame retardancy, bunch burning tests, low smoke and halogen-free properties, and smoke density requirements, applicable to most refineries and onshore oil and gas projects.
• IEEE Standards:Used frequently in AFSL projects and offshore platforms, mainly for marine and offshore power cables, with a focus on the reliability of the cables in wet environments and long-term operating conditions.
• NEK 606:A common requirement for North Sea and Norwegian offshore projects regarding cables’ low smoke halogen-free and high-grade flame-retardant properties, for heavily manned offshore platform areas.
• BS Standards:More common in UK system projects and some EPC projects in the Middle East, mostly used for control cables and instrumentation cables, with specifications for construction and electrical performance.
• ATEX and Hazardous Area Compliance:For areas where explosive atmospheres are present, with emphasis on the cable’s flame retardancy, low smoke and toxicity, and ability to maintain critical circuit operation in fires.

How to Choose the Right Oil and Gas Cable

Define Electrical Load and Voltage Rating

First, learn the electrical parameters. You can find from the project file:

• System voltage rating
• Type of load (motor/instrumentation/control circuit)
• Current capacity
• Short-circuit withstand requirements

The voltage class determines the general direction of cable selection. The current and the laying method together determine the cable cross-sectional area.

Assess Installation Conditions

You should know where the oil and gas cable will be used:

• Offshore or onshore project
• Bridged, buried, or ducted
• Fixed or to be moved
• Constant vibration or not

Installation conditions determine whether you need armoring, reinforced jacketing, for example:

• Equipment that needs to be towed → Consider flexible cables
• Buried or extruded by external forces → Armored construction is often required
• Offshore platforms → Consider corrosion resistance and low smoke and halogen-free

Match Cable Type to Environmental Risk

At oil and gas locations, environmental conditions vary greatly from one area to another, and you need to confirm cable types according to actual risks.

• High-temperature area → Confirm temperature rating
• With oil or chemicals → Select oil-resistant sheath
• Hazardous area → Confirm flame-retardant or fire-resistant rating
• With mechanical shock → Consider armored structure

Evaluate Total Cost of Ownership (TCO)

Oil and gas projects usually have a long operating life cycle, and the price of the cable does not reflect the true cost. It is more reasonable to evaluate the whole life cycle, including the design service life, the difficulty of maintenance in the later stage, the replacement cost, and the loss caused by downtime.

If the initial price of the cable is low, but the life expectancy is short, the failure rate is high, and the replacement is frequent in the later stage, it means a higher overall investment in the oil and gas project.

FAQs

How Do I Handle and Repair Damaged Low-Voltage Cables in the Oilfield?

The goal of on-site repair is to restore cable insulation and make sure it is watertight. For external damage, it is not possible to simply wrap the tape. Use a combination of multi-layer tape wrapping and special insulating coatings, or use the heat-shrink tubing process. However, it should be noted that non-specialized repairs may have a short waterproofing period. For critical circuits, replace the cable segments with special ones.

How Do I Choose the Right Type of Armoured Cable for Oil and Gas Facilities?

Steel Wire Armor (SWA): provides the strongest mechanical protection and is suitable for vertical laying under tension or direct burial.

Aluminum Wire Armor (AWA): lighter, for offshore modules where mechanical protection is required, but weight is a concern.

Steel Tape Armor (STA): provides compressive protection and is for direct burial or horizontal laying.

What Are the Main Environmental Factors That Affect the Service Life of Cables in the Oil and Gas Industry?

Chemical erosion: Long-term exposure to crude oil, natural gas, and various chemical injectors leads to sheath swelling or cracking.

Temperature and humidity: high temperature accelerates the aging of insulation, and high humidity (especially under the sea) is easy to trigger the electric tree effect.

Ultraviolet radiation: cables laid in the open air will become brittle if the sheath has poor UV resistance.

Mechanical stress: platform vibration, submarine current impact, will lead to periodic fatigue.

What Should I Consider When Laying Instrumentation Cables and Power Cables Together in an Oil and Gas Project?

Instrumentation cable transmits weak signals and is very likely to be affected by the electromagnetic interference from power cables. Therefore, the laying should be avoided for long-distance parallel alignment. If you can not avoid it, you need to maintain sufficient spacing (such as more than 300mm) or set the metal shielding partition. At the same time, the shielding layer of the instrumentation cable must be a single point of grounding to avoid ground loop interference.

How Can the Structural Design of Oil and Gas Cables Ensure Their Safety in Explosive Environments?

Oil and gas cables used in explosive environments must comply with explosion-proof installation standards such as IEC 60079-14.

Sheath material: Use flame-retardant and anti-static materials.

Insulation: Increase the insulation thickness to prevent sparks from breaking down.

Metal shielding/armor: As a circuit for ground fault current, it can quickly trigger the protection device to cut off the power supply and prevent arc sparks from existing for a long time.