The Impact of Asphaltene Precipitation and Clay Migration on Wettability Alteration for Steam Assisted Gravity Drainage (SAGD) and Expanding Solvent-SAGD (ES-SAGD)

2015 ◽  
Author(s):  
Taniya Kar ◽  
Jun Jie Yeoh ◽  
Cesar Ovalles ◽  
Estrella Rogel ◽  
Ian Benson ◽  
...  
Keyword(s):  
Wettability Alteration ◽  
Gravity Drainage ◽  
Asphaltene Precipitation ◽  
Steam Assisted Gravity Drainage ◽  
The Impact

Novel insights on the impact of top water on Steam-Assisted Gravity Drainage in a point bar reservoir

2017 ◽  
Vol 42 (2) ◽  
pp. 616-632 ◽  
Author(s):  
Maureen E. Austin-Adigio ◽  
Jingyi Wang ◽  
Jose M. Alvarez ◽  
Ian D. Gates
Keyword(s):  
Gravity Drainage ◽  
Point Bar ◽  
Steam Assisted Gravity Drainage ◽  
The Impact

An Investigation into Current Sand Control Testing Practices for Steam Assisted Gravity Drainage Production Wells

Eng ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 435-453
Author(s):  
Omar Kotb ◽  
Mohammad Haftani ◽  
Alireza Nouri
Keyword(s):  
Fluid Flow ◽  
Testing Procedure ◽  
Gravity Drainage ◽  
Steam Assisted Gravity Drainage ◽  
Mcmurray Formation ◽  
Sand Control ◽  
Production Wells ◽  
Brine Chemistry ◽  
And Performance ◽  
The Impact

Sand control screens (SCD) have been widely installed in wells producing bitumen from unconsolidated formations. The screens are typically designed using general rules-of-thumb. The sand retention testing (SRT) technique has gained attention from the industry for the custom design and performance assessment of SCD. However, the success of SRT experimentation highly depends on the accuracy of the experimental design and variables. This work examines the impact of the setup design, sample preparation, near-wellbore stress conditions, fluid flow rates, and brine chemistry on the testing results and, accordingly, screen design. The SRT experiments were carried out using the replicated samples from the McMurray Formation at Long Lake Field. The results were compared with the test results on the original reservoir samples presented in the literature. Subsequently, a parametric study was performed by changing one testing parameter at a test, gradually making the conditions more comparable to the actual wellbore conditions. The results indicate that the fluid flow rate is the most influential parameter on sand production, followed by the packing technique, stress magnitude, and brine salinity level. The paper presents a workflow for the sand control testing procedure for designing the SCD in the steam-assisted gravity drainage (SAGD) operations.

Experimental Investigation of the Effects of Asphaltene Stability on Interfacial Behavior of Live-Reservoir-Fluid Systems

SPE Journal ◽  
2018 ◽  
Vol 24 (01) ◽  
pp. 21-31 ◽  
Author(s):  
Ram R. Ratnakar ◽  
Cesar A. Mantilla ◽  
Birol Dindoruk
Keyword(s):  
Contact Angle ◽  
Detection System ◽  
Water Systems ◽  
Wettability Alteration ◽  
Sharp Change ◽  
Interfacial Behavior ◽  
Asphaltene Precipitation ◽  
Reservoir Conditions ◽  
The Impact ◽  
Live Oil

