Pressure Info Tab

The Pressure Info tab only appears for gas reservoirs.

The following inputs are used for obtaining the Z-factor in Trap Volumetrics calculation methods, and for the definition of Deliverability (Performance Type) and Quadratic Pressure performance types.

• Reservoir Temperature.
• Initial Pressure: Reservoir pressure before development starts.

Known pane: Either Abandonment Pressure or Recovery Factor must be known to define abandonment conditions for producers in this reservoir. In either case, if Deliverability performance curves are used, abandonment will be based on bottom hole or wellhead pressure.

• Abandonment Pressure.
• Recovery Factor: Gas recovery factor. This input is repeated from the Reserves Tab.

Reservoir Pressure Communication pane: When communication is set to None, each well will follow its own P/Z vs. Well GIP curve with the underlying assumption that there is no pressure communication between wells. When communication is set to Perfect, all wells in the same reservoir will follow the same P/Z vs. Reservoir GIP curve with the underlying assumption that there is full pressure communication between wells; in this case, only Deliverability and Quadratic Pressure performance types will be allowed.

The graph on the right plots reservoir pressure against gas cumulative production; the green curve indicates reservoir actual pressure over the reservoir life cycle, and is interrupted at the point of abandonment (marked by a vertical line on the X axis).

The Z correlation is based on Dranchuck, Purvis and Robinson (Dranchuck et al. 1974 Dranchuck, P.M., Purvis, R.A., Robinson, D.B., “Computer Calculations of Natural Gas Compressibility Factors Using the Standing and Katz Correlations,” Institute of Petroleum Technical Series, No. IP 74-008, 1974.).