A Small Volume Sampling Technique (SVST) allows operators to perforate, record temperature and pressure, and collect a formation sample prior to or in lieu of a well test efficiently and economically. Using this method, formations can be tested on a preliminary basis without the logistical burden of a comprehensive well test. Because of its economy, the SVST can also be used to test zones that were bypassed in older wells when expected production was not considered worth the expense of a comprehensive well test. The test apparatus is run in on drill pipe or tubing. Test procedure consists of

  1. perforation (usually about a 2 ft. interval)

  2. collection of a preliminary sample to allow formation cleanup

  3. collection of a second sample (one to two barrels) in a chamber that also houses quartz-based electronic temperature and pressure recorders and small PVT samplers.

Collection of two samples also yields valuable drawdown and pressure buildup data from two flow periods and two closed-in periods. After the tool is retrieved to the surface, an approximate liquid-gas ratio and water cut can be determined while the sample is drained. PVT analysis is then performed in the lab on samples taken by the small PVT samplers.

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