Characterizing the Effect of Heat Transfer on Multiphase Flow during the Steam-Assisted Gravity Drainage (SAGD) Process

2013 ◽  
Author(s):  
Prince Nnamdi Azom ◽  
Arjan Kamp ◽  
Sanjay Srinivasan
Keyword(s):  
Heat Transfer ◽  
Multiphase Flow ◽  
Gravity Drainage ◽  
Steam Assisted Gravity Drainage

Phase Analysis of Scale Deposition in Boiler Tubes Utilizing Steam-Assisted Gravity Drainage Produced Water

2016 ◽  
Vol 9 (1) ◽  
Author(s):  
Raymond Kuriger ◽  
David Young ◽  
Malcolm Mackenzie ◽  
Hamid Sarv ◽  
Jason Trembly
Keyword(s):  
Heat Transfer ◽  
Produced Water ◽  
Magnesium Silicate ◽  
Solid Content ◽  
Operating Conditions ◽  
Gravity Drainage ◽  
Dissolved Solids ◽  
X Ray ◽  
Steam Assisted Gravity Drainage ◽  
Boiler Tubes

Scale buildup on water-side heat transfer surfaces poses a potential operating challenge for steam-assisted gravity drainage (SAGD) boilers used in the production of bitumen since produced water, which has a high dissolved solid content, is recycled. Scale from deposition of dissolved solids on boiler tubes acts as a thermal insulating layer, decreasing heat transfer and lowering boiler efficiency. Understanding scale deposit composition on heat transfer surfaces is beneficial in the determination of adequate boiler maintenance practices and operating parameters. This research determined the effect of feedwater pH (7.5, 9.0, and 10.0) on scale composition resulting from deposition of dissolved solids under commercially relevant boiler operating conditions at 8.96 MPa (1300 psig) and 37.86 kW/m2 (12,000 Btu/h ft2). Scale deposits were analytically investigated using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDS), powder X-ray diffraction (XRD), and Raman spectroscopy. At feedwater pH values of 7.5 and 9.0, anhydrite (CaSO4), xonotlite (Ca6Si6O17(OH)2), and pectolite (NaCa2Si3O8(OH)) were detected. At the pH of 10.0, xonotlite and pectolite were identified in the absence of anhydrite. Furthermore, the magnesium silicate phase, serpentine (Mg3Si2O5(OH)4), was also postulated to be present.

Convection at the Edge of a Steam-Assisted-Gravity-Drainage Steam Chamber

SPE Journal ◽  
2011 ◽  
Vol 16 (03) ◽  
pp. 503-512 ◽  
Author(s):  
Jyotsna Sharma ◽  
Ian D. Gates
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Relative Permeability ◽  
Convective Heat ◽  
Injection Well ◽  
Gravity Drainage ◽  
Oil Sand ◽  
Production Well ◽  
Steam Chamber ◽  
Steam Assisted Gravity Drainage

Summary Steam-assisted gravity drainage (SAGD) has become the preferred process to recover bitumen from Athabasca deposits in Alberta. The method consists of a lower horizontal production well, typically located approximately 2 m above the base of the oil zone, and an upper horizontal injection well located roughly 5 to 10 m above the production well. Steam flows from the injection well into a steam chamber that surrounds the wells and releases its latent heat to the cool oil sands at the edge of the chamber. This research re-examines heat transfer at the edge of the steam chamber. Specifically, a new theory is derived to account for convection of warm condensate into the oil sand at the edge of the chamber. The results show that, if the injection pressure is higher than the initial reservoir pressure, convective heat transfer can be larger than conductive heat transfer into the oil sand at the edge of the chamber. However, enhancement of the heat-transfer rate by convection may not necessarily imply higher oil rates; this can be explained by relative permeability effects at the chamber edge. As the condensate invades the oil sand, the oil saturation drops and, consequently, the oil relative permeability falls. This, in turn, results in the reduction of the oil mobility, despite the lowered oil viscosity because of higher temperature arising from convective heat transfer.

scholarly journals Expansion Velocity Model of Steam-Assisted Gravity Drainage considering Thermal Convection

