Strat Picks (Stratigraphic Picks) is a general term for Geologic Units or formations and other stratigraphic markers which can be identified in a well bore.
The term "formation" is used in the common petroleum industry parlance, referring to any given stratigraphic unit. The unit may not correspond to a formally named unit, and the interval may include more or less section than a formally recognized formation.
The Strat Picks Subtable contains the following information about each Strat Pick:
Identification number for each Strat Pick record, automatically assigned by Microsoft SQL Server. The number is not shown online, but is included with other data when the Strat Picks Subtable is downloaded so the user can maintain the PDMS table relationships in other software applications.
Measured depth (in feet) from the Log Datum to a point in the well bore where a Strat Pick is made.
True Vertical Depth (TVD) of a Strat Pick or other feature in a well bore for which a depth has been entered in the Pick Depth data field. In order for a Pick TVD to be calculated, the value of its Pick Depth must be entered in the Deviation Subtable.
The term Strat Pick is a general term for Geologic Units or formations and other stratigraphic markers which can be identified in a well bore. Most Strat Picks are formal stratigraphic units but some informal and industry terms are also used. Strat Picks are often referred to by the names "picks," "tops," or "formation tops."
In addition to true Geologic Units, Strat Pick is also used to indicate several other specific features that intersect the well bore, namely faults, unconformities, and Total Depth. These are included as Strat Picks so they can function in certain algorithms in the PDMS—they are treated as Strat Picks so that a Pick SubSea value will be calculated for the datum horizon.
See Geologic Units for a list of all stratigraphic terminology used in the PDMS.
Type of Strat Pick. The PDMS uses the following Pick Types:
Pick represents the top of a formation (Geologic Unit).
Pick represents the base or bottom of a formation (Geologic Unit).
A recognizable marker (marker bed) used for subsurface correlation.
Informal feature where some stratigraphic section is absent due to an unconformity. An informal name is assigned (except for the Mississippian-Pennsylvanian unconformity which is treated like a Strat Pick). For instance, Unconformity “A,” Unconformity “B.” Such designations do not imply regional correlation. This value has not been assigned to wells in the PDMS.
Informal feature indicating where a fault intersects a well bore. An informal name must be assigned. For instance, Fault “A,” and Fault “B.” Such designation does not imply regional correlation.
The measured total depth, Total Depth may be listed as a Strat Pick, but only for deviated holes (horizontal or directional wells).
The pick formation is vague or absent and a "phantom pick" position has been assigned for interpretive purposes.
A unique identification number assigned to each log record. Log ID appears in the Log Info Subtable where the number is automatically assigned by Microsoft SQL Server, and in the Strat Picks Subtable where it is used to link each Pick Depth with the specific log that used to determine the depth.
Log Type, as displayed in the Strat Picks Subtable, is retrieved from its corresponding Log Type value in the Log Info Subtable. It assists the user in identifying which log was used to determine the particular Strat Pick record.
Name of geologist or geological technician who determined the Strat Pick.
Caution. Although the name of the geologist making the pick is routinely recorded for wells as they are entered into the PDMS, for the majority of wells preceding the year 2000, the geologist is not known and the value “unknown” or "staff" has been entered in the Picked By data field instead of a geologist’s name. These data have not been systematically entered into the PDMS.
The Pick Subsea value for each Strat Pick is determined internally in the PDMS by subtracting Pick Depth from the elevation of the Log Datum for a particular log in the Log Info Subtable.
Pick Priority represents the order in which multiple Strat Picks of the same stratigraphic horizon or feature are ranked so that multiple values may be stored for the same Strat Pick. Priority is used to rank the Strat Picks for geologic interpretation. No horizon may be represented by more than one record containing the same value for pick priority.
A subjective confidence factor is assigned as an indication of the “believability” of a particular Strat Pick. The Pick Confidence is assigned by the geologist at the time a new Strat Pick is entered. The purpose of Pick Confidence is to run queries of the Strat Picks that exclude values below a certain confidence level.
Caution. Values have not been systematically assigned to wells before 2001.
The values assigned to Pick Confidence are listed in the Pick Confidence Values Table.
A short abbreviation that indicates a qualification of the Strat Pick. Its purpose is to modify the Pick SubSea value when it is posted on a map. Only one Pick Note may be selected for any single Strat Pick.
Caution. Pick Note has not been systematically applied to wells in the PDMS.
Comments concerning a particular Strat Pick or correlation.