310
K. Leyrer· C. Strohmenger . K. Rockenbauch . T. Bechstaedt
been an important target for exploration for decades; therefore, a lot of modeling-relevant data exist. These data, including lithologic and facies interpretations and also a sequence stratigraphic interpretation of the Ca2, provide the basis for the performance of a high-resolution forward stratigraphic modeling.
One part of these data can serve as inputs while other parts act as a control data
set for the simulation results. The calibration of several sedimentation-governing parameters is possible and helps to simulate Ca2 reservoir facies distribution
at other localities characterized by lower-quality or even missing data. Apart
from well data, published data also were used to simulate the Ca2 sedimentary
history. This integrated approach makes it possible to avoid unrealistic simulation results and creates a synthesis of all previous results.
Data from almost 200 wells were used, including detailed studies on lithology,
pore type and texture classification, sedimentary and diagenetic structures and
the classification of particles (e.g. Mausfeld (1987), Mausfeld and Zankl (1987),
Huttel (1989), Mausfeld and Huttel (199l), Below (1992), Steinhoff (1993), Strohmenger et al. (1993a, b, 1996a, b), Strohmenger and Strauss (1996). In addition,
detailed analyses of core material and the integration of well data, both of which
led to the current depositional and sequence stratigraphic model of the Ca2
(Strohmenger et al. 1996a; Fig. 4), were used to test the model, and, after confirmation, as inputs for simulation.
2.1
A 1/Pre-Ca2 Topographic Setting
Compared to siliciclastic sediments, carbonates are influenced more readily by
topographic setting. Furthermore, topography and sedimentation interact because the deposition of sediments may change topographic settings considerably.
In the South Oldenburg area, Ca2-sedimentation is characterized by a platform-slope-basin configuration and the topographic difference between platform top and basin floor is about 300 m (Fig. 4). The underlying Al platform extends laterally for at least a few thousand square kilometers and is rimmed by a
slope with inclination angles of up to 100. It consists of anhydrites (AI, or Werra
Anhydrite), which have been karstified along the platform and the platform
margin during sea -level lowstand (Zechstein sequence boundary 3, ZSB3) at the
beginning of Zechstein sequence 3 (ZS3). The resulting surficial segmentation of
the platform led to intensive lateral gradations of Ca2 facies representing sediments of the early highstand systems tract.
The pre-Ca2 topographic setting in the southeast Brandenburg area generally
corresponds to that of south Oldenburg. However, important differences exist in
the morphologic differentiation of the platform, because the southeast Brandenburg area is characterized by a highly dissected platform setting (Fig. 6). In addition, a morphological dissection of the Ca2-slope in southeast Brandenburg
led to the existence of isolated highs (detached platforms), called off-platform
highs (Strohmenger et al. 1993c, 1996b). Due to differences in the thickness of
the Werra-Anhydrite (Al), these off-platform highs can be subdivided in high-
K. Leyrer· C. Strohmenger . K. Rockenbauch . T. Bechstaedt
been an important target for exploration for decades; therefore, a lot of modeling-relevant data exist. These data, including lithologic and facies interpretations and also a sequence stratigraphic interpretation of the Ca2, provide the basis for the performance of a high-resolution forward stratigraphic modeling.
One part of these data can serve as inputs while other parts act as a control data
set for the simulation results. The calibration of several sedimentation-governing parameters is possible and helps to simulate Ca2 reservoir facies distribution
at other localities characterized by lower-quality or even missing data. Apart
from well data, published data also were used to simulate the Ca2 sedimentary
history. This integrated approach makes it possible to avoid unrealistic simulation results and creates a synthesis of all previous results.
Data from almost 200 wells were used, including detailed studies on lithology,
pore type and texture classification, sedimentary and diagenetic structures and
the classification of particles (e.g. Mausfeld (1987), Mausfeld and Zankl (1987),
Huttel (1989), Mausfeld and Huttel (199l), Below (1992), Steinhoff (1993), Strohmenger et al. (1993a, b, 1996a, b), Strohmenger and Strauss (1996). In addition,
detailed analyses of core material and the integration of well data, both of which
led to the current depositional and sequence stratigraphic model of the Ca2
(Strohmenger et al. 1996a; Fig. 4), were used to test the model, and, after confirmation, as inputs for simulation.
2.1
A 1/Pre-Ca2 Topographic Setting
Compared to siliciclastic sediments, carbonates are influenced more readily by
topographic setting. Furthermore, topography and sedimentation interact because the deposition of sediments may change topographic settings considerably.
In the South Oldenburg area, Ca2-sedimentation is characterized by a platform-slope-basin configuration and the topographic difference between platform top and basin floor is about 300 m (Fig. 4). The underlying Al platform extends laterally for at least a few thousand square kilometers and is rimmed by a
slope with inclination angles of up to 100. It consists of anhydrites (AI, or Werra
Anhydrite), which have been karstified along the platform and the platform
margin during sea -level lowstand (Zechstein sequence boundary 3, ZSB3) at the
beginning of Zechstein sequence 3 (ZS3). The resulting surficial segmentation of
the platform led to intensive lateral gradations of Ca2 facies representing sediments of the early highstand systems tract.
The pre-Ca2 topographic setting in the southeast Brandenburg area generally
corresponds to that of south Oldenburg. However, important differences exist in
the morphologic differentiation of the platform, because the southeast Brandenburg area is characterized by a highly dissected platform setting (Fig. 6). In addition, a morphological dissection of the Ca2-slope in southeast Brandenburg
led to the existence of isolated highs (detached platforms), called off-platform
highs (Strohmenger et al. 1993c, 1996b). Due to differences in the thickness of
the Werra-Anhydrite (Al), these off-platform highs can be subdivided in high-