bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Heavy Oil Recovery by Low Rate Waterflooding
Authors: Mai A. , Kantzas A. 
Published: October 2008

Abstract
This work details the results of ambient temperature waterfloods in unconsolidated sand containing heavy oil (11°API and viscosity of 11,500 mPa⋅s at 23°C). Experiments are performed at rates ranging from 0.4 – 0.02 m/day, in sand with permeability of under 1 D to 9 D. By varying both the injection rate and the permeability of the sand, the relative influence of viscous and capillary forces can be determined. It is shown that by properly controlling the waterflood, significant heavy oil can still be recovered after water breakthrough has already occurred.
The application of this work is for the significant heavy oil resource in Canada that exists in reservoirs that are too thin for thermal operations. A fraction of oil may initially be recovered through primary production, however at its conclusion a significant amount of oil still remains in the reservoir. Waterflooding is a simple process that has potential for recovery of additional oil, in reservoirs where more expensive options will not be possible.
Due to the adverse mobility ratio between water and oil, water breakthrough occurs early in a waterflood, with a significant amount of the oil still being continuous at this time. The key to understanding the displacement of heavy oil by water is to consider the oil recovery after breakthrough. This oil is produced at high water cuts, and under negligible pressure gradients. Oil is therefore recovered by water imbibition into the water-wet sand. By varying the injection rates and the permeability of the sand, the importance of these capillary forces to oil recovery has been quantified.
Capillary forces are generally deemed to be insignificant in heavy oil waterfloods due to the high oil viscosity. As such, concepts of viscous fingering and mobility ratio dominate discussions of heavy oil waterflood responses. In this work, it is shown that not only are capillary forces actually still important in heavy oil reservoirs, but in fact they are a significant mechanism responsible for oil recovery after water breakthrough. With this understood, heavy oil waterfloods can be properly designed to maximize flood efficiency and oil recovery.
Improved Recovery Potential in Mature Heavy Oil Fields by Alkali-Surfactant Flooding
Authors: Bryan J. , Kantzas A. 
Published: October 2008

Abstract
Many reservoirs in Canada are too small or thin for energy-intensive thermal EOR operations. The reservoirs may also be disturbed during primary production, generating low-resistance flow-pathways between injectors and producers, thus injected fluids will follow these pathways and not contact additional oil. In these conditions, alkali-surfactant injection has considerable potential as a technique for additional non-thermal recovery of heavy oil.
During unstable displacement of heavy oil by water, water breakthrough occurs early, and subsequent water injection will channel mostly through the water fingers and bypass significant volumes of continuous oil. It has been shown in other works that alkali and/or surfactant injection can lead to improved heavy oil recovery compared to waterflooding, but researchers have proposed different reasons for this response. This work summarizes the mechanisms that are responsible for improved heavy oil recovery and presents the results of 30 laboratory core floods investigating alkali-surfactant injection into sand-packs containing heavy oil (viscosity 11,500 mPa⋅s at 23°C).
By injecting less than 1% of alkali-surfactant (AS) solution with water, a combination of oil-in-water (O/W) and water-in-oil (W/O) emulsions will form in the water channels, effectively blocking them off. Further injected solution will therefore contact fresh regions of the core. It is shown that this design of AS injection in heavy oil leads to improved sweep efficiency of the flood. This corresponds to lower apparent relative permeability values to the aqueous phase, and a discussion is provided regarding how AS floods can be controlled and optimized.
In any heavy oil reservoir that is considered a viable candidate for waterflooding, AS flooding can also potentially be applied. The significance of this work is that it describes the mechanisms responsible for the improved oil recovery, which allows for optimized design of chemical flooding conditions. This study demonstrates how a small amount of chemical injected along with water can lead to dramatic improvements in the recovery from previously flooded heavy oil fields.
Bitumen Extraction from Oil Sands Ore-Water Slurry Using CaO (Lime) and/or Ozone
Authors: Babadagli T. , Burkus Z. , Moschopedis S. E. , Ozum B. 
Published: October 2008

Abstract
Bitumen extraction efficiency is increased in oil sands ore-water slurry based extraction process by increasing solubility of naturally occurred asphaltic acids by addition of CaO (lime) and/or by oxidation of bitumen asphaltenes by Ozone (O3) to surfactant species, at as low as 35 °C temperature. Experimental findings suggest that a non-caustic bitumen extraction process (i.e. without using NaOH as extraction process aid) could be used commercially by conditioning the oil sands ore-water slurry with CaO and/or Ozone, which would allow high extraction efficiencies at about 35 °C temperature, reduce energy consumption and CO2 emission for the extraction of bitumen and eliminate the accumulation of Na+ ions in the recycled release water. Further tests are on-going to provide sufficient data for the commercial implementation of the use of CaO and/or Ozone at oil sands-ore water slurry based extraction plants.
Feasibility of using Electrical Downhole Heaters in Faja Heavy Oil Reservoirs
Authors: Rodríguez Raúl , Bashbush José Luis , Rincón Adafel 
Published: October 2008

