Global oil and natural gas operators could be pushed to sell or trade $100 billion-plus in assets because of the energy transition to alternative fuels, but it’s likely the U.S. portfolios would be off the table, according to a new analysis.

Rystad Energy did a deep dive on the geographical spread of some of the largest operators generally defined as majors for its study, using BP plc, Chevron Corp., ConocoPhillips, Eni SpA, Equinor SA, ExxonMobil, Royal Dutch Shell plc and Total SE.

As many companies in the energy field and beyond look to achieve net-zero emissions within 30 years, the eight exploration and production (E&P) giants “may need to divest combined resources of up to 68 billion boe, with an estimated value of $111 billion and spending commitments in 2021 totaling...