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Dian-Fa Du ◽  
Yao-Zu Zhang ◽  
Li-Na Zhang ◽  
Meng-Ran Xu ◽  
Xin Liu
Keyword(s):  
Heat Transfer ◽  
Heat Capacity ◽  
Heavy Oil ◽  
Heat Convection ◽  
Gravity Drainage ◽  
Steam Chamber ◽  
Steam Assisted Gravity Drainage ◽  
Expansion Speed ◽  
Actual Field ◽  
Horizontal Expansion

Steam-assisted gravity drainage (SAGD) is an important method used in the development of heavy oil. A heat transfer model in the SAGD production process is established based on the heat transfer effect caused by the temperature difference at the front edge of the steam chamber and the heat convection effect caused by the pressure difference. The observation well temperature method is used in this model to calculate the horizontal expansion speed of the steam chamber. In this manner, an expansion speed model considering heat convection and heat conduction is established for a steam chamber with a steam-assisted gravity drainage system. By comparing this with the production data extracted from the Fengcheng Oilfield target block, it is verified that the model can be effectively applied for actual field development. Simultaneously, by using the derived model, the temperature distribution at the edge of the steam chamber and production forecast can be predicted. Sensitivity analysis of the expansion rate of the steam chamber demonstrates that the larger the thermal conductivity, the faster is the steam chamber horizontal expansion speed, and the two are positively correlated; the larger the reservoir heat capacity, the slower is the steam chamber horizontal expansion speed. A larger heat capacity of the convective liquid indicates that there are more water components in the convective liquid, the viscosity of the convective liquid is low, and the expansion speed of the steam chamber increases accordingly. This research closely integrates theory with actual field production and provides theoretical support for the development of heavy oil reservoirs.

A New Mathematical Model to Understand the Convective Heat Transfer Mechanism in Steam-Assisted Gravity Drainage Process

2017 ◽  
Vol 10 (1) ◽  
Author(s):  
Zhaoxiang Zhang ◽  
Huiqing Liu ◽  
Xiaohu Dong ◽  
Huanli Jiang
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Analytical Model ◽  
Convective Heat ◽  
Transfer Mechanism ◽  
Gravity Drainage ◽  
Heat Transfer Mechanism ◽  
Oil Viscosity ◽  
Steam Chamber ◽  
Steam Assisted Gravity Drainage

Steam-assisted gravity drainage (SAGD) process has been an optimized method to explore heavy oil reservoirs in the world. The oil viscosity reduction and gravity force near the interface of steam–chamber are the main development mechanisms. In classical models, conductive heat transfer plays the only or dominant role in the heat transmission from high-temperature steam to low-temperature oil sands. Although some mathematical studies have paid attention to the convective heat transfer, the role of heat transfer by flowable oil normal to the steam–chamber interface has been given little attention. In SAGD, the viscosity of bitumen can be reduced by several orders of magnitude by the release of latent heat from injected steam. In this study, an analytical model is developed for the heat transfer process induced by flowable oil. Also, in order to accurately simulate the oil viscosity characteristics in steam–chamber, a correlation between oil viscosity and pressure is proposed. Results indicate that the oil mobility plays an important role on the flow normal to interface when the distance is smaller than 6 m. Even under the most extreme circumstances (μw = 0.1127 cp), the flowing of oil normal to steam–chamber interface also cannot be ignored. Comparing to Irani and Ghannadi model, it can be easy to draw the conclusion that the new model consists with the underground test facility (UTF) field data much better. This new analytical model will benefit to understanding the convective heat transfer mechanism in SAGD process.

scholarly journals A Separate-Phase Drag Model and a Surrogate Approximation for Simulation of the Steam-Assisted-Gravity-Drainage Process

SPE Journal ◽  
2016 ◽  
Vol 21 (02) ◽  
pp. 364-379 ◽  
Author(s):  
Juan C. Padrino ◽  
Xia Ma ◽  
W. Brian VanderHeyden ◽  
Duan Z. Zhang
Keyword(s):  
Multiphase Flow ◽  
Time Scales ◽  
Momentum Equation ◽  
Numerical Code ◽  
Gravity Drainage ◽  
Steam Assisted Gravity Drainage ◽  
Viscous Forces ◽  
Averaged Equations ◽  
Execution Speed ◽  
The Cost

