The Adelaide-based major said it had had discovered a new oil field at the well.
But an initial drill stem test run over the interval 1208.5m-1220m in the Hutton Formation flowed for only 20 minutes before the packers failed.
During this time six barrels of oil were reversed out of the test string, and no water, Beach said.
The well will be further evaluated over the next few days, it said.
The Marcoola prospect, about 35km southwest of Eromanga, is a fault-dependent four-way dip closure.
Structural mapping determined the prospect lies along trend from the prolific Tintaburra-Toobunyah oil fields, which have produced about 5 million barrels of oil, and the Sirius-1 exploration well, which recovered oil from the Birkhead/Hutton interval.
The ATP-269P joint venture comprises Beach Petroleum as operator with 46.95%, Entek Energy (28.15%), IOR Exploration (20%) and Santos (4.9%).
