Grid Files for the 3-D Geologic/Petroleum System Model of the Western Canada Sedimentary Basin (WCSB)

A 3-D geologic/petroleum system model of the Western Canada Sedimentary Basin (WCSB) was created by using elevations on the top of the Lower Cretaceous Mannville Group as a reference horizon for stacking 18 isopach intervals from the base of the Devonian Woodbend Group and age equivalent formations, stratigraphically upward to the ground surface; this includes an estimated thickness of eroded sediments based on 1-D burial history reconstructions for 33 wells across the study area.  Each interval for the construction of the 3-D model was chosen on the petroleum system basis of whether it is primarily composed of reservoir, hydrocarbon source, seal, overburden, or underburden strata, as well as the quality and areal distribution of well and other data.  Data from numerous databases and data sets were accessed to create the isopach intervals.  Interval boundaries are primarily formation tops that were derived from data retrieved from the databases.  Because formation names commonly change across province and national boundaries, formations that comprise the intervals were chosen based on age-equivalent strata.  These isopach files were gridded at approximately 1-kilometer spacing and saved for publication as zmap-format grid files.

The purposes of the zmap-format grid files are to create the 3-D geologic and petroleum system models of the WCSB, and to publish these files such that others can use them in applications such as reservoir and basin modeling.  The digital files listed in table 1 were compiled as part of the Petroleum Processes Research Project being conducted by the Central Energy Resources Team of the U.S. Geological Survey, which focuses on modeling petroleum generation, migration, and accumulation through time for petroleum systems of the WCSB.  Primary purposes of the WCSB study are to:
			1. Construct the 1-D/2-D/3-D petroleum system models of the WCSB.  Actual boundaries of the study area are documented within the metadata; excluded are northern Alberta and eastern Saskatchewan, but fringing areas of the United States are included.
			2. Publish results of the research and the grid files generated for use in the 3-D model of the WCSB.
			3. Evaluate the use of petroleum system modeling in assessing undiscovered oil and gas resources for geologic provinces across the World.

The names of zmap-format grid files listed below are also included in table 1.  Each file name is followed by an explanation of the stratigraphic interval that is represented.  Shown in parentheses is the number of well records that were used to generate the grid files.  Other sources of data include digitized contours, as well as supplementary data that are added to control over-extrapolation and under-interpolation of contours in areas of poor data distribution.  An example of the latter is zero thickness in areas where formations are absent.
			
			Erosion.DAT		Estimated thickness of eroded Holocene- to present-day interval as interpreted from burial history reconstructions of 33 wells.
			
			GrColoiso.DAT	Ground surface to the top of the Colorado Group (11,900)
			
			ColoCard.DAT	Top of the Colorado Group to the top of the Cardium Formation (2,744)
			
			Card2Whsp.DAT	Top of the Cardium Formation to top of the 2nd White Speckled Shale (625)
			
			2WhsBFscale.DAT	Top of the 2nd White Speckled Shale to base of the Fish Scale Marker horizon (223,856)
			
			Westgate.DAT	Base of the Fish Scale Marker horizon to the top of the Viking Sandstone, and includes the Westgate Member of the Ashville Formation (57,835)
			
			Viking.DAT		Isopach of the Viking Sandstone (5,770)
			
			JoliFou.DAT		Top of the Joli Fou Shale (base of the Viking Sandstone) to the top of the Mannville Group (26,036)
			
			MannEle.DAT		Elevation relative to seal level on the top of the Mannville Group (102,138)
			
			UMann.DAT		Isopach of the upper Mannville Group (5,889)
			
			LMann.DAT		Isopach of the lower Mannville Group, and including the Cut Bank Sandstone and Cadomin Formations (6,639)
			
			Jurassic.DAT	Isopach of Jurassic formations across the WCSB (2,807)
			
			TriasPermC.DAT	Isopach of Triassic, Permian, and uppermost Carboniferous to Kibbey Formation and age equivalents (1,986)
			
			RundleChar.DAT	Isopach of the Rundle and Charles Groups (2,297)
			
			Banff.DAT		Top of the Banff Shale to the top of the Exshaw and Bakken Formations (3,378)
			
			ExshBak.DAT		Isopach of the Exshaw and Bakken Formations (10,968)
			
			WabWinter.DAT	Top of the Wabamun Group and Palliser Formations to the base of the Winterburn Group (2,999)
			
			Woodbend.DAT	Isopach of the Woodbend Group (1,855)