CO2 Storage in the Nisku Aquifer in the Wabamun Lake Area, Canada - The Effect of Site Characterization Data on Caprock Integrity Modeling
Bibliographic record
Abstract
Abstract The geomechanical factors put significant constraints on CO2 storage in terms of injection pressures that may be limited by fracture propagation, injection rates that can be achieved without compromising the seal and excessive fracture propagation, and the CO2 placement affected by fracturing. Goodarzi et al (2012) investigated the feasibility of securely storing CO2 in Nisku geological formation located in Wabamun Lake area (Alberta, Canada) using a coupled flow, thermal and geomechanical model. Due to lack of field and lab measurements, the results of the study were reported as pessimistic. This paper utilized recently recorded well log, well test and lab measurements specific to the study area to build porosity, absolute and relative permeability, thermal, mechanical property and stress profiles required for refining the results of the aforementioned study. The results show that injection in the Nisku aquifer (below or at fracture pressure with 1–2 Mt/year) causes only small surface heave in the range of 2–3 mm. Injection above the fracture pressure at 2 Mt/year results in higher well injectivity but also increases the possibility of caprock fracturing. The degree of vertical propagation strongly depends on the caprock stress state and mechanical properties. The importance of the proper site characterization is highlighted by comparison of our current results with our earlier work on the same site reported in Goodarzi et al. (2012), in which estimates were used for many parameters. The predicted fracture dimensions based on updated fluid and rock mechanical properties in the current work are significantly larger than the dimensions reported in the 2012 study. The primary reason for this is the lower initial fracture pressure and higher stiffness of the reservoir rock formation used in this study.This causes smaller fracture width and lower leak-off which will be compensated by larger extent of fracture both horizontally and vertically.. Thermal effects of cold CO2 injection reduce significantly the fracture pressure and enhance the horizontal fracture propagation. The vertical extension of fracture in the thermal model was shown to be smaller than in the isothermal model due to the confining stress contrast created by thermoelastic stresses. This in turn resulted in larger horizontal propagation of fracture in the thermal model. The reduction of fracturing pressure due to thermal effects will reduce the well injectivity if the well is to be operated below fracture pressure, and increase fracture propagation if fracturing is allowed. This aspect needs to be taken into account by operators as well as by regulatory agencies. If it is required to operate below fracturing, the time-variation of fracture pressure under injection condition can be determined using geomechanicaly coupled model and its historical minimum value should be taken as the maximum operating pressure.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".