Abstract: The dataset includes subsurface stratigraphic picks of the top of the Belly River Group in the Alberta Plains (Townships 1 to 50, Ranges 1W4 to 2W5) made from wireline, geophysical well logs. The dataset supplements Alberta Geological Survey Open File Report 2010-10, which describes the methodology. We screened the well data to detect errors resulting from deviated wells, as well as incorrect ground and kelly bushing elevation data. We used statistical methods to identify local and regional statistical outliers, which were examined individually.
Metadata:
File identifier:
DIG_2010_0022.xml
Language:
eng; CAN
Character set:
Character set code:
utf8
Hierarchy level:
Scope code:
dataset
Metadata author:
Responsible party:
Organisation name:
Alberta Geological Survey
Position name:
AGS Information Manager
Contact info:
Contact:
Phone:
Telephone:
Voice:
(780) 638-4491
Facsimile:
(780) 422-1918
Address:
Address:
Delivery point:
Alberta Energy Regulator
Delivery point:
4th Floor, Twin Atria Building
Delivery point:
4999-98 Avenue NW
City:
Edmonton
Administrative area:
Alberta
Postal code:
T6B 2X3
Country:
Canada
Electronic mail address:
AGS-Info@aer.ca
Hours of service:
8:00 a.m. to 12:00 p.m. and 1:00 p.m. to 4:30 p.m.
Role:
Role code:
pointOfContact
Date stamp:
2016-03-29
Metadata standard name:
North American Profile of ISO 19115:2003 - Geographic information - Metadata (NAP-Metadata)
Metadata standard version:
ISO 19115-1.1
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Vector spatial representation:
Geometric objects:
Geometric objects:
Geometric object type:
Geometric object type code:
point
Geometric object count:
6966
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Grid spatial representation:
Number of dimensions:
2
Axis Dimension Properties:
Dimension:
Dimension name:
Dimension name type code:
column
Dimension size:
unknown
Resolution:
uom: decimalDegrees
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Axis Dimension Properties:
Dimension:
Dimension name:
Dimension name type code:
row
Dimension size:
unknown
Resolution:
uom: decimalDegrees
0.000000
Cell geometry:
Cell geometry code:
Transformation parameter availability:
false
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Reference system:
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Reference system:
Reference system identifier:
RS Identifier:
Code:
EPSG:4269
Code Space:
http://www.epsg-registry.org/
Version:
8.4.1
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xlink: https://www.ngdc.noaa.gov/docucomp/65f8b220-95ed-11e0-aa80-0800200c9a66 title: North American Datum 1983
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xlink: https://www.ngdc.noaa.gov/docucomp/c3895520-95ed-11e0-aa80-0800200c9a66 title: Geodetic Reference System 1980
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Data identification:
Citation:
Citation:
Title:
Top of the Belly River Group in the Alberta Plains: Subsurface Stratigraphic Picks and Modelled Surface
(tabular data, tab delimited format, to accompany Open File Report 2010-10)
Date:
Date:
Date:
2010-12-22
Date type:
Date type code:
publication
Cited responsible party:
Responsible party:
Organisation name:
Energy Resources Conservation Board
Role:
Role code:
originator
Cited responsible party:
Responsible party:
Organisation name:
Alberta Geological Survey
Role:
Role code:
originator
Cited responsible party:
Responsible party:
Organisation name:
Glombick, P.M.
Role:
Role code:
originator
Cited responsible party:
Responsible party:
Organisation name:
Alberta Geological Survey
Contact info:
Contact:
Address:
Address:
City:
Edmonton
Administrative area:
Alberta, Canada
Role:
Role code:
publisher
Presentation form:
Presentation form code:
tableDigital
Series:
Series:
Name:
Digital Data
Issue identification:
DIG 2010-0022
Abstract:
The dataset includes subsurface stratigraphic picks of the top of the Belly River Group in the Alberta Plains
(Townships 1 to 50, Ranges 1W4 to 2W5) made from wireline, geophysical well logs. The dataset supplements
Alberta Geological Survey Open File Report 2010-10, which describes the methodology. We screened the well
data to detect errors resulting from deviated wells, as well as incorrect ground and kelly bushing elevation
data. We used statistical methods to identify local and regional statistical outliers, which were examined
individually.
