Americas Petrogas has made another oil and gas discovery at its Agua de Afuera (ADA.x-1) Vaca Muerta formation, unconventional, vertical shale exploration well, which is located on the Los Toldos II block in Neuquén basin, Argentina, according to a news release.

A five-stage hydraulic fracture stimulation in the Vaca Muerta shale formation was conducted on the vertical well. Beginning in late 2013, the first production test started and lasted 20 days. During this time, the well produced high quality 39.5 °API oil, gas, and injected water.

The initial hydrocarbon production rate was 240 boe/d (79% oil), the release said. The average hydrocarbon production during this period was 216 boe/d (79% oil) with 460 bbl of flowback water per day on a 4 mm choke. Over the course of the test the well-head static pressure declined normally from 5,135 pounds per square inch (psia) to 1,427 psia. At the end of this test, 28% of the injected water used for fracturing had been recovered.

After 32 days of pressure build-up and the installation of a preliminary production facility, the well production test was restarted and lasted 24 days.

The average hydrocarbon production during this second test averaged 163 boe/d (77% oil) with 172 bbl of flowback water per day on a 4 mm choke, the release said. Over the course of the test the well-head static pressure declined normally from 4,170 psia to 944 psia. At the end of this test, 40% of the injected water used for fracturing had been recovered.

The ADA.x-1 well was drilled to total depth of 3,448.5 m (11,311 ft) in late 2012 and drilled through 340 m (1,115 ft) of the primary target Vaca Muerta shale formation with oil and gas shows through most of this shale section. Hydrocarbon shows were also encountered in secondary targets such as the Agrio, Quintuco and Tordillo formations.

Americas Petrogas is the operator of the Los Toldos blocks and holds a 45% working interest. ExxonMobil also owns a 45% working interest with the remainder held by Gas y Petroleo del Neuquen.