Abstract: Study of geothermal energy from middle-to-deep layers aims at development of a certain renewable clean energy to reduce dependence of fossil fuels and carbon discharge. It is an important measure for green and low-carbon transition of the energy industry. Focusing on the bottlenecks in geothermal development of the middle-to-deep layers in the Jizhong zone, such as geological identification, development plans and surface engineering, this article makes study of the key underground and surface technologies, which leads to the following results. (1) The thermal reservoirs of the middle-to-deep layers in the Jizhong zone are mainly layered sandstone and block buried hill. The bottleneck for sandstone geothermal development is the difficulty to identify the sandstone layer with a relatively poor re-injection ability. The bottleneck for buried hill geothermal development is the strong heterogeneity of the thermal reservoir requiring high drilling success rate and high designing precision of the development plan. (2) Prediction of the favorable thermal reservoir and sweet spot identification technology are able to effectively identify the sweet spot of a thermal reservoir. Combination of optimized development parameters with dynamic analysis while drilling+production-injection experiment+ five sensitivity experiment brings about high-efficiency sandstone geothermal development. (3) Combined application of geophysical data, drilling log and testing data can precisely identify the position of the buried hill thermal reservoir. The high-efficiency gravity flow buried hill development technology leads to high production based on a few wells and full pressure-free re-injection in the same layer. (4) The technology of using geothermal high temperature differential pump for warming, anti-sewage and anti-scaling improves the geothermal heat-exchanging rate and reduces the operational and maintenance cost. (5) Using geothermal energy for warming, refrigeration and steam generation according to applications based on the different scenarios further expands the range of geothermal utilization and improves the utilization rate of geothermal resources, thus bringing the resource energy into full play.

Key words: geothermal energy of middle-to-deep layers; layered sandstone; buried hill geothermal energy; estimation of resource; high temperature differential heat pump

摘要： 研究中深层地热旨在开发一种可再生的清洁能源，以减少对化石燃料的依赖，降低碳排放，是能源行业绿色低碳转型的重要抓手。针对冀中地区中深层地热效益开发中存在的地质识别、开发方案和地面工程等难题，开展了地下和地面关键技术研究，为中深层地热效益开发提供借鉴。研究取得以下认识：（1） 冀中地区中深层热储主要有层状砂岩、块状潜山等，砂岩型地热开发难点是砂层识别难，回灌能力相对较差；潜山型地热开发难点是热储非均质性强，钻井成功率与开发方案设计精准率要求高。（2） 有利热储预测与甜点识别技术能够有效识别热储甜点，随钻动态分析+采灌试验+五敏试验优化开发参数相结合，实现砂岩型地热高效开发。（3） 地球物理、钻录测试资料等联合应用，可准确定位潜山热储位置，重力流潜山高效开发技术实现少井高产、同层无压全回灌。（4） 通过地热大温差热泵供暖和防污防垢技术，提高了地热换热效率，降低了运维成本。（5） 地热供暖、地热制冷和地热制蒸汽等根据不同场景组合应用，进一步拓展地热利用形式，提高地热资源利用率，使资源效能得以充分发挥。

关键词: 中深层地热；层状砂岩；潜山地热；资源评价；大温差热泵