Feasibility of electromagnetic methods to detect and image steam-assisted gravity drainage steam chambers

Geophysics ◽  
2016 ◽  
Vol 81 (4) ◽  
pp. E227-E241 ◽  
Author(s):  
Sarah G. R. Devriese ◽  
Douglas W. Oldenburg
Keyword(s):  
Oil Recovery ◽  
Oil Sands ◽  
Vertical Component ◽  
Design Procedure ◽  
Production Costs ◽  
Three Dimensions ◽  
Gravity Drainage ◽  
Steam Chamber ◽  
Steam Assisted Gravity Drainage ◽  
Mcmurray Formation

We have investigated the use of electric and electromagnetic (EM) methods to monitor the growth of steam-assisted gravity drainage (SAGD) steam chambers. SAGD has proven to be a successful method for extracting bitumen from the Athabasca oil sands in Alberta, Canada. However, complexity and heterogeneity within the reservoir could impede steam chamber growth, thereby limiting oil recovery and increase production costs. Using seismic data collected over an existing SAGD project, we have generated a synthetic steam chamber and modeled it as a conductive body within the bitumen-rich McMurray Formation. Simulated data from standard crosswell electrical surveys, when inverted in three dimensions, show existence of the chamber but lack the resolution necessary to determine the shape and size. By expanding to EM surveys, our ability to recover and resolve the steam chamber is significantly enhanced. We use a simplified survey design procedure to design a variety of field surveys that include surface and borehole transmitters operating in the frequency or time domain. Each survey is inverted in three dimensions, and the results are compared. Importantly, despite the shielding effects of the highly conductive cap rock over the McMurray Formation, we have determined that it is possible to electromagnetically excite the steam chamber using a large-loop surface transmitter. This motivates a synthetic example, constructed using the geology and resistivity logging data of a future SAGD site, where we simulate data from single and multiple surface loop transmitters. We have found that even when measurements are restricted to the vertical component of the electric field in standard observation wells, if multiple transmitters are used, the inversion recovers three steam chambers and discerns an area of limited steam growth that results from a blockage in the reservoir. The effectiveness of the survey shows that this EM methodology is worthy of future investigation and field deployment.

scholarly journals Identifying Reservoir Features via iSOR Response Behaviour

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 427
Author(s):  
Jingyi Wang ◽  
Ian Gates
Keyword(s):  
Oil Sands ◽  
Gravity Drainage ◽  
Athabasca Oil Sands ◽  
Steam Chamber ◽  
Heterogeneous Reservoirs ◽  
Steam Assisted Gravity Drainage ◽  
Response Behaviour

To extract viscous bitumen from oil sands reservoirs, steam is injected into the formation to lower the bitumen’s viscosity enabling sufficient mobility for its production to the surface. Steam-assisted gravity drainage (SAGD) is the preferred process for Athabasca oil sands reservoirs but its performance suffers in heterogeneous reservoirs leading to an elevated steam-to-oil ratio (SOR) above that which would be observed in a clean oil sands reservoir. This implies that the SOR could be used as a signature to understand the nature of heterogeneities or other features in reservoirs. In the research reported here, the use of the SOR as a signal to provide information on the heterogeneity of the reservoir is explored. The analysis conducted on prototypical reservoirs reveals that the instantaneous SOR (iSOR) can be used to identify reservoir features. The results show that the iSOR profile exhibits specific signatures that can be used to identify when the steam chamber reaches the top of the formation, a lean zone, a top gas zone, and shale layers.

Numerical Simulation of Thermal Solvent Replacing Steam under Steam Assisted Gravity Drainage SAGD Process

2010 ◽  
Author(s):  
Weiqiang Li ◽  
Daulat D. Mamora
Keyword(s):  
High Temperature ◽  
Oil Recovery ◽  
Oil Sands ◽  
Steam Injection ◽  
Thermal Recovery ◽  
Production Performance ◽  
Gravity Drainage ◽  
Steam Assisted Gravity Drainage ◽  
Recovery Technique ◽  
Simulation Results

