Transient-Pressure Behavior of Cold Heavy-Oil Production Wells
Bibliographic record
Abstract
Transient Pressure Behavior of Cold Heavy Oil Production Wells Xiangdong Liu; Xiangdong Liu U. of Regina Search for other works by this author on: This Site Google Scholar Gang Zhao Gang Zhao U. of Regina Search for other works by this author on: This Site Google Scholar Paper presented at the SPE International Thermal Operations and Heavy Oil Symposium, Calgary, Alberta, Canada, November 2005. Paper Number: SPE-97791-MS https://doi.org/10.2118/97791-MS Published: November 01 2005 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Liu, Xiangdong, and Gang Zhao. "Transient Pressure Behavior of Cold Heavy Oil Production Wells." Paper presented at the SPE International Thermal Operations and Heavy Oil Symposium, Calgary, Alberta, Canada, November 2005. doi: https://doi.org/10.2118/97791-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE International Thermal Operations and Heavy Oil Symposium Search Advanced Search AbstractThe objective of this paper is to investigate the transient pressure behavior of Cold Heavy Oil Production (CHOP) wells with the consideration of wormhole configurations and foamy oil flow. Wormholes provide main conduits for foamy oil flow in the production process, and foamy oil is highly compressible owing to the dispersed and encompassed gas bubbles. This study proposes a comprehensive model to describe the transient flow of matured CHOP wells. Then, the transient pressure behavior has been extensively analyzed. The model not only provides reliable transient pressure responses of matured CHOP wells, but also offers a way to estimate the possible wormhole configurations and to understand the possible pressure drop along wormholes.IntroductionThe CHOP technology is one of the most attractive new technologies in heavy oil production. It is a non-thermal process in which sand is aggressively produced to stimulate a production process for a higher oil rate. The transient pressure behavior of CHOP wells has arisen considerable interest over the past few decades. Smith[1] proposed a radial diffusivity equation with a pseudo-pressure form to model pressure behavior of heavy oil reservoirs under solution gas drive. But, the model did not account for any permeability enhancement or wormhole effect. Several traditional models including classical storage & skin factor models,[2] infinite conductive fracture model, and dual porosity flow model[3] were applied to analyze the pressure data of CHOP wells. No applicable results were reported; therefore, it is believed that conventional models cannot be used to generate a reasonable understanding and this is mainly because of the fact that the wormhole and the foamy oil flow in matured CHOP wells were not integrated comprehensively.Wormholes generated by the aggressive sand production provide the main conduits for fluid flow in reservoirs. The presence of wormholes has been confirmed in light of the observations made in oil fields and from investigations through laboratory experiments.[1–7] Rapid communications between wells were observed by tracer tests in several oil fields.[1, 4–6] Pressure testing results[2] showed that the inflow performance behaves like a linear flow. Production logs of the injection tests[3] indicated that the majority of injected water entered a single discrete zone. The high porosity channels were observed in the laboratory experiments.[7]Foamy oil is highly compressible owing to the dispersed and encompassed gas bubbles. Smith1 first proposed the foamy oil presence in matured CHOP wells from the observations of bubbles existed in the produced oil. He inferred that solution gas drive in some heavy oil reservoirs involved simultaneous mixture flow of gas as tiny bubbles entrained in heavy oil, which were much smaller than the pore throat size. The laboratory work8, 9 showed the significance of foamy oil behavior in the primary heavy oil production process. It was observed that oil and gas mixture was flowing mostly in the form of continuous foam in their experiments. Apparently, the foamy oil has a much higher compressibility than that of heavy oil.This study proposes a comprehensive model to describe the transient flow of matured CHOP wells. The reservoir flow model considers foamy oil flow as simultaneous mixture flow of tiny gas bubbles entrained in heavy oil with significant pressure-dependent compressibility. Possible wormhole configurations are roughly estimated by material balance analysis of sand production data and subsequently integrated into the reservoir flow model. Then, the wormhole flow is coupled with the reservoir flow. Finally, a sensitivity study is carried out to investigate the impacts of wormhole growth patterns, pressure drop along wormholes, cumulative sand production volumes, and wellbore storage on the transient pressure and derivative responses. Keywords: reservoir, equation, drillstem/well testing, permeability, wormhole, cold heavy oil production, drillstem testing, influx rate, wormhole section, wormhole segment Subjects: Improved and Enhanced Recovery, Formation Evaluation & Management, Cold heavy oil production, Drillstem/well testing This content is only available via PDF. 2005. SPE/PS-CIM/CHOA International Thermal Operations and Heavy Oil Symposium You can access this article if you purchase or spend a download.
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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 | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".