Home: Issue 5 2012 › Lead Story › Rigged for success
Rigged for success
05/06/2012 | Channel:
Despite a changing economic environment, rig design and development remains vital for oil and gas companies
Understandably the global economic downturn seriously affected everyone in the industry, and at every level. From the major oil companies producing the resources, to the workers operating across the sector, through to the equipment manufacturers, suppliers and developers, cost-cutting and financial difficulties have had far ranging impacts.
And while inevitable cutbacks have been made, for some time there have been signs that the industry is on its way back to full strength, with new contracts, discoveries and technology again fuelling the desire and necessity of natural resource production. Naturally, one area that suffered considerable doubt was that of the vastly expensive production equipment – namely rigs, jackups and FPSOs. In a method to save costs, production companies cancelled contracts for new rigs and equipment, or scaled back their requirements for the immediate development of such technology.
During 2010 into the beginning of 2011 for example, the market for deepwater semi-submersibles was conservative to say the least, only beginning to grow as operators actively sought an increase in activity. Regardless of activity however, the difficulty presented in finding and producing modern resources means that, understandably, the design, construction and maintenance of new, and existing oil and gas platforms is one of the most essential factors in the modern oil and gas sector.
New platforms must be designed to adhere to even stricter standards than older structures, due in part to both better engineering measurements and lessons learned from the past, whilst existing, operational structures that have been in operation for some time must be frequently analysed to ensure they are maintained at operational standards and suitable for operations.
The amount that rig design and development has changed since the pioneering days of oil exploration is vast. Initial offshore units were simple structures that were only capable of drilling in shallow waters, and were partially limited by the fact that they were simply designed in an uncomplicated fashion by creative individuals in the burgeoning oil sector. Today it may be true that the concept remains the same - what is required is a strong, self-contained structure to effectively explore for oil and gas - yet the design is vastly improved.
One of the most widely used oil and gas exploration platforms, since large-scale production commenced in the 1960s and 1970s, is the semi-submersible platform. One of the most recognised pieces of oil and gas exploration equipment, the semi-submersible provides one of the most stable, productive and most effective ways in which to drill for natural resources.
The premise of the semi-submersible lies in its specialised design, combined with an inherent stability that other drilling platforms and production rigs do not have. With offshore drilling becoming increasingly carried out in deep waters and harsh environments this characteristic is vital for oil operations. The modern semi-submersible oil rig actually floats above the designated oil field, obtaining its buoyancy from ballasted, watertight pontoons located below the ocean surface and away from the localised wave action. This also means that the operating deck, which of course houses the necessary equipment for exploration and production, can be located high above the sea level due to the good stability concept.
The semi-submersible has experienced a long and interesting history in the industry, and one that goes hand-in-hand with the pioneering spirit in the market. Indeed, the first of its type was invented in the early 1960s, with the idea being arrived at during the transit of a submersible drilling rig. Following this, the first purpose built semi-submersible, the Ocean Driller, was launched in 1963, with the design being rapidly accepted by industry insiders. In fact, such was the recognition of the potential of the semi-submersible, that by 1972 the global fleet had increased rapidly to 30 units.
The key problem for this particular design is cost - quite simply the semi-submersible is an incredibly expensive option for an oil and gas company, with a number of factors having to be recognised before any commitment is taken. As such the global market for this type of platform has fluctuated alongside the drilling market itself, with typically ‘batches’ of rigs being produced during certain boom periods.
One increasing trend however has been the conversion of semi-submersible drilling rigs for combined use as drilling and production platforms. Housing both the drilling equipment and storage and production facilities, this type of rig offers a far more efficient and effective investment. The first converted production platform was the Argyll FPF, which operated in the Argyll field in the North Sea, but this was closely followed by purpose built structures, the first of which was launched in 1986 for use in the Balmoral field in the North Sea.
As the industry develops and production moves deeper and into more harsh environments the nature of the rig market is changing also. With new resource discoveries happening at a quickening pace many oil and gas companies are looking for a cheaper alternative to the large, costly semi-submersibles. One such example is the jackup rig, a smaller, cheaper, and most importantly, re-locatable rig that can be moved to drilling areas quickly and can effectively exploit the energy source.
The basic premise of the jackup is simple. Rather than the large cumbersome semi-submersible platform, which represents an enormous investment and provides a long-term drilling capability in deepwater fields, the jackup represents a smaller, simpler structure that is self-elevating and can be towed or carried to drilling locations through the use of tug vessels or a heavy-lift ship.
Key to the success of the jackup is its stability in shallow, often rough waters despite standing on unfixed, moveable legs. These columns or legs, usually numbering three or four, are moved independently via an hydraulic system to the sea floor, having already been pre-loaded in order to form a safe anchor. In turn, this raises the platform structure itself above the water surface to a pre-determined drilling height in order to enable the most efficient drilling to take place. This in turn does not have to be fixed drilling similar to that of a semi-submersible anchored in deep waters.
Of course, each type of modern platform has its pros and cons, and all are suited to particular areas or drilling regimes. Ultimately, the basic premise remains the same, what is required is a stable platform large enough to house the necessary equipment, but also efficient and effective enough to allow natural resources to be exploited to their full potential.
In the current exploration field there are a number of alternatives that are operating in the market, such as the FPSO, which is gaining in popularity, particularly in the type of fields that are becoming increasingly common. The FPSO offers a number of advantages – namely cost – which means that rig developers are looking at innovation in new ways. Similarly, the advent of new and alternative energies such as shale gas and onshore drilling is placing further challenges on the rig design market. Despite this, there is no doubt that, for the major oil and gas companies, continuing to develop state-of-the-art, cost-effective and efficient exploration and production platforms will be key to continued success, as well as to meeting the world’s future energy demands.