TY - THES

T1 - The Exergy Analysis in Production Engineering

AU - Smaoui, Ines

N1 - embargoed until 07-05-2026

PY - 2021

Y1 - 2021

N2 - In order to improve the efficiency of oil wells equipped with gas lift, a thermodynamic analysis has led to creating a simulation model with a design modification that mitigates the innate losses of the system. The results are compared to other simulation models representing the original state of these wells. The new approach is based on both the nodal and exergy analyses and aims at identifying inefficiency nodes within the well. An assessment of the completion and the gas lift system of two selected wells focused on the quantification of the exergy losses and destructions. A GAP® model, linked to a PROSPER® file of each well, has been constructed and included modifications to minimize these losses. The comparison considered oil production rates, gas injection rates, the potential economic costs, and benefits, along with the efficiency of the system. By combining the nodal and exergy analyses, it was possible to identify two main sources of exergy destruction: the gas lift valve and the flow control valve. Using the GAP® model, the simulations show that even when a fraction of the exergy lost in these two nodes is recycled, there is an increase in production rates. The study of the behavior of the wells, when varying the gas injection rate, demonstrated that, starting from a specific rate, the exergy model presents higher production rates than the conventional gas lift model. To strengthen the analysis, an exergy-economic evaluation along with an efficiency index have completed the technical method by setting specific conditions from which the proposed exergetic alternative is better suited than the conventional gas lift method. The novelty of this paper is that it provides concluding insights on the limitations of the conventional energetic method and provides solutions to mitigate them. Moreover, it highlights the benefits of adopting the exergy methodology: essentially a higher efficiency and a lower environmental impact.

AB - In order to improve the efficiency of oil wells equipped with gas lift, a thermodynamic analysis has led to creating a simulation model with a design modification that mitigates the innate losses of the system. The results are compared to other simulation models representing the original state of these wells. The new approach is based on both the nodal and exergy analyses and aims at identifying inefficiency nodes within the well. An assessment of the completion and the gas lift system of two selected wells focused on the quantification of the exergy losses and destructions. A GAP® model, linked to a PROSPER® file of each well, has been constructed and included modifications to minimize these losses. The comparison considered oil production rates, gas injection rates, the potential economic costs, and benefits, along with the efficiency of the system. By combining the nodal and exergy analyses, it was possible to identify two main sources of exergy destruction: the gas lift valve and the flow control valve. Using the GAP® model, the simulations show that even when a fraction of the exergy lost in these two nodes is recycled, there is an increase in production rates. The study of the behavior of the wells, when varying the gas injection rate, demonstrated that, starting from a specific rate, the exergy model presents higher production rates than the conventional gas lift model. To strengthen the analysis, an exergy-economic evaluation along with an efficiency index have completed the technical method by setting specific conditions from which the proposed exergetic alternative is better suited than the conventional gas lift method. The novelty of this paper is that it provides concluding insights on the limitations of the conventional energetic method and provides solutions to mitigate them. Moreover, it highlights the benefits of adopting the exergy methodology: essentially a higher efficiency and a lower environmental impact.

KW - Exergy

KW - Analysis

KW - Efficiency

KW - Production

KW - Artifical Lift

KW - Gas Lift

KW - Exergo-economy

KW - Sustainability

KW - Environmental Impact

KW - Oil and Gas

KW - Energy

KW - Exergie

KW - Analyse

KW - Effizienz

KW - Produktion

KW - Artifical Lift

KW - Gas Lift

KW - Exergo-Economy

KW - Nachhaltigkeit

KW - Umweltbelastung

KW - Öl und Gas

KW - Energie

M3 - Master's Thesis

ER -