After years of upstream underinvestment and a short-lived foray into clean energy, the world’s biggest oil and gas firms are accelerating exploration efforts as they look to replenish their upstream portfolios. Executives at Big Oil have been signaling for nearly a year that they seek to boost upstream portfolios in a world where oil and gas demand is growing and will continue to grow for years to come. During the 2025 earnings calls and at last week’s CERAWeek event in Houston, the top brass of the largest oil and gas majors reiterated…