Abstract Steam Assisted Gravity Drainage (SAGD) is one successful thermal recovery technique applied in the Athabasca oil sands in Canada to produce the very viscous bitumen. Water for SAGD is limited in supply and expensive to treat and to generate steam. Consequently, we conducted a study into injecting high-temperature solvent instead of steam to recover Athabasca oil. In this study, hexane (C6) coinjection at condensing condition is simulated using CMG STARS to analyze the drainage mechanism inside the vapor-solvent chamber. The production performance is compared with an equivalent steam injection case based on the same Athabasca reservoir condition. Simulation results show that C6 is vaporized and transported into the vapor-solvent chamber. At the condensing condition, high temperature C6 reduces the viscosity of the bitumen more efficiently than steam and can displace out all the original oil. The oil production rate with C6 injection is about 1.5 to 2 times that of steam injection with oil recovery factor of about 100% oil initially-in-place. Most of the injected C6 can be recycled from the reservoir and from the produced oil, thus significantly reduce the solvent cost. Results of our study indicate that high-temperature solvent injection appears feasible although further technical and economic evaluation of the process is required.

Approximate Physics-Discrete Simulation of the Steam-Chamber Evolution in Steam-Assisted Gravity Drainage

SPE Journal ◽  
2018 ◽  
Vol 24 (02) ◽  
pp. 477-491 ◽  
Author(s):  
Enrique Gallardo ◽  
Clayton V. Deutsch
Keyword(s):  
Oil Sands ◽  
Recovery Process ◽  
Thermal Recovery ◽  
Porous Media Flow ◽  
Gravity Drainage ◽  
Discrete Simulation ◽  
Flow Equations ◽  
Integrity Assessment ◽  
Steam Chamber ◽  
Steam Assisted Gravity Drainage

Summary Steam-assisted gravity drainage (SAGD) is a thermal-recovery process to produce bitumen from oil sands. In this technology, steam injected in the reservoir creates a constantly evolving steam chamber while heated bitumen drains to a production well. Understanding the geometry and the rate of growth of the steam chamber is necessary to manage an economically successful SAGD project. This work introduces an approximate physics-discrete simulator (APDS) to model the steam-chamber evolution. The algorithm is formulated and implemented using graph theory, simplified porous-media flow equations, heat-transfer concepts, and ideas from discrete simulation. The APDS predicts the steam-chamber evolution in heterogeneous reservoirs and is computationally efficient enough to be applied over multiple geostatistical realizations to support decisions in the presence of geological uncertainty. The APDS is expected to be useful for selecting well-pair locations and operational strategies, 4D-seismic integration in SAGD-reservoir characterization, and caprock-integrity assessment.

scholarly journals A Workflow for Optimization of Flow Control Devices in SAGD

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3237
Author(s):  
Anas Sidahmed ◽  
Siavash Nejadi ◽  
Alireza Nouri
Keyword(s):  
Flow Control ◽  
Oil Sands ◽  
Net Present Value ◽  
Gravity Drainage ◽  
Operation Performance ◽  
Steam Assisted Gravity Drainage ◽  
Mcmurray Formation ◽  
Flow Control Devices ◽  
Recovery Technique ◽  
Control Devices

In McMurray Formation, steam assisted gravity drainage is used as the primary in-situ recovery technique to recover oil sands. Different geological reservoir settings and long horizontal wells impose limitations and operational challenges on the implementation of steam-assisted gravity drainage (SAGD). The dual-string tubing system is the conventional completion scheme in SAGD. In complex reservoirs where dual-string completion cannot improve the operation performance, operators have adopted flow control devices (FCDs) to improve project economics. FCDs secure more injection/production points along the horizontal sections of the SAGD well pairs, hence, they maximize ultimate bitumen recovery and minimize cumulative steam-oil ratio (cSOR). This paper will focus on the optimization of outflow control devices (OCDs) in SAGD reservoirs with horizontal wellbore undulations. We present the detailed optimization workflow and show the optimization results for various scenarios with well pair trajectory undulation. Comparing the results of the optimized OCDs case with a dual-string case of the same SAGD model shows improvements in steam distribution, steam chamber growth, bitumen production, and net present value (NPV).

