Development of a new simple hydrostatic equilibrium model for sustainable evaluation in geothermal energy

Abstract

Geothermal energy is a renewable energy, that is, the energy removed from the geothermal reservoir is continuously replaced on time scales similar to those required for energy removal. Replacement energy to the geothermal reservoir is supplied by fluid of natural recharge and injection. Sustainable geothermal utilization is the ideal condition of the applied production system to sustain the stable production level over long times. It is very important to manage the mass balance between production, injection and natural recharge in the geothermal reservoir to maintain sustainability during exploitation. A new simple hydrostatic equilibrium model is developed by this mass balance model of geothermal reservoir. This paper builds up a new simple hydrostatic equilibrium model to consider hydrostatic connection between recharged reservoir and discharged reservoir. Principle of fluid-pressure transmission states that pressure exerted anywhere in a confined incompressible fluid is transmitted equally in all directions. Hydrostatic equilibrium occurs when compression due to gravity is balanced by a pressure gradient force in the opposite direction. Mass changes data in this hydrostatic equilibrium model is estimated by gravity changes from repeat gravity measurement method. The equation result between production, injection and mass change rate calculates recharge factor from discharged reservoir. This model also assessed a relatively constant of entered mass flow rate from the surface that continues working during the production and injection well activity. This new simple hydrostatic equilibrium model is applied in Kamojang Geothermal Field, the geothermal reservoir with limited natural recharge.