Khaledi, Rahman (Imperial Oil Resources) | Motahhari, Hamed Reza (Imperial Oil Resources) | Boone, Thomas J. (ExxonMobil Retiree) | Fang, Chen (ExxonMobil Upstream Research Company) | Coutee, Adam S. (ExxonMobil Upstream Research Company)
Thermal-Solvent Assisted Gravity Drainage processes are heavy oil recovery processes in which the stimulation mechanism for bitumen viscosity reduction is by heating and dilution. The range of the injected solvent concentration with steam may be low such as in Solvent Assisted-SAGD or very high such as in Heated Vapour Extraction. The performance behaviour of these processes is significantly driven by the complex thermodynamic interaction of steam and solvent, heat transfer, multiphase fluid equilibrium and flow in the porous medium.
ExxonMobil and its affiliate Imperial have been optimizing the existing recovery processes and developing new technologies to improve the efficiencies and environmental performance of the heavy oil production operations. Recent focus has been on developing thermal-solvent based recovery processes through an integrated research program that includes fundamental laboratory work, advanced numerical simulation studies, laboratory scaled physical modeling, and field piloting. The research program aims at in-depth investigation and understanding of process physics and mechanisms, and evaluating process performance and behaviour to enable development of new recovery methods and to enhance the performance.
This paper focuses on the fundamental concepts of Azeotropic Heated Vapour Extraction, a new thermal solvent recovery technology developed by ExxonMobil-Imperial. This technology takes the combined advantages of the solvent dilution mechanism for enhanced oil production rate with the minimum required energy (GHG emission), as well as the effectiveness of energy transport of steam to minimize the required solvent in circulation for the extraction process. In this paper, the complex solvent-steam phase behaviour and reservoir fluid flow and their interaction under operating conditions are investigated. The analysis of experimental and modeling data shows that the injection of solvent-steam mixture at its azeotropic condition results in significant improvement in process key performance indicators (KPI's). At these conditions, the reservoir is heated to the minimum boiling temperature of the solvent-steam mixture compared to a Heated VAPEX or Solvent Assisted-SAGD process resulting in the reduction of the required energy thereby minimizing the solvent-to-oil ratio. Also, due to phase equilibrium, the vaporization of in-situ water is prevented resulting in the reduction of retained solvent in the depleted zone of the reservoir. It is found that an improvement in the process KPI's is dependent on the volatility of the selected solvent. The process KPI's also vary with operational conditions. The recovery process is optimized for certain reservoir constraints through the selection of the solvent boiling range and consequently the azeotropic steam content in the injected mixture.
Khaledi, Rahman (Imperial Oil Resources) | Boone, Thomas J. (ExxonMobil Upstream Research Company) | Motahhari, Hamed Reza (Imperial Oil Resources) | Subramanian, Ganesan (ExxonMobil Upstream Research Company)
Solvent Assisted-Steam Assisted Gravity Drainage (SA-SAGD) process is an enhancement to SAGD recovery technology. In this process a hydrocarbon solvent is injected simultaneously with steam to accelerate the oil production rate and reduce steam-to-oil ratio (SOR) compared to classical SAGD. SA-SAGD is a complex process; its physics and mechanisms are not fully understood. ExxonMobil and its affiliate Imperial Oil have been investigating SA-SAGD through an integrated research program that includes fundamental laboratory work, advanced numerical simulation studies, laboratory scaled physical modeling, and field piloting. This research program aims at in-depth understanding of process physics and mechanisms, evaluating process performance and behavior, and improving SA-SAGD recovery technology.
This paper focuses on SA-SAGD optimization and assessing the effects of operating conditions and solvent choice on the process performance. The complex solvent-steam phase behavior and their interaction under reservoir operating conditions are investigated in the current work. Phase behavior analysis shows that the solvent boiling range affects solvent-steam condensation temperature at the condensation and mixing front and consequently it affects the solvent effectiveness in terms of performance enhancement. The effect of phase behavior on SA-SAGD performance has been evaluated by analyzing experimental and simulation performance data. It is shown that the composition of injected fluid significantly affects the process performance. It is also shown that the solvent composition can be customized to improve SA-SAGD process performance under different operating conditions.
