How do you select the best electric line tools and equipment for different subsea intervention scenarios?

1 Cable type

The cable type depends on the depth, pressure, temperature, and electrical requirements of the intervention. There are three main types of electric line cables: mono-conductor, multi-conductor, and fiber-optic. Mono-conductor cables have a single wire that carries both power and data, and are suitable for shallow and low-pressure wells. Multi-conductor cables have multiple wires that can handle higher power and data rates, and are more flexible and reliable. Fiber-optic cables have optical fibers that can transmit large amounts of data at high speeds, and are ideal for real-time monitoring and high-resolution imaging.

2 Tool string

The tool string is the assembly of tools and sensors that perform the intervention tasks. The tool string should be compatible with the cable type, the well geometry, and the intervention objectives. Some common tools and sensors include: logging tools, which measure physical properties of the formation and fluids; perforating tools, which create holes in the casing or tubing to enable fluid flow; plugging tools, which isolate zones or seal leaks; and fishing tools, which retrieve lost or stuck objects from the wellbore.

3 Surface unit

The surface unit is the device that controls and monitors the electric line intervention. It consists of a power source, a cable drum, a tension device, a depth measurement system, and a data acquisition system. The surface unit should be able to provide sufficient power and data transmission to the tool string, as well as adjust the cable tension and speed according to the well conditions. The surface unit can be mounted on a vessel, a platform, or a subsea structure.

4 Subsea unit

The subsea unit is the interface between the surface unit and the wellhead. It provides a connection point for the cable, a pressure seal for the wellbore, and a safety valve for emergency situations. The subsea unit should be compatible with the wellhead design, the water depth, and the environmental conditions. There are two main types of subsea units: wet units and dry units. Wet units are deployed directly into the water and are exposed to the ambient pressure. Dry units are enclosed in a pressure vessel and are isolated from the water.

5 Operational parameters

The operational parameters are the variables that affect the performance and safety of the electric line intervention. They include: the well pressure and temperature, which determine the cable and tool ratings; the well deviation and diameter, which influence the cable friction and tool movement; the well fluid composition and flow rate, which affect the cable corrosion and tool function; and the well intervention history and status, which indicate the potential risks and challenges.

6 Selection criteria

The selection criteria are the factors that help you choose the best electric line tools and equipment for different subsea intervention scenarios. They include: the intervention objectives and requirements, which define the purpose and scope of the intervention; the technical feasibility and reliability, which evaluate the capability and availability of the tools and equipment; the operational efficiency and cost-effectiveness, which measure the time and resources needed for the intervention; and the environmental impact and compliance, which assess the potential effects and regulations of the intervention.