Repsol handed over its LNG assets in Peru and Trinidad and Tobago to Shell, the world's biggest LNG supplier, as part of a huge debt-reduction plan.
The Spanish group has been fighting to regain its financial footing, and avoid a credit rating downgrade to junk-bond status, since Argentina's shock 2012 seizure of its profitable YPF subsidiary.
The sale of Repsol's LNG assets to Shell followed a smaller $200 million sale of a Basque power plant to BP in October, bringing in a combined $4.3 billion to the Spanish group.
The sale generated a net $2.9 billion in profits and capital gains for Repsol, the Spanish group said, more than had been anticipated when the deal was first announced in February 2013.
As a result, Repsol cuts its net debt by $3.3 billion, "and significantly strengthens its balance sheet", it said.
Repsol boasted that it had already beaten its own target of shedding up to €4.5 billion in assets from 2012–2016, a plan launched following the loss of its YPF subsidiary in Argentina.
In November, Repsol's board backed a proposed compensation deal with Argentina over the seizure of YPF.
A source close to the matter said the YPF compensation offer amounted to $5 billion in Argentine government bonds.
Argentina's President Cristina Kirchner ordered the the nationalization of Repsol's 51-percent stake in YPF in April 2012, blaming Repsol's failure to make agreed investments in the firm.
The decision soured relations between Argentina and Spain and sparked an international chorus of outrage including from Spain's European Union partners.
After the YPF grab, Repsol filed a complaint against Argentina with a World Bank arbitration panel, seeking $10.5 billion, and sued in a New York court seeking an undetermined amount of damages.
Settlement of the legal tangle could help to lure investment into the vast Vaca Muerta shale oil and gas field in Argentina, discovered by YPF in 2010, which is the equivalent of 22.8 billion barrels of oil.
Foreign investors have been hesitant, showing concern about Argentina's interventionist economic policies since its 2002 sovereign debt default and a threat by Repsol to sue future partners of YPF.