There are many different types of rig including:
Production platforms are permanent, immobile structures built on steel and/or concrete legs that are fixed directly onto the seabed. They are the largest type of structure you would work on offshore. They are built once oil or gas (hydrocarbon) has been found in commercially produce-able quantities and although further drilling will often take place on the platform, its main purpose is producing the hydrocarbon. Often, a single platform will gather hydrocarbon from a number of outlying wells through what are known as ‘tiebacks’ – a network of valves and pipes that rest on the sea bed.
Platform Semi-submersible platforms or rigs are floating (mobile) structures used for drilling for oil and natural gas in offshore environments. They have a number of pontoons and/or columns that are flooded with seawater, causing the installation to sit very low in the water, providing the stability that is required for drilling operations. The unit is fixed in position with very large mooring anchors and is moved from location to location by tugs. These types of installation can drill in very deep, rough water due to their excellent stability.
A Jack-up rig is a self-contained combination drilling rig and floating barge, which has been fitted with long legs that are raised when moving and lowered to the sea bed when on location. The rig is limited to operating in water depths of a maximum of about 400 feet (depending on the rig) – which is sufficient for many parts of the North Sea. Like the semi-submersible it is moved from location to location by tugs.
A Drill ship is a maritime vessel that has been fitted with drilling equipment. They can move under their own power and, though not as stable as semi-submersible platforms, they can drill in deep water. A drill ship is held in position over the well by a combination of its own engines turning powerful screws in the hull and global positioning satellite (GPS) technology.
Production and Storage Offloading Vessel (FPSO’s)
A FPSO is a type of floating tank system used by the offshore oil and gas industry. They are often converted oil tankers – although increasingly they are purpose built – which attach to a sea bed wellhead from which they produce and store the oil. The oil is then offloaded to another tanker for transport to the refinery. They are particularly used for production from small reservoirs where it would be too expensive to build a production platform – one of the major advantages is that the FPSO is re-usable as it can be moved from well to well.
Flotels are literally floating accommodation units. They are quite often converted from semi-submersible platforms; these are then moored alongside a production platform or other type of rig, and connected to them via a long gangway. This is one way of keeping the accommodation, leisure and catering facilities remote from the working areas which is a legal requirement in the North Sea.
Jack-up Rig Steel Production Platform
Semi-submersible Rig Concrete Production Platform
Drillship Tension Leg Platform
Reaching the offshore installation you’re working on generally involves flying by helicopter. Where the installation is located around the coast of Britain will dictate where you fly from, but for all the central and northern North Sea installations, the departure point is Aberdeen. The generous time off allowances dictated by the working pattern means you can live all around the country and not just in Aberdeen and its surrounding areas.
The helicopters used for offshore travel usually have 18 seats, although smaller helicopters may be used for inter-platform transfers. Nevertheless the same stringent safety regulations apply. For example, you must wear immersion suits and lifejackets at all times and before every single flight there will be a safety briefing including a detailed video.
Click here to learn more about the offshore survival certificate that every offshore worker must have.
The usual working pattern for most people offshore is 12 hour shifts. Not all shifts change at the same time, however, so you will need to find out when you apply for a position exactly what the working pattern is.
In the North Sea it is normal to spend two or three weeks offshore and then two or three weeks onshore – whether you work 2/2, 2/3 or 3/3 depends on the company you work for. In a contracting company, it depends on the company they are providing your services to. In the Well Services sector, the work is more ad hoc with very few staff having regular rotation schedules. Generally speaking holiday entitlement is included in the time off. However, different companies have different arrangements, so you should check at the time you apply.
In other parts of the world the work trips may be longer – perhaps four or even six weeks – but your time ashore (or ‘on the beach’ as it is known) would be correspondingly longer as well.
Working at height
Some jobs, such as drilling from a hydraulic workover unit, or as an abseiler on rig inspection and maintenance, involve working at height. However, in all cases there are stringent safety regulations including the use of appropriate protective equipment. In this picture, these men are replacing a lifeboat winch assembly.
There is a public perception that working in the oil and gas industry – particularly offshore – is extremely well paid, but something you do only for a short time. It is true that the industry does pay well, especially given the offshore work pattern of two weeks on and two or three weeks off, although the differential with other industries is not as large as you might think.
What it most certainly isn’t, is a short term prospect. Indeed, many workers in the UK sector of the offshore North Sea oil industry have over 20 years service. So you can see that this is a very experienced workforce.
Furthermore, although most of the major oil and gas reservoirs in the North Sea have been tapped, the improvement in technology is allowing the industry to produce from smaller, more marginal reservoirs and to significantly extend the working life of most of the existing production facilities. There will be jobs in the North Sea oil industry well into the foreseeable future as well as opportunities for skilled and experienced workers in other parts of the world.
Most jobs in the Oil & Gas industry offer a generous renumeration package, with salaries varying from company to company.