Ships are key to cost-effective well intervention

Light well intervention using ships rather than cumbersome, expensive mobile offshore drilling units rigs is gaining momentum. The population of vessels capable of handling this type of work is poised for a growth spurt and the technologies required to carry out the work are maturing.

Moreover, a track record is now established – petroleum companies have to acknowledge that the approach works and it saves them a packet at the same time.

Within a few years, servicing of subsea wells will be commonplace and that should work wonders in terms of their ability to produce more hydrocarbons, and over a longer period than originally anticipated.

For now, at least, the resource remains scarce. However, a very particular milestone was achieved in February when an agreement was initialled between the UK’s Expro Group and Aker Oilfield Services (AOS) of Norway.

The intent is to jointly market Expro’s ground-breaking AX-S rigless intervention technology, together with the Norwegian company’s fleet of well intervention vessels, the first four of which are on order, with options for two further ships.

Earlier, Aberdeen-headquartered Expro had signed a related agreement with BP covering development and commercialisation of the AX-S system.

The BP deal basically means that the system, which has been under development since 2004 – and which could potentially be deployed from any Class 3 dynamically-positioned offshore support vessel (OSV) capable of being retrofitted with a stern-mounted A-frame to enable deployment of well servicing equipment – will be viable.

BP has committed to providing partial project funding and technical input, including field trials on subsea wells, contingent upon the system passing agreed testing milestones.

The BP-Expro agreement anticipates that field trials will take place during the first half of 2009, which is more or less when the first of the Aker Offshore ships will be delivered.

In its trading update of March 24, Expro said: “The development of new technology remains essential to our positioning and we have invested record amounts to develop and deliver the next generation of Expro products. Our flagship AX-S rigless intervention concept continues to take shape. Technically, the project is progressing well against a very demanding schedule and our objective remains to be ready to perform deepwater trials mid-2009.”

While there are now competing systems, notably the FMC concept that beat Expro into the marketplace (it was developed with Statoil input), the Aberdeen group believes it is at the threshold of playing a leading role in solving many of the issues associated with lightweight subsea well intervention, especially deepwater to 3,000m (10,000ft).

Now that the technology is being matched up with a fleet of purpose-designed light intervention ships, all with the same characteristics, both Expro and AOS should be set fair in what is now a fast-growing and still sparsely resourced aspect of deepwater oil&gas.

The lack of suitable intervention technologies began to be commented on extensively 10-15 years ago, since when progress has, frankly, been slow.

Meanwhile, the global population of subsea wells is growing rapidly and is forecast to reach about 2,600 by 2010.

More than 400 such wells are to be found in Norwegian waters. It could be 500 within a decade or so.