HOUSTON (Reuters) -Chevron will lay off 15% to 20% of its global workforce by the end of 2026, the U.S. oil company said on Wednesday as it seeks to cut costs, simplify its business, and complete a major acquisition. The No. 2 U.S. oil producer has faced production challenges including cost overruns and delays in a large Kazakhstan oilfield project. Meanwhile, its $53-billion deal to acquire oil producer Hess and gain a foothold in Guyana's lucrative oilfield is in limbo due to a court battle with larger rival Exxon Mobil, which has outperformed it with production growth, achieving record production in Guyana and the biggest oilfield in the United States.