Research on environmentally friendly chelating acid system for ultra-high temperature carbonate reservoirs.
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| Title: | Research on environmentally friendly chelating acid system for ultra-high temperature carbonate reservoirs. |
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| Authors: | Wang, Jiayu1 (AUTHOR), Li, Nianyin1 (AUTHOR) linianyin@swpu.edu.cn, Xiong, Ying2 (AUTHOR), Hu, Yanan1 (AUTHOR), Zhang, Haiyan1 (AUTHOR), Jiang, Chen1 (AUTHOR), Zhang, Hong1 (AUTHOR) |
| Source: | Journal of Dispersion Science & Technology. 2026, Vol. 47 Issue 3, p437-455. 19p. |
| Subject Terms: | *Chelating agents, *Fracturing fluids, *Corrosion resistance, *Carbonate reservoirs, *Chemical kinetics, *Thermal stability |
| Abstract: | Conventional acid fracturing fluids for ultra-high-temperature deep carbonate reservoirs generally exhibit issues such as rapid reaction rates, high corrosion, and easy precipitation. The thermal- stable, slow-reacting and low-corrosion chelating acid system can effectively address these issues. This study develops an eco-friendly chelating acid system using GLDA and HEIDA as primary agents, aiming for biodegradability, ultra-high-temperature resistance, low corrosion, and slow reaction rates. Experimental results indicate that adding 5 wt% NaCl and adjusting the pH to 4 with HAC yields the best overall performance for the chelating acid, maintaining excellent thermal stability and high solubility at 200 °C. Additionally, the reaction rate of this chelating acid at 200 °C is 1.25E-05 mol/s cm2 for calcite and 3.00E-06 mol/s cm2 for dolomite, which represent a decrease of 1 to 2 orders of magnitude compared to conventional acid fluids. Despite its lower acid-rock reaction rates, this chelating acid still demonstrates the ability to effectively communicate fractures at low injection volumes. Moreover, compared to conventional acids like hydrochloric acid and gelled acid, it retains high fracture conductivity under a closure pressure of 50 MPa. The findings of this study are significant for enhancing acid fracturing effectiveness in ultra-deep, ultra-high-temperature carbonate reservoirs. [ABSTRACT FROM AUTHOR] |
| Database: | Energy & Power Source |
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| Abstract: | Conventional acid fracturing fluids for ultra-high-temperature deep carbonate reservoirs generally exhibit issues such as rapid reaction rates, high corrosion, and easy precipitation. The thermal- stable, slow-reacting and low-corrosion chelating acid system can effectively address these issues. This study develops an eco-friendly chelating acid system using GLDA and HEIDA as primary agents, aiming for biodegradability, ultra-high-temperature resistance, low corrosion, and slow reaction rates. Experimental results indicate that adding 5 wt% NaCl and adjusting the pH to 4 with HAC yields the best overall performance for the chelating acid, maintaining excellent thermal stability and high solubility at 200 °C. Additionally, the reaction rate of this chelating acid at 200 °C is 1.25E-05 mol/s cm2 for calcite and 3.00E-06 mol/s cm2 for dolomite, which represent a decrease of 1 to 2 orders of magnitude compared to conventional acid fluids. Despite its lower acid-rock reaction rates, this chelating acid still demonstrates the ability to effectively communicate fractures at low injection volumes. Moreover, compared to conventional acids like hydrochloric acid and gelled acid, it retains high fracture conductivity under a closure pressure of 50 MPa. The findings of this study are significant for enhancing acid fracturing effectiveness in ultra-deep, ultra-high-temperature carbonate reservoirs. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 01932691 |
| DOI: | 10.1080/01932691.2024.2416445 |
