--> Abstract: Integration of Sequence Stratigraphy, and Stratigraphic Simulations to Generate a High-Resolution Geologic Model for Exploitation of a Kimmeridgian Oolitic Shoal Complex, by Bowman, Scott; Banda Hernandez, Javier; Hernandez Garcia, Sergio; Cabrera Rivera, Ignacio; and Gonzalez Morales, Julian; #90166 (2013)

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Integration of Sequence Stratigraphy, and Stratigraphic Simulations to Generate a High-Resolution Geologic Model for Exploitation of a Kimmeridgian Oolitic Shoal Complex

Bowman, Scott1; Banda Hernandez, Javier; Hernandez Garcia, Sergio; Cabrera Rivera, Ignacio; and Gonzalez Morales, Julian
1[email protected]

A geologic model of an oil field in an oolitic shoal was constructed to provide input to a reservoir simulation. Seismic is limited to providing a structural form. The 500 meter thick interval is represented by 1/2 a wavelength in PSTM seismic. Sequence stratigraphic interpretation of petrophysical logs determine the internal reservoir properties. The shoal developed around an emergent salt diapir which ascended along a vertical wall until the end of the Kimmeridgian. The shoal deformed into an anticline during regional Miocene shortening. Sequence analysis defined fifteen cycles characterized by lowstand prograding, transgressive, and hightstand systems tracts. In addition, two gravity-flow systems tracts deposited filling in depositional lows. Gamma ray logs record a detailed history of shoaling upward and deepening patterns. Channelization is apparent at or near the tops of several lowstand prograding systems tracts. Incision removed section in one well.

We constructed hundreds of stratigraphic simulations in parallel to understand the parameters controlling shoal development. The principle parameters include the sea level history and interval bounding ages. The top contains Kimmeridgian fauna and the base is not dated. Regional correlations suggest it could be Oxfordian. Models of different eustatic records spanning this interval were compared with the stratal packaging to determine possible scenarios. The Snedden and Liu, 2010 curve produced the best match in frequency, although the cycle magnitudes were reduced by 1/4. The correlation to cyclicity in the eustatic curve suggests the lower part of the section was in the Oxfordian. The simulation required a carbonate production function with peak at 2 meters and 90% of all production in less than 13 meters of water-depth. A workflow captures the details of the sedimentation history and calculates a paleowaterdepth history.

The workflow assumed subsidence rates for the entire interval are representative of the tectonic changes during deposition of each systems tract. Isopachs of each systems tract are place on the substrate and the flexural response determines the remaining space. The remaining space represents the paleowaterdepth. The waterdepth and rate of space creation correlates to the type of primary sediment chemistry. Subsequent diagenetic alteration correlated to concentrations of dolomitization, where high concentrations correlate to low rates of space creation and shallow waterdepths.

 

AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013