ARC Resources (Canada)

Abstract The Paris Agreement aims to limit global warming to well below 2°C and pursue efforts to limit it to 1.5°C above pre-industrial levels. In response to the Paris Agreement, carbon dioxide storage, also known as carbon capture and storage (CCS), is a critical part of efforts to mitigate climate change in response to the Paris Agreement. Canada has abundant heavy oil resources, but to recover this immobile liquid, hot water or solvents are often injected underground as a heat carrier (SAGD) or dilution (VAPEX) or hybrid (ES-SAGD) to mobilize the heavy oil. However, these processes often result in energy losses and CO2 emissions. Thus, how to effectively treat the produced carbon dioxide seems to be an economic and environmental problem especially under the context of the Paris Agreement and the increasing carbon tax in Canada. To address the urgent problem, this study first establishes the SAGD, warm VAPEX, and solvent-based ES-SAGD process through numerical simulation. Then carbon dioxide is injected underground in the post EOR phase. In steam-based technology (SAGD or ES-SAGD), water is used as an excellent heat carrier to inject underground to displace heavy oil, The left water underground forms an excellent dissolution trapping barrier for carbon sequestration. In solvent-based technology (ES-SAGD or VAPEX), carbon dioxide produced by heating can not only be injected for underground storage in reducing the environmental impact, but also can recover the underground solvent from gas, oil and even water phases further reducing the cost of solvent-based technology. The outcome of this research not only provides potential for carbon sequestration from post-EOR activities, but also supports the transformation of Canada's heavy oil industry towards more solvent-based methods, resulting in economic and environmental benefits.

Abstract The primary goal of this project was to prove the feasibility of a Cyclic Gas Injection/Production (Huff & Puff) enhanced oil recovery (EOR) scheme and evaluate its economic viability in the Viking formation in Saskatchewan, Canada. Historically, the Viking formation has challenging waterflood economics due to limited injectivity into the tight sand reservoir and formation damage caused by movable and swelling clays. The objectives were to test horizontal well injectivity at desired pressures, assess the use of produced gas injection to repressurize the extremely depleted Viking reservoir, evaluate enhanced oil recovery with various inter-well spacings, and to optimize injection and production cycle lengths. This pilot was designed by utilizing analytical evaluation and numerical simulation. The Huff & Puff pilot consists of four 0.7 mile (1100 m) horizontal wells with two different inter-well spacings; 667 ft vs 1333 ft (200 m vs 400 m). The pilot consisted of two parallel horizontal well pairs, which were designed to alternate injection and production cycles. A detailed reservoir surveillance program was implemented to collect extensive data, including reservoir and wellhead pressures, gas composition analysis, production and injection rates of the pilot wells, and the production rates of surrounding wells to evaluate reservoir response and pilot performance. Whitecap has been operating this pilot project since its initiation in September 2021 with technical success. Six Huff & Puff cycles with varying durations, between one to three months on injection, have been completed without major operating issues. Per-well injectivity has reached higher than designed 750 Mscf/d (21 e3m3/d) at desired surface pressures. Through the course of six injection cycles, average reservoir pressure has increased from an initial 174-319 psi (1.2-2.2 MPa) to 623-885 psi (4.3-6.1 MPa). The incremental oil recovery factor for the pilot area is expected to be 1%, which is considerable for a reservoir with typical primary recovery factors expected to be only 6-8%. The gas injection has resulted in production increases in some offset wells, and a higher degree of gas breakthrough has been observed in the section with 667 ft (200 m) well spacing. The 3-month injection cycle has resulted in the largest incremental recovery and cycle time optimization efforts are ongoing. The pilot results are encouraging, indicating that a cyclic gas injection EOR scheme could have potential for further commercial expansion. The pilot has demonstrated Huff & Puff's potential economic viability as an EOR scheme for the tight Viking sand formation, which is one of the most prominent producing formations with low oil recovery factors in the Western Canadian Sedimentary Basin (WCSB). There is no such published pilot information available before. Detailed pilot design, production performance evaluation and learnings are presented in this paper.

