Definition - What does Breakdown Pressure mean?
Breakdown Pressure is the pressure at which the formation rock will break and allow fluids to flow inside. Breakdown Pressure value is used to calculate minimum principal stress and maximum horizontal stress of formation rocks and to access the formation treatment operations. It is also referred to as Formation break down pressure or fracture initiation pressure.
Petropedia explains Breakdown Pressure
Breakdown Pressure mainly depends on the compressive stress associated with the formation rock and the strength of the formation itself. When the applied pressure exceeds both the compressive stress and formation strength the formation will break. By maintaining the pressure above the Breakdown Pressure value, the formation rock fractures and these fractures propagate in a perpendicular direction to the least principal stress.
Operations like matrix stimulation, surging & leak off test are conducted below the Breakdown Pressure while hydraulic fracturing jobs are conducted above the Breakdown Pressure value. The Breakdown Pressure depends on formation type, size, fracture fluid and well deviation angle.
Determining Breakdown Pressure:
- Run in hole with bit string and Drill 1 m app the new formation below casing shoe.
- Close Rams and apply pressure in the well by pumping equal amounts of mud in intervals.
- Record pressure Vs volume of mud pumped and plot.