Purpose:
To provide a set of stratigraphic picks of the top of the Belly River Group in the Alberta Plains.
Status:
Progress code:
completed
Point of contact:
Responsible party:
Organisation name:
Alberta Geological Survey
Position name:
AGS Information Manager
Contact info:
Contact:
Phone:
Telephone:
Voice:
(780) 638-4491
Facsimile:
(780) 422-1918
Address:
Address:
Delivery point:
Alberta Energy Regulator
Delivery point:
4th Floor, Twin Atria Building
Delivery point:
4999-98 Avenue NW
City:
Edmonton
Administrative area:
Alberta
Postal code:
T6B 2X3
Country:
Canada
Electronic mail address:
AGS-Info@aer.ca
Hours of service:
8:00 a.m. to 12:00 p.m. and 1:00 p.m. to 4:30 p.m.
Role:
Role code:
pointOfContact
Resource maintenance:
Maintenance information:
Maintenance and update frequency:
Maintenance frequency code:
notPlanned
Descriptive keywords:
Keywords:
Keyword:
bearpaw formation
Keyword:
bedrock geology
Keyword:
belly river group
Keyword:
campanian
Keyword:
dinosaur park formation
Keyword:
lethbridge coal zone
Keyword:
stratigraphic picks
Keyword:
stratigraphy
Keyword:
subsurface mapping
Keyword:
upper cretaceous
Keyword:
well log signature
Type:
Keyword type code:
theme
Thesaurus name:
Citation:
Title:
none
Date:
unknown
Descriptive keywords:
Keywords:
Keyword:
72e
Keyword:
72l
Keyword:
72m
Keyword:
73d
Keyword:
73e
Keyword:
82g
Keyword:
82h
Keyword:
82i
Keyword:
82j
Keyword:
82o
Keyword:
82p
Keyword:
83a
Keyword:
83b
Keyword:
83g
Keyword:
83h
Keyword:
alberta
Keyword:
canada
Type:
Keyword type code:
place
Thesaurus name:
Citation:
Title:
none
Date:
unknown
Resource constraints:
Legal constraints:
Access constraints:
Restriction code:
otherRestrictions
Use constraints:
Restriction code:
otherRestrictions
Other constraints:
Access Constraints: Public Use Constraints: Acknowledgement of the Alberta Energy Regulator/Alberta
Geological Survey as the originator/source of this information is required as described in the Open
Government License - Alberta. Distribution Liability: The Alberta Energy Regulator/Alberta Geological
Survey (AER/AGS) licenses this information under the Open Government License - Alberta. Any references
to proprietary software in our documentation, and/or any use of proprietary data formats in our
releases, do not constitute endorsement by the AER/AGS of any manufacturer's product.
Aggregation Info:
AggregateInformation:
Aggregate Data Set Name:
Citation:
Title:
Top of the Belly River Group in the Alberta Plains: Subsurface Stratigraphic Picks and Modelled Surface
Date:
Date:
Date:
2010-12-22
Date type:
Date type code:
publication
Cited responsible party:
Responsible party:
Organisation name:
Energy Resources Conservation Board
Role:
Role code:
originator
Cited responsible party:
Responsible party:
Organisation name:
Alberta Geological Survey
Role:
Role code:
originator
Cited responsible party:
Responsible party:
Organisation name:
Glombick, P.M.
Role:
Role code:
originator
Cited responsible party:
Responsible party:
Organisation name:
Alberta Geological Survey
Contact info:
Contact:
Address:
Address:
City:
Edmonton
Administrative area:
Alberta, Canada
Online Resource:
Online Resource:
Linkage:
URL:
http://ags.aer.ca/
Role:
Role code:
publisher
Presentation form:
Presentation form code:
documentDigital
Series:
Series:
Name:
Open File Report
Issue identification:
OFR 2010-10
Other citation details:
Association Type:
Association type code:
crossReference
Spatial representation type:
Spatial representation type code:
vector
Language:
eng; CAN
Topic category:
Topic category code:
geoscientificInformation
Extent:
Extent:
Geographic element:
Geographic bounding box:
West bound longitude:
-114.3
East bound longitude:
-110
South bound latitude:
49
North bound latitude:
54
Temporal element:
Temporal extent:
Extent:
Time period:
Description:
ground condition
Begin date:
2008-01-01
End date:
2010-01-01
Supplemental Information:
Language: In English;
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Feature catalogue description:
Included with dataset:
false
Feature catalogue citation:
Citation:
Title:
Entity and Attribute Information
Date:
Other citation details:
Detailed Entity and Attribute information is provided with the dataset, formatted as Federal Geographic
Data Committee (FGDC) Content Standard for Digital Geospatial Metadata.
