Novel Water-Based Drilling and Completion Fluid Technology to Improve Wellbore Quality During Drilling and Protect Unconventional Reservoirs

The efficient exploration and development of unconventional oil and gas are critical for increasing the self-sufficiency of oil and gas supplies in China. However, such operations continue to face serious problems (e.g., borehole collapse, loss, and high friction), and associated formation damage can severely impact well completion rates, increase costs, and reduce efficiencies. Water-based drilling fluids possess certain advantages over oil-based drilling fluids (OBDFs) and may offer lasting solutions to resolve the aforementioned issues. However, a significant breakthrough with this material has not yet been made, and major technical problems continue to hinder the economic and large-scale development of unconventional oil and gas. Here, the international frontier external method, which only improves drilling fluid inhibition and lubricity, is expanded into an internal-external technique that improves the overall wellbore quality during drilling. Bionic technologies are introduced into the chemical material synthesis process to imitate the activity of life. A novel drilling and completion fluid technique was developed to improve wellbore quality during drilling and safeguard formation integrity. Macroscopic and microscopic analyses indicated that in terms of wellbore stability, lubricity, and formation protection, this approach could outperform methods that use typical OBDFs. The proposed method also achieves a classification upgrade from environmentally protective drilling fluid to an ecologically friendly drilling fluid. The developed technology was verified in more than 1000 unconventional oil and gas wells in China, and the results indicate significant alleviation of the formation damage attributed to borehole collapse, loss, and high friction. It has been recognized as an effective core technology for exploiting unconventional oil and gas resources. This study introduces a novel research direction for formation protection technology and demonstrates that observations and learning from the natural world can provide an inexhaustible source of ideas and inspire the creation of original materials, technologies, and theories for petroleum engineering. (c) 2021 THE AUTHORS. Published by Elsevier LTD on behalf of Chinese Academy of Engineering and Higher Education Press Limited Company. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).