Development of oil sands in northeastern Alberta is an important contributor to the economies of both Alberta and Canada, but this type of hydrocarbon resource is often perceived by some as representing daunting environmental challenges. One particular area of stakeholder focus is the nature of the surface-land footprint associated with mineable oil-sands developments. This paper provides the facts and context of progressive reclamation in Canada's mineable oil-sands industry with a focus on the Kearl Oil-Sands Mine (Kearl) operated by Imperial Oil Resources Ventures Limited (Imperial). It demonstrates how progressive land reclamation has been integrated into the mine-planning process for Kearl from the outset of project planning and how the soil, overburden, groundwater, surface water, vegetation, and wildlife resources are considered throughout the life of the mine from a reclamation perspective. Nearly 22 000 ha of land will be disturbed during 40+ years of operation of the Kearl. Imperial is committed to progressive reclamation of the disturbed land throughout the life of the mine. As part of Kearl's long-term vision for reclamation success, Imperial is currently salvaging, segregating, and storing soil, and collecting and banking native seeds so that these valuable reclamation materials are readily available in the future. Ongoing mine-closure planning and the integration of progressive reclamation from the outset of the mine-planning process have identified opportunities, vulnerabilities, and technical constraints to mine closure.
ExxonMobil and its Canadian affiliate Imperial Oil Resources are pursuing an integrated research program targeted at developing the next generation of heavy oil recovery processes which utilize light hydrocarbon solvents in conjunction with steam or as an alternative to steam-only processes to mobilize the in-situ heavy oil. The key benefits of employing solvent are improved economics and increased recovery from resource that is impractical with steam-only processes, improved environmental performance, particularly reduced greenhouse gas emissions and reduced water use.
A suite of field trials, pilots and commercial applications have been operating over the past several years at Imperial Oil’s Cold Lake field in Alberta, Canada. These have included both solvent-assisted and solvent-only field trials. Collectively, the results of these trials show that solvent recovery processes for heavy oil are technically viable and have considerable commercial potential. This paper summarizes the dimensions of the integrated research program that have been key to delivering the successful results to date. Simulation, laboratory testing and physical modelling with a focus on scaling to the field have been employed extensively prior to field testing. Short-term, relatively low cost field trials have been utilized to calibrate models prior to more costly, longer term pilots with dedicated facilities. Extensive field characterization has been conducted prior to final site selection and pilot operation. Integrated operational and surveillance plans have been employed to ensure measurable and reliable field performance data is acquired that can be used to calibrate and validate simulation performance. Finally, learnings from this integrated research program can be more broadly applied to the commercialization of other EOR processes and the research and development processes leading up to the decision to execute a major pilot.
Thermal recovery processes including steam flooding, cyclic steam stimulation (CSS) and steam-assisted gravity drainage (SAGD) are among the most broadly applied and commercially successful enhanced oil recovery (EOR) processes. In recent years there has been considerable growth in production utilizing these methods in the Canadian oil sands deposits which are primarily located in the Cold Lake and Athabasca regions of Alberta. These processes can be very efficient and economic when applied in thick, high porosity, high permeability reservoir deposits. However, significant volumes of natural gas are required to generate the steam used in these processes and associated with the steam generation are greenhouse gas (GHG) emissions. There are strong economic, technical and environmental drivers to develop enhanced thermal recovery processes that reduce steam utilization, enable more efficient recovery from lower quality resources and improve environmental performance. The enhanced heavy oil recovery processes described in this paper target these challenges. An overview of this integrated technology development program was provided previously by Boone et al1. This paper reports on the continued successful development in subsequent years and expands on some of the key factors for success. Those factors include:
Jonk, Rene (ExxonMobil Upstream Research Company) | Potma, Ken (Imperial Oil Resources) | Bohacs, Kevin (ExxonMobil Upstream Research Company) | Advocate, David (Imperial Oil Resources) | Starich, Patrick (Imperial Oil Resources)
Studying outcrop sections is a cost effective way to obtain datasets comparable to those that may be obtained from long, continuous drill cores. These studies have the added benefit of enabling larger-scale lateral observations. In particular, critical observations can be made about lithology, depositional environments, stacking patterns and sequence stratigraphic interpretations that can be extrapolated to wireline log and seismic data for the subsurface play analysis.