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Distribution:
Distributor:
Distributor:
Distributor contact:
Responsible party:
Organisation name:
Alberta Geological Survey
Position name:
AGS Information Manager
Contact info:
Contact:
Phone:
Telephone:
Voice:
(780) 638-4491
Facsimile:
(780) 422-1918
Address:
Address:
Delivery point:
Alberta Energy Regulator
Delivery point:
4th Floor, Twin Atria Building
Delivery point:
4999-98 Avenue NW
City:
Edmonton
Administrative area:
Alberta
Postal code:
T6B 2X3
Country:
Canada
Electronic mail address:
AGS-Info@aer.ca
Hours of service:
8:00 a.m. to 12:00 p.m. and 1:00 p.m. to 4:30 p.m.
Role:
Role code:
distributor
Transfer options:
Digital transfer options:
Online:
Online Resource:
Linkage:
URL:
https://static.ags.aer.ca/files/document/DIG/DIG_2010_0022.zip
Name:
Tabular Data
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Data quality:
Scope:
Scope:
Hierarchy level:
Scope code:
dataset
Report:
Absolute external positional accuracy:
Name of measure:
Horizontal Positional Accuracy
Measure description:
Evaluation method description:
The latitude and longitude co-ordinates for well surface and bottom-hole locations are from IHS (Petra
software). The horizontal positional accuracy is unknown.
Result:
Quantitative result:
Value unit:
Base unit:
Identifier:
Units system: xlink: http://www.bipm.org/en/si/
Value:
Report:
Absolute external positional accuracy:
Name of measure:
Vertical Positional Accuracy
Measure description:
Evaluation method description:
In vertical wells, the subsurface depth of a pick in a well, measured with respect to sea level, is
calculated by taking the elevation of the kelly bushing (on the drilling platform) and subtracting the
measured depth of the pick on the geophysical well log. Some uncertainty in the vertical depth of the
pick will result if the borehole is not entirely vertical. The author compared the bottom-hole latitude
and longitude of each well location with the surface latitude and longitude for each well to ensure they
were the same. If either the surface or bottom-hole latitude and longitude are incorrect, some degree of
vertical error may result. In general, the amount of vertical depth due to deviations from the vertical
in boreholes is deemed negligible with respect to other potential sources of vertical error in this
study. Perhaps the greatest source of vertical uncertainty in this study is potential error in the
elevation of the kelly bushing (KB). Any errors in surveying the ground elevation of the well site can
result in vertical error. In addition, once the ground elevation is determined, the site is usually
prepared for the drilling rig. If the original survey marker is disturbed or moved, this can result in
potential vertical errors. The KB elevation is usually derived from adding the height of the drilling
platform above the ground surface to the survey ground elevation. If this is not done correctly, it can
introduce vertical error in the KB elevation, which is then propagated in the measured depth to the pick
and the subsea pick depth. Although incorrect KB elevation data can be difficult to detect, the data
were screened by comparing the ground elevation and the KB elevation (derrick height) for each well. An
acceptable range of derrick height (calculated by subtracting ground elevation from KB elevation) of two
to six metres was used. Wells with derrick heights outside this range were excluded. To check for
potential gross errors in the ground elevation for wells, ground elevations were compared with
shuttle-radar digital elevation model (DEM) elevations extracted for well surface locations. If the
difference between the ground elevation and the elevation derived from the DEM data was more than 2 ± 6
metres (i.e., -4 to 8 metres; approximately the mean of this difference plus or minus two standard
deviations for all wells in the Alberta Plains), the data from those wells were excluded. This method
potentially excluded wells for which well ground elevation values are correct, but for which the DEM
data for that well location are incorrect. It also may have not detected relatively small errors in
either ground or KB elevation data for a well, as long as those values met the screening criteria.