Summary Wettability alteration resulting from asphaltene precipitation in a reservoir affects rock/fluid interactions that have a potential impact on oil production, recovery, and flow in the production network. The current predictive wettability models are inherently inaccurate and do not consider asphaltene stability. This study investigates the impact of pressure-depletion-induced asphaltene precipitation on interfacial tension (IFT) and contact angle for live-oil and water systems at reservoir conditions (high pressure, high temperature), and it presents a graphical (quantitative) method for determining asphaltene onset pressure (AOP) based on interfacial behavior. Water/oil IFT was measured at reservoir temperature using a pendant-drop-shape method for a system of live oils over a range of pressures above and below the AOP, which was already independently determined by means of particle-size-distribution and solid-detection-system techniques. The same pressure and temperature conditions were used to measure contact angle with quartz in the presence of deionized (DI) water as the surrounding medium. The temperature was controlled with an accuracy of ±0.1°C. Some measurements were performed twice to ensure the reproducibility of the experiments and methodology. This work presents the experimental study to quantify the change in interfacial behavior because of asphaltene precipitation and deposition. IFT/contact-angle measurements above and below AOP show that the interfacial behavior follows the normal trends above AOP as observed in other water/hydrocarbon systems. However, as evident when the pressure was reduced below the AOP, a relatively sharp change in the trend is observed in both the IFT and contact angle, which is caused by asphaltene migration to the interface in a way that acts as a natural surfactant. As asphaltenes precipitate and deposit in the mineral substrate, the surface turns less water-wet and the contact angle naturally increases to balance the equilibrium forces. This study sets a quantitative and alternative method to determine AOP, and presents new experimental data on IFT/contact angle of live-oil and water systems at reservoir conditions. Near the wellbore, asphaltene deposition can lead to pore plugging, where a large number of pore volumes flow through the productive life of the well. In this scenario, the size of aggregates (of asphaltene) is an important factor, especially when it is comparable with the pore size. On the other hand, deep in the reservoir, the effects of asphaltene precipitation and deposition on interfacial properties are more important because this can lead to wettability alteration. Thus, the results of this technique can be used to assess the potential impacts deep in the reservoir.

Optimisation of Steam Assisted Gravity Drainage [SAGD] for Improved Recovery from Unconsolidated Heavy Oil Reservoirs

2011 ◽  
Vol 367 ◽  
pp. 403-412 ◽  
Author(s):  
Babs Mufutau Oyeneyin ◽  
Amol Bali ◽  
Ebenezer Adom
Keyword(s):  
Oil Recovery ◽  
Heavy Oil ◽  
Oil Industry ◽  
Steam Injection ◽  
Thermal Capacity ◽  
Thermal Recovery ◽  
Viscosity Reduction ◽  
Gravity Drainage ◽  
Steam Assisted Gravity Drainage ◽  
The Impact

Most of the heavy oil resources in the world are in sandstone reservoir rocks, the majority of which are unconsolidated sands which presents unique challenges for effective sand management. Because they are viscous and have less mobility, then appropriate recovery mechanisms that lower the viscosity to the point where it can readily flow into the wellbore and to the surface are required. There are many cold and thermal recovery methods assisted by gravity drainage being employed by the oil industry. These are customised for specific reservoir characteristics with associated sand production and management problems. Steam Assisted Gravity Drainage (SAGD) based on horizontal wells and gravity drainage, is becoming very popular in the heavy oil industry as a thermal viscosity reduction technique. SAGD has the potential to generate a heavy oil recovery factor of up to 65% but there are challenges to ‘’realising the limit’’. The process requires elaborate planning and is influenced by a combination of factors. This paper presents unique models being developed to address the issue of multiphase steam-condensed water-heavy oil modelling. It addresses the effects of transient issues such as the changing pore size distribution due to compaction on the bulk and shear viscosities of the non-Newtonian heavy oil and the impact on the reservoir productivity, thermal capacity of the heavy oil, toe-to-heel steam injection rate and quality for horizontal well applications. Specific case studies are presented to illustrate how the models can be used for detailed risk assessment for SAGD design and real-time process optimisation necessary to maximise production at minimum drawdown. Nomenclature

Predicting Geomechanical Dynamics of the Steam-Assisted-Gravity-Drainage Process. Part I: Mohr-Coulomb (MC) Dilative Model

SPE Journal ◽  
2018 ◽  
Vol 23 (04) ◽  
pp. 1223-1247 ◽  
Author(s):  
Mazda Irani
Keyword(s):  
Shear Zones ◽  
Thermal Recovery ◽  
Absolute Permeability ◽  
Test Facility ◽  
Gravity Drainage ◽  
Steam Assisted Gravity Drainage ◽  
Recovery Processes ◽  
Stress Changes ◽  
Caprock Integrity ◽  
The Impact

