A Mechanistic Study of Single-Well Steam Assisted Gravity Drainage

Singhal, A.K.; Das, Swapan Kumar; Goldman, Jon; Turta, Alex

doi:10.2118/59333-ms

Cited by 5 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In both processes, introduction of an additional resistance to flow in the horizontal section of the producer improved the performance by forcing the steam to further spread laterally (8) ; the same positive effect was confirmed during the investigation of a non-thermal TTH process, namely TTHW (2) . It must be emphasized that the TTH steamflooding process must be operated so that it is both pressuregradient and gravity-controlled, for maximizing volumetric sweep of the oil.…”

Section: Discussion Of the Results: Sw-sagd Connectionmentioning

confidence: 68%

“…However, to some extent, phenomena occurring in SW-SAGD process also occur in the TTH steamflooding-for example, the dichotomy between steam overriding and hot water underriding. That is likely the reason that some SW-SAGD tests gave better results when the horizontal leg was placed at the upper part, compared to placing the horizontal leg at the bottom of the layer (8) . It is assumed that the formation of a large amount of condensate water, while the steam chamber was very small or almost nonexistent, was the reason behind this behaviour.…”

Section: Discussion Of the Results: Sw-sagd Connectionmentioning

confidence: 99%

“…The SW-SAGD process uses the same well for both steam injection and for production and therefore the ability to control the process is much lower than for normal SAGD. Experiments in a 3D physical model with the addition of CO 2 showed improved performance of SW-SAGD, for a dead oil of 40 mPa.s viscosity (8) . These tests were carried out with co-injection of superheated steam and CO 2 .…”

Section: Introductionmentioning

confidence: 96%

See 2 more Smart Citations

Preliminary Considerations on Application of Steamflooding in a Toe-to-Heel Configuration

Turta¹,

Singhal²,

Xia

et al. 2009

Journal of Canadian Petroleum Technology

View full text Add to dashboard Cite

With the advent of horizontal wells, a distinct change is tacitly taking place in our approach to the improved recovery of heavy oil-from displacing mobilized oil in a flood pattern from injector to producers over long distances on the order of hundreds of metres to short-distance oil displacement (SDOD) processes (typically over a few tens of metres).SDOD processes comprise Steam Assisted Gravity Drainage (SAGD), Cyclic Steam Stimulation (CSS) and Toe-to-Heel (TTH) Displacement Processes, which comprise Toe-to-Heel Air Injection (THAI), with its variant catalytic THAI (CAPRI), and Toe-to-Heel Waterflooding (TTHW). Presently SAGD is commercially used, while THAI has been under field testing for 3 years; testing of CAPRI is scheduled to start in 2010. TTHW has been under field testing both in the US and Canada for more than 4 years.Steamflooding in a TTH configuration (TTH steamflooding) uses vertical wells as injectors and horizontal wells as producers, arranged in a staggered line drive, with producers having their toes close to the shoes of vertical injectors; the horizontal section of producers is located at the base of the pay. The vertical wells are used for initiating the steam front, which subsequently is anchored at the toe of the horizontal producer; it is then propagated towards the producer's heel. In TTH steamflooding, the existing deficiency of conventional steamflooding schemes in terms of low vertical sweep is overcome by the beneficial use of gravity.To investigate the potential of TTH steamflooding, some laboratory tests were conducted. The objective was to assess the feasibility of TTH steam and thermo-solvent flooding (steam+propane co-injection) by carrying out 3D model experiments using heavy oil with a viscosity of 15,000 cP.Laboratory results showed that the concepts of TTH steamflooding and TTH steamflooding with solvent are feasible. All in all, stability of TTH steamflooding was relatively good, while the stability of TTH steamflooding with the addition of nitrogen or propane was much better. Significant improvements in design and operation of these processes were needed in order to promote override during the early phase, and obtain a stable and efficient process. The improvements included a cold (gas fingering) and a hot (steam-based) communication phase; and controlling lateral spread of steam by using two additional vertical control wells (positioned laterally but close to the heel of the horizontal producer) for conducting a limited steamflood. Nitrogen was injected along with steam in the conventional steamflood; propane replaced nitrogen in TTH steamflooding with solvent. With these improvements, rise of steam chamber to the top occurred much earlier, and a favourable tilt-forward-angle of the thermal front was quickly obtained. TTH steamflooding with solvent proved superior to the TTH steamflooding, as the channeling of steam

show abstract

Section: Discussion Of the Results: Sw-sagd Connectionmentioning

confidence: 68%

Section: Discussion Of the Results: Sw-sagd Connectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

