Integrated well-path and surface-facility optimization for shallow-water oil and gas field developments

Following the discovery of an offshore oil or gas field, extensive facilities must be built to drill, produce and transport the hydrocarbon from the reservoir to a plant for processing. Selecting the site, number and size of these facilities is one of the most crucial decisions in developing the field – impacting not only the total investment, but also the ultimate recovery. Due to the complexity of the task, several numerical methods have been proposed to aid in the development of offshore fields. However, typical approaches consider surface facilities or well paths in isolation, or rely on highly idealized representations of both to plan the field development. This paper outlines a numerical model that integrates optimization of well paths and surface facilities in shallow-water offshore oil and gas field developments. The integrated model determines the locations, size and number of offshore platforms, tie-in and separation facilities, as well as optimizing the well paths and pipeline routes. We compare different methods to calculate the well path, including an explicit determination of the trajectory of complex horizontal and extended reach wells. In addition, the model implements shallow-water facility design constraints, such as the minimum and maximum allowable water depth for installation. We demonstrate the model through case studies examining small and large shallow-water field developments from the North Sea, the Gulf of Mexico, and offshore California.