Abstract Geothermal energy is an important renewable energy. Oilfields in high water cut stage are also geothermal fields. We propose a geothermal cascade utilization system, including organic Rankine cycle (ORC) power generation, Li-Br absorption refrigeration, oil gathering and transportation heat tracing (OGTHT) and heat. Associated geothermal water from abandoned oil wells is used as a renewable heat source. The thermodynamic and economic analysis of the cascade utilization system is carried out by establishing a mathematical model. In ORC system, we use two-stage series evaporation to reduce irreversible losses. The results show that there is an optimum evaporation temperature to maximize the net output power, thermal efficiency and exergy efficiency. It is found that the mass flow of the working fluid has a great impact on the system performance. In economic analysis, we find that both cost and benefit increase with the increase of geothermal water temperature (Tgw in) and driving heat source temperature. We use the payback period (PBP) as a comprehensive evaluation index of economy. The results show that there is an optimal temperature combination to minimize PBP. The smallest payback period occurs at the Tgw in is 383 K and the driving heat source temperature is 363 K, which is 3.07 years.

中文翻译：

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高含水油田油地热水伴生混合驱动多代能源系统技术经济性能

摘要 地热能是一种重要的可再生能源。高含水期油田也是地热田。我们提出了一种地热梯级利用系统，包括有机朗肯循环 (ORC) 发电、溴化锂吸收式制冷、石油集输伴热 (OGTHT) 和热量。来自废弃油井的伴生地热水被用作可再生热源。通过建立数学模型，对梯级利用系统进行热力学和经济分析。在 ORC 系统中，我们使用两级串联蒸发来减少不可逆损失。结果表明，存在使净输出功率、热效率和火用效率最大化的最佳蒸发温度。发现工作流体的质量流量对系统性能有很大的影响。在经济分析中，我们发现随着地热水温度（Tgw in）和驱动热源温度的升高，成本和收益都增加。我们使用投资回收期（PBP）作为经济的综合评价指标。结果表明，存在使 PBP 最小化的最佳温度组合。最小投资回收期出现在 Tgw 处为 383 K，驱动热源温度为 363 K，即 3.07 年。结果表明，存在使 PBP 最小化的最佳温度组合。最小投资回收期出现在 Tgw 处为 383 K，驱动热源温度为 363 K，即 3.07 年。结果表明，存在使 PBP 最小化的最佳温度组合。最小投资回收期出现在 Tgw 处为 383 K，驱动热源温度为 363 K，即 3.07 年。