Andrew Oilfield - Hardware

Hardware

The Andrew field is produced using a fixed platform, with topsides facilities supported on a four leg steel jacket. The platform is relatively small accommodating only 80 people. It contains a full process plant for separating water and gas from the production fluids. Platform power is provided from three 6MW gas turbines, fed principally from produced gas.

There are presently 17 operational wells, 15 producing oil from the Palaeocene, one reinjecting gas into the gas cap and another producing gas from the Cretaceous reservoir (known among the asset simply as "The Lower Cretaceous"). The Andrew well bay has plenty of room for further wells as it has a total of 24 slots, only 18 of which are occupied (17 with wells and one slot with umbilical lines to Farragon). The Andrew also receives flowlines from the Cyrus subsea wells.

The Xmas trees and wellheads are supplied by Vetco. The four original pre-drilled wells (though one has since been side-tracked) on the South side of the well bay use slightly smaller wellheads than the rest because they were part of the original template before the platform was put in place.

The Xmas trees have the unusual property of having two Swab valves, rather than just one. The intention behind this was to allow the rigging up and down of pressure control equipment for well work without having to shut in the well. This would save money in lost revenue for the day the well would normally not be flowing. However, the experience over the past ten years has shown that the increased cost of maintaining an extra valve does not match the savings.

Processed oil is exported to the Forties pipeline system then on to Cruden Bay. Natural gas is exported to the Central Area Transmission System to Teeside. Produced water is cleaned in the process plant to sufficient quality that it is dumped overboard.