I. Research Process and Scope
The Quaternary loose strata are widely distributed in 18 cities under the jurisdiction of Henan Province, which are rich in low-grade geothermal energy resources in the shallow soil and shallow groundwater. In order to rationally develop and utilize the shallow geothermal energy resources in the cities, Henan Geological Survey Institute applied to the Henan Provincial Department of Land and Resources for the project of "Research on Evaluation and Development and Utilization of Shallow Geothermal Energy in Key Cities of Henan Province" in 2006, which was approved by the Henan Provincial Department of Land and Resources and listed as a "Scientific and Technological Tackling of Geology and Mineral Resources in Henan Province". The project was approved by Henan Provincial Department of Land and Resources, and listed as "Geology and Mineral Science and Technology Research Project of Henan Provincial Department of Land and Resources" (scientific research project No. 02), and the project design was prepared at the beginning of 2007, and passed the audit of Henan Provincial Department of Land and Resources in March 2007, and the acceptance and scientific and technological appraisal of the Department of Land and Resources of Henan Province in August 26th, 2009.
The scope of the original project: the urban built-up area and planning area of 11 key cities, including Zhengzhou, Kaifeng, Xinxiang, Xuchang, Luohe, Zhoukou, Anyang, Puyang, Jiaozuo, Luoyang and Nanyang, covering an area of about 5000km2. The area of the working area was adjusted to the area of the planning area in 2020 according to the social development situation in the course of the study.
The research scope of this book is based on expert opinions and the actual situation in Henan Province, adding the corresponding content of Hebi, Jiyuan, Sanmenxia, Shangqiu, Pingdingshan, Zhumadian, Xinyang and other 7 cities, at the same time, according to the "Shallow Geothermal Energy Survey and Evaluation Specification" (DZ/TO225-2009), adding the suitability evaluation of the application of ground buried pipe heat pump system and zoning research content.
Second, the purpose of the study
The purpose of this project is to provide scientific basis for the scientific utilization and protection of shallow geothermal resources, preliminary study on the type and potential of shallow geothermal resources in key cities of Henan Province, development and utilization of zoning, promotion of rational development and utilization of shallow geothermal energy in cities of Henan Province, and reduction of investment risks.
Third, the content of the study
In order to ensure the realization of the research objectives and tasks of this project, conducive to scientific and technological research, improve the scientific and technological level of the results and practicality, this book is mainly from the following four aspects of the study.
1. Shallow geothermal energy buried in the distribution of laws and cycle characteristics
The subject of the city is located in the pre-mountain alluvial flood plains, river flood plains, river valleys and basins and other hydrogeological units, shallow geothermal energy buried in the distribution of laws and cycle characteristics of the research is the basis of this research project, focusing on the following research content.
1) Thickness of the Quaternary System and depth of the annual thermostat.
2) Shallow geothermal energy burial, distribution and circulation characteristics.
3) Dynamic changes of water level, water temperature, water quality and influencing factors.
4) Establishment and determination of shallow geothermal resources evaluation parameter series, including infiltration coefficient, water storage coefficient, geothermal temperature gradient, recharge infiltration coefficient, thermal conductivity and geothermal heat flow value.
5) Establish the conceptual model of shallow geothermal energy for a typical city and determine the boundary conditions.
2. Evaluation of shallow geothermal energy resources
This subject is the main basis for the rational development and utilization zoning of shallow geothermal energy resources in cities, and the following contents are mainly studied for different hydrogeological units:
1) Calculating and determining the values of parameters for calculation and evaluation of shallow geothermal energy resources based on the observation of the earth's (water) temperature, the test of pumping and recharge, and indoor tests.
2) Establish a mathematical model based on the conceptual model.
3) Calculate the shallow geothermal energy storage and recoverable resources using different evaluation methods.
4) Calculate the extraction potential based on the current extraction and recoverable resources of shallow geothermal resources, and carry out the extraction potential zoning.
3.Research on shallow geothermal energy collection and recharge technology
This subject is also the main basis for rational development and utilization zoning of shallow geothermal energy. Mainly for the geological and hydrogeological conditions of different hydrogeological units, combined with existing projects to carry out recharge technology and field tests, study the recharge volume and water quality and water temperature on the shallow geothermal energy storage conditions and the impact of extractable resources; study the construction process, to determine the collection of shallow geothermal energy and recharge the technical conditions, including reasonable well depth, well spacing, well structure, mining volume and depth reduction, recharge volume, etc.; to determine reasonable The program of "immediate use and irrigation" is determined.
4. Comprehensive development and utilization zoning of shallow geothermal energy
Based on the research of the above topics, it will carry out zoning of the suitability of development and utilization of shallow geothermal energy; determine the development and utilization mode of shallow geothermal energy according to the development and utilization technical conditions; and put forward the corresponding protection measures and protection targets for the groundwater resources and shallow geothermal energy resources.
Fourth, the main research methodology
1. Data collection and secondary development
In the course of the project, the data on socio-economic development, regional geology, hydrogeology, shallow geothermal energy utilization, remote sensing, hydrology, meteorology, environmental protection, urban construction planning and urban energy conservation planning of the 18 key cities were widely collected and systematically synthesized. The study includes: ① stratigraphic structure, tectonic features; ② shallow geothermal energy utilization layer hydrogeological conditions; ③ summarize the current situation of development and utilization of shallow geothermal energy and existing problems.