Summary General, ensemble phase-averaged equations for multiphase flows were specialized for the simulation of the steam-assisted-gravity-drainage (SAGD) process. In the average momentum equation, fluid/solid and fluid/fluid viscous interactions are represented by separate force terms. This equation has a form similar to that of Darcy's law for multiphase flow but augmented by the fluid/fluid viscous forces. Models for these fluid/fluid interactions are suggested and implemented into the numerical code CartaBlanca. Numerical results indicate that the model captures the main features of the multiphase flow in the SAGD process, but the detailed features, such as plumes, are missed. We find that viscous coupling among the fluid phases is important. Advection time scales for the different fluids differ by several orders of magnitude because of vast viscosity differences. Numerically resolving all these time scales is time consuming. To address this problem, we introduce a steam-surrogate approximation to increase the steam-advection time scale, while keeping the mass and energy fluxes well-approximated. This approximation leads to approximately a 40-fold speedup in execution speed of the numerical calculations at the cost of a few percentage errors in the relevant quantities.

Discussion on the Effects of Temperature on Thermal Properties in the Steam-Assisted-Gravity-Drainage (SAGD) Process. Part 1: Thermal Conductivity

SPE Journal ◽  
2013 ◽  
Vol 21 (02) ◽  
pp. 334-352 ◽  
Author(s):  
Mazda Irani ◽  
Marya Cokar
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Temperature Profile ◽  
Conductive Heat Transfer ◽  
Gravity Drainage ◽  
Conductive Heat ◽  
Temperature Dependent ◽  
Steam Chamber ◽  
Steam Assisted Gravity Drainage ◽  
Temperature Dependent Thermal Conductivity

Summary Steam-assisted gravity drainage (SAGD) is the preferred thermal-recovery method used to produce bitumen from Athabasca deposits in Alberta, Canada. In SAGD, steam injected into a horizontal injection well is forced into the reservoir, losing its latent heat when it comes into contact with cold bitumen at the edge of a depletion chamber. Heat energy is transferred from steam to reservoir, resulting in reduced bitumen viscosity that enables the bitumen to flow toward the horizontal production well under gravity forces. Conduction is the main heat-transfer mechanism at the edge of the steam chamber in SAGD, and reservoir thermal conductivity is a key parameter in conductive-heat transfer. Conductive-heat transfer occurs at higher rates across reservoirs with higher thermal conductivity, which in turn affects the temperature profile ahead of the steam interface. Consequently, a reservoir with higher thermal conductivity will result in higher reservoir-heating rates, which lead to higher oil rates. However, when oil-sand reservoirs are heated from reservoir temperature to steam-chamber temperature, the thermal conductivity can decrease up to 25%, which affects the temperature profile and conductive heating at the edge of the steam-saturated zone known as the steam chamber. This study provides an analytical model that includes a temperature-dependent thermal-conductivity value. This novel approach is the first of its kind to incorporate a temperature-dependent thermal-conductivity value within an analytical SAGD model to predict temperature front, oil production, and steam/oil ratio (SOR). Furthermore, if Butler's (1985) model is used, the results reveal that the arithmetic average thermal-conductivity values at reservoir and steam temperatures could be used for temperature-profile prediction, which would result in an error of less than 1% for the range of SAGD applications. The results of this study suggest that the minimum error for oil rates depends on the viscosity/temperature correlation. The optimum thermal conductivity should be calculated at the temperature that gives dimensionless temperatures [i.e., (T−Tr)/(Tst−Tr)] varying between 0.75 to 0.85 for m-values [Butler-suggested power constants (Butler 1985, 1991; Butler and Stephens 1981)] between 3 and 5.6. This study also investigates the effect of including temperature-dependent thermal conductivity on SOR variation and suggests that for both laterally expanding and angularly expanding reservoirs the SOR is independent of the thermal conductivity.

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