Page 5: Chevron's project development and execution process
The process which Chevron has created for project development and execution is set out in the illustration below. Chevron was able to use this approach in the development of Phase II of the Alba field. In analysing this phase, the project team was able to narrow down a range of alternatives into an optimum solution:
- 21 options were identified for further study
- 4 failed on grounds of technical feasibility
- 9 were favoured
- 4 failed the economic hurdle
- 5 remained for further study, including a floating production vessel and building a sub-sea production centre.
After further analysis, the final option selection was between upgrading the original platform or building a second, bridge-linked, platform to the Northern Platform. The chosen option was a ‘retrofit’ to upgrade the original platform to handle increased production.
Phase II was divided into two stages, IIa and IIb, in order to introduce new platform facilities. Phase IIa of the Alba project involved installing a new 300 tonne production module. This was carried out in July 1996. New technologies were employed including the utilisation of an ERD programme, the first time that such technology had been used in the North Sea. ERD enables the furthest reaches of the field to be tapped with some wells nearing 5 miles in length. Phase IIa of the project increased oil handling capacity from 70,000 to 100,000 barrels per day.
Phase IIb is planned for completion in December 1998. This will sustain production levels and lessen the rate of decline by increasing fluid handling capacity from 240,000 barrels to 390,000 barrels per day. This phase involves adding additional modules to the Northern Platform. (See picture below and right). It also includes improvements in the technology employed to ensure the minimisation of environmental problems. The water which is pumped into the well to push the oil out comes back mixed with oil, in addition to the water that naturally occurs in the reservoir. The separation of the oil and water is a critical requirement and a difficult task, especially with heavier crude oil like Alba’s. It is accomplished in several stages in the platform facilities to ensure that the water for disposal is environmentally safe.