Analyzing an Observation Well

To analyze the interference pressure response observed between two wells:

1. Enter the pressure data obtained at a shut-in well (observation well) in the Production Editor tab.

2. Enter the production / injection rates measured at the producer / injector (active well) in the Production Editor tab.

Note:   Any combination / number of production rates and injection rates can be accommodated, but injection rates should be entered as production rates with a negative value.

Usually an analysis is completed through modeling, and without a diagnostic analysis of the observation well data.

3. Select the appropriate model type from the Models menu.

4. Enter model parameters based on your available information. For example, initial estimates of permeability are usually obtained from pressure buildup (PBU) tests and/or from pressure falloff (PFO) tests performed with active well data.

5. Select the Observation Well checkbox, and set the location of the observation well relative to the active well.

6. Compare measured and calculated pressures at the observation well by clicking the Plots tab. If required, adjust your model parameters to improve the match.

For example, a simple interference test sequence including one flow and one shut-in period is shown below. Given the defined pore volume, the fluid produced during the flow period is indicated to cause a pressure loss of 6.1 psi.