This research proposes an investigative experiment employing binary classification for short-term electricity price spike forecasting. Numerical definitions for price spikes are derived from economic and statistical thresholds. The predictive task employs two tree-based machine learning classifiers and a deterministic point forecaster; a statistical regression model. Hyperparameters for the tree-based classifiers are optimized for statistical performance based on recall, precision, and F1-score. The deterministic forecaster is adapted from the literature on electricity price forecasting for the classification task. Additionally, one tree-based model prioritizes interpretability, generating decision rules that are subsequently utilized to produce price spike forecasts. For all models, we evaluate the final statistical and economic predictive performance. The interpretable model is analyzed for the trade-off between performance and interpretability. Numerical results highlight the significance of complementing statistical performance with economic assessment in electricity price spike forecasting. All experiments utilize data from Alberta’s electricity market.

Bioconcentration factors (BCFs) in rainbow trout were measured for 10 anionic surfactants with a range of alkyl chain lengths and different polar head groups. The BCFs ranged from 0.04 L kg–1 ww (for C10SO3) to 1370 L kg–1 ww (C16SO3). There was a strong correlation between the log BCF and log membrane lipid–water distribution ratio (DMLW, r2 = 0.96), and biotransformation was identified as the dominant elimination mechanism. The strong positive influence of DMLW on BCF was attributed to two phenomena: (i) increased partitioning from water into the epithelial membrane of the gill, leading to more rapid diffusion across this barrier and more rapid uptake, and (ii) increased sequestration of the surfactant body burden into membranes and other body tissues, resulting in lower freely dissolved concentrations available for biotransformation. Estimated whole-body in vivo biotransformation rate constants kB-BCF are within a factor three of rate constants estimated from S9 in vitro assays for six of the eight test chemicals for which kB-BCF could be determined. A model-based assessment indicated that the hepatic clearance rate of freely dissolved chemicals was similar for the studied surfactants. The dataset will be useful for evaluation of in silico and in vitro methods to assess bioaccumulation.

Positive psychological well-being (PPWB) is generally associated with improved physical health, mental well-being, and healthy behaviors. However, it is not clear how PPWB differs in women with obesity or if improving PPWB will improve their health. The objective of this study was to summarize the evidence on PPWB in women with obesity. A scoping review was conducted in APA PsycINFO, EMBASE, MEDLINE, Cochrane Central Register of Controlled Trials, CINAHL, SocINDEX, Family & Society Studies Worldwide, ProQuest Dissertations and Theses Global databases. Primary research studies, with an analysis of adult women with a BMI ≥30kg/m2 with measures of PPWB are included. Thirty-two studies encompassing >57,000 women with obesity, measured constructs of PPWB included: self-esteem, life satisfaction, positive affect, social support, vitality, happiness, self-acceptance, and optimism. Most studies showed that PPWB was lower in women with obesity although this association dissipated in studies when health and negative social factors were considered. Improvements in PPWB were associated with weight loss and with successful lifestyle changes with and without weight loss. Positive psychological interventions (PPIs) were used to bolster psychological well-being. PPIs were associated with improved measures of self-esteem and well-being. Prospective longitudinal and intervention studies are required to understand how evaluating and fostering PPWB might support gender-informed obesity care.

Abstract Enrichment of the heavy rare earth elements (HREE) in carbonatites is rare as carbonatite petrogenesis favours the light (L)REE. We describe HREE enrichment in fenitized phonolite breccia, focusing on small satellite occurrences 1–2 km from the Songwe Hill carbonatite, Malawi. Within the breccia groundmass, a HREE-bearing mineral assemblage comprises xenotime, zircon, anatase/rutile and minor huttonite/thorite, as well as fluorite and apatite.A genetic link between HREE mineralization and carbonatite emplacement is indicated by the presence of Sr-bearing carbonate veins, carbonatite xenoliths and extensive fenitization. We propose that the HREE are retained in hydrothermal fluids which are residually derived from a carbonatite after precipitation of LREE minerals. Brecciation provides a focusing conduit for such fluids, enabling HREE transport and xenotime precipitation in the fenite. Continued fluid–rock interaction leads to dissolution of HREE-bearing minerals and further precipitation of xenotime and huttonite/thorite.At a maximum Y content of 3100 µg g−1, HREE concentrations in the presented example are not sufficient to constitute ore, but the similar composition and texture of these rocks to other cases of carbonatite-related HREE enrichment suggests that all form via a common mechanism linked to fenitization. Precipitation of HREE minerals only occurs where a pre-existing structure provides a focusing conduit for fenitizing fluids, reducing fluid – country-rock interaction. Enrichment of HREE and Th in fenite breccia serves as an indicator of fluid expulsion from a carbonatite, and may indicate the presence of LREE mineralization within the source carbonatite body at depth.