Summary In the steam-assisted-gravity-drainage (SAGD) recovery process, the injection of high-pressure/high-temperature steam causes significant stress changes at the edge of the heated zone or steam chamber. These stress changes include shear dilation, which can both enhance the absolute permeability and result in horizontal and vertical formation displacements. The importance of considering geomechanical effects in thermal-recovery processes has been extensively discussed in the literature, but the prediction and surveillance of the resulting effects, such as the impact on production enhancement and reservoir displacement, have in many cases been neglected. Furthermore, issues related to these geomechanical effects on thermal production have been the subject of considerable debate in the industry with no conclusive, meaningful assessments of the effect on reservoir deliverability and production, or of the associated risks that such geomechanical effects have on wellbore and caprock integrity. This study will focus on identification of the main findings from an extensive monitoring program conducted on the original SAGD pilot project conducted at the Underground Test Facility (UTF) in the late 1980s and a seismic program conducted during the last several years by an SAGD operator at a commercial thermal-recovery project. The measured displacements and identified dilation shear zones in these applications were compared with a Mohr-Coulomb (MC) dilative model. This paper illustrates some of the pros and cons of using such analytical models through comparison of the results based on field evidence of the dilation and shearing effects, and how these mechanisms affect both reservoir productivity (revenue) and wellbore and caprock integrity. Although the discussion on the geomechanical effects in thermal-recovery processes will no doubt continue, this study will provide field-supported results to illustrate both beneficial and potentially challenging impacts that these geomechanical effects can have in a thermal-recovery project.

Asphaltene Precipitation During Bitumen Extraction With Expanding-Solvent Steam-Assisted Gravity Drainage: Effects on Pore-Scale Displacement

SPE Journal ◽  
2016 ◽  
Vol 21 (02) ◽  
pp. 380-392 ◽  
Author(s):  
Albina Mukhametshina ◽  
Taniya Kar ◽  
Berna Hascakir
Keyword(s):  
High Energy ◽  
Economic Benefits ◽  
Gravity Drainage ◽  
Steam Generation ◽  
Injection Strategy ◽  
Steam Chamber ◽  
Steam Assisted Gravity Drainage ◽  
Asphaltene Fraction ◽  
Solvent Type ◽  
The Impact

Summary Steam-assisted gravity drainage (SAGD) is a proved enhanced-oil-recovery technique for oil-sand extraction. However, the environmental and the economic challenges associated with steam generation limit the application of this technology. To address these issues, we have investigated the effectiveness of expanding-solvent-SAGD (ES-SAGD) over base SAGD on a bitumen sample (8.8 °API). Experimental studies are conducted with a 2D physical model. Different strategies for solvent injection are tested (coinjection and cyclic injection) to examine the impact of the deposition of the asphaltene fraction of the bitumen on porous media and the behavior of the asphaltene fraction in produced oil. Toluene is used as asphaltene-soluble solvent, and n-hexane is selected as asphaltene-insoluble. Steam-chamber development is monitored with temperature profiles from 47 separate positions. The oil rate, recovery factor, and the produced-oil quality are evaluated together. The effectiveness of SAGD and ES-SAGD is discussed by considering the role of asphaltenes and their interactions with clays in both produced- and residual-oil samples. This study reveals that coinjection of hydrocarbon solvents with steam enhances the steam-chamber development with higher oil-production rate. Moreover, ES-SAGD results in recovery of more-upgraded oil and has a lesser environmental impact. We observe that the selections of solvent type and injection strategy are the most crucial parameters for the design of a hybrid SAGD process, and solvent cost and toxicity can be minimized with the recycling of solvent for continuous injection of solvents. High-energy consumption for steam generation during the SAGD process can be reduced by coinjection of proper solvent type with steam at a proper injection strategy. Our study reveals that the ES-SAGD process has environmental and economic benefits that are preferable to those of the base SAGD. However, some solvents can cause undesirable effects because of asphaltene destabilization and precipitation in production or transportation lines. The results of this work show that not only asphaltenes but also the other fractions of oil, along with the reservoir-clay type and the clay amount, affect the ES-SAGD performance.

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.

Sign in / Sign up

Export Citation Format

Share Document