Harding
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Harding was discovered in February 1987 in acreage licensed to Britoil in the 9th licensing round. Oil was discovered in the Eocene at a depth of approximately 1,850 metres below the seabed in a water depth of 100 metres. It covers an area of approximately 20 square kilometres.
After this discovery, an extensive appraisal programme was carried out with some 18 additional wells and a 3D seismic survey. The field was initially developed from two pools of oil: Harding Central and South. Since then, two further pools have been developed: Harding South East and by extended reach drilling, Harding North. The reservoirs also contain gas, which will be developed at a later date. |
The oil from the Harding field requires a form of offshore storage. This is because the crude is heavy and naphthenic and therefore is generally of a lower value compared to some North Sea crudes. Consequently, the decision was made to export it by tanker rather than co-mingle it in a pipeline.
A number of options were considered for the development. The final solution was:
- A heavy-duty steel jack-up production unit, based on a proprietary design by Technip Geoproduction resting on a concrete gravity base/storage tank (GBT) capable of holding 580,000 barrels of oil.
- A 2 kilometre, 24-inch diameter pipeline to a tanker loading system - the Submerged Turret Loading buoy (STL).
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In April 1993, the field partners announced their intention to develop the field and a number of major contract awards were announced with EU companies utilising some 70% of the total #400 million budget.
Harding was developed in line with the CRINE (Cost Reduction Initiative for the New Era) principles. A small project team provided leadership, alignment of objectives and co-ordination between the contractors involved in the design and fabrication of the platform. |
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Extensive efforts were made to simplify the processes and extract unnecessary costs by using proprietary designs and simple specifications. As a result of these efforts Harding was one of the lowest cost field developments in the North Sea.
Since starting up in April 1996, there have been two major de-bottle necking projects called 'Headroom' and ''Super Headroom'. These are aimed at increasing the gas plant capacity and improving produced water quality for re-injection.
- The first of these, the Headroom Project, was completed in 1997 and production increased to 80 mbd dry oil.
- The second, 'Super Headroom' was completed in 1999 and took production to 95 mbd.
- In order to develop the N/NE, SE, an Extended Reach Drilling project involved extensive upgrading of existing drilling equipment, including the addition of a third mud pump. The drilling programme of infill production wells is ongoing.
- All platform safety systems have been upgraded and extended to cover the new structures and equipment.
To date (2003) the field has:
- 15 production wells.
- 4 water injection wells.
- The field only has one gas injection well because there is currently no gas export.
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In addition two wells produce water form a shallow aquifer for re-injection into the main reservoir and hence provide pressure support. The production wells are horizontal in the reservoir and one has dual wellbores, as the wells water out they are being put on gas lift to keep them flowing.
There are further satellite oil pools in the area to develop including, ''Deep South' and 'North East'. Harding features two innovations to limit oil discharges to the sea: produced water is re-injected into the reservoir and drilling cuttings are ground up and injected into a well casing and hence into an underground formation. In addition, a 'green' compressor has been recently added to recompress LP gas rather than flare it as per the original design. |
