May 31(Reuters) - Cash-rich Exxon Mobil ( XOM ) and

Chevron ( CVX ) are bolstering their oil and gas drilling

inventory with multi-billion-dollar takeovers as they bet on

resilient demand for years to come.

The consolidation wave sweeping through the U.S. energy

sector that spurred deals worth $250 billion in 2023 shows no

signs of slowing as companies rush to deploy their cash hoard

from higher oil prices into building even bigger reserves

through acquisitions.

Earlier this month, Exxon closed its $60 billion purchase of

Pioneer Natural after receiving a go-ahead from U.S. regulators.

The deal would increase Exxon's total production to more

than 5 million barrels of oil equivalent per day (boepd) by

2027, making it the biggest producer in the Permian, the largest

and most highly valued U.S. oilfield.

Meanwhile, Hess shareholders last week approved the

company's proposed $53 billion takeover by Chevron ( CVX ), which will

get a foothold in rival Exxon's massive Guyana discoveries and

see its production rise to more than 4 million boepd by 2027.

Oil-rich Guyana's lucrative offshore fields are expected to

hold more than 11 billion barrels of oil and gas resources.

Exxon currently holds a 45% stake in Stabroek block in

Guyana, with Hess and China's CNOOC Ltd as its

minority partners.

The approval by Hess's shareholders clears one hurdle, but

the merger still needs regulatory approval and must face a

lengthy arbitration battle against Exxon.

Chevron ( CVX ), Exxon and other U.S. oil companies have booked

soaring profits from strong energy prices since Russia invaded

Ukraine.

Although their earnings are down from the bonanza year of

2022, they are still at strong levels.

At the end of 2023, Exxon had $31.54 billion in cash and

cash equivalents, while Chevron ( CVX ) held $8.18 billion.

Shares of Exxon and Chevron ( CVX ) have risen 14% and 6%

respectively, so far this year, compared with nearly an 8% rise

in the S&P 500 energy sector.