Quicksilver Resources Inc. late Tuesday announced a public offering of its partnership units in competitor BreitBurn Energy Partners L.P., a move that likely will lead to Quicksilver’s exit from the company.

Quicksilver, a Fort Worth oil and gas developer, said that it would sell 6.97 partnership units. That’s about 87 percent of its current 13.6 percent stake in the Los Angeles oil and gas developer.

Its stake would drop to zero if underwriters exercise an option to buy 1.04 million additional units to cover any overallotments.

In June, Quicksilver sold 7 million BreitBurn units, which roughly cut its stake in half. The two sales come nearly two years after resolution of a legal dispute between the companies. Quicksilver sued in 2009 for a larger role in BreitBurn after accumulating a significant stake. In February of last year, BreitBurn settled the litigation by paying Quicksilver $13 million and agreeing to management changes that included giving Quicksilver two board seats.

Breitburn shares on Tuesday closed up 49 cents, or 3 percent, to $17.25 on the Nasdaq, but following the late announcement fell 4 percent in after-hours trading.