An operator required a tool that would make it possible to perform a 24-h inflow test under HPHT conditions (333 degF [167 degC] and 18.1 lbm/galUS [2.17 sg]) without applying excessive forces to the 7-in × 5-in liner top. During a standard test, cumulative downward forces experienced during a test are applied to the liner top. This becomes a concern under HPHT conditions due to the higher differential pressures experienced across the test tool.

Schlumberger developed a version of the WELL COMMISSIONER liner-top test tool that is suited to higher well temperature and pressures where the large force or load created is applied to the casing wall as opposed to the liner top. This is achieved using hydraulically activated slips.