The caveat of extrapolating outcrop data to the subsurface is that uplifted and exhumed outcrops may exhibit the effects of a retrograde pressure and temperature history. Mechanical and chemical surface weathering processes can dramatically alter rock properties. This means we need to be cautious when extrapolating aspects of the plays such as maturity, porosity, and mechanical properties of the outcrops to the subsurface. However, within these constraints, outcrop data can add value in understanding play commodity type, reservoir quality, and mechanical properties as well as general lithology, depositional setting and sequence stratigraphic interpretation.
In this study we integrate outcrop observations made in the Mackenzie Mountains, Northwest Territories, Canada to further our understanding of relatively data-poor Devonian-aged shale plays in the adjacent Peel and Mackenzie Valley Basins. Several vertical sections were measured and correlated to understand the distribution of lithofacies within a sequence stratigraphic framework. This allows us to deduce depositional settings and understand the distribution of favorable shale reservoir types in the area. Spectral Gamma Ray profiles measured in outcrops were used to correlate surfaces from outcrop to well logs in the basins.
We found that the basin architecture and the presence of both siliciclastic and carbonate depositional systems provide first-order controls on the distribution of favorable shale reservoirs. The learnings from the outcrop work can be used to better understand other age-equivalent shale plays in North America that lack high-quality outcrops.
The final step in the regulatory process related to C&R is the granting of a reclamation certificate. The application for a reclamation certificate requires the filing of documentation showing that all the approval conditions have been met and that through satisfaction of the approval conditions, the previously disturbed land has achieved equivalent capability. To date, one oil sands mine has received a reclamation certificate for land that has been permanently reclaimed: in March 2008, the GoA issued its first oil sands mining reclamation certificate to Syncrude Canada Ltd. for a 104 ha parcel of land known as Gateway Hill. Understanding the Environmental Setting/Condition The Kearl lease is situated in the Boreal Forest Natural Region of Alberta. Short summers, long, cold winters and vast deciduous, mixedwood, and coniferous forests interspersed with extensive peatlands (bogs or fens) characterize the Boreal Forest Natural Region (Natural Regions Committee, 2006).
Problem Statement: Development of the oil sands in northeastern Alberta is an important contributor to the economies of both Alberta and Canada, but this type of hydrocarbon resource is often perceived as representing daunting environmental challenges. One area of particular stakeholder focus is the nature of the surface land footprint associated with
mineable oil sands developments.
Objectives and Scope of Study: This paper will provide the facts and context of progressive reclamation in Canada’s mineable oil sands industry with a focus on the Kearl Oil Sands Mine operated by Imperial Oil Resources Ventures Limited. It will demonstrate how progressive land reclamation has been integrated into the mine planning process for Kearl from the outset of project planning and how the soil, overburden, groundwater, surface water, vegetation and wildlife resources are considered throughout the life of the mine from a reclamation perspective
Method: The role of progressive reclamation as the design and operational basis for the Kearl Oil Sands Mine is highlighted.
•Up to 21,608 ha of land will be disturbed over 40+ years of operation of the Kearl Oil Sands Mine. Imperial Oil is committed to progressive reclamation of the disturbed land throughout the life of the mine.
• As part of Kearl’s long-term vision for reclamation success, Imperial Oil is currently salvaging, segregating and storing soil and collecting and banking
native seeds so that these valuable reclamation materials are readily available in the future.
• Prior to the start-up of operations of the Kearl Oil Sands Mine in April 2013, over 25 ha of land was permanently reclaimed, 15 million cubic meters of reclamation material was salvaged and seeds from over 30 boreal forest plant species were banked.
Applications: This paper will contribute to the ongoing discussion regarding the environmental sustainability of Canada’s mineable oil sands.
