How is Subsea Oil & Gas Produced?

In basic terms, subsea technology can be neatly put into three boxes. The first is how to get the oil and gas out of the ground safely without harming the environment. The second is how to transfer what is coming out of the wells to somewhere else for processing, or cleaning up. And third, how to make this equipment do what you want and do it safely.

The first piece of this puzzle is the subsea Christmas, or xmas, tree. People around the oil industry have been asking the question, who called a xmas tree a xmas tree first and when, for many years and no one seems to know the answer. What it is, in simple terms, is a complex tap, something like the taps that open and close in a sink or bathtub, allowing the oil and/or gas to come out of the ground in a controlled safe manner. On xmas trees, these taps are called valves.

Part two is the pipeline for transporting what comes out of the wells to another location. Pipelines are everywhere – for moving water and gas to homes and processed petroleum products, like aviation fuels, from refineries to airports. Those used in the oil and gas industry are often made from exotic alloys – combinations of different metals – to prevent corrosion.

The final piece of the jigsaw– and this is where Viper Innovations comes in – is the control system which is used to open and close the valves on xmas trees and sometimes to open and close similar types of valves associated with pipelines to stop or start the flow of fluids. They are also used to gather information, such as pressure and temperature, that originates from specially designed and located sensors, strategically placed around the subsea equipment.

Control systems have become increasingly complex and sophisticated over the years as equipment went into more challenging environments. Originally the control system worked a bit like the brakes on a car. The driver steps on the brake pedal which forces brake fluid down a narrow tube which moves the brakes to close. That was how controls, dubbed hydraulic systems, worked in the early days of subsea when the xmas trees were located no more than a few miles from its host platform.

Now wells are in much deeper waters – more than 2km below the surface in some cases – and the wells can be as far away as 100 miles (or 160km). Control systems now have to work much quicker than pushing hydraulic fluid. The signals to open and close valves are now electronic and reach the equipment in seconds, but the valves still have to be moved by fluids which are stored near to the valves. Such systems are now called electro-hydraulic because they combine electric signals and hydraulic force.