GEOLOGIC AND POROUS MEDIA FACTORS AFFECTING THE 2007 PRODUCTION RESPONSE CHARACTERISTICS OF THE JOGMEC/NRCAN/AURORA MALLIK GAS HYDRATE PRODUCTION RESEARCH WELL
Bibliographic record
Abstract
A short-duration production test was undertaken at the Mallik site in Canada’s Mackenzie Delta in April 2007 as part of the JOGMEC/NRCan/Aurora Mallik 2007 Gas Hydrate Production Research Well Program. Reservoir stimulation was achieved by depressurization of a concentrated gas hydrate interval between 1093 and 1105m (RKB). Geologic and porous media conditions of the production interval have been quantified by geophysical studies undertaken in 2007 and geophysical and core studies undertaken by previous international partnerships in 1998 and 2002. These investigations have documented that the production interval consists of a sand-dominated succession with occasional silty sand interbeds. Gas hydrate occurs mainly within the sediment pore spaces, with concentrations ranging between 50-90%. Laboratory experiments conducted on reconstituted core samples have quantified the effects of pore water salinity and porous media conditions on pressure-temperature stability, suggesting that the partition between gas hydrate stability and instability should be considered as a phase boundary envelope or zone, rather than a discrete threshold. Strength testing on natural core samples has documented the dramatic changes in physical properties following gas hydrate dissociation, with sediments containing no hydrate behaving as unconsolidated sands. While operational problems limited the duration of the production test, a vigorous reservoir response to pressure draw down was observed with increasing gas flow during the testing period. We interpret that pressure temperature (P-T) conditions within the test zone were close to the gas hydrate phase equilibrium threshold, with dissociation initiated at 10 MPa bottomhole pressure (BHP), approximately 1 MPa below in situ conditions. The observation of an increase in production rates at approximately 8.2 MPa BHP may be consistent with the notion of an indistinct gas hydrate stability threshold, with rates increasing as P-T conditions traverse the phase boundary envelope. Significant sand inflow to the well during the test is interpreted to result from the loss of sediment strength during gas hydrate dissociation, with the sediment behaving as a gasified slurry. The increase in gas production rates during the final hours of the test may result from non-uniform gas hydrate dissociation and be affected by accelerated dissociation along water filled natural fractures or fine-scale geologic heterogeneities. These may initiate worm hole or high permeability conduits in association with sand production.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 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 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".