Assigning logs

The Assign Logs form is used to select and assign three types of logs to your fluid model. These logs are fluid log data, pressure log data and (optionally) net rock log data.

  • Fluid log  A discrete log which indicates the fluid type (e.g. oil, gas, water etc.)
  • Net rock log  A discrete log which indicates 'reservoir' (i.e. net) and 'non-reservoir' (i.e. non-net) intervals, and acts as a filter on the fluid logs.
  • Pressure log  Fluid pressure data obtained from various formation tests. It shows the local measurements at specific points.

The fluid model will automatically aggregate log data per compartment, based on the wells intersecting that compartment. The information related to fluid levels and pressure per compartment is generated on the Fluid Levels and Pressure Overview forms respectively. In this regard, the aggregated log data will serve as the main source of information to QC the assumption of compartments. On the Fluid Levels form, each compartment will be confronted with its own aggregated data. Since fluids within a compartment should be in hydrostatic equilibrium, any inconsistency or violation to this equilibrium is indicated as a warning. The aggregated data will also serve as constraining information, which can be used to define the compartment fluid levels.

You can import the logs via the standard log import process or you can create logs using the Create Fluid Log form (model > Fluids > Tools > Fluid Log) or the Convert to Fluid Log form / Convert to Net Rock Log form (model > Fluids > Tools > Conversion Tools).

To assign logs

  1. Select the fluid model of interest. If you need to check the associated structural model, hover over the factsheet icon ( ) adjacent to the fluid model drop-down list.
  2. Select the fluid log from the Fluid log set drop-down list. This list is populated with log sets whose property type is set to Fluid Type.
  3. Select the pressure log from the Pressure log set drop-down list. This list is populated with log sets whose property type is set to Pressure.
  4. If you have a net rock log that you want to apply to the fluid logs, you can select it from the Net rock log set drop-down list. This list is populated with log sets whose property type is set to Net Rock. See Using net rock logs below for details.
  5. In the Wellbores table, all wells in the solution are listed. Select only those wellbores that you want to use in the consecutive fluid modeling steps. In other words, if you do not trust data of a certain well, leave it unselected. Only the log data of the selected wellbores is used to generate the information on the Fluid Levels and Pressure Overview forms. If a wellbore has log data for the selected log set(s), the 'Wellbores' table is populated with check marks.
    6. Checkbox selection on the form can be done in bulk by holding down SHIFT while selecting a range (the selected items turn blue). Checking the box of one item in the selected range will automatically check the box of all of them.
  6. Click OK to assign the logs to the model. This will close the Assign Logs form and open the Fluid Levels form. Otherwise, click Apply to assign the logs and keep the Assign Logs form open. At this stage in the workflow the log data per compartment is aggregated and is ready for review on the Fluid Levels form.

Using net rock logs

Net rock logs, applied to your fluid model as part of the Autofill feature on the Fluid Levels form, aid in distinguishing areas of non-reservoir rock from liquid and gas filled compartments. The fluid logs as calculated by petrophysicists typically cover both reservoir and non-reservoir sections and the fluid logs in the non-reservoir sections are not reliable or relevant. The objective of the net rock log is to filter out the non-reservoir sections from your fluid log. See How the 'Autofill Fluid Levels' button works for how the net rock log is used.

You can import net rock logs via the standard log import process, or create them using the Converting to Net Rock Log (model > Fluids > Tools > Conversion Tools). You can also create net rock logs using Property Calculator. In all cases, the log data must be of Property type: Net Rock. You can only specify two values in the net rock logs, 0 and 1, with 0 representing non-net (i.e. non-reservoir) rock and 1 representing net (i.e. reservoir) rock intervals.