One of the geothermal challenges is the ability to estimate the changes of geothermal reservoir behavior over time. Some of reservoir properties are influenced by production and injection activities during the exploitation stage. The decreasing of pore pressure affects the level of effective stress, and it leads to change the values of permeability and porosity also the possibilities of compaction or subsidence. To overcome it, the geomechanics effect involved in reservoir modeling by coupling heat flow and geomechanics simulator, namely TOUGH2® and ABAQUS®. The purposes of the research are to investigate important parameters between geomechanics and heat flow simulation and to propose a coupling method between geomechanics and heat flow simulator. The proposed coupling scheme is iterative coupling, which is linking the input and output from both software iteratively at each time step. The program has built in python codes. The synthetic model has been used as a representative of a water dominated geothermal reservoir, which has 10 wells with total production of 600 kg/s. The simulation is set for 10 years with 1 year of time step. The results of simulation are the decreasing of porosity and permeability values of some layers in the production area, including the occurrence of level depletion. The sensitivity test is conducted by comparing the changes of porosity, permeability, and level depletion between 600 kg/s and 1,000 kg/s of total mass production. The highest decreased values of those three parameters happened in 1,000 kg/s simulation. Based on the results, the coupling program is considered able to perform iterative coupling between TOUGH2® and ABAQUS®. The important parameters which influence the heat flow simulation are the porosity and permeability, as well as changes in the shape or volume of elements.

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