Injection Tab

All parameters related to water and gas injection are defined in this tab.

Water Injection Options

Water Injection Options pane

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  • Keep the reservoir's producers to injectors ratio: Enter a ratio to be honored in Automatic Development jobs. Note that patterns defined for that job may be altered by this setting.
  • Abandon Injectors on Total Producer/Injection Ratio: As producers are abandoned, injectors will be abandoned to maintain the Producer/Injector ratio prior to abandonment of production wells.
The option to Keep the reservoir's producers to injectors ratio refers to the drilling of wells only, not to maintaining a given PI Ratio of all existing wells. This means that even if producers are abandoned while wells are still being drilled, injectors will keep being drilled regardless of how many injectors are already active in the reservoir. To ensure a constant PI Ratio of active wells the Abandon Injectors... option should be used.
  • Defer drilling injectors alongside producers: If production wells are deferred either because of an Excess Policy Tab or for lack of available rigs, injection wells will be deferred as well to maintain the specified PI Ratio.
  • Voidage Replacement: Check this option to set a maximum percentage of voidage replacement, which will be used as an injection limit control:

cum injection = cum liquid production * voidage replacement factor

where cum injection and cum liquid production are bottom volumes, and therefore take into account the oil formation volume factor (Bo) and the water formation volume factor (Bw) defined in the Fluids Tab. Voidage replacement deduction will be distributed among all injectors in the reservoir, proportionally to each well's performance defined in the Well Performance Tab. It will also be subject to the maximum facility injection capacity as well as to injection water availability.

  • Use water shortage impact: Use this option to model the impact that insufficient water injection will have on reservoir production. Only enabled when the Voidage Replacement option is active. See Fluid shortage impact below.

Gas Injection Options

  • Keep the reservoir's producers to injectors ratio: Enter a ratio to be honored in Automatic Development jobs. Note that patterns defined for that job may be altered by this setting.
  • Abandon Injectors on Total Producer/Injection Ratio: As producers are abandoned, injectors will be abandoned to maintain the Producer/Injector ratio prior to abandonment of production wells. Defer drilling injectors alongside producers: If production wells are deferred either because of an Excess Policy Tab or for lack of available rigs, injection wells will be deferred as well to maintain the specified PI Ratio.
  • Gas Injection-Oil Ratio: Check this option to set a target gas injection as a function of produced oil in reservoir volume. Injection gas will be distributed among all injectors proportionally to each well's performance defined in the Well Performance tab. It will also be subject to the maximum facility injection capacity as well as to injection gas availability.
  • Use gas shortage impact: Use this option to model the impact that insufficient gas injection will have on the reservoir’s production. Only enabled when the Gas Oil Ratio option is active. See Fluid shortage impact below.

Fluid Shortage Impact

When the target injection determined by the Voidage Replacement Ratio (for water) or the GOR (for gas) is not met, the production of each active well in the reservoir will be affected at each step according to the values entered in the table.

Injection allocation among producers: There are two policies for allocating the available injection fluid among the injectors:

  • Proportional: The production of each well will be affected proportionally (actual production = potential production * (1 - Impact fraction)
  • Sequential: Some wells will be affected first based on a specific parameter or
  • Criterion (Water cut, Oil rate, Gas rate, Water rate or Total Liquid rate). Use the arrow Sort ascending/descending on the right to select whether to use an ascending (Well with the lowest value receives injection first) or a descending order (Well with the highest value receives injection first).

In the table, enter the following:

  • Shortage: Percentage of required injection fluid that could not be provided. This should always go from 0% to 100%.
  • Impact: Fraction of potential production that will be cut.
Modeling Injection-Production Dependencies