A Novel Surfactant-Enhanced DNAPL Remediation Technology with Horizontal Wells

Betty Cepeda-Salgado; Gyu Lee; Frank Tsai; Seung Kam

doi:10.69631/241eb066

Authors

Betty Cepeda-Salgado Louisiana State University, Craft and Hawkins Department of Petroleum Engineering, Baton Rouge, USA https://orcid.org/0009-0008-1695-4032
Gyu Lee Rural Research Institute in Korea Rural Research Corporation, Ansan/Naju, South Korea
Frank Tsai Louisiana State University, Department of Civil and Environmental Engineering, Baton Rouge, USA https://orcid.org/0000-0002-8005-5575
Seung Kam Louisiana State University, Craft and Hawkins Department of Petroleum Engineering, Baton Rouge, USA

DOI:

https://doi.org/10.69631/241eb066

Keywords:

surfactant imbibition, horizontal wells, DNAPL, in-situ remediaiton, simulation

Abstract

This study investigates surfactant-enhanced in-situ DNAPL (Dense Non-Aqueous Phase Liquids) remediation methods by using both vertical and horizontal wells. This novel technology is examined in two steps: (i) matching the pattern of DNAPL plume leakage and spreading and (ii) predicting the remediation efficiency in various design and optimization scenarios when the surfactant solution is continuously imbibed from the upper vertical well and the formation fluids (containing DNAPLs) are extracted from the lower horizontal wells. A dimensionless number comparing two capillary pressure values is introduced to understand pore-scale governing displacement mechanisms, which is combined with the concept of large-scale sweep efficiency.

By positioning these extraction wells beneath the contaminant plume with the surfactant solution introduced from the top, the simulation results show that the system configuration and remediation process successfully create a sufficient pressure gradient to overcome capillary trapping and mobilize oil blobs, generating enough contact areas to sweep the contaminants. The results also demonstrate that the surfactant-enhanced remediation technique, if properly designed and implemented with horizontal wells, can achieve the cumulative oil recovery of up to 36 - 37% (resulting from gravity drainage and low interfacial tension) and up to 52 - 53% (with additional well-to-well spacing adjustment) more than simple water injection methods, underscoring the potential of this innovative technology in the real-world applications. Discussions on the future research directions are also included.