Interpretation of a stabilized well test yields what information?

• A. Average Reservoir Pressure in the Well Drainage Area, and the Well Productivity or Injectivity Index
• B. Reservoir Porosity and Permeability
• C. Surface Temperature and Flow Rate
• D. Fluid Viscosity and Density

Answer: (B)

A stabilized well test focuses on how the reservoir stores and transmits fluids in the region drained by the well. When the well has been produced or injected at a steady rate long enough for the pressure field to settle, the pressure response reflects the rock’s ability to store fluid (porosity) and to let fluid flow through the rock (permeability). Porosity governs how much fluid can be stored in the pore space within the drained volume, while permeability controls how easily fluids move through that pore network. By interpreting the stabilized pressure and known production or injection rate, engineers back out these rock properties for the reservoir section contacted by the well. Surface temperature and the flow rate themselves aren’t the properties being determined, and fluid viscosity and density are dictated by the fluid rather than the rock’s storage and flow characteristics.