Interpretation of Temperature Profiles from the Steam-Stimulated Cold Lake Reservoir

Vittoratos, E.

doi:10.2118/15050-ms

Cited by 21 publications

(5 citation statements)

References 10 publications

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“…ft2/hr [0.0023 m 2 /h], which is in close agreement with values reported by Wheeler 5 and Vittoratos6 for the Clearwater reservoir. The heated zone extended across the entire Clearwater formation, with a limited degree of preferential heating in Sand C2 and upperFig.…”

supporting

confidence: 90%

“…The location of the combustion front near an injector can be controlled by either gravity or reservoir mob'ility effects. 6. The combustion process improved the off-trend heating.…”

Section: Discussionmentioning

confidence: 99%

“…Occurrences of horizontally heated zones away from a vertical fracture have been observed in the Cold Lake area. 6 The transformation of a vertical fracture into a horizontal fracture has also been reported in the literature. 7 The delayed responses at these wells, however, suggested a longer travel path and, coupled with the size of the temperature peaks, indicated that the wells were not linked by a fracture.…”

mentioning

confidence: 84%

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Interpretation of Temperature Observations From a Cyclic-Steam/ In-Situ-Combustion Project

Nzekwu

Hallam

Williams

1990

SPE Reservoir Engineering

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Data collected at 10 temperature observation wells were analyzed to evaluate the implementation of a combined process of cyclic steam stimulation followed by pressure-uplblowdown combustion for the in-situ recovery of bitumen. The temperature profiles at four observation wells, along the northeast/southwest fracture plane (on-trend direction), confirmed the height and orientation of the vertical fractures during cyclic steam stimulation. Six off-trend wells indicated that the heat transfer away from the fracture plane was predominantly conductive, with varying amounts of convective flow. During the in-situ combustion phase, frontal temperatures > 2, 200°F [1200°C] were detected. Data also indicated that the vertical location of the combustion front can be controlled by either gravity or mobility effects. The off-trend heating was improved as a result of higher convective heat fluxes. Reservoir GeologyThe Clearwater formation, at a depth of about 1,475 ft [450 m], is an unconsolidated sand with several upward-coarsening trends called Sands CI, C2, and C3. Sand Cl has a net pay thickness of 13 ft [4.0 m], a gross thickness of 19 ft [5.9 m], a porosity of 32%, and a bitumen saturation of 58 %. This zone contains an occasional interbedded tight streak. Sands Cl and C2 are separated by 12.5 ft [3.8 m] of shale, which frequently is separated into two shale layers by 2.6 ft [0.8 m] of sand. Sand Cl is overlain by 16 ft [4.9 m] of shale that forms an effective seal with the Lower Grand Rapids formation.Sand C2 has a net pay thickness of9 ft [2.8 m], a gross thickness of 14.8 ft [4.5 m], a porosity of 29%, and a bitumen saturation of 68 %. Horizontal permeabilities are high, but vertical permeability is reduced by up to two tight streaks. Sands C2 and C3 are separated by a thin shale that varies in thickness from 0 to 3 ft [0 to 1 m].Sand C3 has a net pay thickness of 53 ft [16.2 m], a gross thickness of 65 ft [19.8 m], a porosity of33%, and a bitumen saturation of 65 %. Horizontal permeability is high (1 to 3 darcies) but vertical permeability is reduced by frequent clay laminae and up to three indurated ferroan calcite-cemented layers dispersed within the sand. The lower 9 to 12 ft [3 to 4 m] consists of silts and clays, and the perforated intervals were selected several feet above this zone. The basal shale is more than 10 ft [3 m] thick and forms an effective seal between the Clearwater and McMurray formations.The bitumen has a dead-oil viscosity of 100,000 cp [100 000 mPa' s] at the original reservoir temperature of 60°F [15°C]. Field data have shown that the bitumen can be produced when the viscosity is reduced to about 100 cp [100 mPa . s] by heating to 212 OF [l00°C].

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supporting

confidence: 90%

“…The location of the combustion front near an injector can be controlled by either gravity or reservoir mob'ility effects. 6. The combustion process improved the off-trend heating.…”

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 84%

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Interpretation of Temperature Observations From a Cyclic-Steam/ In-Situ-Combustion Project

Nzekwu

Hallam

Williams

1990

SPE Reservoir Engineering

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“…Besides large commercial operations, Esso also operates several pilots [1][2][3][4] to test various production scenarios and to study the physics of cyclic-steam stimulation. 5 Observation wells play a key role in the pilots, and much has been learned from temperature observations.…”

Section: Introductionmentioning

confidence: 99%

Application of Time-Series Analysis to Induced Gamma Ray Spectroscopy Logs From Two Cold Lake Heavy-Oil Observation Wells

