复杂地质条件下浅层地热能场地开发适宜性评价

Evaluation of the Site Suitability for Shallow Geothermal Development under Complicated Geological Conditions

浅层地热能是一种清洁高效的可再生能源。浅层地热能的成功开发取决于多种人为因素和自然因素。在地质条件复杂的地区,建设地源热泵项目前应对其场地开发的适宜性做出科学和充分的评价。当前对浅层地热能资源开发适宜性的研究,大多都是针对大区域内、普适性的场地进行开发适宜性评价,而对于复杂地质条件下小区域内的浅层地热资源场地开发适宜性问题缺乏科学的评价方法。从小区域场地特征和影响因素出发,分别对场地条件、地层条件、地下水条件和地层热物性参数等主要影响因素进行了分析评价并给出了赋值参考,通过数学模型及计算公式得出复杂地质小区域场地的开发适宜性综合评价指数。得出结论:裂隙水流速、溶洞发育程度和裂隙发育程度是适宜性评价权重最大的三个指标。根据层次分析法给出开发影响因素权重分析,并根据分级打分给出适宜性评价判断标准。该研究方法和结论为分析复杂地质小区域场地开发适宜性,以及进一步评估其技术经济效益提供了分析工具和决策依据,通过分析具体的评价指标,建立科学的评价体系,对实际工程中复杂地质小区域场地浅层地热开发适宜性评价具有一定指导意义。

Shallow geothermal is a clean and efficient renewable energy.Successful development of shallow geothermal energy depends on a variety of artificial and natural factors.In areas with complicated geological conditions,the suitability of site development should be scientifically and adequately evaluated before the construction of ground source heat pump projects.Most of the current studies on the suitability of shallow geothermal development are focused on universal evaluation in large-scale areas,while there is a lack of scientific evaluation methods for the suitability of site development in small-scale areas under complicated geological conditions.The site conditions,stratigraphic conditions,groundwater conditions and stratigraphic thermophysical parameters are analyzed and evaluated from the characteristics and influencing factors of the project sites.The comprehensive evaluation index of site development suitability in small areas with complicated geology is derived and verified through mathematical models and calculation formulas.It is concluded that fracture water flow rate,scale of cavity development and scale of fracture development are the three indexes with the greatest weight to the suitability evaluation.The weight analysis of development influence factors is conducted according to the hierarchical analysis method,as well as the suitability evaluation judgement criteria according to the hierarchical scoring.Research methods and conclusions provide an analytical tool and decision bases for analyzing the suitability of project sites with complicated geological conditions for development and further evaluating techno-economic benefits.By analyzing specific evaluation indexes and establishing a scientific evaluation system,it has a guiding significance for evaluating the suitability of shallow geothermal development in complicated geological sites in engineering practice.