Offshore Oil & Gas Floating Structures by definition are placed in an ocean environment where hydrodynamic interaction effects and dynamic response become major considerations in their design. In addition, the range of possible design solutions, such as: ship-like Floating Production Systems, (FPSs), and Tension Leg Platform (TLP) deep water designs; the more traditional jacket and jack-up (space truss like) oil rigs; and the large member sized gravity-style offshore platforms themselves, pose their own peculiar demands in terms of hydrodynamic loading effects, foundation support conditions and character of the dynamic response of not only the structure itself but also of the riser systems for oil extraction adopted by them. Invariably, non-linearities in the description of the hydrodynamic loading characteristics of the structure-fluid interaction and in the associated structural response can assume importance and need be addressed. This Database was designed to perform Onshore Oil & Gas Facilities Cost Estimates, based on generic cost curves for several Activity families types generated using benchmarking techniques. The benchmarked curves give Cost as a function of a capacity variable or combination of variables. The cost curves and other information contained in this application can be used to develop the overall process plant capital cost.