Pre-stack Bayesian lithofacies classification technology and application in oil-sand reservior prediction

2021 ◽  
pp. 1-50
Author(s):  
Zongjun Wang ◽  
Nan Tian ◽  
Hongchao Dong
Keyword(s):  
Probability Distribution ◽  
Elastic Parameter ◽  
Field Application ◽  
Thin Layers ◽  
Oil Sand ◽  
Steam Assisted Gravity Drainage ◽  
Technical Requirements ◽  
Spatial Distribution Characteristics ◽  
Lithofacies Classification ◽  
Classification Probability

The oil sand reservoirs in the Athabasca region of Canada are estuarine deposits affected by tides. The strata are inclined and the interlayers are well-developed. Accurate spatial characterization of reservoirs and interlayers is the key for efficient oil-sand development. In this paper, we use pre-stack Bayesian lithofacies classification technology to predict the spatial distribution characteristics of reservoirs and interlayers of oil-sand reservoirs. We first use log lithofacies data as a label, select lithofacies sensitive elastic parameters to make a lithofacies classification probability distribution cross-plot, and then project the lithofacies-sensitive elastic parameter volumes into the lithofacies classification probability distribution cross-plot. Finally, we predict the spatial probability distribution of different lithofacies. Probabilistic characterization can enhance the recognition of transitional lithology and thin layers in the inversion results, reduce the uncertainty in the prediction of reservoirs and interlayers, and significantly improve the prediction accuracy of reservoirs and interlayers. The field application results in the Kinosis study area show that the probability volume predicted by this technology can distinguish interlayers greater than 1 meter thick and identify interlayers greater than 2 meters thick, which meets the technical requirements of oil-sand SAGD (Steam Assisted Gravity Drainage) development.

scholarly journals An Overview on Major Design Constraints, Impact and Challenges for a Conventional Wastewater Treatment Design

2020 ◽  
Vol 9 (1) ◽  
pp. 7-16
Keyword(s):  
Wastewater Treatment ◽  
Analytical Calculation ◽  
Treatment Plant ◽  
Field Application ◽  
Design Parameters ◽  
Plant Design ◽  
Political Commitment ◽  
Design Constraints ◽  
Technical Requirements ◽  
Set Up

The conventional wastewater (WW) treatment plant includes physical, chemical, and biological treatment processes that can protect the receiving water bodies from water pollution. The common design constraints, challenges as well as environmental impact would make the wastewater treatment plant’s (WWTP) construction and operation more complex and demanding tasks. Major project constraints for WW plant design are economic, accessibility, fulfilling technical requirements, institutional set-up, health and environment, personnel capacity, and political commitment etc. Design methodology adopted in the current study included project location, unit selections, the design capacity, design period as well as proximity to the population and layout plan. The present manuscript discussed briefly about effluent quality requirements, design issues, environmental impacts, details, and safety concerns. It also highlighted the necessary flexibility to carry out satisfactorily within the desired range of influent WW characteristics and flows. In the present study, every step of the design was verified with Environmental Regulations and suggested to overcome all constraints while designing WWTPs so that standard operational code for the specific region could be implemented to achieve the best treatment performance. The results obtained from analytical calculation were optimized to achieve the best design parameters for field application. The optimized values also reduce the construction and operation cost during the field application.

Overview of Performance and Analytical Modeling Techniques for Electromagnetic Heating and Applications to Steam-Assisted-Gravity-Drainage Process Startup

SPE Journal ◽  
2016 ◽  
Vol 21 (02) ◽  
pp. 311-333 ◽  
Author(s):  
Sahar Ghannadi ◽  
Mazda Irani ◽  
Rick Chalaturnyk
Keyword(s):  
High Viscosity ◽  
Gravity Drainage ◽  
Induction Medium ◽  
Oil Sand ◽  
Steam Assisted Gravity Drainage ◽  
Production Wells ◽  
Reservoir Conditions ◽  
Startup Time ◽  
Industry Practice ◽  
High Level

Summary Steam-assisted gravity drainage is the method of choice to extract bitumen from Athabasca oil-sand reservoirs in Western Canada. Under reservoir conditions, bitumen is immobile because of high viscosity, and its typically high level of saturation limits the injectivity of steam. In current industry practice, steam is circulated within injection and production wells. Operators keep the steam circulating until mobile bitumen breaks through the producer and communication is established between the injector and the producer. The “startup” phase is a time-consuming process taking three or more months with no oil production. A variety of processes could be used to minimize the length of the startup phase, such as electromagnetic (EM) heating in either the induction (medium frequency) or radio-frequency ranges. Knowledge of the size of the hot zone formed by steam circulation and of the benefits of simultaneous EM-heating techniques increases understanding of the startup process and helps to minimize startup duration. The aim of the present work is to introduce an analytical model to predict startup duration for steam circulation with and without EM heating. Results reveal that resistive (electrothermal) heating with/without brine injection cannot be a preferable method for mobilizing the bitumen in startup phase. Induction slightly decreases startup time at frequencies smaller than 10 kHz, and at 100 kHz it can reduce startup time to less than two months.