Abstract Whole-rock major- and trace-element data are presented on a sample collection from the >3 Ga Amikoq Layered Complex (ALC), and hosting amphibolites within the Mesoarchean Akia terrane, SW Greenland. The lithologies range from leuconorite to melanorite/feldspathic orthopyroxenite, orthopyroxenite to harzburgite through to dunite, and tholeiitic basaltic–picritic mafic host rocks. The Amikoq Layered Complex samples are primitive (Mg#: 65–89) with elevated Ni and Cr contents. However, the absence of troctolitic lithologies and the presence of two orthopyroxene compositional trends, suggests that the successions might not be comagmatic. On the basis of trace-element cumulate models, relatively low Ni contents and minor negative Sr-Eu anomalies in some high-Ti ultramafic rocks, it is not possible to exclude a petrogenesis related to a melt similar to that of the mafic host-rocks. Ultramafic samples with U-shaped trace-element distribution patterns are petrogenetically related to the noritic sequences, either through cumulus mineral accumulation or melt-rock reactions. Assimilation-fractional-crystallisation modelling of melanorites nevertheless require the parental melt to have been contaminated/mixed with a component of island-arc-like tholeiite affinity. A boninite-like parental melt might have been derived from the subcontinental lithospheric mantle of the Akia terrane, or alternatively via assimilation of an ultramafic parental melt with island-arc-like tholeiite. Given the complex geological evolution and high-grade metamorphic overprint of the Amikoq Layered Complex, we are unable to differentiate between the two models.

Bioaccumulation (B) assessment is challenging because there are various B‐metrics from laboratory and field studies, multiple criteria and thresholds for classifying bioaccumulative (B), very bioaccumulative (vB), and not bioaccumulative (nB) chemicals, as well as inherent variability and uncertainty in the data. These challenges can be met using a weight of evidence (WoE) approach. The Bioaccumulation Assessment Tool (BAT) provides a transparent WoE assessment framework that follows Organisation for Economic Co‐operation and Development (OECD) principles for performing a WoE analysis. The BAT guides an evaluator through the process of data collection, generation, evaluation, and integration of various lines of evidence (LoE) (i.e., B‐metrics) to inform decision‐making. Phenanthrene (PHE) is a naturally occurring chemical for which extensive B and toxicokinetics data are available. A B assessment for PHE using the BAT is described that includes a critical evaluation of 74 measured in vivo LoE for fish and invertebrate species from laboratory and field studies. The number of LoE are reasonably well balanced across taxa (i.e., fish and invertebrates) and the different B‐metrics. Additionally, in silico and in vitro biotransformation rate estimates and corresponding model‐predicted B‐metrics are included as corroborating evidence. Application of the BAT provides a consistent, coherent, and scientifically defensible WoE evaluation to conclude that PHE is not bioaccumulative (nB) because the overwhelming majority of the bioconcentration, bioaccumulation, and biomagnification metrics for both fish and invertebrates are below regulatory thresholds. An analysis of the relevant data using fugacity ratios is also provided, showing that PHE does not biomagnify in aquatic food webs. The critical review identifies recommendations to increase the consistency of B assessments, such as improved standardization of B testing guidelines, data reporting requirements for invertebrate studies, and consideration of temperature and salinity effects on certain B‐metrics. Integr Environ Assess Manag 2021;17:911–925. © 2021 Concawe. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC)