Comparative Review of Thermodynamic Cycles for Co-Produced Geothermal Energy Recovery in Oil and Gas Wells

Geothermal heat co-produced with oil and gas offers a largely untapped renewable energy source that can enhance hydrocarbon recovery while reducing lifecycle emissions. This review critically examines five leading thermodynamic cycles—Organic Rankine Cycle (ORC), Kalina Cycle, Flash Steam, Cascade ORC, and supercritical CO₂ Brayton—for electricity generation from co-produced fluids in the ۸۰–۱۵۰ °C range. By synthesizing performance and cost data from over sixty peer-reviewed studies, we normalize first-law and exergy efficiencies, specific capital costs (USD/kW), levelized cost of electricity, operational complexity, and environmental impacts to a common reference case (۱۲۰ °C inlet, ۲۰ °C sink, ۲۰-year project life). Organic Rankine Cycles consistently deliver ۸–۱۲ % thermal efficiency at $۲,۸۰۰–$۳,۵۰۰/kW and remain the most practical choice for sub-۱۲۰ °C resources. Cascade ORC offers a ۴–۶ % efficiency uplift when temperatures vary seasonally, while Kalina systems achieve ۱۴–۱۶ % efficiency above ۱۳۰ °C at higher capital costs and complexity. Flash Steam cycles are constrained by temperature thresholds, and supercritical CO₂ represents a high-efficiency, high-risk option for ≥۱۵۰ °C wells. A temperature-driven decision framework is proposed, guiding technology selection based on resource temperature, project economics, and operational considerations. This work highlights knowledge gaps in long-term field performance and calls for standardized trials to support deployment.

کلیدواژه ها:

Geothermal Energy ، Organic Rankine Cycle ، Kalina Cycle ، Flash steam Cycle