Three-Dimensional Approach to Sequence Stratigraphy Interpretation and Subsurface Architectural Modeling of X-Field, Niger Delta
Utilizing 265km2 3D seismic data, suite of well log information, and biostratigraphic data, prolific insight was gain into the field geometry, stratigraphic configuration, structural trend, and hydrocarbon potential of the X - field. Landmark Geographix Discovery software modules were employed in making a high resolution deduction of the sequence stratigraphic framework and to develop three-dimensional subsurface architectural models of the study area. Four sequence boundaries were identified with ages ranging from 17.7Ma to 10.35Ma, and three intervening maximum flooding surfaces with ages between 15.0Ma and 10.4Ma denoted by the correlatable Bolivina 25, Uvigerina 5, Nonion 6, and Nonion 4 markers, which falls within the Central Swamp Depobelt of the Niger Delta
Three mappable horizons were delineated in the study area, the horizons interpreted in a highly faulted region have the deepest occurrence at 8900ft (SSTVD), were laterally continuous with structural undulations. Valuable stratigraphic and reservoir information obtained from the amplitude maps generated show areas with bright spots indicating possibility of hydrocarbon existence. Attribute based seismic profile analyses was used to map different horizons and separate subsurface sequences into different facies A, B and C associated with the pre-channel and channel deposits with reflection patterns ranging from continuous parallel to hummocky and sigmoidal.
Depositional environments inferred includes tidal channel, shoreface and shelf environments, which typifies the marginal marine setting. Structural plays like anticlinal and fault influenced closures identified dominate over stratigraphic plays both of which exist in the pre-channel sequence. However, more exploration wells can be cited at points where structural closures overlap with bright spots and for hydrocarbon recovery to be optimized in the X - Field an integrated approach of stratigraphic and structural analyses is imperative as exploration in the frontier fields of the offshore enters into a more productive realm.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009