A study on the impact of storage boundary and caprock morphology on carbon sequestration in saline aquifers

Abstract

Structural trapping is known to be the primary storage mechanism in geological carbon sequestration (GCS), where the injected CO 2 rises upwards due to buoyancy forces and becomes trapped under an ultra-low permeability layer. Although it is relatively common in GCS studies to assume a planar caprock for the synthesised models, in a real scenario this is not always the case as the caprock might exhibit some small-or large-scale topography changes. Moreover, little is known about the impact of the caprock morphology on the CO 2 plume migration and the storage capacity. In this work, we performed a preliminary study of the effects of boundary conditions on the CO 2 plume migration and dissolution. This was performed because most of the case study models which are employed for GCS studies are part of larger reservoirs. The obtained results were used in the simulation models of the second part of the work, to model an infinite-acting reservoir appropriately. Three different volume modifier values of 10 5 , 10 7 and 10 9 were considered on either one side or both sides of the reservoir for both horizontal and tilted caprock models. The CO 2 dissolution in the tilted models was seen to be higher once the multiplier was on the opposite side of the slope. Horizontal models closed on one side (closed faults, salt walls, etc.) were also found to exhibit more significant dissolution than models which were open from both sides. We subsequently investigated the impact of caprock morphology on the CO 2 plume advancement and its structural and dissolution trapping mechanisms by performing numerical simulations on nine synthetic models. The dissolution and migration distance are seen to be at a maximum for tilted reservoirs, where the CO 2 has more space to migrate upwards and to interact with more formation water. The lowest dissolution occurred where the significant portion of the injected CO 2 was trapped in a sand ridge or an anticline. Moreover, the possibility and also the amount of structural trapping was evaluated using an analytical method, and the results showed a fair match with the ones from the numerical simulation. We believe that this methodology could be applied for site screening prior to performing numerical simulations.

The Application of Geographic Information System in Urban Forest Ecological Compensation and Sustainable Development Evaluation

“…In Equation (11), G de represents the annual water purification amount of the evaluated forest, and K s represents the water purification cost. In terms of carbon sequestration and oxygen release capacity, the calculation of the carbon sequestration value is shown in Equation ( 12) [36].…”

Storage Sites for Carbon Dioxide in the North Sea and Their Particular Characteristics

“…Ahmadinia and Shariatipour [89,90] found that slight variation of the topography of the interface between the caprock and the upper reservoir, within the aforementioned limits on seismic resolution, led to substantial improvement in the agreement between Darcy flow simulations and the observations of plume distribution.…”

Effects of Injection Temperature and Pressure on CO2 Storage Capacity and Safety in a Sloping Formation

“…As a result, the cumulative amount of CO 2 to be stored in the formation decreases, with a larger extent updip and smaller downdip . Ahmadinia found that increasing the dip angle increased the buoyancy of CO 2 , resulting in more space for injected CO 2 to migrate upward, with a larger migration distance and interaction with more formation water. Wang , and Jing , found that formation dip angle had a certain impact on CGS.…”