Abstract
The Orinoco Belt (Faja) in Venezuela contains one of the largest resources of heavy and extra-heavy oil in the world. Due to the production decline of conventional light crude, projects must focus on increasing the recovery of heavy and extra-heavy oils using thermal and non-thermal methods. Steam-based thermal recovery processes are more efficient in low pressure reservoirs; however due to their depth, the initial pressures of the reservoirs in the Faja are relatively high, in the range of 600 to 1,500 psi with viscosities typically greater than 2,000 cp. For the above reasons, it is important to decrease the pressure of the reservoirs with primary production techniques to facilitate the economical implementation of steam injection based methods.
The initial production of heavy and viscous oils can be accelerated by the adequate use of downhole heaters that, by providing energy to the vicinity of the well, decrease oil viscosity and increase the oil production rate. A consequential advantage of using downhole heaters as a preamble to a steam injection process is that they accelerate early production and reservoir pressure decline while the equipment associated with steam injection, including steam boilers, insulated pipes and proper facilities are designed, ordered, installed and commissioned.
This paper analyzes the effects of downhole heaters as a stimulation method through the use of a numerical model of a representative field in the Ayacucho area of the Orinoco Oil Belt.
The study has been divided in three parts. The first part relates to the use of downhole heaters in thick sands, stimulating both vertical and horizontal wells in the reservoir. The second one evaluates the temporary application of downhole heaters in horizontal wells for a limited period of time to accelerate production and pressure decline, followed by a full implementation of a Steam Assisted Gravity Drainage (SAGD) process. The third part of the paper covers basic economical analyses performed using estimated capital and operating expenses with oil production curves from each case, to assist in the comparison of their worth using common economic parameters.
In-Situ Combustion with Solvent Injection
Authors: D'Silva J. , Kakade G. 
Published: October 2008

Abstract
Production of heavy oil has always been associated with a lot of problems. A major one being the high viscosity of heavy oil due to which it does not flow easily into a producer well. In-Situ techniques like Cyclic Steam Stimulation (CSS), Steam Assisted Gravity Drainage (SAGD), and Vapor Extraction Techniques (VAPEX) are not mutually exclusive and it is becoming increasingly common for wells to be put through one of the techniques followed by the other so as to improve recovery rates.
The main purpose of this paper is to discuss the effect of combining the techniques of In-Situ Combustion with heavy hydrocarbon vapor injection on the same heavy oil reservoir.
This paper with the help of an example case study, gives a detailed explanation of this combination technique as an integrated unit and its various advantages over using just a single technique.
Horizontal Alternating Steam Drive Process for the Orinoco Heavy Oil Belt in Eastern Venezuela
Authors: Fernandez R. Edgar A. , Bashbush José Luis 
Published: October 2008

Abstract
The Orinoco Heavy Oil Belt (Faja) has been exploited under primary recovery techniques using mainly horizontal, fishbone and multilateral wells. This cold development can only recover between 6% and 9 % of the considerable original oil in place existing in the area. Owing to the high viscosities, widely different formation thicknesses and heterogeneities found, the implementation of different thermal recovery methods is necessary.
This project covers a feasibility study considering the Horizontal Alternating Steam Drive (HASD) process geared to increase the recovery efficiency of heavy oil within the Faja reservoirs. The process is based on a repetitive pattern using horizontal wells acting alternatively as oil producers and steam injectors. The recovery mechanism is a combination of horizontal steam flooding between wells and cyclic steam stimulation of each of the horizontal wells in the pattern. Properly implemented, HASD could be more efficient than classical cyclic steam injection and more effective than direct steam flooding.
In contrast to the Steam Assisted Gravity Drainage process (SAGD), HASD uses single horizontal wells cyclically switching between injection and production phases. The steam chamber generated while each well is injecting is laterally driven by the pressure differentials created by adjacent producers, forming a sweeping front between wells. Injectors are converted to producers (and vice versa) providing heat directly to the zones where production will occur gradually extending the steam chambers to the entire reservoir region. Thus, the impact of steam is not that of a simple well stimulation, but also achieves an effective sweep in the vicinity of the producers while decreasing oil viscosity and improving oil drainage.
This project is based on the numerical simulation results from a representative model from one of the Faja main blocks using Eclipse Thermal applied to medium thickness sands in the 20-50 net ft range.
A five-horizontal well array set up was used as the model to assess this fairly new thermal recovery technique. During the investigation, different scenarios were analyzed to obtain a generalized step-by-step optimization procedure for the process under the specified fluid and reservoir conditions.
Sensitivity analyses were performed considering the relative positioning of the horizontal well placement in the reservoir column; different injection sequences; varying the duration of each injection cycle; various injection rates; and lengths of the horizontal reach of the wells.
The results of this investigation can be used as a reference to optimize the performance of the HASD process for sand bodies of medium thickness.
Electro-Magnetic Heating in Viscous Oil Reservoir
Authors: Das Swapan 
Published: October 2008

