||Numerical Simulation of Binh Chau Geothermal Reservoir in South Vietnam
||Department of Resources Engineering
||Le Minh Ly
The future development of Vietnam energy strategies focusing on the renewable energy in order to reduce dependence on fossil fuel energy source as well as to meet the target of mitigating global warming effect by reducing greenhouse gases emission, which also contribute to guarantee energy security, and sustainable socioeconomic development. Considering above concerns, the geothermal energy is one of the most promising renewable resources. There are some geothermal potential area in Vietnam such as South Central, North West, North Central, North East and North Plain. Binh Chau is one of the most geothermal potential area in South Central Vietnam.
Binh Chau geothermal field has highly productive fracture fault zone (eruptive rhyolite) which contains the hot water that reach 82 ℃ around the depth about 15-35 m underground. The heat sources at the bottom supplies the heat through the fractured fault zone. The heat sources is about 160 oC according to geochemical calculation. This geothermal reservoir is also supplied by surface stream as a ground water.
Numerical simulation is the most common method to evaluate the geothermal system throughout the development. In this study, numerical models are built to simulate the fluid flow and heat transfer through the geothermal system. Then a series of sensitivity analysis and optimization of the heat production is done accordingly.
This study was successful in establishing a conceptual model from the geological researches, hydrological reports and surface hot springs history data, observation wells data; the calibration of the conceptual model by natural state conditions and matches with the temperature profile from hot spring wells; the uncertainty analysis of expected energy capacity calculated most likely about 5.2 MWe, suggesting that building a geothermal power plant in Binh Chau area is economical choice.
TABLE OF CONTENTS
1.1 Global Geothermal energy. 1
1.2 Geothermal energy in Vietnam 2
1.2.1 Distribution of geothermal resources in Vietnam 3
1.2.2 Potential of geothermal areas in Vietnam 3
1.3 Vietnam Energy 7
1.3.1 Renewable Energy in Vietnam 7
1.3.2 Energy demand forecast 8
1.4 Technology in the development of geothermal power. 9
1.4.1 Binary 9
1.4.2 Flash steam. 10
1.4.3 Dry steam. 11
1.5 Motivation and Purpose 12
CHAPTER 2 LITERATURE REVIEW 14
2.1 Numerical simulation of geothermal reservoir and evaluation of geothermal system 14
2.2 Binh Chau geothermal area 17
2.3 Summary of literature review 17
CHAPTER 3 REGIONAL GEOLOGICAL SURVEY 18
3.1 Binh Chau geothermal area 18
3.2 Geologic characteristic 19
3.3 Stratigraphy 19
3.4 Characteristic of faults 20
3.5 Hydrogeology 22
3.5.1 Surface water 22
3.5.2 Underground water 23
CHAPTER 4 STUDY PROCESS AND SIMULATION DESIGN 27
4.1 Study Process 27
4.2 The application of CMG STARS for geothermal simulation 28
4.2.1 Governing Equations 29
4.2.2 Conservation Equations 29
4.3 Conceptual model 34
4.3.1 Heat source 34
4.3.2 Geological setting 35
4.3.3 Reservoir Geometry 36
4.4 Numerical model-base case 37
4.4.1 Reservoir model construction 37
4.4.2 Base case 38
4.5 Calibration of the model-natural state simulation 43
4.6 Production model 47
CHAPTER 5 RESULTS AND DISCUSSION 48
5.1 Results of the base case 48
5.1.1 Spatial distribution of the pressure. 48
5.1.2 Spatial distribution of temperature. 51
5.1.3 Results of base case 54
5.2 Sensitivity analysis 55
5.2.1 Fractured porosity 55
5.2.2 Fracture permeability 56
5.2.3 Production rate 57
5.3 Final Case 58
5.3.1 Result of final case 58
5.3.2 Spatial distribution 59
5.3.3 Determining the energy potential in the forecast for geothermal sources. 63
5.3.4 The uncertainty of results 64
CHAPTER 6 CONCLUSION AND SUGGESTION 72
6.1 Conclusion 72
6.2 Suggestions 72
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