Gå til hovedinnhold

Audit of implementation of light well intervention

On 18-19 January 2005, the Petroleum Safety Authority Norway (PSA) carried out a verification activity targeting Statoil's implementation of light well intervention (LBI) on board the Seawell. The impression gained is that the well intervention work was executed with good results. However, our impression is also that improvements could be made in the general HSE level on the Seawell.


Background for the audit

In recent years, the PSA has made a relatively large effort vis-à-vis the industry to promote development and use of light well intervention (LBI) in subsea wells, with the intention of contributing to greater value creation on the Norwegian shelf.

It is expected that value creation associated with such well intervention can be achieved in the form of improved operational safety, a better overview of the condition of the well, production control, well integrity and improved production of petroleum resources with prudent cost exposure.

illustration LBI
Illustration light well intervention

In this context, Statoil has initiated two well intervention campaigns on the Norwegian shelf, in part to qualify the LBI technology for "Norwegian conditions".

These activities were conducted during the fall of 2003 with the facility MSV Regalia and FMC lubricator, and during the period 2 October 2004 - 2 February 2005 with Seawell and Schlumberger lubricator.

Statoil's rig acquisition process in the beginning of 2004 resulted in the choice of Seawell for the latter LBI campaign, expected to take about 150 days.

Seawell's extensive experience from this type of activity was particularly emphasized, although a switch had to be made to a lubricator system with greater capacity in order to meet the operational needs for the wells in question.

In the time that ensued, significant work was done in order to meet needs with regard to qualification of adapted LBI technology, integration on Seawell, and facilitation of relevant technical and management-related HSE requirements for activities on the Norwegian continental shelf.

The facilities regulations were used as a basis for the evaluation process and application for consent.

On 22 June 2004, Statoil received consent to use the Seawell to commence the above-mentioned LBI campaign under special conditions.

Application of new technology and work methods called for a particular evaluation with regard to potential future application, and that the consent was not to be regarded as setting a precedent for future requirements/standards for these types of facilities/arrangements.

However, the start-up date was delayed from 25 July 2004 to 2 October 2004 due to late commissioning and testing of technical equipment, including a new well pig assembly.

Because of the delayed start-up, combined with limited operational availability during demanding weather and sea conditions, only a few of the planned LBI operations were carried out. A need thus arose for extending the consent period by up to two months.

Statoil's application for extension contained three new non-conformities, while 11 of the original 76 non-conformities had then been closed.

The extension did not entail an expansion of the scope of work, and the PSA granted a limited extension on the basis of this situation.

On 15 December 2004, the PSA gave notice of this audit. The verification preparations were made on the basis of the submitted lists of non-conformities, overviews of incidents and consent documentation with conditions.

It was difficult to find an opportunity to board the facility to conduct the audit during normal activities because there were long periods of interrupted operations due to rough seas.

Eventually, a decision was made to conduct the audit on the Seawell while the facility was moored at the quay in Bergen.

The actual verification on board was conducted over a shorter period of time, but with a larger than normal number of personnel involved, and somewhat less than four hours at our disposal.

The technical areas included emergency preparedness, working environment, maintenance, marine systems, electrical/safety systems and well technology.

Purpose of the audit

The objective of the audit was to verify that the basis and preconditions for the consent were followed up by the operator and contractor in accordance with the regulations.

In addition, the PSA intended to gather first-hand information from the testing of the relevant LBI technology, including ensuring that experiences gained are addressed in the ongoing work, both as regards technical and operational conditions.

Result of the audit

Several new non-conformities from the regulations were identified, but based on the relevant verification terms, the degree of inspection was too limited to provide conclusions with comprehensive technical evaluations.

This situation also leads the PSA to question whether Statoil and Cal Dive have a sufficiently effective management system and involvement in order to ensure a correct overview of non-conformities/condition evaluation in relation to the Norwegian shelf regulations.

Furthermore, it is our impression that some effort remains before the general HSE condition on the Seawell can be deemed to be compatible with other mobile facilities on the Norwegian shelf.

The completed well intervention work is perceived as having been executed with good results.

The LBI campaign sequence now completed has, however, taken quite a long time with many interruptions, mainly due to the facility's operational limitations under demanding weather and sea conditions of the season.

Activities carried out under conditions of inadequate continuity and close to the facility's operational limits are not desirable from a safety point of view, and the operator must make a better operability evaluation and assume more stringent seasonal/area restrictions in connection with its future plans for possible use of the types of ship-based solutions represented by the Seawell.

Contact person i the Petroleum Safety Authority
Mike Theiss