EXR Trading 2022, page-1468

Not sure if this was the first one, but:

"QGC hits record flowsThe final quarter of 2003 saw Queensland Gas Company (QGC) record its highest gas flows to date with the commencement of testing of the Argyle wells in ATP620P. The company also continued testing for reserves certification at the Berwyndale South pilot, from which first gas deliveries are expected in early 2005.

During the three months to 31 December 2003, QGC started testing its Argyle wells in ATP620P, recording gas flows of up to 427,000 cfd from its Argyle #4 well, along with increasing gas flows of over 140,000 cfd from two other Argyle wells.The company also drilled three core wells, with the Argyle #6 well confirming that the Argyle wells are located in an area where coal seams have both high gas contents and high permeability - ideal conditions for commercial extraction of coal seam gas.At its Berwyndale South Project QGC returned the pilot wells to their original configuration following a three month test of individual coal seams. Testing of the pilot is continuing, with the target to deliver first gas to market in early 2005 after the initial technical feasibility study of the Berwyndale South field development was completed.Additionally QGC formed a new joint venture with AJ Lucas Group, the long-distance pipelines and horizontal drilling technologies specialist, through a farmout of a portion of ATP651P.Through the current quarter QGC will continue to test the gas flow rates of the wells, with the expectation of achieving an initial certification of commercial gas reserves within the next six months."

Also a good indication for timeframes - Certification for gas reserves took 6 months and about 18 months from flow testing to bringing gas to market.