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Steam-assisted gravity drainage (SAGD) is an efficient technology that has been used to develop oil sand resources, and it has been successfully and maturely applied in Canada. However, oilfield production has demonstrated that reservoir heterogeneity has a serious impact on SAGD development, among which the most drastic impact is caused by multiple barrier layers in the reservoir. These barrier layers can severely impede the development of a steam chamber and the drainage of oil. Hence, it is important to investigate their influence mechanism. In this study, oil samples from the Long Lake oil field were used in laboratory experiments to study the development of the steam chamber and the residual oil distribution under the effect of multiple barrier layers. Then, a theoretical numerical simulation model was established to describe the fluid flow more precisely. In addition, the production characteristics of SAGD under the influence of different numbers of barrier layers were analyzed by comparing the development of the steam chamber. Finally, the impacts of multiple barrier layers with different modes of combinations were studied for their effects on SAGD production. The results indicated that for impermeable barrier layers of the same length, the steam primarily developed upward after flowing around the first barrier layer. After the steam chamber reached the top of the reservoir, the steam began to enter into the interbedded zone. Based on an unchanged first barrier layer, the number of barrier layers had little influence on the overall shape of the steam chamber and SAGD production, which confirmed that the first barrier layer played a dominant role in the influence of multiple barrier layers. In addition, characteristic points (P 1 , P 2 , P 3), which corresponded to changes in the stage of steam chamber development, were established and used to evaluate the effect of the barrier layers. Different combinations of barrier layers were realized by changing the relative properties of the first barrier layer. The results showed that the longer the length of the first barrier layer, the closer it was to the steam injection well and the lower the permeability; hence, the more obvious its hysteresis effect on the SAGD process. • A physical model is used to study the effect of multiple barrier layers on SAGD. • A theoretical numerical model is established to describe the fluid flow more precisely. • The first barrier layer plays a dominant role in the influence of multiple barrier layers. • Several characteristic points (P 1 , P 2 , P 3) on the productivity curve are established. • The impact of multiple barrier layers with different combinations is analyzed in detailed. [ABSTRACT FROM AUTHOR]

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Abstract: About one-quarter of the 1.7trillion barrels of bitumen resource located in Alberta, Canada is hosted in thin reservoirs with thickness less than about 10m and is at this time considered inaccessible by current commercial recovery processes such as Steam-Assisted Gravity Drainage (SAGD) and Cyclic Steam Stimulation. SAGD is effective at recovering heavy oil and bitumen in reservoirs greater than about 15m thickness but under this thickness, heat losses from the steam depletion chamber are too large and the energy efficiency of the process suffers. Since a large amount of steam is used per oil unit volume produced, this implies large amounts of natural gas combustion which also implies large amounts of carbon dioxide emitted per unit oil volume produced. Thus, thermal processes in thin pay are not energy efficient and produce excessive amounts of flue gases per unit oil volume produced. Solvent additives injected with steam, as done in Expanding-Solvent SAGD (ES-SAGD), can improve oil production rates or at least maintain similar oil production rates with reduced steam injection. The central idea is that steam plus solvent is better than steam alone to mobilize heavy oil in the reservoir. This implies that ES-SAGD can potentially use less water and require smaller water handling and treatment facilities than that in SAGD. Also, the operating temperature is lower than in steam-only processes so that heat losses are reduced and potentially ES-SAGD could be productive in thin reservoirs. In this research, the solvent injection pressure and volume fraction are designed for a single wellpair ES-SAGD operation by optimizing the net energy injected to oil ratio in a detailed and realistic, three-dimensional, heavy oil reservoir. The results show that the operating pressure and injection strategy can be controlled in a sequence that provides high energy efficiency and solvent recovery. [ABSTRACT FROM AUTHOR]

The article discusses the innovative methodology used in Joslyn field wells to design a robust cement sheath in shallow conditions in Canada. It states that the stress is evaluated through integrating density-log data and the cement sheaths temperature was measured through thermohydraulic simulation. It mentions that the methodology shows how the properties of cement can resist the thermal stress in cement sheaths and the possible solution is the cement with low Young modulus.

Steam-assisted gravity drainage [SAGD) is a robust thermal process that has revolutionized the economic recovery of heavy oil and bitumen from the immense oil-sands deposits in western Canada. which have 1.6 to 2.5 trillion bbl of oil in place. With steam injection, reservoir pressures and temperatures are raised. These elevated pressures and temperatures alter the rock stresses sufficiently to cause shear failure within and beyond the growing steam chamber. The associated increases in porosity, permeability, and water transmissibility accelerate the process. Pressures ahead of the steam chamber are substantially increased, promoting future growth of the steam chamber. A methodology for determining the optimum injection pressure for geomechanical enhancement is presented that allows operators to customize steam pressures to their reservoirs. In response, these geomechanical enhancements of porosity. permeability, and mobility alter the growth pattern of the steam chamber. The stresses in the rock will determine the directionality of the steam chamber growth: these are largely a function of the reservoir depth and tectonic loading. By anticipating the SAGD growth pattern, operators can optimize on the orientation and spacing of their wells. Core tests are essential for the determination of reservoir properties, yet oil sand core disturbance is endemic. Most core results are invalid, given the high core-disturbance results in test specimens. Discussion on the causes and mitigation of core disturbance is presented. Monitoring of the SAGD process is central to understanding where the process has been successful. Methods of monitoring the steam chamber are presented, including the use of satellite radar interferometry. Monitoring is particularly important to ensure caprock integrity because it is paramount that SAGD operations be contained within the reservoir. There are several quarter-billion-dollar SAGD projects in western Canada that are currently in the design stage. It is essential that these designs use a fuller understanding of the SAGD process to optimize well placement and facilities design. Only by including the interaction of SAGD and geomechanics can we achieve a more complete understanding of the process. [ABSTRACT FROM AUTHOR]

This study investigates using exergy analysis the technical factors that influence the feasibility of substituting steam supplied for other energy sources in industrial heating. Some alternative configurations for the steam-supply system capable of broadening the range of industries able to use the steam for heating are proposed. When examining the feasibility of substituting steam for other energy currencies for providing process heat, exergy analysis quantitatively determines the increase in process efficiency when a lower value energy currency such as steam is used in place of a higher value energy currency such as electricity. Many industries can benefit from using steam for some or all of their heating requirements. An illustrative example for the Bruce Energy Center in Ontario, Canada is presented to demonstrate the importance of using exergy analysis to assess the feasibility of industrial steam process heating. Some alternate reconfigurations of the Center are considered to supply steam at a variety of thermodynamic states, and better match the steam-state requirements of many industries. The results suggest that exergy analysis should be used as the central tool in process optimization when the use of large quantities of the steam in energy centers is contemplated. [ABSTRACT FROM AUTHOR]

Introduction: This analysis reported outcomes of treating catheter-dependent urinary retention with Rezūm water vapor therapy., Materials and Methods: A prospective registry was established at two high-volume Canadian centers. Patients had baseline medical and benign prostatic hyperplasia (BPH) history documented. The subgroup of patients with refractory, catheter-dependent urinary retention was analyzed. The primary outcome was the proportion of patients who were spontaneously voiding and catheter-free at 6 months., Results: Sixteen patients (age: 68.7 years) with catheter-dependent urinary retention were treated with Rezūm. Average prostate volume was 84.4 mL and 75% had median lobe. All patients had at least one recent failed trial without catheter (TWOC) and 87.5% were on BPH oral therapy. Mean number of vapor injections was 14.5. Visibility and bleeding during procedure were assessed using a 5-point scale, and were rated as 1.4 and 1.3, respectively. Anesthesia was either intravenous propofol sedation (n = 13) or self-administered methoxyflurane inhaler (n = 3). Mean catheter duration until first planned TWOC was 28.4 days. Three patients needed catheter replacement due to initial failed TWOC. One patient was lost to follow up, one patient did not return at 1 month, and one patient did not return at 3 months. At 1 month, 13/14 patients were spontaneously voiding and catheter-free. At 3 months, 14/14 patients were spontaneously voiding, and at 6 months, 15/15 patients were spontaneously voiding and catheter-free (1 patient was lost to follow up)., Conclusions: Rezūm water vapor therapy can successfully treat catheter-dependent urinary retention after initial failed TWOC in an outpatient setting.

