Die Explorationsunternehmen ADX Energy und MCF Energy haben die Vorbereitungen zur Wiederaufnahme der Testarbeiten in der Bohrung Welchau-1 in Oberösterreich abgeschlossen.
The exploration companies ADX Energy and MCF Energy have completed preparations to resume testing operations in the Welchau-1 well in Upper Austria and are now commencing an acid treatment of the Reifling Formation. The companies announced this. The tests had been suspended in January 2025 following objections by environmental organizations against existing permits. In September 2025, the competent Oberösterreichisches Landesverwaltungsgericht ruled that drilling and testing activities may be resumed.
At the center of the current program is the Reifling Formation, the uppermost of four carbonate reservoirs penetrated in Welchau-1. It is a limestone reservoir traversed by natural fractures. Such fractured structures can store and transmit hydrocarbons, but they are sensitive to drilling damage.
An acid treatment is intended to remove possible blockages in the area of the wellbore and to improve the permeability of the rock. This method has been used in limestone reservoirs for decades. A subsequent flow test is intended to determine whether movable hydrocarbons are present, what the hydrocarbon content is, and what flow characteristics the formation exhibits. Decisive is whether oil or gas can be produced in economically relevant quantities under natural pressure conditions.
The well is located in an anticline in the Northern Calcareous Alps. Approximately 500 meters to the west and structurally higher, a potential light oil accumulation has been mapped. According to the company, the current test zone is located near the interpreted oil-water contact. Light oil is comparatively low in viscosity and is generally easier to produce and process than heavier grades.
According to ADX, Welchau-1 showed hydrocarbon indications over an interval of approximately 450 meters in several limestone reservoirs. In addition, continuous traces of hydrocarbons as well as light oil were detected. Pressure and structural data indicated a connection to the deeper gas-condensate discovery Molln-1. This suggests a connected petroleum system with additional
gas-condensate potential. Gas condensate refers to natural gas that, when pressure declines, separates liquid components that can be marketed.
The well was drilled to test the gas and condensate potential of fractured carbonate reservoirs from the Middle Triassic below the regionally sealing Lunz-Partnach Complex. According to the company, a section of a complex, hydrocarbon-bearing carbonate reservoir with continuous occurrences was penetrated.
For further development, management names two options: a sidetrack of the existing well in the direction of the assumed light oil structure or a deepening to test deeper gas-condensate targets. The test of the Reifling Formation is intended to serve as a basis for decision-making for the further course of action. In the coming weeks, it is expected to become clear whether the geological indications can be converted into producible quantities.
