Trawling risk assessment

The problem

A field development off West Africa was being developed by a major global operator. As part of the development a subsea isolation valve (SIV) was to be included at the base of an export riser.
The SIV was designed to be installed within a protection structure to guard against dropped object and cable contact damage only.
Situated within the 500 m fishing exclusion zone of the injection platform no trawl gear interaction would theoretically occur. However, the operator required a risk assessment to be undertaken to validate this assumption.

The solution

Jee undertook a review of trawl activity recorded in the area based on public domain statistics, published papers and non-restricted in-house data. This review then enabled the following assessments to be completed:

•  Determination of interaction probabilities and frequencies
•  An estimation of the consequences of trawl gear interaction
•  Development of a quantitative risk assessment for the SIV
•  Completion of a cost/benefit analysis for the provision of a trawl protection structure

• Assurance. The review enabled the client to validate the assumptions they had made during the design process and to understand the conditions required for those assumptions to remain valid.
• On-time delivery. Stringent time constraints were placed on the project. These constraints were met without compromising quality.
• Experience. Jee’s experience in fishing interaction assessment enabled relevant data to be identified with alacrity.