Hydrothermal Fluid Posted on 15th November 20159th September 2020 by ThePD (The Project Definition) Hydrothermal Fluid is the natural heated water solutions that can be either water or steam trapped in fractured or porous rocks. Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on LinkedIn (Opens in new window) Related Posted in Substance and tagged fluid, gas, oil. ThePD (The Project Definition) ThePD has been developing the Preferred Project Definitions based on the actual project execution and operation experiences and knowledge with the Project Language, and sharing with you daily basis.