2. Survey and research on the current situation of shallow geothermal energy development and utilization
Based on the ground survey, the survey focuses on the shallow geothermal energy utilization projects in the 18 urban areas of the study, and the survey includes the project area, the application of building area, the number of wells for pumping and recharging, the spacing of the wells, the volume of pumping water and the temperature of the groundwater, the volume of recharge and recharge water temperature, the dynamic change of the groundwater during the operation, and the cooling (heat) effect, etc. The study is expected to be completed in the next few years. The cooling (heat) effect, etc.
3. Hydrodynamic Methods of Investigation and Monitoring
Shallow geothermal energy resources can be described as a flowable resource mainly carried by water, and in order to study the conditions of groundwater runoff, groundwater level statistical surveys and dynamic monitoring have been carried out. Deployment of groundwater level monitoring in the dry season, the density of monitoring points is generally one point per 4km2; selection of existing shallow geothermal energy air-conditioning system for long-term monitoring, in order to study the impact of the operation of the groundwater source heat pump system on the groundwater environment, the monitoring time is not less than one hydrological year, the monitoring content, including the pumping volume, recharge volume, water level, water quality, water temperature, and the utilization of the effectiveness of the water, etc.. Among them, water quality monitoring selection in shallow geothermal energy air conditioning system before, during and after the operation of water samples were taken; water level and water temperature observation frequency of 1 every 5 days.
4. Investigation and Monitoring of Hydrothermodynamic Methods
In order to study the distribution characteristics of shallow ground temperature, the shallow groundwater temperature was investigated. Mainly combined with hydrodynamic field research to carry out groundwater temperature field distribution measurements, the instrument used in the well pyrometer (model JL-1), the density of measurement points on the plane roughly every 25m2 set up a point; vertical upward density of measurement points every 2m set up a point, the depth of measurement depending on the structure of the well to determine the specific conditions.
5. Hydrogeochemical research methods
The hydrochemical composition of groundwater reflects the formation environment and conditions of shallow geothermal energy, which can be used to study the cause and age of formation through the hydrochemical composition, and to evaluate the scientific use of shallow geothermal energy. In order to analyze the influence of different water quality on the shallow geothermal energy air conditioning system, the study proposes the corresponding treatment process measures, combined with the existing information, respectively, in the shallow geothermal energy air conditioning system dynamic monitoring point and the water chemistry data is relatively less in the study area to supplement the arrangement of the water quality of the full analysis of the water samples and sent to the laboratory for testing.
6. Field experimental methodology study
In order to understand the water-rich nature of the aquifer, calculate hydrogeological parameters, study the impact of groundwater recharge volume and water quality, water temperature on the shallow geothermal energy storage conditions and extraction of resources, to determine a reasonable "ready to use and irrigate" program; to study the suitability of the eastern plains fine-grained water pumping, recharge and recharge in the aquifer area. study the scientific construction technology and well structure of pumping and recharging wells suitable for fine-grained aquifer areas in the eastern plains, study the applicable conditions of shallow geothermal energy harvesting technology, and set up water injection and pumping tests in combination with existing or under-construction shallow geothermal energy utilization projects under different hydrogeological conditions. In order to obtain the thermophysical parameters of different stratigraphic lithology, one construction geological sampling hole was arranged in Zhengzhou City, and the sample taken was sent to Nanjing University laboratory for testing.
7. Modeling and research
Establishing the equilibrium model of shallow geothermal energy recharge, discharge and storage changes, and evaluating the amount of shallow geothermal energy resources; using the heat flow method or numerical method to predict and evaluate the amount of shallow geothermal energy resources according to the hydrogeological conditions; and evaluating the potential of shallow geothermal energy exploitation according to the mining resources and the current mining amount.
Selecting the geothermal zones with abundant data and typical types, using HST3D numerical simulation software to simulate the geothermal fluid transport; predicting and evaluating the temporal and spatial trends of the temperature of the geothermal fluid under the conditions of planned exploitation and utilization of the shallow geothermal fluid; simulating the distribution characteristics of the flow and temperature fields of the groundwater in different geologic, hydrogeologic and geothermal conditions; and evaluating the heat storage function and heat storage capacity of the shallow aquifer, in order to provide a rational basis for the development and utilization of the shallow geothermal energy. function and heat storage capacity of the shallow aquifer, and provide scientific basis for rational and scientific development of shallow geothermal fluid resources.
8. Comprehensive Research on Development and Utilization of Shallow Geothermal Energy
Based on the research of the above methods, the research proposes technical solutions for collecting shallow geothermal energy under different geological and hydrological geologic conditions, and formulates the zoning for the reasonable development and utilization of shallow geothermal energy in each city.
9. Database Construction
The collected data and newly acquired data will be organized and bound into books, and the database will be established according to the requirements by using the GIS software platform in a unified way. The implementation of the original map and the results of the map, such as the implementation of digitization, and the establishment of graphic attribute library and external attribute library.