Important: Well Events for Deviated Holes are treated differently in the PDMS than for most other wells
Deviated wells require special processing in the PDMS. It is absolutely critical to follow the prescribed procedures to the letter.
On the Well Header of the Well Record, choose Surface as the Symbol. Exception: If the well is a workover of a straight hole, choose instead the appropriate Symbol for the straight hole portion of the well.
For each Well Event corresponding to a deviated well bore, click the Deviated Hole toggle button in the lower left portion of the Event Header. If the well includes an initial straight hole portion, it should be entered as the first Well Event and assigned a Event Status of Straight Hole. Even though the Status is Straight Hole, the Deviated Hole toggle button should be checked -- this assures that the Event's TD will be part of the calculation for the well's Posted TD.
Fill in the Log Info Subtable in the normal way, listing both Geophysical and Physical logs. The TVD Log (Directional Survey) is treated as a Geophysical Log Type.
Complete the Strat Picks Subtable. Several aspects of the Strat Picks Subtable are treated in very particular ways for the data to correctly link with the Deviation Subtable.
Pick Depth = measured depth of the Strat Pick being entered. In addition to the usual Stratigraphic Picks, enter the value of the borehole's Total Depth as if it were a Strat Pick. This is done so that the Total Depth will be assigned a subsea value for calculating the Posted TD for the well.
Pick TVD = will be automatically calculated when the Deviation Subtable is filled-in for that measured depth (see next section).
Stratigraphic Pick (Strat Pick) is the horizon selected from the drop-down lists. In addition to formations and other horizons intersecting the well bore, a pick for Total Depth of the corresponding Well Event must be selected from the drop-down list (see 4.a.)
Pick Type = Select from the drop-down list. ‘Top’ is the usual choice, however; Total Depth must be selected as the corresponding value for the record identified as Total Depth in the Strat Pick data field.
Log ID: The ID number is used to link a Strat Pick with a particular log. The Log ID must be selected from the drop-down list of available Log ID numbers in order for the values to be correctly processed in the database. If you can’t remember which Log ID number corresponds to the correct log, you can either go back to the Log Info Subtable, or use trial and error by simply choosing a Log ID and see if it returns the correct log as the Log Type data value – if not, choose another Log ID until the correct log appears in the Log Type data field.
Log Type (either Log Type Geophysical or Log Type Physical) This value is retrieved automatically from the Log Info Subtable. Its purpose here is to confirm that the Log ID has been associated with the correct log.
Picked By = The geologist who identified the Strat Pick. The name is chosen from the drop-down list of geologists.
Pick Subsea = The subsea value for the Strat Pick. This value is calculated automatically from the Pick Depth (if the well is a vertical hole) or from the Pick TVD (if the well is a Deviated Hole) and the Reference Elevation value in the Log Info Subtable. The Pick Subsea for Deviated Holes is calculated after the Deviation Subtable is filled in (see item 5 below).
Pick Priority = the order in which multiple Strat Pick 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.
Pick Note = See Pick Note Description.
Pick Comments = Comments concerning a particular Strat Pick or correlation.
Open the Deviation Subtable. A record should be present each measured depth that was entered in the Strat Picks Subtable. Also, add a new record to represent the surface hole location in the first Deviated Well Event only, as subsequently drilled horizontal legs (bore holes) continue to use the same surface hole (and location). The surface location is entered in the first record of the first Deviated Well Event so that the Well Symbol of SURFACE" will be spotted at the well's surface location.
measured depth:
Values are already filled in for each depth that was entered in Strat Picks Subtable.
A new depth of 0 ft should be entered for the surface location in the first Deviated Well Event only, as subsequently drilled horizontal legs (bore holes) continue to use the same surface hole.
bottom hole location = measured depth at TD
offset = difference between Measured Depth and TVD (True Vertical Depth) as determined from directional survey. Generally tab over (skip) this value and move on to TVD--the offset will be calculated from the TVD.
TVD = True Vertical Depth. The TVD is a obtained from the well's TVD Log (Deviation Survey). In many instances, the matching depth falls between values on the TVD Log and must be extrapolated using the TVD Calculator.
X shift = the east-west distance in feet from the surface hole location (E = +, W = -). Be careful! When entering data because some TVD logs list the north-south coordinates first followed by the east-west coordinates. Sometimes the shift value falls between values on the TVD Log and must be extrapolated using the TVD Calculator.
Y shift = the north-south distance in feet from the surface location (N = +, W = -). Sometimes the shift value falls between values on the TVD Log and must be extrapolated using the TVD Calculator.
UTM X = the east-west UTM coordinate (in meters) of the datum location as calculated from the X Shift (in feet). This value is automatically calculated and inserted in the database.
UTM Y = the north-south UTM coordinate (in meters) of the datum location as calculated from the Y Shift (in feet). This value is automatically calculated and inserted in the database.
Deviation Type = the type of deviated hole at the datum horizon:
Horizontal = at this depth, the well is a ‘horizontal’ well.
Directional = at this depth, the well is a ‘directional’ hole (an well that is angled from vertical, but which is not a ‘horizontal’ well).
Leave this field value blank if the datum horizon is within the straight hole portion of a deviated well.
Deviation Symbol = symbol at the location of the datum horizon when that horizon is shown on a map.
SURFACE = The symbol code SURFACE must be entered here if the record represents the surface location. This is true even if SURFACE or some other symbol was entered as the ‘Symbol’ on the Well Header (Location Table).
PATH is the name for the small dot to be shown along the path of the well bore (in map view) at the intersection of the datum horizon. Generally, one PATH symbol is sufficient for each 500 ft of horizontal offset.
At the depth that corresponds to TD (total depth), select the Symbol that would correspond to the completion status of that particular Well Event. This is the symbol that will be placed on the map at the bottom hole location for this Well Event.
Leave this field blank if no Symbol is to be shown when this point is shown in map view.