HOUSTON (AP) — Shares of Cobalt International Energy Inc. fell 8.2 percent Monday after the company said that repairs on a drilling rig could delay the results of production tests off the coast of Angola.

THE SPARK: The company said in a regulatory filing Monday that because of a malfunction in a positioning system, it sent a drilling rig to Diamond Offshore Drilling for repairs.

The company said it wouldn't be able to continue with production testing until the rig is repaired or it finds a replacement. That could mean the company won't be able to report results of tests in the lower reservoir of Cobalt's Cameia No. 2 well by the end of the year.

SHARE ACTION: The shares fell $2.02 to close at $22.69. In the past year, they have ranged from $6.30 in October 2011 to $36.51 in February. Volume on Monday was more than twice the daily average, with nearly 4.2 million shares changing hands.