Box 833836, Richardson, TX 750S3-3836, USA,, fax 01-972-952-9435. AbstractThe Captain field in the North Sea UKCS is a highly viscous crude accumulation produced via watertlooding with extended reach horizontal wells. Captain's high oil-water mobility ratio and exceptional reservoir quality make it an ideal candidate for improved oil recovery by polymer augmented water flooding.Polymer storage tanks and subsea polymer flowlines were included in the design and build of the Captain facilities to simplify future implementation of a polymer tlood pilot.Offshore logistical considerations led to the selection of liquid hydrolyzed polyacrylamide (HPAM) as a basis for the polymer flood design. We report in this paper the methods and results obtained from a series of laboratory studies undertaken to identify HPAM's that could be used at Captain and to provide data for reservoir simulation input. This work, conducted by the operator and two polytner vendors, included coreflood tests, scaled polymer mixing tests, and polymer shear degradation tests.Although good viscosity yield, low polymer retention, and good coreflood oil recoveries were obtained with HPAM's, the solutions caused face plugging of Captain cores. Using a membrane filtration method to quickly screen new products, both vendors developed improved HPAM's that were judged suitable for use in the Captain reservoir. Results of the shear degradation experiments indicated that shear degradation should be insignificant in tubulars at field design flowrates, but possibly substantial at the sandface.

Box 833836, Richardson, TX 750S3-3836, USA,, fax 01-972-952-9435. AbstractThe Captain field in the North Sea UKCS is a highly viscous crude accumulation produced via watertlooding with extended reach horizontal wells. Captain's high oil-water mobility ratio and exceptional reservoir quality make it an ideal candidate for improved oil recovery by polymer augmented water flooding.Polymer storage tanks and subsea polymer flowlines were included in the design and build of the Captain facilities to simplify future implementation of a polymer tlood pilot.Offshore logistical considerations led to the selection of liquid hydrolyzed polyacrylamide (HPAM) as a basis for the polymer flood design. We report in this paper the methods and results obtained from a series of laboratory studies undertaken to identify HPAM's that could be used at Captain and to provide data for reservoir simulation input. This work, conducted by the operator and two polytner vendors, included coreflood tests, scaled polymer mixing tests, and polymer shear degradation tests.Although good viscosity yield, low polymer retention, and good coreflood oil recoveries were obtained with HPAM's, the solutions caused face plugging of Captain cores. Using a membrane filtration method to quickly screen new products, both vendors developed improved HPAM's that were judged suitable for use in the Captain reservoir. Results of the shear degradation experiments indicated that shear degradation should be insignificant in tubulars at field design flowrates, but possibly substantial at the sandface.

This study uses electrical resistivity measurements of soils and weathered rock to perform a fast and reliable evaluation of field anisotropy. Two test sites at New Concord, Ohio were used for the study. These sites are characterized by different landform and slightly east dipping limestone and siltstone formations of Pennsylvanian age. The measured resistivity ranged from 19 Ω∙m to 100 Ω∙m, and varied with depth, landform, and season. The anisotropy was determined by a comparison of resistance values along the directions of strike and the dip. Measurements showed that the orientation of electrical anisotropy in the shallow ground may vary due to fluid connection, which is determined by the pore geometry in soil and rock, as well as by the direction of fluid movement. Results from this study indicated that a portable electrical resistivity meter is sensitive and reliable enough to be used for shallow ground fluid monitoring.