Question

Things never seem to slow down, particularly on your existing subsea project. While all this activity is going on with the new oil zones, SIT issues, you and your team have to keep up with the design, procurement, fabrication, testing and installation scope for the rest of the subsea project.

The latest problem involves the subsea connectors used throughout your project. Before you hired on, decisions were made to use an older model so-called legacy connection system, which had been used successfully in the past in this area by your company. This particular connection system had not been used in a long time by anyone, and although this connection system load capacities were known, there has been a change to the API Standards that require connector load capacities be re-calculated using different methods and factors. And while your new order for the old design connection system was progressing for your project, the revised design calculations were made, and they are sitting on your desk for review. As your luck would have it, to general surprise the calculations using the current methods proved the connector load capacities to be much smaller than previously shown in the legacy project documentation, which was all that your company had when the decision was made to use this system. Changing the connector system to a different design is a last resort, as it would delay the project by more than a year. You have been asked to investigate this and recommend an action plan.

Question 1. What are the minimum ten key concerns here, and what are your recommendations for how to approach this?

Answer 1

Subsea oil production systems can range in complexity from a single satellite well with a flowline linked to a fixed platform, FPSO or an onshore installation, to several wells on a template or clustered around a manifold, and transferring to a fixed or floating facility, or directly to an onshore installation.^[5]

Subsea production systems can be used to develop reservoirs, or parts of reservoirs, which require drilling of the wells from more than one location. Deep water conditions, or even ultradeep water conditions, can also inherently dictate development of a field by means of a subsea production system, since traditional surface facilities such as on a steel-piled jacket, might be either technically unfeasible or uneconomical due to the water depth.^[5]

The development of subsea oil and gas fields requires specialized equipment. The equipment must be reliable enough to safeguard the environment and make the exploitation of the subsea hydrocarbons economically feasible. The deployment of such equipment requires specialized and expensive vessels, which need to be equipped with diving equipment for relatively shallow equipment work (i.e. a few hundred feet water depth maximum) and robotic equipment for deeper water depths. Any requirement to repair or intervene with installed subsea equipment is thus normally very expensive. This type of expense can result in economic failure of the subsea development.