How to choose the proper instruments and equipment for an Oil & Gaz storage plant?

I am an electrical engineering student during my end of studies internship and I've been given the project of designing the instrumentation and control system of a nearshore oil & gaz storage plant. And I am wondering how to choose the proper instruments for my system to measure temperature, volume in tanks, fluid level in tanks, flow and density and also motorized valves to control the fluid.
Thank you very much!
Pick a technolgy for whatever needs to be measured to be controlled.
Tank gauging instrumentation for high value contents is a different class than fill/empty level measurement. For instance, are multiple temperature measurements over an elevation gradient required?

Most manufacturers have a fill-in-the-blanks document that they might call an application data sheet. One selects materials of construction. sensing range, output types, installation specific requirements like hazardous area rating that is used to select the features needed for an instrument of a given technology.

Write out a control narrative explaining what's being measured and what's being controlled. Create an I/O list. Pick a PLC, add some HMI's.