However, it did detect large errors in well KB or ground elevation data. Vertical error in the pick
subsea elevation can also result from human or geological error resulting from uncertainty or incorrect
placement of the pick on the well logs. The occurrence and magnitude of this error is difficult to
identify, but comparison with existing published pick datasets and checks for internal consistency (such
as identification of global and local outliers using statistical methods and gridding data while
picking) minimized this source of error as much as possible.
Result:
Quantitative result:
Value unit:
Base unit:
Identifier:
Units system: xlink: http://www.bipm.org/en/si/
Value:
Report:
Completeness commission:
Result:
unknown
Report:
Completeness omission:
Evaluation method description:
The author used a minimum well density of one well per township (about 100 square km). However, in most
areas the well density greatly exceeded that number, especially in areas with anomalous structures.
About 550 townships were picked, resulting in an average well density of 13 wells per township.
Result:
unknown
Report:
Conceptual consistency:
Measure description:
The data are tabular (point data with X, Y and Z values). The author generated all stratigraphic picks.
All picks are ranked the same in quality. As the dataset includes only vertical wells, all location data
and well-identifier data (UWI and UWI_MODIFIED) are unique. In non-vertical wells, surface and
bottom-hole latitude and longitude may be different, and several wells may share a common surface
location but have different bottom-hole locations. By choosing only vertical wells, this problem was
avoided. The author collected the data from the Alberta Plains where deformation of the Cretaceous
sedimentary succession is relatively minor. All points are east of the deformation front at a given
latitude; thus, rocks should not be thrusted or structurally duplicated. Therefore, the top of the
Oldman Formation should only occur once in any given vertical well. No data are missing. Attribute
values were checked to ensure reasonable values. For instance, the author plotted the well locations on
a map and observed no obvious anomalous locations. A query checked for any deviations from the vertical
of the well surface location compared with the bottom-hole location. These wells were removed from the
dataset. If a well is deviated, its surface and bottom-hole co-ordinates should be different. As all
remaining wells should be vertical if the surface and bottom-hole co-ordinates are correct, measured
depth and true vertical depth should be equal.
Result:
unknown
Report:
Non quantitative attribute accuracy:
Measure description:
A stratigraphic pick in a well is a point defined in three dimensions (X, Y and Z).
The accuracy of the pick depth, either in measured depth from the kelly bushing or with respect to sea
level, is difficult to quantify and includes (but is not necessarily limited to) errors in:
- well surface or bottom-hole latitude and longitude (X and Y);
- well ground elevation (Z);
- well kelly bushing elevation (Z);
- geological or human error resulting from errors in picking the incorrect stratigraphic top (Z);
- data entry or data transfer (X, Y and/or Z); and
- incorrect well log depth calibration (Z).
Result:
inapplicable
Lineage:
Lineage:
Statement:
The author used a minimum well density of one well per township (about 100 square km). However, in most
areas the well density greatly exceeded that number, especially in areas with anomalous structures.
About 550 townships were picked, resulting in an average well density of 13 wells per township.
Process step:
Process step:
Description:
Prior to making picks for a given surface, the author studied the published geological literature with
emphasis on type and/or representative sections. Studies including both core and geophysical well
logs were particularly valuable, as they provided a link between the rock and geophysical signatures.
Geophysical well logs (both digital and raster format) were examined using Petra® and Accumap®
software and picks were recorded in a database. When sufficient well density and log availability
permitted it, the author selected wells according to the following criteria:
1) vertical wells only;
2) wells with a spud date between 1975 and the present; and
3) wells with down-hole geophysical well-log suites that included gamma ray, density or sonic, and
resistivity logs.
The author preferred wells with a bottom surface casing shoe of less than 50 metres deep. If
sufficient well density was not available using the above criterion, the criterion was expanded to
include wells with the bottom of surface casing in the 50-150 m range. A minimum well density of one
well per township was used, although, in most areas, well density greatly exceeded that number,
especially if an anomalous structure was detected. The author picked about 550 townships, resulting
in an average well density of 13 wells per township.
