Geoscience Reference
In-Depth Information
418,000.0
420,000.0
422,000.0
424,000.0
426,000.0
418,000.0
420,000.0
422,000.0
424,000.0
426,000.0
(A)
(B)
Åre 5.2 THICKNESS
4.00
6.00
8.00
10.00
12.00
14.00
16.00
18.00
20.00
22.00
24.00
2.00
Åre 5.1 THICKNESS
3.00
9.00
15.00
21.00
27.00
33.00
39.00
45.00
0
1
2
0
1
2
km
km
416,000.0
418,000.0
420,000.0
422,000.0
424,000.0
426,000.0
416,000.0
418,000.0
420,000.0
422,000.0
424,000.0
426,000.0
Fig. 23.
Thickness maps of the 5.1 (A) and 5.2 (B) Sub-zones (thickness indicated in metres). Blue dots represent wells
with data on which the maps are based. The Åre 5.1 Sub-zone shows a thinning towards the NW and the overlying Åre 5.2
Sub-zone displays a corresponding thickening in this area. This trend is related to the down-cutting of tide-influenced
distributary channels at the base of the Åre 5.2 Sub-zone.
resonance are described from the Cretaceous Sego
Sandstone Member, central Utah, by Willis &
Gabel (2001; 2003). However, this interpretation
does not fully explain the transgressive facies
development succeeding the incision.
into the overlying Åre 6.2 Sub-zone. This interval
comprises a laterally persistent belt of heterolithic
tide-dominated, channel sandbodies (Fig. 20) and
subtidal flats, with subordinate brackish-water
bay-fill deposits (< 10% of the reservoir sub-
zone). The onset of channelling in the Åre 6.2
Sub-zone can be identified in a majority of wells,
although wireline log-based facies correlations
within this reservoir zone are generally uncertain
due to the non-characteristic log response of these
heterolithic facies associations. Nonetheless,
integration with production data confirms that
the tide-dominated heterolithic channel bodies
are laterally connected for considerable distances
(> 2 km).
The field-wide channel belts of the Åre 6.2 Sub-
zone show strong similarities to the tidal deposits
filling-in the incision at the base of the 5.2 Sub-
zone, except from two characteristics: 1) the estu-
arine facies display stronger influence of tide
processes; and 2) although the base boundary
is sharp, it appears to have low relief (Fig. 18).
Åre 6 Zone
Coeval existence of estuarine facies and wave-
influenced bay deposits also characterises the Åre
6 Zone (20 m to 35 m thick). The base of this reser-
voir zone is characterised by an interval of bay-
floor mudstone and heteroliths (0.5 m to 2 m thick)
overlying sand-rich deposits of the Åre 5.3 Sub-
zone. This surface can be correlated across the
field and is interpreted as a flooding event (FS3;
Table 11, Figs 4 and 18).
The Åre 6.1 Sub-zone is dominated by mud-
prone, wave-influenced bay-fill deposits, with
a minor component of sandy tide-influenced
channels and tidal flats (Figs 4 and 18). A significant
shift into tide-dominated facies marks the transition
Search WWH ::
Custom Search