SS: Hydrates: Experimental results for long term CO2 injection near methane hydrate formations
Bibliographic record
Abstract
Abstract CO2 has been focused for improving recovery factor of methane hydrate. The most of the principle is replacing guest molecular. It is also known that CO2 hydrate formation generates a large amount of exothermic heat. This heat can warm sediments up to 10 degrees Celsius as one of heating method. But a problem is how to inject CO2 at near fields of methane hydrate formations. CO2 hydrate formed in sediment blocks the pore of sediments. Then CO2 cannot inject into sediments for about ten-year term. But it is possible to inject CO2 for long term by a thermo-dynamic principle of the stability zone of CO2 hydrate. We will present experimental results to prove the principle of CO2 injection into formations. 1. Introduction Methane hydrate is solid, and it doesn't flush and flow from production well. Methane hydrate must be dissolved into gas and water in sediments by lowering the water pressure of the sediments or by heating the sediments to flow out from production well. Research consortium for methane hydrate resources in Japan succeeded to onshore depressurization test at permafrost in Canada for 6 days, and the consortium estimated the resources in the east part of Nankai trough[1]. The first trial of offshore test in Nankai trough is planed in 2012. On the other hand, CO2-enhanced oil recovery is commercialized by injecting CO2 into oil wells in the U.S. to enlarge oil production [2]. This method mitigates CO2 release into atmosphere. A research development is therefore necessary for an enhanced recovery of methane hydrate by using CO2. There is a problem of productivity by dropping of temperature for methane hydrate production by depressurization, because dissolving methane hydrate is endothermic reaction. It absorbs heat. Combining a heating method as an option to the depressurization to warm sediments, the productivity would be kept for long term. The recovery factor can also be expected to enlarge by the heating method. The productivity and the recovery factor are very important for commercialization of methane hydrate production. However, if we use fossil energy for the heating method, production rate, which is produced energy over input energy, become small. Then new technical developments are necessary for heating sediments for commercialization. We focused that CO2 hydrate formation is exothermic reaction, and we have proposed a heating method using heat of CO2 hydrate formation [4,5]. Sediments can be warmed up to 10 degrees Celsius when the pressure is more than or equal to 4.5 MPa to accelerate dissolving methane hydrate. CO2 works as heating energy of sediments in this case. Blockage of gas transportation pipeline cased by gas hydrate was reported in 1934. If CO2 is injected in to sediments, CO2 hydrate is formed and it blocks the pore of sediments in the same manner. Then CO2 can't inject into sediments. A subject for applying the heating method using exothermic heat of CO2 hydrate formation is to show a method to inject CO2 in to sediments continuously for long terms. The point of this method is using equilibrium state. No CO2 hydrate formation and dissolving are occurred. It balanced on the boundary of CO2 hydrate stability zone. Then the pore is kept opening for flow. Also the temperature of the formations is kept at 10 degrees Celsius by formation and dissolving of CO2 hydrate naturally. Then CO2 can inject into sediments continuously for long terms by using the equilibrium state. When the pressure is more than or equal to 4.5 MPa, the temperature of the equilibrium state is 10 degrees Celsius. In the following chapter, the principle of CO2 injection into formation continuously for long terms is verified by experiments are presented.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".