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PSGenesis and Expression of a Clinoforming Carbonate Ramp from a Geological and Geophysical Perspective*

 

Jean-Yves Chatellier1, Jeff Closson1 and Anne Hargreaves2

 

Search and Discovery Article #50148 (2009)

Posted January 26, 2009

 

*Adapted from oral presentation at AAPG Annual Convention, San Antonio, TX, April 20-23, 2008

 

1Talisman Energy Inc., Calgary, AB, Canada ([email protected])

2Canadian Stratigraphic Services 2000 Ltd, Calgary, AB, Canada

 

Abstract 

Progradation in a carbonate ramp is not always well expressed in seismic or in geological cross sections. Clinoforms in the Carboniferous Banff Formation (Alberta, Canada) have been studied in an integrated approach using log analysis, sedimentology and seismic data. The genesis and geometry of several clinoforms have been examined against their structural settings. Cutting descriptions from Canstrat have been used to better understand the sedimentology and lithologies above and below the clinoforming surfaces. 

In the Western Alberta Basin, the Carboniferous Banff Formation is a prograding carbonate ramp with some very well developed clinoforms. Three main types of clinoforming surfaces have been recognized on wireline logs in association with transgressive shales, slump related chert units or catastrophic grain supported carbonate events. The seismic expression associated with the carbonate ramp has been tested against lateral facies variations. 

Synthetic seismograms have been generated on many wells from a variety of clinoforms in order to determine if and when a progradation would be seen on seismic. A comparison between two geographically distinct clinoforms with apparently identical log expressions has outlined extreme differences in their potential to be seismically visible. The structural context favorable to recognizable clinoforming pattern is variable and the direction of progradation may vary dramatically especially when alternate fault activity is syndepositional. One example shows two successive clinoforming patterns at 90 degrees from each other within the Lower Banff.

 

 

 

uAbstract

uBanff Formation

uExample 1

uExample 2

uClinoform profiles

uFaulting

uMain points

uReferences

uAcknowledgments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

uAbstract

uBanff Formation

uExample 1

uExample 2

uClinoform profiles

uFaulting

uMain points

uReferences

uAcknowledgments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

uAbstract

uBanff Formation

uExample 1

uExample 2

uClinoform profiles

uFaulting

uMain points

uReferences

uAcknowledgments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

uAbstract

uBanff Formation

uExample 1

uExample 2

uClinoform profiles

uFaulting

uMain points

uReferences

uAcknowledgments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

uAbstract

uBanff Formation

uExample 1

uExample 2

uClinoform profiles

uFaulting

uMain points

uReferences

uAcknowledgments

Figure 1. Approximate location of the examples shown.

Figure 2. Clinoform associated with a cherty unit

 

Banff Formation: A Prograding Carbonate Ramp 

(Figures 3, 4, 5, 6, 7, 8, 9 and 10) 

Figure 3. Outcrop of Banff Formation at Mount McGillray and stratigraphic column of Banff Formation, with two coarsening upward sequences.

Figure 4. Outcrop at West Exshaw

Figure 5. Outcrop at West Exshaw. 

Figure 6. Outcrop at Grotto Mountain. 

Figure 7. Outcrop at Grotto Mountain. 

Figure 8. Outcrop at Grotto Mountain. 

Figure 9. Locally well developed clinoforms. 

Figure 10. 3-D proposed model.

 

Clinoform Case Example 1 

(Figures 11, 12, 13 and 14

Figure 11. Carbonate ramp progradation very well defined using a log facies map. 

Figure 12. Poor seismic expression in a synthetic profile (top) and a very good clinoform expression with wireline logs. 

Figure 13. Synthetic profile split to show match between seismic and cutting descriptions. 

Figure 14. Various clinoform surfaces against logs and cutting descriptions.

 

Banff Clinoform Case Example 2 

(Figures 15, 16, 17 and 18) 

Figure 15. Very well defined clinoforms from wireline logs. 

Figure 16. Very well defined clinoforms from synthetic seismograms. 

Figure 17. Clinoforms surfaces with lithologies from cutting descriptions. 

Figure 18. Clinoform expression as a function of depth: seismic profile for various frequencies (upper) and summary for the Western Canadian Basin (lower).

  

Clinoform profiles 

(Figures 19 and 20) 

Figure 19. Clinoform profiles comparing reflection geometry to field examples. 

Figure 20. Clinoforms in horizon Previous HitslicesNext Hit: Well defined linear patterns are a common expression of clinoforms and prograding carbonate ramp.

 

Alternate Fault Activity Controlled Two Successive Carbonate Ramp Progradations  

(Figure 21

Figure 21. Dramatic change in progradation direction within the Lower Banff. Two fault systems controlling the progradation are orthogonal to each other; the yellow progradation is posterior to the pink

 

Main points to remember 

·        The expression of clinoforms is highly variable.

·        On logs:

o       Log facies map are incredibly powerful at displaying progradation patterns.

o       Major shaly transgressive events are outstanding markers.

·        Seismic expression versus lithology:

o       No clear-cut relationship has been found based on cuttings description.

o       Cherty units and bases of gradual coarsening up sequence seem best.

·        On Seismic cross section:

o       Frequency is a very critical parameter (40 Hz being a limit).

o       Depth is a major controlling factor to the frequency of the signal.

·        On seismic horizon/Previous HittimeNext Hit Previous HitslicesTop:

o       Repetition of parallel and long linear features is a common characteristic of clinoforming settings.

References 

Chatellier, J-Y., 1988, Carboniferous Carbonate Ramp, The Banff Formation, Alberta, Canada, Bull. Centre Rech. Explor. Prod. Elf-Aquitaine, Vol. 12-2, p. 569-599.

 

Chatellier, J-Y., 2004, Chert, a diagenetic and sedimentological indicator often underused, Mississippian examples from Alberta and world analogues, CSPG convention 2004, Calgary, 10 page extended abstract

http://www.cspg.org/conventions/abstracts/2004abstracts/066S0129.pdf.

 

Chatellier, J-Y. and Porras C., 2004, The Multiple Bischke Plot Analysis, a Simple and Powerful Graphic Tool for Integrated Stratigraphic Studies, AAPG Search and Discovery Article #40110 (2004), http://www.searchanddiscovery.com/documents/2004/chatellier/index.htm.

 

Chatellier, J-Y., 2008, Fault locking and alternate activity in outcrops and subsurface, a transfer mechanism, AAPG Annual Convention, San Antonio, Abstract.

 

Grelaud, C., 2005, Enregistrement stratigraphique des phases d’emersion sur les plate-formes carbonatees, Unpublished PhD thesis, Bordeaux III University, 285 pages.

 

Handford, C.R. and Baria, L.R., 2007, Geometry and seismic geomorphology of carbonate shoreface clinoforms, Jurassic Smackover Formation, north Louisiana, Geological Society, London Special Publications, vol. 277, p.171-185.

 

Acknowledgments 

The authors would like to thank Talisman Energy Inc. for permission to present this material and Canadian Stratigraphic Services (2000) Ltd for providing the needed cuttings description. They also want to thank Gary Labute for his support of this project

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