(Corrects paragraph 3 to say THQ, not Quantum Energy, will get $2.6 bln in cash and about $2.6 bln in EQT stock)

Sept 6 (Reuters) - Top U.S. natural gas producer EQT Corp said on Tuesday it would buy Quantum Energy-backed THQ Appalachia I LLC for $5.2 billion, expanding its operations to reap the benefits of strong commodity prices.

A surge in global natural gas prices following Russia's invasion of Ukraine has benefited U.S. natural gas producers and encouraged deals in the industry as companies try to scale up.

THQ, which is backed by private equity firm Quantum Energy, will receive $2.6 billion in cash and about $2.6 billion in EQT stock.

EQT also doubled its share repurchase authorization to $2 billion and raised its 2023 debt reduction target to $4 billion.

Reuters on Monday reported that EQT was in advanced discussions to buy THQ Appalachia I.

The deal, expected to close in the fourth quarter, will add an estimated 800 million cubic feet per day of gas equivalent production for EQT, and includes pipeline infrastructure supporting that production, the company said. (Reporting by Shariq Khan and Rithika Krishna; Editing by Shinjini Ganguli)