Biomineralization – A New Solution for Surface Casing Vent Flow
Bibliographic record
Abstract
Abstract A new solution to the increasingly important issue of surface casing vent flow (SCVF), a biocementation process involving the squeezing of biomineralizing fluids was utilized on a Canadian well. Initially developed by the United States Department of Energy (DOE) for the purpose of sealing leaks in carbon sequestration wells, this technology has been utilized in over 100 oil and gas wells across the United States and Canada to seal and repair damaged cement, restore wellbore integrity, and prevent the unwanted flow of hydrocarbons up the production and surface casing annular. The following paper represents a case study detailing a risk-based approach and field deployment assessing the technology's effectiveness on a well in Alberta. Abandonment operations which began on a well in Alberta, Canada in 2020 consisted of a series of zonal isolation plugs and cement retainer squeezes to eliminate surface casing vent flow. In March of 2023, with the vent flow still persistent at approximately 1 m3/day with 154 kPa build pressure, nonroutine abandonment operations began. The two previous cement retainer squeezes were drilled out down to the Mannville formation so new logs could be run. Biomineralization was identified as a viable solution to address SCVF on the well after initial analysis of the well indicated the presence of small aperture channels in the cemented annulus. In July 2023, the well was prepared for an annular squeeze utilizing biomineralization technology, and treatment commenced. Biomineralizing fluids were injected in intervals over the course of 48 hours, reducing injectivity by forming crystalline calcium carbonate, which has a similar chemical composition to limestone, to seal leakage pathways and eliminate gas flow. Over the course of treatment, 219 L of biomineralizing fluids were pushed into leakage pathways, with the injection rate reduced from 0.776 lpm to 0.026 lpm, constituting a 97% reduction. The injection rates, pressures, and total volumes at the conclusion of treatment indicated successful sealing of micron-sized channels. Vent monitoring technology confirmed this via a steady reduction in flow over the course of treatment, and the total elimination of flow and bubbles at surface just seven days later. Biomineralization technology has been used as a solution for sealing and repairing micro annuli and other channels in annular cement by several operators to eliminate surface casing vent flow in Canada.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".