Understanding ESP Performance Under High Viscous Applications and Emulsion Production

2021 ◽  
Author(s):  
Luiz Pastre ◽  
Jorge Biazussi ◽  
William Monte Verde ◽  
Antonio Bannwart
Keyword(s):  
High Viscosity ◽  
Field Application ◽  
Oil Field ◽  
Two Phase ◽  
Water Emulsion ◽  
Technical Requirements ◽  
Artificial Lift ◽  
Controlled Environments ◽  
Oil Water ◽  
Field Deployment

Abstract Although being widely used as an artificial lift method for heavy oil field developments, Electrical Submersible Pump (ESP) performance in high viscous applications is not fully understood. In order to improve knowledge of pump behavior under such conditions, Equinor has developed stage qualification tests as part of the technical requirements for deploying ESPs in Peregrino Field located offshore Brazil and has funded a series of research efforts to better design and operate the system more efficiently. Qualification tests were made mandatory for every stage type prior to field deployment in Peregrino. It is known that the affinity laws don´t hold true for high viscosity applications. Therefore, extensive qualification tests are required to provide actual stage performance in high viscous applications. Test results are used to optimize ESP system design for each well selecting the most efficient stage type considering specific well application challenges. In addition, the actual pump performance improves accuracy in production allocation algorithms. A better understanding of ESP behavior in viscous fluid application helps improving oil production and allows ESP operation with higher efficiency, increasing system run life. Shear forces inside ESP stages generate emulsion that compromises ESP performance. Lab tests in controlled environments have helped Equinor to gather valuable information about emulsion formation and evaluate ESP performance in conditions similar to field application. Equinor has funded studies to better understand two-phase flow (oil-water) which allowed visualization and investigation of oil drops dynamics inside the impeller. In addition, experimental procedures were proposed to investigate the effective viscosity of emulsion at pump discharge and the phase inversion hysteresis in the transition water-oil and oil-water emulsion. In addition to qualification tests and research performed to better understand system behavior, Equinor has developed and improved procedures to operate ESP systems in high viscous applications with emulsion production during 10 years of operation in Peregrino field. Such conditions also impose challenges to ESP system reliability. Over the years, Equinor has peformed failure analysis to enhance ESP system robustness which, combined with upper completion design, have improved system operation and reliability decreasing operating costs in Peregrino field.

Drained/Undrained-Zones Boundary in Steam-Assisted-Gravity-Drainage Process

SPE Journal ◽  
2016 ◽  
Vol 21 (05) ◽  
pp. 1721-1742 ◽  
Author(s):  
Mazda Irani ◽  
Ian Gates
Keyword(s):  
Pore Pressure ◽  
Volume Change ◽  
Injection Pressure ◽  
Point Of View ◽  
Gravity Drainage ◽  
Oil Sand ◽  
Steam Assisted Gravity Drainage ◽  
Shear Dilation ◽  
Temperature Front ◽  
Undrained Conditions

Summary Li et al. (2004) described three zones at the edge of steam chambers on the basis of drainage conditions: drained, partially drained, and undrained. In the drained zone, the pore pressure is controlled by injection pressure, and fluid mobility within this region is sufficient to drain additional pore pressures because of shear dilation and pore-fluid thermal expansion. The undrained zone lies beyond the partially drained zone and extends to virgin reservoir far beyond the chamber. In this zone shearing behaves under undrained conditions; by this, Li et al. (2004) mean no volume change occurs but shear lead to changes in pore pressure. Li et al. (2004) proposed that the boundaries of these zones are dependent on bitumen viscosity, which relates to the temperature distribution beyond the steam interface. Because drained/undrained conditions affect the geomechanics at the edge of the chamber, we investigate whether the assumption of Li et al. (2004) that there is no volume change within the sheared zone is correct and is supported by field data. Here, we establish the physics associated with the undrained zone at the edge of steam-assisted gravity-drainage steam chamber and explore the pressure front vs. temperature front of different oil-sand field projects. The results reveal that the drained zone governed by pressure-front advancement is greater in extent than the sheared zone. The thermodynamics of the undrained zone are discussed to derive a new theory for mechanothermal phenomena at the edge of the chamber. The results from the theory show that the drained zone extends beyond the temperature front and thus, from a geomechanical point of view, the system solely consists of the drained and partially drained zones.

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 The Application of Stefan Problem in Calculating the Lateral Movement of Steam Chamber in SAGD

2015 ◽  
Vol 2015 ◽  
pp. 1-11
Author(s):  
Xiong Chen ◽  
Ren-Shi Nie ◽  
Yong-Lu Jia ◽  
Lin-Xiang Sang
Keyword(s):  
Analytic Solution ◽  
Field Application ◽  
Temperature Data ◽  
Sensitivity Analyses ◽  
Gravity Drainage ◽  
Lateral Movement ◽  
Mathematical Methods ◽  
Monitoring Wells ◽  
Steam Chamber ◽  
Steam Assisted Gravity Drainage

It is extremely important to monitor the development of steam chambers in reservoirs in the process of SAGD (Steam Assisted Gravity Drainage). By analyzing the temperature data of monitoring wells, the extending velocity and direction of steam chamber can be obtained, which helps to regulate and improve production effectively. Based on Stefan’s inverse problem, a mathematical model is established in this paper for acquiring the extending velocity of steam chamber by using the temperature data of monitoring wells. Mathematical methods are utilized to solve the model such as Fourier transformation as well as an analytic solution using the moving velocity of steam chamber’s edges. Finally, sensitivity analyses concerning some factors such as the formation heat transfer coefficient, the temperature of steam chamber, and the rate of temperature rise of monitoring wells are made. Field application showed that the model can be used to calculate the moving velocity in real time and determine the boundary scope of the steam chambers easily.

scholarly journals Monitoring of steam chamber in steam-assisted gravity drainage based on the temperature sensitivity of oil sand

2021 ◽  
Vol 48 (6) ◽  
pp. 1411-1419
Author(s):  
Yunfeng GAO ◽  
Ting'en FAN ◽  
Jinghuai GAO ◽  
Hui LI ◽  
Hongchao DONG ◽  
...  
Keyword(s):  
Temperature Sensitivity ◽  
Gravity Drainage ◽  
Oil Sand ◽  
Steam Chamber ◽  
Steam Assisted Gravity Drainage

A New Thermogeomechanical Theory for Gravity Drainage in Steam-Assisted Gravity Drainage

SPE Journal ◽  
2013 ◽  
Vol 18 (04) ◽  
pp. 736-742 ◽  
Author(s):  
M.. Cokar ◽  
M.S.. S. Kallos ◽  
I.D.. D. Gates
Keyword(s):  
Thermal Expansion ◽  
Oil Sands ◽  
High Viscosity ◽  
Gravity Drainage ◽  
Oil Sand ◽  
Steam Assisted Gravity Drainage ◽  
Volumetric Expansion ◽  
Drainage Rate ◽  
In Situ Conditions ◽  
Effective Drainage

Summary Oil-sands reservoirs in western Canada hold more than 170 billion bbl of recoverable heavy oil and bitumen representing a significant source of unconventional oil. At in-situ conditions, the majority of this oil has essentially no initial mobility because of its high viscosity, which is typically in the hundreds of thousands to millions of centipoises. In steam-assisted gravity drainage (SAGD), steam injected into the formation heats oil at the edge of a depletion chamber, thus raising the mobility, ko/μo, of bitumen. Three main effects account for the increase of oil mobility. First, bitumen at steam temperature has viscosity typically less than 20 cp. Second, it is believed that shear, which is caused by thermal-expansion gradients, dilates the oil sand and causes enhanced permeability. Third, dilation at the chamber edge leads to smaller residual oil saturation (ROS). Because the production rate of SAGD is directly tied to the drainage rate of mobilized oil at the chamber edge, the thermogeomechanics of the oil sand at the chamber edge is a control on the performance of SAGD. In this study, a novel SAGD formula is derived that accounts for thermogeomechanical effects at the edge of the chamber. This paper couples dilation effects arising from thermal expansion into an analytical model for SAGD oil rate. The results reveal that volumetric expansion at the edge of the chamber plays a significant role in enabling effective drainage of bitumen to the production well.

Sign in / Sign up

Export Citation Format

Share Document