Downhole pump for formation testing.

摘要

A downhole progressive cavity test pump (28) has a housing (50) comprising first (52) and second (54) housing sections telescopingly arranged so that the two sections are movable between a collapsed and an extended arrangement. One section includes a helical rotor (60) and the other section includes a helical cavity (64) of a stator (62). The pump may be engaged and disengaged by respective movement of the housing sections. When the sections are extended, a bypass position is formed so that the downhole formation being tested can be allowed to flow freely if it is capable. A method of testing a subsurface zone comprises including such a pump in the testing string. <IMAGE>