The ECLIPSE 2023.1 industry-reference simulator offers the industry’s most complete and robust set of numerical solutions for fast and accurate prediction of dynamic behavior for all types of reservoirs and development schemes. The ECLIPSE simulator has been the benchmark for commercial reservoir simulation for more than 25 years thanks to its extensive capabilities, robustness, speed, parallel scalability, and unmatched platform coverage. With over 30 years of continuous development and innovation, the ECLIPSE simulator is the most feature-rich and comprehensive reservoir simulator on the market—covering the entire spectrum of reservoir models, including black oil, compositional, thermal finite-volume, and streamline simulation. By choosing from a wide range of add-on options—such as local grid refinements, coalbed methane, gas field operations, advanced wells, reservoir coupling, and surface networks—simulator capabilities can be tailored to meet your needs, enhancing your reservoir modeling capabilities. This release of the ECLIPSE suite 2023.1 includes developments enhancing the performance, usability and functionality capabilities of the simulators.