PSGenesis and Expression of a Clinoforming Carbonate Ramp from a Geological and Geophysical Perspective* 1 1 2 Jean-Yves Chatellier , Jeff Closson , and Anne Hargreaves 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. Genesis and expression of a Clinoforming carbonate ramp from a geological and geophysical perspective Jean-Yves Chatellier Talisman Energy Inc. Calgary Jeff Closson Talisman Energy Inc. Calgary Anne Hargreaves Canadian Stratigraphic Services (2000) Ltd, Calgary Abstract Progradation in a carbonate ramp is not always well expressed in seismic or Approximate location in geological cross sections. Clinoforms in the Carboniferous Banff of the examples shown Formation (Alberta, Canada) have been studied in an integrated approach using log analysis, sedimentology and seismic data. The genesis and geometry of several clino forms have been examidined against thiheir structural settings. Cutting descriptions from Canstrat have been used to better Alberta understand the sedimentology and lithologies above and below the clinoforming surfaces. In the Western Canadian Basin, the Carboniferous Banff Formation is a Edmonton 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 Calgary associated with the carbonate ramp has been tested against lateral facies British variations. Columbia 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 Clinoform associated apparently identical log expressions has outlined extreme differences in their with a cherty unit 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. 0.08 degrees After Chatellier 2004 Banff Formation a prograding carbonate ramp Cherty slump unit Field data Cherty indicates Slump unit Crinoidal mass transport Grainstone in Middle Banff Fine-grained Outcrop at West Exshaw Crinoidal grainstone Mount McGillivray Outcrop at West Exshaw Banff Fm Chert Middle Banff Palliser Fm Synsedimentary rotation (Wabamun Fm) of crinoidal Grainstone Chert Outcrop at Grotto Mountain Slump at 0.5m Grotto Mountain Road cut Upper Outcrop at Grotto Mountain Middle Outcrop at Grotto Mountain Lower Locally well developed clinoforms after Chatellier 1988 3-D proposed model after Chatellier 1988 after Chatellier 1988 Clinoform case example 1 Carbonate ramp X’ progradation very well defined using a log facies map Progradation towards SW (North 215) angle = 1.1 degrees 06-24-34-8 10-16-34-7 08-14-34-7 10-03-34-6 Wells with cutting description Top Banff Poor seismic expression in a not expressed synthetic profile in wireline logs Top Wabamun Very good clinoform expression with wireline logs synthetic profile split to show match between seismic and cutting descriptions 06-24-34-08 10-16-34-07 08-14-34-07 10-03-34-06 Various clinoform surfaces against logs and cutting descriptions Blue Clinoform Blue Clinoform Red Clinoform Red Clinoform Strong seismic reflector No expression Possible expression Limited expression Not used in Well correlation Green Clinoform Red Clinoform Seismic Green Clinoform Limited expression Strong marker Very limited expression Red Clinoform no expression expression Remarks Green Clinoform Strong seismic reflector No expression Not identified in wells Banff Clinoform case example 2 SW NE Well 1 Well 3 Well 7 Very well defined clinoforms from 0.6 degrees wireline logs 1 mile 04-15-59-15Well 1 14-14-59-15Well 3 11-24-59-15Well 7 Banff Very well defined clinoforms from synthetic seismograms Wabamun Well 1 Well 3 Well 7 clinoforms surfaces with lithologies from cutting descriptions Clinoform expression as a function of depth Seismic profile Banff for various Wabamun frequencies 80 Hz 60 Hz 40 Hz Visible Clinoforms shallower 1700 m 60 Hz Summary for the Sometimes visible Western Canadian Basin 2200 m 40 Hz Clinoforms not visible deeper Clinoform profiles ReflectionReflection geometrygeometry Dip Banff Formation Examples Sub- Horizontal <0.01 Not studied Strong 1.7 to 4.5 Not Identified in our study Oblique Sigmoidal weak to strong 0.35 to 1.5 angle 0.60 degrees 1.1 degrees 0.35 degrees Sigmoidal very weak 0.08 to 0.25 angle 0.08 degrees 0.25 degrees Banff Formation Smackover Formation Clinoforms in horizon slices Well defined linear patterns are a common expression Progradation of clinoforms and prograding carbonate ramp Negative amplitude 5 km Positive amplitude From Handford and Baria 2007 Alternate fault activity controlled two successive carbonate ramp progradations 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 3 km References Main points to remember 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. The expression of clinoforms is highly variable: 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 On logs http://www.cspg.org/conventions/abstracts/2004abstracts/066S0129.pdf Log facies map are incredibly powerful at displaying Chatellier, J-Y. and Porras C., 2004, The Multiple Bischke Plot Analysis, a Simple and Powerful Graphic Tool for Integrated Stratigraphic Studies, progradation patterns 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 Major shaly transgressive events are outstanding markers subsurface, a transfer mechanism, AAPG Annual Convention, San Antonio, Abstract Grelaud, C., 2005, Enregistrement stratigraphique des phases d’emersion Seismic expression versus lithology sur les plate-formes carbonatees, Unpublished PhD thesis, Bordeaux III University, 285 pages No clear-cut relationship has been found based on cuttings description Handford, C.R. and Baria, L.R., 2007, Geometry and seismic Cherty units and bases of gradual coarsening up sequence seem best geomorphology of carbonate shoreface clinoforms, Jurassic Smackover Formation, north Louisiana, Geological Society, London Special Publications, vol. 277, p.171-185 On Seismic cross section Frequency is a very critical parameter (40 Hz being a limit) Acknowledgments Depth is a major controlling factor to the frequency of the signal The authors would like to thank Talisman Energy Inc. for permission to present this material and Canadian Stratigraphic On seismic horizon/time slices Services (2000) Ltd for providing the needed cuttings description. Repetition of parallel and long linear features are a common They also want to thank Gary Labute for his support of this project. 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