Abstract: A method and apparatus for testing a production stream comprised of oil, water, and gas flowing through a conduit to determine the percentages of oil, water, and gas in the stream. A sample portion of the production stream is pumped through a sample line into a sample chamber where it is heated and allowed to set for a retention period to substantially separate the sample portion into oil and water layers. Gas that evolves from the sample portion is vented from the chamber. At the end of the retention period, the sample portion is pumped back through the sample line into the conduit. As the sample portion flows through the sample line the oil and water content of the sample and the volume of the sample are measured to determine the oil and water percentages in the sample portion.