Meeting the Challenges in the Downhole Scale Control for High-Water-Production Horizontal Wells in Environmentally Sensitive Part of the Norwegian North Sea

Abstract

Due to the seawater injections in one of in Norwegian Sea oil fields, sulfate scale depositions have been identified in the near well bore region and inside the production well. The scale inhibitor squeeze treatments are regularly carried out. Most of the production wells are horizontal producing with a fairly high water cut and increasing the squeeze treatment life is one of the major issues for the selection of scale inhibitors and placement technologies. In addition, the inhibitor selected has to be environmentally acceptable and meet the regulations from the environmental authorities. Both challenges from the high water production wells and environmental requirements limited the choice of the inhibitor candidate selections.Through extensive laboratory qualification testing, a newly developed polymer inhibitor was qualified for the field and satisfactory results were achieved from several field trials. This paper presents the inhibitor chemistry as well as the laboratory tests such as inhibitor efficiency, compatibility and inhibitor core flood. The environmental properties of the chemistry will be outlined. A comparison was made between the field treatments using this polymer inhibitor and widely applied polymer chemistries. The treatment optimization using a software package will also be highlighted. The field has utilized the gelled scale inhibitor package and the technology improved the inhibitor placement in the horizontal well. The updated treatment data will be reviewed in this paper.