10.11440060469_si_001.pdf (16.86 MB)
Download fileThe Magnus Field - Extending Field Life through Good Reservoir Management and Enhanced Oil Recovery
journal contribution
posted on 2020-04-30, 14:18 authored by A. G. MACGREGOR, P. TRUSSELL, S. LAUVER, M. BEDROCK, J. BRYCE, T. MOULDSintra Volgian/Kimmeridgian age, of the Magnus Sandstone Member (MSM) and
the Lower Kimmeridge Clay Formation (LKCF). The reservoir sandstones of the
Magnus Field are enveloped by the organic-rich mudstones of the Kimmeridge
Clay Formation that form the source rock. The MSM is dominated by a high net to gross, stacked accumulation of thickbedded
fine- to coarse-grained sandstone units (individually about 2 m thick,
but occasionally up to 7 m thick) separated by thin shale layers. The main
reservoir sands were primarily deposited by high-density turbidity currents
although low-density turbidites resulted in deposition of poorer quality sands.
In contrast, the LKCF comprises a low net to gross sequence of thin sands
(generally 0.1 up to 3m in thickness) separated by thicker shale units
representing influx of dilute muddy turbidites with intermittent episodes of sand
deposition from high density turbidites. The shale interbeds provide local to field-wide layering of the reservoir and
may locally be pressure barriers. In recent wells, the lower parts of each sand
package is shown to have been well-swept by waterflood whereas the upper
part of the sands has remained relatively unswept. It is this unswept oil that is
a key prize for Enhanced Oil Recovery by gas injection.