Water Quality In The North Sea And Injection Water Standards For North Sea Oil Fields

Abstract

Discussion of this paper is invited. Three copies of any discussion should be sent to the Netherland Section of the Society of Petroleum Engineers, P.O. box 228, The Hague, the Netherlands. Such discussions may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract Seawater injection will probably be required to maintain reservoir pressure in most North Sea oilfields. Since there is little published data on North Sea water quality was carried out in the vicinity of the Auk and Brent fields. From these measurements conclusions have been drawn about the filtration and chemical treatment requirements for the seawater that will be injected into the reservoirs of these two fields. Introduction Water injection will be needed to maintain initial reservoir pressure in the Auk and Brent fields and will probably be required in most North Sea oil fields. The Auk project will require about 70,000 b/d injection water and each Brent production platform will require about 250,000 b/d. Because of its greater size, the emphasis of the work was directed towards the Brent field. The most convenient source for injection water is North Sea water taken from below the production platforms and in order to design facilities for filtering and treating this water a knowledge of its quality and its effect on the reservoir is needed. At presented there is no published data on the quality of North Sea water with respect to suspended solids, micro-organisms or scaling tendencies. This paper describes the results of a programme of on-site measurements of North Sea water quality which were made in the vicinity of block 211/29, 90 miles northeast of the Shetland Islands. The objectives of the programme were:To determine the type of chemical treatment needed to prevent corrosion, scaling and bacteriological problems.To find the pump intake depth that yields the best quality water.To determine whether the suspended solids level can be substantially reduced by filtration.To estimate the rate of impairment due to suspended solids that would result in the Brent formation from the injection of either filtered or unfiltered seawater.