Innovations or Technical Contributions: Ongoing mine closure planning and integration of progressive reclamation from the outset of the mine planning process has identified opportunities, vulnerabilities and technical constraints to mine closure
Problem Statement: Water is a necessity for society, economic development, and the environment. Fresh water is not distributed equally around the world, and many regions experience seasonal or longer-term water shortages. With increasing population and growth in economic development, stress on the water supply is growing in many regions. While water use in the petroleum industry is not intensive on a regional basis relative to other users, it can be material at the local scale. Water resource management in the oil and gas industry is increasingly recognized as a priority area in global operations.
Objectives and Scope of Study: Develop a standardized guide to water resource management for ExxonMobil’s Upstream oil and gas production projects and operations. Provide environmental, regulatory, and socioeconomic practitioners with a methodology to assess and manage water resource risks consistently and effectively.
Method: Apply water management concepts and available tools to complement existing environmental management and risk assessment and mitigation practices.
Conclusions: A four step framework with embedded and scalable tools was developed for application by local advisors and Corporate subject matter experts:
1. Data Acquisition: Data needs are identified for specific projects and producing assets. Data are then collected and used to develop a water footprint.
2. Data Analysis: Data are analyzed to facilitate benchmarking, stewardship, risk screening, managing external stakeholder expectations, and identifying and acting on continuous improvement opportunities.
3. Risk Assessment: A structured risk assessment is then used to determine the resources required to manage the identified water related risks.
4. Risk Management: An appropriately scaled water management plan is developed to manage water resource risks for each project/producing
Applications: ExxonMobil’s Upstream Water Resources Management Guide provides an approach and tools for local environmental, regulatory, and socioeconomic advisors to identify and manage water resources-related risks.
Innovations or Technical Contributions: The Water Resources Management Guide is anticipated to result in the enhanced recognition and management of water resources-related risks, decreased capital and operating costs, fewer project and operational delays, improved environmental performance, and a sustained social license to operate.
The Norman Wells operation in northern Canada is applying for renewal of its water license. The facility has been in operation since 1919 on the banks of the Mackenzie River. No changes to the operation are being contemplated, and no changes to the water license requested. What is new is that the regulator is requiring Traditional Knowledge (TK) studies be undertaken. Of what possible use could such studies be at this almost century old site? Turns out quite a bit.
Traditional Knowledge has been used in Canada during the planning stages of new projects, and been required as part of Environmental Impact Assessment submissions, for a number of years. This would be a first at an operating site with a static footprint. Rather than focussing on the facility footprint itself, as is the more usual approach for project driven TK studies, these studies instead focussed on emergency response on the Mackenzie River.
Workshops were held in the local town and in the next down-river commmunity. Elders selected by local Councils were invited to participate. A detailed map of a 120km stretch of River was created highlighting things like access points, areas of open water in winter, cabins, sand bar movement. The draft map was brought to public consultation sessions to show what data had been gathered, and provide an opportunity for all community members to add to it. At the suggestion of some elders, an on-river workshop was held to visit important sites, photograph them, and prepare summary description sheets. Community members were invited to observe an emergency response exercise and provide their suggestions during the debrief.
Traditional Knowledge has enhanced Operations ability to respond to incidents on the Mackenzie River by providing valuable added detail to maps and by one-on-one knowledge sharing between first responders, elders and other community members. Additionally, it has provided a meaningful forum for local people and Operations to discuss issues and share information that is of importance to both.
Jonk, Rene (ExxonMobil Upstream Research Company) | Allen, Janice (Dalhousie University) | Magennis, Lochlann (Imperial Oil Resources) | Potma, Ken (Imperial Oil Resources) | Wamsteeker, Michael (Imperial Oil Resources)
This paper shows an example of a geocellular facies model constructed for a shale gas play in the Horn River Basin, Canada. It shows that traditional techniques of identifying lithofacies within a sequence stratigraphic framework can be utilized to setup the framework for constructing a geocellular model. Relationships between elastic parameters and lithofacies allow us to obtain low-resolution larger-scale 3-dimensional geobody geometries and facies relationships from inverted seismic data. These help constrain variograms and allow propagation of geocellular facies models away from well control, both vertically and laterally. Lithofacies are tied to distinct porosity, permeability and water saturation distributions and thus the resulting geologic model can be used to evaluate in-place resources, assist in well planning and ultimately help understand recovery factors and influence well spacing and infill drilling during development stages of the field.