** Shares of oil major Chevron CVX.N fall 1% to $153.80 premarket

** CVX posts lower Q1 adjusted profit as oil and gas production and refining margins were down year-over-year

** Company posts Q1 adjusted profit of $3.8 billion, or $2.18 per share, compared with $5.42 billion, or $2.93 per share, a year ago

** CVX's U.S. upstream segment posts Q1 income of $1.86 billion compared with $2.07 billion a year ago

** CVX's U.S. downstream segment reports Q1 income of $103 million compared with $453 million a year ago

** Company's Q1 net oil-equivalent production at 3.35 mln barrels of oil equivalent per day, in line with the levels a year ago

** CVX's Q1 total earnings fall to $3.5 billion from $5.5 billion a year ago

** Up till last close, shares down ~7.3% YTD

(Reporting by Pooja Menon in Bengaluru)

((Pooja.Menon@thomsonreuters.com;))