The Bowers Method, developed by Glenn L. Bowers in 1995, is an effective stress method for calculating pore pressure which not only accounts for undercompaction as the overpressure mechanism but also for fluid expansion using acoustic or velocity log data. Fluid expansion mechanisms can include clay dehydration, hydrocarbon maturation, smectite-ilite transformation, mineral precipitation/cementation reactions, charging from other zones, and aquathermal pressuring.
The Bowers method uses a power law equation that describes normal compaction, undercompaction and unloading in a single equation that you can calibrate to existing pore pressure data.
The Bowers Method of pore pressure calculation is applicable only to scenarios where unloading is encountered in the subsurface. Pore pressure prediction using compaction analysis is recommended for projects in which unloading does not occur.
The Bowers Method workflow has the following steps:
- Defining the input data
- Defining the minimum and maximum velocity
- Calculating the effective overburden stress from the hydrostatic pore pressure
- Determining the theoretical velocity and equivalent depth pore pressure
- Calculating Bowers pore pressure
For more information on the equations used in the Bowers method, see Pore pressure prediction methods.