In orifice measurement, the flow extension
represents the major contribution of the flow variables (static pressure, differential pressure, and sometimes temperature) to the overall flow calculation. While not normally used by most downstream Electronic Gas Measurement (EGM) systems, this value can be utilized to manually calculate gas volumes for a differential meter over a specific time period with minimal added uncertainty.
The U.S. Department of the Interior's Bureau of Land Management (BLM) now asks producers to include the flow extensions
for their monthly gas production volumes reported on their monthly volume statements. This value is one of the mandatory items in the BLM list of regulatory requirements for a comprehensive measurement audit trail.
Though flow computers from different manufacturers vary in how flow extensions
are generated, they're generally stored in the flow computer's logged electronic data and available for producing a volume statement in a downstream data management application such as the Flow-Cal®
system. However, be aware that not all data collection systems are routinely configured to download flow extensions
or export them to the software used for generating the volume statements.
If you are operating on BLM-administered properties, we strongly recommend that you confirm that you're properly logging this number in your measurement process and including it in your reports...before the BLM performs an audit. The flow extension
is just one of the many requirements needed to comply with the BLM. For more information on all of the BLM's current requirements for your production operations, visit their web site at www.blm.gov
. As an example, if you are operating in NM, OK, TX, and KS, the BLM Onshore Orders for that region may be found by clicking here
, and the BLM's latest standards for EGM are available by clicking here
for the document in PDF file format.
"Fast is fine, but accuracy is everything."
~ Wyatt Earp, famous frontier lawman of the American West