Abstract
Formation resistive heating, commonly known as EM (Electro-Magnetic) heating, has been considered as a potential thermal recovery method in the viscous oil reservoirs for almost three decades. In situ viscosity reduction by the heat generated in the formation helps in the recovery process. The formation acts as a resistor in the current flow path. Numerous patents and reports have been published on this. Application in deep reservoir and negligible heat loss in the overburden, are the two most important features of this thermal recovery process. There are examples of few pilots in Canada, Brazil and elsewhere. This also has been proposed as an option to accelerate SAGD start up.
This paper presents the limitation of EM heating in the formation and its applicability in few viscous oil reservoirs. It appears that in the EM heating process, heat penetration is significantly lower than that of a steam based process. Simulation of electrical heating in the simulator is tricky. The amount of estimated heat input is very sensitive to grid refinement. In reality, there is a potential for generating hot spots at the electrodes which was reported to be one of the reasons for failures in the field applications.
Distribution of Multi-Component Solvents in Solvent Vapor Extraction Chamber
Authors: Das Swapan 
Published: October 2008

AbstractIn the solvent vapor extraction of heavy oil and bitumen, commonly known as the Vapex process, viscosity of the oil is reduced by dilution with solvent. Although laboratory experiments are generally carried out using single component solvents, in the field application the commercially available solvents always contain impurities. These components distribute in the in situ oil at different proportions depending on their solubility at the operating conditions and their concentration in the injected mixture. In general it is expected that the non-condensable solvent components hinder the process.This paper presents the results of a simulation study to investigate partitioning of solvent components inside the vapor chamber in the Vapex process. It appears that the non-condensable solvent components accumulate at the solvent vapor-viscous oil interface. The solvent component diffuses through this vapor boundary layer to the oil interface. However, the rate of diffusion in the gaseous phase is much faster than that of the molecular diffusion in the liquid phase. The later is the rate controlling step and dominates the performance of the process.
Effects of Well Placement and Intelligent Completions on SAGD in a Full-Field Thermal-Numerical Model for Athabasca Oil Sands
Authors: Akram F. 
Published: October 2008

Abstract
Estimated at 2.5 trillion barrels, Canada has the world's largest share of ultra-heavy oil and bitumen resources. While shallow heavy oil reserves are extracted from pit mines, deeper reserves can only be extracted through wells. Production of these reserves requires methods such as steam-assisted gravity drainage (SAGD) and cyclic steam simulation (CSS) (Butler, 1991). Optimal well placement defines the propagation of steam within the reservoir and the resulting flow of crude.
SAGD recovery methods require tremendous amounts of steam in order to get the crude to flow. Costs to generate and inject steam in a SAGD pad are significant. Finding ways to use steam more effectively in these operations should result in increased production efficiency and improved financial return on these projects. By strategically placing steam injectors and by controlling the amount of steam injected it may be possible for these results to be achieved.
A study was conducted to examine several completion strategies and to test, with the use of a simulation model, what the expected production, and steam requirements for these strategies would be. The simulation model examined multiple well pairs to see these results in a full-field environment. To assess the financial impact of these strategies, a fiscal model was developed that evaluated SAGD project costs and then examined the incremental cost and value of each of the completion strategies. Results show that although using steam effectively in these strategies may not yield the highest recovery, it does improve the expected value of these projects.
This paper describes the process, operational control, and financial analysis used to design and validate the SAGD model. The study focuses on a completion strategy that demonstrates a strong potential to reduce SOR and ultimately operational cost. Incremental financial analysis is included to examine the impact of choosing any such strategy.
A Singular Methodology to Design Cement Sheath Integrity Exposed to Steam Stimulation
Authors: Garnier A. , Saint-Marc J. , Bois A. -P. , Kermanac'h Y. 
Published: October 2008