The use of global navigation satellite systems (GNSS) precise point positioning (PPP) to estimate zenith tropospheric delay (ZTD) profiles in kinematic vehicular mode in mountainous areas is investigated. Car-mounted multi-constellation GNSS receivers are employed. The Natural Resources Canada Canadian Spatial Reference System PPP (CSRS-PPP) online service that currently processes dual-frequency global positioning system (GPS) and Global'naya Navigatsionnaya Sputnikovaya Sistema (GLONASS) measurements and is now capable of GPS integer ambiguity resolution is used. An offline version that can process the above and Galileo measurements simultaneously, including Galileo integer ambiguity resolution is also tested to evaluate the advantage of three constellations. A multi-day static data set observed under open sky is first tested to determine performance under ideal conditions. Two long road profile tests conducted in kinematic mode are then analyzed to assess the capability of the approach. The challenges of ZTD kinematic profiling are numerous, namely shorter data sets, signal shading due to topography and forests of conifers along roads, and frequent losses of phase lock requiring numerous but not always successful integer ambiguity re-initialization. ZTD profiles are therefore often only available with float ambiguities, reducing system observability. Occasional total interruption of measurement availability results in profile discontinuities. CSRS-PPP outputs separately the zenith hydrostatic or dry delay (ZHD) and water vapour content or zenith wet delay (ZWD). The two delays are analyzed separately, with emphasis on the more unpredictable and highly variable ZWD, especially in mountainous areas. The estimated delays are compared with the Vienna Mapping Function 1 (VMF1), which proves to be highly effective to model the large-scale profile variations in the Canadian Rockies, the main contribution of GNSS PPP being the estimation of higher frequency ZWD components. Of the many conclusions drawn from the field experiments, it is estimated that kinematic profiles are generally determined with accuracy of 10 to 20 mm, depending on the signal harshness of the environment.

• Cellulosic carbohydrates were recovered from residual sorghum lignocelluloses. • ASTM international and the novel SACH cellulose hydrolysis approaches were compared. • A maximum of 24.3 wt% of cellulosic carbohydrates (dw) were recovered using SACH. • 51.7 wt% total free and constitutive sorghum carbohydrates were recovered. • Fermentation assays suggested 6378 L/ha/year when sorghum was cultivated in Canada. Cellulosic ethanol could play a major role in the upcoming circular-economy once the process complexity, low carbohydrate extraction yields and high costs are resolved. To this purpose, different steam-treatment severity factors were employed on whole sweet sorghum biomass, followed by the delignification and hydrolysis of resulted lignocellulose fibers. A modified ASTM International (American Society for Testing and Material) standard cellulose hydrolysis approach as well as a newly developed SACH (Sulfuric Acid Cellulose Hydrolysis) process were used, recovering up to 24.3 wt% of cellulosic carbohydrates. This amounted to a total extractable and constitutive carbohydrate recovery of 51.7 wt% (dry basis) when a mild steam-treatment of whole sorghum biomass and the SACH cellulose hydrolysis were employed. An ethanol potential of 6378 L/ha/year was determined, comparable to values obtained from biomass such as sugarcane in warmer climates, supporting thus the opportunity of implementing this novel approach on a wider scale. [ABSTRACT FROM AUTHOR]

Unlabelled: Measurements of combustion product concentrations were taken in 30 homes where unvented gas fireplaces were used. Measurements of CO, CO(2), NO(x), NO(2) , O(2) (depletion), and water vapor were taken at 1-min interval. The analyzers were calibrated with certified calibration gases for each placement and were in operation for 3-4 days at each home. Measured concentrations were compared to published health-based standards and guidelines. The two combustion gases that exceeded published values were NO(2) and CO. For NO(2) , the Health Canada guideline of 250 ppb (1-h average) was exceeded in about 43% of the sample and the World Health Organization (WHO) guideline of 110 ppb (1-h average) was exceeded in 80% of the sample. Carbon monoxide levels exceeded the U.S. EPA 8-h average standard of 9 ppm in 20% of the sample. Moisture problems were not evident in the test homes. An analysis of the distribution of CO showed that the CO is dispersed throughout the home almost immediately upon operation of the fireplace and that the concentrations throughout the home away from the immediate vicinity of the fireplace are 70-80% of the level near the fireplace. Decay analysis of the combustion gases showed that NO was similarly stable to CO and CO(2) in the indoor environment but that both NO(2) and water vapor were removed from the air at much greater rates., Practical Implications: Previous studies on unvented gas fireplaces have made assumptions of how they are operated by users. This article presents the results of field monitoring of 30 unvented gas fireplaces under normal operation, regardless of whether users follow industry recommendations regarding installation, usage patterns, and maintenance. The monitoring found that health-based standards and guidelines were exceeded for CO in 20% of homes and for NO(2) in most homes. There were no identified moisture problems in these homes. Nearly, half of the fireplaces were used at least once for longer than 2 h, counter to manufacturers' intended usage as supplemental heating. This demonstrates that given actual usage patterns and compared to current health-based thresholds, these appliances can produce indoor air concentrations considered to be unhealthy to at least sensitive or at-risk individuals.