Georgi

1991

SPE Formation Evaluation

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Induced gamma ray spectroscopy (IGRS) logs from two cyclic-steam-stimulation observation wells in Cold Lake were analyzed to determine the vertical resolution and repeatability of data derived from gamma rays of inelastic and capture neutron reactions. Time-series analysis, a technique that uses the Fourier representation of the log data, was used to quantify the vertical resolution and the signal/noise characteristics of various IGRS log curves and .to compute the coherence vs. spatial frequency of data .collected on multiple IGRS passes. The coherence function .ranges from 1.0 for perfect repeatability to 0.0 for incoherent noise. Because no real variations in the measured data were expected for the 12-to 24-hour data-collection period, any deviation of the coherence function from 1.0 is attributed to incoherent noise. Generally, coherence is high at low frequencies (large vertical scales) and low at high frequencies (small vertical scales). By noting the frequency at which the coherence level decreases to the expected value of random noise, we can quantify the vertical resolution of a log curve.Data analysis from these wells indicates that both the vertical resolution and repeatability of individual capture and inelastic curves differ. We found that the H-yield and capture curves have the highest vertical resolution (""' 0.3 m) and the best signal/noise ratios (FSN=30: 1). In contrast, the capture Ca and Si yields are of significantly lower quality (FSN=2: 1). Only a small difference exists between the vertical resolution of the inelastic C (1.0 m) and 0 (1.3 m) yields, but the F SN of the 0 yield is only one-half that of the C yield. Fortunately, the vertical resolution and the repeatability of the C/0 ratio, F CO• are determined primarily by the quality of the inelastic C data. Specific to our application of monitoring heavy-oil saturations during cyclic-steam stimulation in a relatively uniform, high-porosity unconsolidated sand, we developed a simplified F co interpretation that does not rely on the elemental yields from capture data. This linear model permits us to assess the uncertainties in computed saturations from the statistical noise in the inelastic Fco data.

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“…This value is estimated for saturated unconsolidated sandstone with 0.33 porosity, based on Butler (1991). The literature presents a broad range of values for thermal conductivity; that is, ranging from 1.45 to 4.03 (measured for the Cold Lake oil-sand reservoir by Scott and Seto, 1986), but it is relatively consistent regarding the thermal diffusivity of the oil-sand ( thermal ), equal to 7.0 ϫ 10 -7 m 2 /s [this value originally calculated by Vittoratos (1986) for Cold Lake oil sand reservoir and later was honoured by most publications from Imperial Oil Resources Limited (was formerly known as Esso Resources Canada Limited) such as: Bharatha, 1991 andButler, 1991].…”

mentioning

confidence: 97%

On Thermodynamics of Undrained Zone in SAGD Process

Irani

Ghannadi

2014

Day 2 Tue, December 09, 2014

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In Part 1 of this study (SPE 165457-MS) a permeability enhancement at the edge of steam chamber where the oil sand has been sheared under thermal stimulation was described and an increase in oil drainage rates was calculated for different conditions. Finally, a modified Butler's Theory that includes geomechanical effects was described.Since heat transfer mechanisms are pivotal to the SAGD process and there are some doubts on the behaviour of the undrained zone at the edge of SAGD steam chamber in this study thermodynamics of undrained zone is discussed and new mechano-thermal equations are described. At the edge of steam chamber heat energy is transferred from steam to reservoir, reducing the viscosity of the bitumen, which flows under gravity toward a horizontal production well. Some of the heat transferred into the reservoir is used to increase the temperature of the reservoir, and some is stored as strain energy associated with the thermal stress field. The classical approach to exploring heat transfer studies in the SAGD industry is designed to satisfy only the "conservation of energy". Therefore, there is a lack of understanding of strain energy absorbed within the reservoir, and its effect on temperature variation inside the reservoir. The aim of the present work is to introduce a thermodynamic model to explore the effects of strain energy on temperature within the reservoir. This study explores the negative effect of developed stress field on heat transfer normal to the steam chamber interface. The novelty of this approach is the fact that it fully honours the energy equation. This study suggests the strain-energy number (N ⌬ ) as a new dimensionless number representing an importance of the strain energy effect on the temperature profile within the reservoir. The results obtained from this study reveal that it is suitable to use Butler's theory and to exclude the strain energy effects in heat transfer in the SAGD process. This study uses both thermodynamic approach and pressure front evaluation to argue the current practice of suggesting no permeability enhancement occurrence beyond the 12 m from the steam interface suggested by Li et al. (2004) based on the bitumen viscosity greater than 20,000 cP. This study proposes using one tenth-length of pressure front for drained zone which is beyond the temperature front advancement. Knowing that the shear is mostly induced within temperature front, geomechanical effects within the reservoir can be studied suggesting drained condition.

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Interpretation of Temperature Profiles from the Steam-Stimulated Cold Lake Reservoir

Cited by 21 publications

References 10 publications

Interpretation of Temperature Observations From a Cyclic-Steam/ In-Situ-Combustion Project

Interpretation of Temperature Observations From a Cyclic-Steam/ In-Situ-Combustion Project

Application of Time-Series Analysis to Induced Gamma Ray Spectroscopy Logs From Two Cold Lake Heavy-Oil Observation Wells

On Thermodynamics of Undrained Zone in SAGD Process

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