TOKYO (Reuters) - TG Natural Resources LLC (TGNR), co-owned by Tokyo Gas ( TKGSF ) and Castleton Commodities International, has bought a 70% stake in the east Texas gas assets from Chevron ( CVX ) for $525 million, the company said on Tuesday, as it expands its U.S. gas business.

TGNR is already the fourth biggest producer in the Haynesville shale basin and the deal would allow to realize synergies of over $170 million during the asset's development, Craig Jarchow, the company's chief executive, said in a statement.

Haynesville's location in east Texas and northwest Louisiana is ideal for exports from liquefied natural gas (LNG) facilities and projects clustered on the nearby Gulf Coast, and has investors' attention as U.S. President Donald Trump aims to boost gas exports.

Tokyo Gas ( TKGSF ), Japan's largest city gas provider, said last week it wanted to increase coordination between its LNG trading and shale gas businesses in the U.S. and expand there, as it sees shale gas as a major profit pillar in the coming years.