Location Tab - Well Properties

Location

Well Properties

The Location area of the Well Properties is used to define the Wellhead location and Well position error. The Wellhead Location defines the Wellhead centre location. This location is defined in terms of map coordinates referenced to the Map Zone, Geographic Latitude/Longitude coordinates, or Local Site coordinates (N/S, E/W) from the Site Centre Location. All three sets of coordinates are kept synchronized using the Project Geodetic configuration. A Slot may be selected from Site templates.

Special Fields and Functions

Wellhead Location

The Wellhead Location relative to the Site can be defined by one of the following methods. Select the appropriate option and enter appropriate coordinates for that option.

Slot - Select the wellhead location and using a predefined template created in COMPASS™ software select the template from the Name field. The Slot Coordinates for Site Centre will be used to populate the Offset from Site, Map and Geographic fields. When Slot is selected the Offset from Site, Map and Geographic fields are greyed-out. Note: Slot templates cannot be created in OpenWells software.
Offset from Site - Select this option to define the wellhead location by the offset distance from Site Centre to the wellhead location. Enter the distances North and East from the site center.
Map - Select this option to define the Wellhead by map coordinates. Enter the Northing or Easting of the wellhead and the local coordinates will be calculated from the Site Centre. The Well location is stored relative to the Site; therefore, if the Site moves the Well will also move.
Geographic - Select this option to define the Wellhead location by latitude and longitude. Select this option and enter Latitude and Longitude coordinates to indicate the location of the wellhead. For information on these field types see the Latitude and Longitude topic.

Note: Regardless of the method selected all other values are automatically calculated and displayed greyed-out.

Well Position Error

A position error may be associated with the Well location used for anti-collision analysis. This error is added to all errors generated on Wellbores in this Well. The Well error is designed for special cases. For example, when there are a number of Wellheads in close proximity to each other (grouped in the same Site) but not connected by a template. The well error in this case is the error in measurement of one Well relative to the others, but not the error in the group’s location, which is the Site position error. It is recommended that Well error be left as zero for template Wells.

Note: EDM now uses the ISCWSA survey error framework for calculating all survey errors and requires that all instrument & location error input is to 1 sigma confidence. This means that the Site and Well location errors are now 0.5 the value entered in previous versions of COMPASS software where the Company error model was Systematic or Cone of Error.

Convergence

This greyed-out field is the difference between Grid North and True North. Representing the angle from True North to Grid North (also known as Map North).This angle correction is applied in the opposite sense to azimuths only when using a Grid North reference. Convergence is used when computing anti-collision between sites when using a True North coordinate system.