METHOD AND APPARATUS TO PROVIDE MINIATURE FORMATION FLUID SAMPLE

摘要

An apparatus (20) and method is given for evaluating a well fluid sub-sample at the well surface as the sample is transported to the well surface from a downhole wellbore location (11). The invention collects a formation fluid sample under pressure. The fluid sample is further pressurized with a travelling piston (94) powered by the hydrostatic wellbore pressure. The pressurized formation fluid sample is contained under high pressure within a fixed volume chamber (95) for retrieval to the well surface. Multiple collection tanks (30) can be lowered into the wellbore during the same run t o sample different zones with minimal rig time. A pair of valves (75 and 76) i n series along the supply/discharge conduit (78) respective to each tank (30) accommodates extraction of a filed sample to verify the sample integrity whi le still on location. The tanks (30) can be emptied at the well surface with an evacuation pressure so that the fluid sample pressure is maintained above a selected pressure at all times or transported to an analytical laboratory.