Mechanisms causing injectivity decline and enhancement in geothermal projects

Luo, W.; Kottsova, A.; Vardon, P.J.; Dieudonné, A.A.M.; Brehme, M.

doi:10.1016/j.rser.2023.113623

Mechanisms causing injectivity decline and enhancement in geothermal projects

Title

Mechanisms causing injectivity decline and enhancement in geothermal projects

Author

Luo, W. (TU Delft Geo-engineering)
Kottsova, A. (TU Delft Reservoir Engineering; ETH Zürich)
Vardon, P.J. (TU Delft Geo-engineering)
Dieudonné, A.A.M. (TU Delft Geo-engineering)
Brehme, M. (ETH Zürich)

Date

2023

Abstract

In geothermal projects, reinjection of produced water has been widely applied for disposing wastewater, supplying heat exchange media and maintaining reservoir pressure. Accordingly, it is a key process for environmental and well performance assessment, which partly controls the success of projects. However, the injectivity, a measure of how easily fluids can be reinjected into reservoirs, is influenced by various processes throughout installation and operation. Both injectivity decline and enhancement have been reported during reinjection operations, while most current studies tend to only focus on one aspect. This review aims to provide a comprehensive discussion on how the injectivity can be influenced during reinjection, both positively and negatively. This includes a detailed overview of the different clogging mechanisms, in which decreasing reservoir temperature plays a major role, leading to injectivity decline. Strategies to avoid and recover from injectivity reduction are also introduced. Followed is an overview of mechanisms underlying injectivity enhancement during reinjection, wherein re-opening/shearing of pre-existing fractures and thermal cracking have been identified as the main contributors. In practice, nevertheless, mixed-mechanism processes play a key role during reinjection. Finally, this review provides an outlook on future research directions that can enhance the understanding of injectivity-related issues.

Subject

Clogging
Geothermal projects
Injectivity changes
Reinjection
Thermal stimulation

To reference this document use:

http://resolver.tudelft.nl/uuid:63e6cb6f-0f12-42ae-a056-5b728ead948d

DOI

https://doi.org/10.1016/j.rser.2023.113623

ISSN

1364-0321

Source

Renewable & Sustainable Energy Reviews, 185

Part of collection

Institutional Repository