To correlate and check internal consistency, a series of north-south and east-west cross-sections,
with a spacing of approximately ten km (one township), were used to make picks. Therefore, a pick in
a well was typically compared with three to four picks in nearby wells to ensure consistency. During
picking, picks were gridded using the triangulation method using Petra® to identify and check
outliers, which appear as bull's-eyes on a structure contour map.
After making the picks, and prior to modelling the surface, steps were taken to detect errors in:
- depth data (true vertical depth compared with measured depth data for non-deviated wells);
- kelly bushing (KB) elevation data for wells;
- ground elevation data for wells; and
- pick depth due to human error.
Picks and well header information, including KB elevation, ground elevation, surface location
(longitude and latitude in decimal format) and bottom-hole location (longitude and latitude in
decimal format), were exported from Petra® (IHS) software into a comma-separated value file. The
datum for the well location is NAD83, and the picks are in metres, given as measured depth relative
to KB elevation. Subsea pick depths were calculated by subtracting measured depth from the KB
elevation.
A query of the well surface location compared with the bottom-hole location checked for any deviations
from vertical. The author removed these wells from the dataset. If a well is deviated, its surface
and bottom-hole co-ordinates should be different. As all remaining wells should be vertical if the
surface and bottom-hole co-ordinates are correct, measured depth and true vertical depth should be
equal.
The author then screened the data for both global and local outliers. Outliers are values outside a
specified normal range compared with the entire dataset (global outliers) or within a local area
(local outliers). If caused by errors, outliers can have several detrimental effects on the
interpolated surface. One should either correct or remove outliers before creating a surface.
Outliers may result from one or more of the following factors:
- incorrect ground elevation and/or KB elevation data not detected during the initial screening;
- incorrect location data for a well;
- deviated wells not marked as such with either incorrect surface or bottom-hole location data;
- incorrect pick data due to human error; and
- geological structure.
A variety of geostatistical methods identified the outliers, including examining neighbourhood
statistics, inverse-distance weighting interpolation and Voronoi maps. In addition, the
inverse-distance weighted interpolation method was useful in locating outlier data points, which
appeared as bull's-eyes on the resulting map. Outliers were flagged and the well data and
geophysical logs were examined to determine whether the outlier was due to geological structure or
bad data. In cases where no error could be identified, additional data were gathered to refine the
definition of local structure. In these cases, if the datum was a single point and no geological
evidence was present to corroborate structure, then the data point was removed.
Once outliers were either removed or confirmed, the outlier screening process was repeated three
times. This iterative process identified increasingly more subtle outliers. As each pick was made
during this study and all statistical outliers were examined and some removed, the largest source of
error and uncertainty in the elevation of the Belly River Group pick is likely to be related to the
surveyed KB (and ground elevation) for a given well.
Date and time:
2010-01-01T00:00:00
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Legal constraints:
Access constraints:
Restriction code:
otherRestrictions
Use constraints:
Restriction code:
otherRestrictions
Other constraints:
Metadata Access Constraints: none Metadata Use Constraints: none
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Maintenance information:
Maintenance and update frequency:
unknown
Maintenance note:
This metadata was automatically generated from the FGDC Content Standard for Digital Geospatial
Metadatastandard version FGDC-STD-001-1998 using the January 2013 version of the FGDC CSDGM to ISO 19115-2
transform.
Metadata author:
Responsible party:
Organisation name:
Alberta Geological Survey
Position name:
AGS Information Manager
Contact info:
Contact:
Phone:
Telephone:
Voice:
(780) 638-4491
Facsimile:
(780) 422-1918
Address:
Address:
Delivery point:
Alberta Energy Regulator
Delivery point:
4th Floor, Twin Atria Building
Delivery point:
4999-98 Avenue NW
City:
Edmonton
Administrative area:
Alberta
Postal code:
T6B 2X3
Country:
Canada
Electronic mail address:
AGS-Info@aer.ca
Hours of service:
8:00 a.m. to 12:00 p.m. and 1:00 p.m. to 4:30 p.m.
Role:
Role code:
custodian
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