(ShareCast News) - Circle Oil froze drilling operations at its ANS-2 exploration well in the Lalla Mimouna Permit as it called into question whether operations were worth completing, sending shares into the red.Reservoir quality dipped below pre-drilling expectations, the analysis of wireline logs revealed, although further investigation is to follow."The ANS-2 exploration well has provided important data to help further our understanding of the Lalla Mimouna permit," said chief executive Mitch Flegg."We will now interpret this along with the results from the recent successful LAM-1 well test before we decide on whether to complete and test ANS-2," he added.Drilling will go ahead as planned at other wells and prospects in the program, such as the NFA-1 in the south of the permit area, which is tracking seismic anomalies, an indicator of gas-bearing potential.As of 0930 BST, Circle Oil was trading 7% lower at 9p.