Fluid contacts
A fluid contact records a fluid boundary that can be reused in several zones and models of the Conceptual Model: an oil-water contact (OWC), a gas-oil contact (GOC), a gas-water contact (GWC) or the free water level (FWL). Create and edit contacts in the Data Manager, even before preparing a conceptual model. Assigned contacts can also be edited in the Conceptual Model panel; edits affect the shared contact wherever it is assigned. They are not used in structural modeling; a constant-level FWL contact can, however, supply the free-water level when applying a Saturation Height Model.
A zone is the interval between two adjacent geological objects and is shown as a Zone row in the tree. Contacts assigned to a zone appear as separate rows beneath it, with the contact type in the Type column. Each assignment that defines a contact is listed as a child row below the contact.
Creating and assigning contacts
In the Data Manager, right-click Fluid contacts and choose Add contact, then OWC, GOC, GWC or FWL. The Fluid contacts folder expands automatically and the new entry is selected. This reveals the entry in the tree; the contact still needs a level or depth map before it can be displayed in views. The new contact takes its type as its default name; additional contacts receive a numeric suffix. Right-click a contact to define it or choose Rename. Its entry shows the type and level or map; point at it to see where it is used.
To assign it, choose Assign to Conceptual Model, then the model and zone, or drag the contact from the Data Manager onto a Zone row. The same contact can be assigned to several zones and several models; a zone can hold several contacts.
In the Conceptual Model panel, right-click a zone and choose Assign contact... to select an existing contact, or choose New contact and its type to create one in the Data Manager and assign it immediately. On a geological object, use Assign contact to Zone Above... or Assign contact to Zone Below....
To detach a contact without deleting it, choose Remove from Conceptual Model in the Data Manager; if it has several assignments, choose the one to remove. In the Conceptual Model panel, Remove from Zone removes only that assignment. Remove contact in the Data Manager deletes the shared contact; zones that referenced it retain a warning until the missing assignment is removed or a replacement is assigned.
Defining a contact
A contact is defined either by a constant level, optionally limited laterally by a polygon, or by a depth map. Right-click the contact in the Data Manager and use:
- Set Level... – enter the contact's TVDSS level in the project's depth unit, as shown in the dialog.
- Assign Polygon... – choose a polygon that limits the contact laterally, for example to one fault block.
- Assign Depth Map... – choose a depth map that the contact follows, for a tilted or variable contact.
The Conceptual Model panel offers the same editing actions, with Assign Map... for the depth map. When a contact has data, Save as map saves it as a depth map. The two definitions are mutually exclusive: assigning a map clears the level and the polygon, and setting a level or assigning a polygon clears the map. A depth map or a polygon can also be dragged from the Data Manager onto the contact row; other item types are refused with a message.
In the Conceptual Model panel, each part of the definition is listed as a child row of the contact, with Level, Polygon or Depth Map in the Type column; a level row shows the depth with its unit. Right-click such a row and choose Change... to select a different value, or Remove to clear it. Maps and polygons are references: the contact points at the item in the Data Manager and does not copy it.
Warnings
A warning icon on a contact row means that the contact needs attention. Point at the row to read the reason:
- No data is assigned yet, so the contact has nothing to draw.
- A referenced Data Manager item is missing, for example because the map or the polygon was deleted. The contact itself is kept, so a new item can be assigned to it.
- The zone changed. When a geological object is removed, the zones above and below it merge, and the contacts of the affected zones move to the merged zone instead of being deleted – check that their definition is still valid.
Visibility and existing projects
Contacts are listed directly in the Data Manager's Fluid contacts folder. Use an entry's check box to show or hide it on maps, in 3D views, in Well correlation view and on seismic sections, whether or not it is assigned to any conceptual model. A contact without a level or depth map is greyed out, has a disabled check box and explains the missing data in its tooltip.
When an existing project is opened, contacts previously defined inside conceptual models appear in the Data Manager and keep their zone assignments. Their names identify the original zones. No Show in Data Manager option is needed. For using a constant-level FWL in the Saturation Height Model wizard, see Saturation Height Model.
Contacts on sections
A visible contact is drawn as a horizontal line on seismic sections – inline, crossline and arbitrary, in both the time and the depth domain – and on Well correlation view sections, at the depth where the contact crosses each well trajectory.
A contact defined by a level is drawn at that constant depth, and a contact defined by a map follows the map along the section. Where a polygon is assigned, the line is drawn inside the polygon only and breaks outside it. Contacts are defined in depth, so on a time section the line is converted with the project velocity model.
Each contact type has a default colour: OWC blue, GOC green, GWC teal, and FWL blue with a dashed line. In Visual Settings the section overlay is listed as All fluid contacts, with one entry per contact named after its type and its level or map – OWC 2417.0, for example. The colour and the line style of each entry can be changed there.
See Also