Pore-Level Observation of Gravity Assisted Tertiary Gas-Injection Processes
Bibliographic record
Abstract
Pore-Level Observation of Gravity Assisted Tertiary Gas-Injection Processes W. Ren; W. Ren University of Alberta Search for other works by this author on: This Site Google Scholar R. Bentsen; R. Bentsen University of Alberta Search for other works by this author on: This Site Google Scholar L.B. Cunha L.B. Cunha University of Alberta Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Latin American and Caribbean Petroleum Engineering Conference, Port-of-Spain, Trinidad and Tobago, April 2003. Paper Number: SPE-81007-MS https://doi.org/10.2118/81007-MS Published: April 27 2003 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Ren, W., Bentsen, R., and L.B. Cunha. "Pore-Level Observation of Gravity Assisted Tertiary Gas-Injection Processes." Paper presented at the SPE Latin American and Caribbean Petroleum Engineering Conference, Port-of-Spain, Trinidad and Tobago, April 2003. doi: https://doi.org/10.2118/81007-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Latin America and Caribbean Petroleum Engineering Conference Search Advanced Search AbstractIn water drive oil reservoirs, more than half of the initial oil in place is trapped in the water-contacted zone after natural water influx or waterflooding. Gas injection into such reservoirs, with the assistance of gravity, interfacial tension and oil film flow, can cause the displacement of excess water and the redistribution of reservoir fluids in the pore space. As the result of such fluid redistribution, most of the residual oil can be recovered. Moreover, a second water flood following the gas injection can recover the oil in a shorter period of time.Gravity assisted tertiary gas injection processes include the Double Displacement Process (DDP) and the Second Contact Water Displacement Process (SCWD). The DDP consists of injecting gas into waterflooded oil zones. The SCWD process consists of submitting these gas-flooded zones to a new water displacement process. In this work, the double displacement process (DDP) and the second contact water displacement (SCWD) process were conducted in a transparent sand-pack micromodel, and a pore-level observation was performed to investigate the microscopic mechanisms of the two processes.Observation of the two processes confirmed that the oil films play a very important role in achieving high recovery efficiencies in the DDP. The oil film was seen clearly. Such observation showed also that oil flowing through oil films and layers was driven not only by its own weight, but also by the increasing volume of the gas. In the SCWD process, trapped gas reduces the possibility of the residual oil being trapped in the center of the pores. Consequently, residual oil can be recovered quickly by a second water flood. Therefore, the SCWD process is suitable to apply in situations where the source of gas is not sufficient, and where the formation has a high irreducible gas saturation.IntroductionA waterflood can only recover 40% - 60% of the IOIP in conventional oil reservoirs. However, it has been shown, in the laboratory, that nearly 100% of the IOIP can be recovered by tertiary gas injection in the presence of connate water1. This tertiary recovery method involving the up-dip injection of gas into steeply dipping, high permeability, strongly water-wet, light oil reservoirs to recover the residual oil is called the gravity assisted tertiary gas injection process. It is also known as the Double Displacement Process (DDP) because it involves the use of gas to displace the oil remaining after a waterflood. The high recovery efficiency made the DDP such an attractive process that numerous laboratory studies2,3,4,5,6,7,8,9,10 of the DDP have been conducted in different media to investigate the mechanisms of the process. Moreover, four field tests have proved the technical feasibility of the DDP11,12,13,14,15,16,17.Besides gravity drainage, it has been suggested that oil film flow plays a most important role in the process. Imagine a steeply dipping waterflooded reservoir in which gas is being injected into the crestal region of the reservoir. After a short period of gas injection, a gas cap appears and an oil bank is formed ahead of the gas front. The gas front is stable and moves slowly downward to push the oil bank towards the producing wells. The oil in the gas swept zone may form a thin oil film if the spreading coefficient of the oil is positive. The oil films re-establish the hydraulic continuity of the oil by connecting all of the residual oil to the oil bank. Oil flowing through the oil films contributes to the development of the oil bank. When the oil bank reaches the production wells, oil production begins. The production characteristics of the process are that the main oil production takes place in a relatively short period of operating time and, after gas breakthrough, the oil is produced at a very low rate because the oil flows mainly through the oil films. Given sufficient time, the flow of oil through the oil films can result in very low oil saturation. However, the long production time at a low rate is detrimental to the economic success of the process. When such is the case, the Second Contact Water Displacement (SCWD) process can be used, provided the conditions are favorable. The SCWD process was introduced by Lepski18 to shorten the operating time of the DDP, and it is referred to as an extension of the DDP. Keywords: spe 81007, ddp, enhanced recovery, pore, pore-level observation, residual oil, scwd process, upstream oil & gas, coefficient, gravity Subjects: Improved and Enhanced Recovery, Gas-injection methods This content is only available via PDF. 2003. Society of Petroleum Engineers You can access this article if you purchase or spend a download.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".