First tests disappoint at Hungary's Mako Trough

ExxonMobil Corp., Hungary’s MOL Rt., and Falcon Oil & Gas Ltd., Denver, were discussing the next steps after testing sour gas at disappointing flow rates in Hungary’s Mako Trough.

By OGJ editors
HOUSTON, Oct. 8
-- ExxonMobil Corp., Hungary’s MOL Rt., and Falcon Oil & Gas Ltd., Denver, were discussing the next steps after testing sour gas at disappointing flow rates in Hungary’s Mako Trough.

ExxonMobil Hungary (Mako) Ltd. recommended ceasing operations at the Foldeak-1 well after testing the Szolnok formation following two fracs at 4,358 m and 4,200 m. Szolnok is 1,200 m thick and has a base depth of 4,394 m in the Foldeak-1 well, Falcon said.

The frac at 4,358 m was completed successfully, yielding average flow rates of 200 Mscfd of gas and 15-370 b/d of water in 10 days. The frac at 4,200 m was completed successfully and yielded average flow rates of 50 Mcfd of gas and 1,200-3,100 b/d of water in 46 hr. The well is still flowing.

ExxonMobil also reported the presence of carbon dioxide and hydrogen sulfide at levels of up to 16% and up to 400 ppm, respectively, for both tests. Water from both tests was very fresh, less than 5,000 ppm of total dissolved solids.

Falcon said, “The very high water flow rates and calculated test permeability experienced in the Foldeak-1 well leads Falcon to believe that the fracture stimulation connected to a fresh water filled natural fracture system. It is possible that the matrix Szolnok formation remains largely untested due to preferential flow from the natural fractures.

“Falcon interprets the intervals above the tested section to be a separate reservoir and a potential sweet spot within the Szolnok formation. Core data indicate that the permeability of these prospective intervals is considerably higher than permeability measured below.

“Additionally, net to gross reservoir quality sand is also much higher and logs indicate that the gas saturation may increase upwards through the Szolnok formation. Pressure in these prospective intervals of the Szolnok formation is interpreted to be considerably lower than the pressures encountered deeper.”

Falcon said it is evaluating the rest of the Szolnok determine if it is possible to move away from this potential natural fracture system. Pursuant to the $50 million initial work program requirement as defined by the parties’ agreement to test the Szolnok formation, Falcon has recommended further fracs at 3,942 m and 3,906 m. Falcon believes that the remaining capital in the program budget is enough to complete this testing.

Expressing disappointment in the results, Marc A. Bruner, Falcon chief executive officer and president, said Mako “is an enormous geography with numerous potential zones and formations which remain untested. It’s our opinion that the tests to date do not represent a complete evaluation of the hydrocarbon potential of the Szolnok formation or the Mako Trough overall. We believe that it may be prudent to complete additional testing in the Foldeak-1 well to fully understand the true potential of this resource.”

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