ADX Energy has reported initial results from the resumption of testing of the Reifling Formation at the Welchau-1 well in the ADX-AT-II licence, in Upper Austria. ADX holds a 75% economic interest in the Welchau-1 discovery. The 128-metre thick Reifling Formation is the shallowest of four fractured carbonate reservoirs intersected in the Welchau-1 well.

The well was stimulated by pumping six (6) cubic metres of acid, followed by a completion brine flush, into the well to ensure full acid displacement into the reservoir. The acid was allowed to soak before the well was flowed back. To initiate flow in the well it was necessary to unload the hydrostatic column of brine by swabbing the well. Swabbing resulted in brine, methane (CH 4) gas and CO 2 being flowed to surface. The CO 2 being the result of a reaction between the acid and the carbonate reservoir.

The initial results of testing are positive for the following reasons:

• The recovered well fluids include hydrocarbon gas (CH 4) observed at surface.
• Hydrocarbon gas observed at surface is the first from the Reifling Formation from within the Welchau anticline or the basin, and
• The relatively small amount of acid used for the stimulation of the Reifling Formation successfully induced flow from a previously unresponsive reservoir.

Ongoing testing operations will include further swabbing to clean up the well and assess the potential for continuous flow of oil, gas or oil and gas. Produced well fluids will be sampled to determine hydrocarbon content and type. Well bore pressure measurements will be taken to confirm the pressure connectivity of the Reifling Formation with the remainder of the Welchau anticline. If continuous production is established, the well flow rate will be measured.

It should be noted that well workover operations are scheduled for twelve hours per day during week days. The well is currently shut in until swabbing operations resume.

KeyFacts Energy: ADX Energy Austria country profile