Cased Hole DST
Pressure Operated
In a cased hole drillstem test, where a closed system is desirable due to a high pressure, high temperature environment, this set of tools can be run and activated using differential pressures between the tubing and annulus. These tools are multi-cycle tools that have an infinite repeatability of cycle. The Cased Hole Pressure Operated tools can be run in combination with a TCP/DST program and can support operations with circulation and well control.
Mechanically Operated
In a mechanical cased hole test, the operator has determined from core samples and logs exactly where the casing has been perforated. The packer is positioned appropriately on the drillstem and the tools lowered into the cased hole. Placing weight on the tool string opens the hydraulic valve allowing the formation to flow into the tool and rise to the surface. The formation is flowed for a specified time period, after which weight is removed from the tool string closing the hydraulic valve for a specified shut-in period. Measuring flows and shut-ins with this procedure can be performed as many times as are deemed necessary.