Potential Benefits of Horizontal Wells for CO2 Injection to Enhance Storage Security and Reduce Leakage Risks

Abstract

This study used numerical simulations of CO2 storage to identify the benefits of horizontal wells for geological carbon storage, such as enhancing CO2 trapped in porous media due to relative permeability and capillary hysteresis. Two injection schemes were tested: one using a vertical injector and the other employing a horizontal well. The results revealed two main findings. Firstly, the horizontal injection well effectively prevented or minimized CO2 penetration into the caprock across various sensitivity scenarios and over a thousand years of CO2 redistribution. Secondly, horizontal wells provided a safe approach to trapping CO2, increasing its entrapment as a residual phase by up to 19% within the storage site. This, in turn, reduced or prevented any unexpected events associated with CO2 leakage through the caprock. Additionally, the paper proposes a practical method for designing the optimal length of a horizontal well. This method considers a combination of two parameters: the additional CO2 that can be trapped using a horizontal well and the gravity number. In the case of the reservoir model of this study, a horizontal branch with a length of 2000 m was found to be the most effective design in enhancing CO2 entrapment and reducing CO2 buoyancy.

Unveiling Valuable Geomechanical Monitoring Insights: Exploring Ground Deformation in Geological Carbon Storage

“…At the end of the injection phase (Figure 7B), the CO 2 has predominantly remained within the reservoir boundaries. By 70 years (Figure 7C), there is a slight presence of CO 2 detectable in the surrounding rock formation mainly through diffusion or a numerical artifact driven by diffusion due to the course grid considered in our model, as discussed in [59,85]. However, this penetration is minimal and does not constitute a leakage concern as absence of fractures or other flow localization features in this model is assumed.…”

“…The imbibition curves are generated according to the hysteresis model, which is detailed in the next section. The dynamic properties used in this model are based on the characterization proposed by Machado et al [59], and it will be discussed in the next paragraphs. The relative permeability curves for CO2 and brine in sandstone and shale were obtained from Bennion and Bachu [60].…”

Unveiling the Essential Parameters Driving Mineral Reactions during CO2 Storage in Carbonate Aquifers through Proxy Models

“…Furthermore, the primary changes observed in the model are concentrated at the top of the injection interval and in the shallowest layers. This observation raises concerns regarding the integrity of the caprock, as discussed in [62]. These changes can be attributed to the upward migration of CO 2 within the reservoir, driven by its buoyancy, resulting in a localized concentration of effects near the injection zone.…”

The Interplay between Experimental Data and Uncertainty Analysis in Quantifying CO2 Trapping during Geological Carbon Storage

“…One of the most critical barriers to long-term and large-volume CO2 storage in geological formations is the proof of safe and reliable storage. For that, CO2 can take advantage of different trapping mechanisms in porous media [2][3][4][5][6]; for example, free CO2 migration is controlled by the structural and stratigraphic trapping exerted by the caprock during the short-term encompassing the injection time, known as a primary mechanism [7]. Part of that mobile CO2 will be dissolved in the water (solubility trapping) as time passes.…”