The Edson dataset is a tabular type of data consisting of unique records (no duplicates) for each individual well.
Other characteristics:
- all spatial locations were checked for uniqueness;
- each stratigraphic (formation, member and other stratigraphic sub-divisions) or lithological (sandstone, coal, marker) pick is unique;
- all attributes have been assigned values; in some circumstances when the unit is absent the pick quality code assigned is (0);
- all the attributes have well defined domains and were found valid within the domain;
- coal picks followed a strict protocol described in ESR 2007-06;
- picks are consistent with the stratigraphic model and the relative stratigraphic position (no cross-over).
The Edson data set was created to provide detail maps for the Edson CBM exploration block. The source of information consisted of selected oil and gas exploration wells. The selected wells meet the following criteria: good geographic distribution, not deviated, adequate geophysical log record (Gamma-ray, density, Induction) and appropriate depth (Battle-Scollard-basal Paskapoo channels stratigraphic interval).
The dataset comprises 28 correlative attributes, 3 formation attributes and 5 lithological attributes that correlate with 28 representative stratigraphic units with extensive lateral correlation, 3 stratigraphic intervals described as formations and 5 lithological categories. Most of the names of the units are new, for instance the names of the sandstone channels. The description of the units and the protocol used for picking the units on the geophysical logs can be found in ESR 2007-06 as associated publication.
A description of the correlative, formation and lithological attributes can also be found in the entity and attribute section of the metadata record and in the tables 'tbl_List_of_Unit_Names', 'tbl_List_of_Formations' and ' tbl_List_of_Lithologies' respectively, within the database itself.
The Edson block dataset represents a new collection of stratigraphic and lithological picks (sandstone, coal and selected markers) reflecting a new sequence stratigraphic model applied to the fluvial succession including the Scollard Formation and the basal Paskapoo channels in the study area.
The dataset describes a detailed interpretation of the considered correlative lithological units (Scollard and Paskapoo individual sandstone channels, Ardley coal sub-zones and individual coal seams, and tonstein strata considered as stratigraphic markers).
The MS Access database is structured in:
a. general well information (WID, geographic coordinates, Kb, etc.);
b. stratigraphic and lithological picks (depth values and associated attributes);
c. reference tables that describe the attribute data;
The picks have depth values of tops and of bases for each stratigraphic and lithological unit. The depth values resulted from the interpretation of Gamma-ray, density, induction and calliper geophysical log records. Criteria applied to the well log selection were: the presence of the Gamma-ray -density-induction combination of geophysical logs and the appropiate depth. The picks were compared with the core observations. The picks were recorded manually into the MS Access database. The errors were identified by running simple statistical methods and during the mapping process. The correction of the errors was made by checking the anomalous values against the log signature.
The data set was processed by queries to extract the desired information for mapping.