Steam-Assisted Gravity-Drainage Performance With Temperature-Dependent Properties—A Semianalytical Approach

SPE Journal ◽  
2016 ◽  
Vol 22 (03) ◽  
pp. 902-911 ◽  
Author(s):  
M.. Heidari ◽  
S. H. Hejazi ◽  
S. M. Farouq Ali
Keyword(s):  
Oil Sands ◽  
Oil Production ◽  
Thermal Recovery ◽  
Effect Of Temperature ◽  
Gravity Drainage ◽  
Temperature Dependent ◽  
Rock Density ◽  
Steam Chamber ◽  
Steam Assisted Gravity Drainage ◽  
Temperature Dependent Properties

Summary Steam-assisted gravity drainage (SAGD) is one of the successful in-situ thermal-recovery methods for oil-sands production. In this paper, we provide a simple semianalytical model that can accurately analyze an SAGD project with variable properties. In particular, we investigate the effect of temperature-dependent properties such as thermal conductivity, heat capacity, and rock density on SAGD performance. The proposed model sequentially solves the transient nonlinear heat-transfer equation coupled with the continuity equation with Kirchhoff's transformation and the heat integral method (HIM). A criterion for timestep selection is defined on the basis of the Courant and Péclet numbers to guarantee the stability of the sequential technique. The results illustrate that the temperature-dependent physical properties affect temperature distributions ahead of steam chamber which consequently have a significant impact on the cumulative oil production and oil-production rate. Moreover, the results show that the temperature profile ahead of the steam chamber changes with time and space, and a 2D transient assumption for SAGD modeling is necessary. The semianalytical model runs in a small fraction of numerical-simulator runtime, yet it provides reasonable results. Thus, it has the potential to be used as a tool for quick SAGD evaluations.

Investigation of Emulsion Flow in Steam-Assisted Gravity Drainage

SPE Journal ◽  
2013 ◽  
Vol 18 (03) ◽  
pp. 440-447 ◽  
Author(s):  
C.C.. C. Ezeuko ◽  
J.. Wang ◽  
I.D.. D. Gates
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Oil Recovery ◽  
Vital Role ◽  
Gravity Drainage ◽  
Steam Assisted Gravity Drainage ◽  
Emulsion Flow ◽  
Very High ◽  
Effective Representation

Summary We present a numerical simulation approach that allows incorporation of emulsion modeling into steam-assisted gravity-drainage (SAGD) simulations with commercial reservoir simulators by means of a two-stage pseudochemical reaction. Numerical simulation results show excellent agreement with experimental data for low-pressure SAGD, accounting for approximately 24% deficiency in simulated oil recovery, compared with experimental data. Incorporating viscosity alteration, multiphase effect, and enthalpy of emulsification appears sufficient for effective representation of in-situ emulsion physics during SAGD in very-high-permeability systems. We observed that multiphase effects appear to dominate the viscosity effect of emulsion flow under SAGD conditions of heavy-oil (bitumen) recovery. Results also show that in-situ emulsification may play a vital role within the reservoir during SAGD, increasing bitumen mobility and thereby decreasing cumulative steam/oil ratio (cSOR). Results from this work extend understanding of SAGD by examining its performance in the presence of in-situ emulsification and associated flow of emulsion with bitumen in porous media.

scholarly journals Breccia interlayer effects on steam-assisted gravity drainage performance: experimental and numerical study

2021 ◽  
Author(s):  
Qichen Zhang ◽  
Xiaodong Kang ◽  
Huiqing Liu ◽  
Xiaohu Dong ◽  
Jian Wang
Keyword(s):  
Numerical Simulation ◽  
Oil Recovery ◽  
Oil Sands ◽  
Numerical Study ◽  
Middle Part ◽  
Experimental Results ◽  
Production Performance ◽  
Peak Oil ◽  
Steam Chamber ◽  
The Impact

AbstractCurrently, the reservoir heterogeneity is a serious challenge for developing oil sands with SAGD method. Nexen’s Long Lake SAGD project reported that breccia interlayer was widely distributed in lower and middle part of reservoir, impeding the steam chamber expansion and heated oil drainage. In this paper, two physical experiments were conducted to study the impact of breccia interlayer on development of steam chamber and production performance. Then, a laboratory scale numerical simulation model was established and a history match was conducted based on the 3D experimental results. Finally, the sensitivity analysis of thickness and permeability of breccia layer was performed. The influence mechanism of breccia layer on SAGD performance was analyzed by comparing the temperature profile of steam chamber and production dynamics. The experimental results indicate that the existence of breccia interlayer causes a thinner steam chamber profile and longer time to reach the peak oil rate. And, the ultimate oil recovery reduced 15.8% due to much oil stuck in breccia interlayer areas. The numerical simulation results show that a lower permeability in breccia layer area has a serious adverse impact on oil recovery if the thickness of breccia layer is larger, whereas the effect of permeability on SAGD performance is limited when the breccia layer is thinner. Besides, a thicker breccia layer can increase the time required to reach the peak oil rate, but has a little impact on the ultimate oil recovery.

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