Last checked at 
LONDON, July 19 (Reuters) - Former BP chief executiveJohn Browne is to preside over the biggest set of oil and gasassets in the shallower, mature section of the Gulf of Mexicoafter buying them from U.S.-based Apache Corp.
Private equity firm Riverstone Holdings LLC, where Browne isa partner, is to pay Apache $3.75 billion for its continentalshelf assets, Houston-based Apache announced on Thursday.
The area covering 1.9 million net acres and 500 blocks willbe held through a Riverstone portfolio company, Fieldwood EnergyLLC, Riverstone said in its own statement.
Browne ran BP from 1995 to 2007 through an era when it builta position as one of the most important players in the Gulf,especially in the deeper water, where it still is a big player.He was replaced by Tony Hayward - who became the public face ofthe company's 2010 oil spill. Hayward has also since left theBritish company, which is now embroiled in costly litigationover the spill.
The assets sold by Apache ended 2012 with estimated provedreserves of 133 million barrels of oil and natural gas liquidsand 636 billion cubic feet of natural gas. The fields producedaround 50,000 barrels of oil and liquids and 254 million cubicfeet of natural gas per day. Apache is keeping a 50 percentstake in the unexplored portions of the properties.
Apache is looking to focus on growth from its U.S. onshoreassets. Having spent more than $16 billion acquiring oil and gasproperties over the last three years, it is now selling offassets as it has struggled to grow production and its shareshave suffered.
Fieldwood will also assume $1.5 billion in estimated futurecosts related to plugging and abandoning old oil and gas wells,Apache said.
Riverstone is an energy and power-focused private investmentfirm founded in 2000 with approximately $25 billion of equitycapital raised across seven investment funds.