Abstract
Heavy oil production is one of the new challenges the Oil and Gas industry faces today with reserves of trillions of barrels. When well production is considered, heavy oils viscosity must be reduced to gain mobility and have oil flowing. Between all possible techniques, steam stimulation is today the most promising.
Steam is injected through the well down to the reservoir to warm it up with temperature up to 250°C, inducing extreme thermal stresses to the well, especially when the temperature gradient through the well components is maximum, like during first steam injection or during work-over when the well should be quickly cooled down and heated up again to rapidly restart production.
To avoid zonal isolation failure and steam release at surface, new rules should be considered when designing barriers of a well exposed to steam stimulation, especially in very shallow fields. If classic rules could be applied for casing design, pioneering rules should be considered to design cement sheath.
This paper presents a singular methodology to design cement sheath long term integrity in very shallow conditions. First, stresses in the field are evaluated with a rock mechanics simulation. Then, thermal gradient in well components while heating are evaluated with a thermal simulation of the well. Both results are injected in Total's dedicated software to determine the mechanical properties the cement should have to withstand thermal stresses. Different cement systems from service companies are then triaxial tested before being evaluated in a cell reproducing the field to validate simulations' results.
This methodology was successfully applied to Joslyn field wells, Canada, where a resilient cement system with low Young's modulus and high tensile strength was selected and pumped. Since results are positive, this methodology has been extended to other Total's fields worldwide where steam simulation is considered.
A Novel Process for Heavy Residue Hydroconversion Using a Recoverable Pseudo-homogeneous Catalyst (PHC) System
Authors: Romocki S. M. , Rhodey W. G. 
Published: October 2008

Abstract
Conventional hydroconversion of residue has been achieved through high pressure, capital intensive processes with significant operating costs associated with maintaining catalyst activity. Despite the usefulness of heterogeneous catalysts in numerous refining processes, their potential for hydroconversion of heavy feeds with high levels of sulfur, nitrogen, resins, asphaltenes and metals is limited.
This paper will introduce a Pseudo-homogeneous Catalyst (PHC) developed for the specific chemistry of heavy hydrocarbon feeds. The term pseudo-homogeneous provides a convenient description of nano-scale unsupported catalyst particles uniformly dispersed throughout the feed. As a result of particle size, nanoparticle suspensions exhibit properties similar to colloidal solutions.
Residue processing using a high performance pseudo-homogeneous catalyst system results in improved cracking and hydrogenation performance at lower process severity. The PHC system in the Heavy Residue Hydroconversion (HRH) process achieves up to 95% residue conversion at pressure below 7.3 MPa, reaction temperatures between 400 - 460 °C, with feed space velocity between 1,0-2,0 h-1; making PHC systems well suited for deep conversion of hydrocarbon residues.
The sustainability profile of the HRH process is improved as residue conversion to liquids is maximized, while up to 95% catalyst is recovered and regeneration within the process.
Pilot plant results from hydroconversion of Athabasca vacuum bottoms using a pseudo-homogeneous catalyst (PHC) system are discussed.
Increase Oil Recovery of Heavy Oil in Combustion Tube Using a New Catalyst based Nickel Ionic Solution
Authors: Ramírez-Garnica M. A. , Hernández-Pérez J. R. , Cabrera-Reyes M. C. , Schacht-Hernández P. , Mamora D. D. 
Published: October 2008

Abstract
In this research an ionic liquid base Nickel was used in a combustion tube with heavy oil from Gulf of Mexico. The underlying objective is to increase the mobility and quality of the oil inside the reservoir by effect of the ionic solution catalyst during the combustion.
The catalyst, used in the experiments was previously mixed with heavy crude oil of 12.5 °API. The catalyst in liquid phase is based Nickel. This ionic catalyst is highly soluble and ultradispersed in heavy oil, and it was mixture with heavy crude oil with a concentration of 500 ppm wt.
The porous media used in the combustion tube was a triturated dolomite carbonated rock with a 35.23% of porosity, and a particle size of 0.42 mm. This rock was used for two experiments at the same saturation conditions: heavy crude oil (23.79%), and water (25.26%).
The results obtained shown the advantages of use of this catalyst in relationship of a conventional combustion as follows: (1) important viscosity reduction, (2) increment of oil production, 85% vs. 77.67%, (3) faster combustion front, (4) higher efficiency in the combustion, 75.86 vs. 197.28 ft3 air/ft3 hydrocarbons, (5) higher temperatures through the combustion process, around 600 °C, and (6) reduction of the contain of sulphur, resins and asphaltenes in the oil produced.
Using this kind of Nickel ionic solution catalyst at low concentration would permit to increase the recovery factor, and upgrade the oil properties in-situ.