See 1 more Smart Citation

Preliminary Considerations on Application of Steamflooding in a Toe-to-Heel Configuration

Turta¹,

Singhal²,

Xia

et al. 2009

Journal of Canadian Petroleum Technology

View full text Add to dashboard Cite

show abstract

“…In contrast with the SAC-SAGD, this type uses one single horizontal well through which it injects steam and produces oil simultaneously (Elliot, 1999;Singhal, 2000). Steam is injected at the end of the horizontal well (Toe) through an isolated concentric Coiled Tubing with…”

Section: Single Well Sagd (Sw-sagd)mentioning

confidence: 99%

Feasibility to apply the steam assited gravity drainage (SAGD) technique in the country's heavy crude-oil fields

Rodríguez,

Orjuela

2004

CT&F Cienc. Tecnol. Futuro

View full text Add to dashboard Cite

The Steam Assisted Gravity Drainage (SAGD) processes are one of the most efficient and profitable technologies for the production of heavy crude oils and oil sands. These processes involve the drilling of a couple of parallel horizontal wells, separated by a vertical distance and located near the oilfield base. The upper well is used to continuously inject steam into the zone of interest, while the lower well collects all resulting fluids (Oil, condensate and formation water) and takes them to the surface (Butler, 1994) (Figure 1). This technology has been successfully implemented in countries such as Canada, Venezuela and United States, reaching Recovery Factors in excess of 50%. This article provides an overview of the technique's operation mechanism and the process' most relevant characteristics, as well as the various categories this technology is divided into, including all its advantages and limitations. Furthermore, the article sets the oilfield's minimal conditions under which the SAGD process is efficient, which conditions, as integrated to a series of mathematical models, allow to make forecasts on production, thermal efficiency (OSR) and oil to be recovered, as long as it is feasible (from a technical point of view) to apply this technique to a defined oil field. The information and concepts compiled during this research prompted the development of Software which may be used as an information, analysis and interpretation tool to predict and quantify this technology's performance. Based on the article, preliminary studies were started for the country's heavy crude-oil fields, identifying which provide the minimum conditions for the successful development of a pilot project.

show abstract

Promising Approaches to Enhance SAGD Performance in Uneconomical Tar-Sands

et al. 2012

View full text Add to dashboard Cite

Low permeability, shale barriers and low thickness are the main issues making significant portion of the immense heavy oil and bitumen resource uneconomical to produce. Two main troublesome cases were investigated in this study to address by applying appropriate solutions in SAGD process; firstly reservoirs with shale barriers and low permeability and secondly thin reservoirs.In cases of low vertical permeability due to shale inclusion in the reservoirs, the effect of induced vertical fracture resulted in faster upward steam chamber expansion and increased oil recovery rate. Sensitivity analysis showed higher well spacing is beneficial to the process while applying the induced vertical fracture. In thin reservoirs, steam chamber reaches overburden faster and increases cumulative steam-oil ratio (cSOR), hence making recovery processes uneconomical. Appropriate placement of Induced Horizontal-Fractures (IHF) and off-set vertical wells with the later being in halfway of two adjacent horizontal well pairs in SAGD and acting as a steam injector was applied. The results showed such applications reduce cSOR.Found from the sensitivity analysis, Induced Horizontal-Fractures positioned in the injector and the producer place improves oil recovery in thin reservoirs. When applying the fracture just in producer location, the oil recovery result is superior to the former case. In fact, IHF provide a path facilitating the oil drainage to producer that leads to faster oil transportation. The Off-set vertical well in the thin reservoir sweeps a part of the reservoir located beyond the chamber edges of two adjacent well pairs, hence reducing recovery time and cSOR. Based on sensitivity analysis, the most promising result of the process is achieved when initiating steam injection in the vertical injector from the beginning of the process.

show abstract

A Mechanistic Study of Single-Well Steam Assisted Gravity Drainage

Cited by 5 publications

References 0 publications

Preliminary Considerations on Application of Steamflooding in a Toe-to-Heel Configuration

Preliminary Considerations on Application of Steamflooding in a Toe-to-Heel Configuration

Feasibility to apply the steam assited gravity drainage (SAGD) technique in the country's heavy crude-oil fields

Promising Approaches to Enhance SAGD Performance in Uneconomical Tar-Sands

Contact Info

Product

Resources

About