Abstract: The marine engineering survey focuses on the geological hazards that have potential threats to the marine engineering. In the process of moving towards deep water, it has also found several unique geological phenomena that are different from shallow water areas, which have a certain impact on the positioning of drilling platforms, the design of jacket platforms and floating platforms, and the optimization of submarine pipeline and cable routes. Based on the results of many deepwater well site surveys and deep-water oil and gas field development project surveys, this paper expounds the characteristics of deep-water geological hazards, the methods of research and evaluation and the impact on marine engineering through the results of engineering geophysical survey, engineering geological survey and marine environmental survey, and provides a better idea for the investigation and design of deep-water marine engineering. The research shows that the deep water is widely developed with sand waves, scarps, hard seabed, faults, submarine canyons, MTDs and other geological disaster phenomena. When conducting engineering geophysical survey, the use of AUV and other survey methods to obtain higher resolution survey results can effectively reduce the observation period of seabed sand wave movement rate, and obtain more accurate water depth topographic data to support the marine engineering design, Combined with the shallow soil sample results and shallow profile results of the engineering geological survey, the seabed strata can be effectively divided and the slope stability analysis can be carried out, providing the design basis for the offshore engineering construction.

Key words: Deep water geological hazards, Oil and gas field development, Submarine pipeline, Deep water foundation