Multi-Cycle Annular Pressure Operated DST

Maximum well control is achieved with redundant valves controlling flow and multiple circulation points. The tool assembly is custom designed for each operation with adequate expansion joints (slip joints) installed to compensate for thermal and hydraulic expansion/contraction of the work string. Down hole pressure/temperature gauges record data throughout the tool string. The gauge data recorded below the closed downhole valve closest to the formation sandface is used for pressure transient analysis (PTA). Isolating the formation with pressure recorded below the downhole valve drastically reduces the amount of time required to collect the necessary data due to the elimination of dead volume (wellbore storage effect) in the workstring.