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Liquid-phase mutual diffusion coefficients are a key parameter in reservoir simulation models related to both primary production and envisioned secondary recovery processes for heavy oil and bitumen. The measurement of liquid-phase mutual diffusion coefficients in bitumen and heavy oil + light hydrocarbon or gas mixtures present numerous experimental and data analysis challenges due to the viscosity and opacity of the mixtures, the variability of density, viscosity and mutual diffusion coefficient with composition, and the multi-phase nature of these mixtures. Data analysis challenges are particularly acute. For example, recently reported mutual diffusion coefficient values for liquid mixtures of bitumen + carbon dioxide vary over three orders of magnitude when different analysis methods are applied to the same experimental data. In this contribution, we illustrate the importance of measuring composition profiles within liquids as a function of time, as a basis for mutual diffusion coefficient c...

A non‐intrusive x‐ray transmission video based method for measuring local concentrations of one phase dispersed or emulsified in another, on‐line and without sampling, is described using illustrative examples. The method involves passing a polychromatic x‐ray beam through a multiphase fluid/slurry contained in an x‐ray transparent or translucent vessel. The leading dimensions for the unit cell for local concentration measurements are the cross‐sectional area of a single pixel (magnification dependent) and the length of the path followed by the x‐ray beam through the vessel (vessel dependent). Measurement frequency is dictated by the data acquisition system or the video format employed—typically thirty measurements per second. X‐ray transmission radiography is sensitive to small density differences. For example, in a prototype apparatus, the water content in a water‐in‐oil emulsion/dispersion is readily measured to within 5000 ppm. The water + nano scale silica particle content in a water + silica...

Our interest in the phase behavior of asymmetric, industrial organic fluids focuses on understanding the impact of phase behavior, particularly solid phase behavior, on flow assurance and other reservoir fluid management and production issues, as well as on heavy oil partitioning processes in upgrading operations. Recent developments in X-ray view cell technology allow us to examine the phase behavior of fluids containing large mass fractions of asphaltenes, and dispersed organic and inorganic solids, in a routine manner. Over the past three years we have been preparing detailed phase behavior maps, including phase densities, for the model system Athabasca Bitumen Vacuum Bottoms (ABVB), a 525+ °C fraction containing 32 wt% pentane asphaltenes + pentane, heptane and dodecane using a variable volume X-ray view-cell. The X-ray view-cell experimental program focused on the temperature range, 100 to 340°C, and the pressure range, 0.1 to 30 MPa. The mixtures exhibit complex but reversible multiphase be...

The correlation and prediction of deposit formation are at the core of flow assurance, risk assessment, and other reservoir fluid management issues and are equally important for heavy oil or bitumen partitioning and upgrading. Asphaltene deposition in particular is a key topic in both sectors. Hydrocarbons from condensate-rich reservoir fluids to bitumen + diluent mixtures share constituents, from asphaltenes and resins to pentane, and can all be classified as asymmetric from a phase behavior perspective. The phase dia-grams for these asymmetric fluids are characterized by zone of four-phase behavior surrounded by three-phase and two-phase regions in both pressure-composition at constant temperature, and pressure–temperature at constant composition diagrams. Adherent asphaltenic solid and liquid deposits only arise within some multiphase zones. Zones such as the SL1, SL1V, L1L2V, and L1L2 are prone to the production of adherent asphaltenic deposits particularly when combined with intermittent or ...

Multiphase solids (slag + matte, metals + inclusions) are frequently sectioned and the areas of the phases visible at the resulting surfaces are obtained using one of a number of microscopic techniques. Number concentrations of particles can be obtained unambiguously from these images. However, misinterpretation of these area distributions as particle size distributions for the dispersed phases arises frequently and in diverse contexts. When particles are binned coarsely and the particles are nearly spherical, the impact of such misinterpretations on mean particle size and interfacial area per unit volume and even relative dispersed phase volume fraction is shown to be small. In other cases the errors can be significant. In all cases, the number fraction of small particles is overstated. Thus, interfacial area per unit volume of dispersed phase tends to be overstated, the mean particle size and relative dispersed phase volume fraction underestimated. In this note, an analytical method for the dec...

A partial phase diagram for the system athabasca bitumen vacuum bottoms (ABVB) (24.6 wt% / 2 mole % ) + dodecane (73.8 wt. % / 47 mole % ) + hydrogen (1.6 wt % / 51 mole % ) was constructed in the temperature range 425 K to 725 K and the pressure range 2 MPa to 7 MPa using an X-ray view cell apparatus. This fluid system is shown to exhibit two phase L1V and three phase L1 L2 V phase behaviour over parts of this P-T region. The shape of the low temperature boundary between the L1V and L1 L2 V zones is characteristic of dilute asymmetric mixtures where a heavy liquid phase, L2 appears then disappears within the light liquid phase L1 on isothermal compression. Such phase behaviour is referred to as unusual retrograde condensation and is of both practical and theoretical interest. Transitions between the multiphase regions were found to be reversible at temperatures less than 660 K., in all cases. At higher temperatures irreversible “ asphaltene precipitation” arose within the L2 phase “ Asphaltene p...

The appearance of solid-liquid-liquid-vapour phase equilibria in reservoir fluids is explained as an extension of the phase behaviour of binary asymmetric fluids. The theoretical approach is demonstrated for the model condensate-rich reservoir-fluid ethane (10 mole %) butane (40 mole %) phenanthrene (50 mole %), to which propane is added. Extant solid-liquid-liquid-vapour phase equilibrium data for reservoir fluids, which include asphaltenes, are found to be consistent with the phase behaviour of this model fluid. The implications for the prediction of asphaltene “precipitation” are discussed.

Onyx River has three characteristic reaches, bedrock incision, moraine breaches, and alluvial. Antecedent geomorphological events control the slope of these reaches and to some extent the bed material. Coarse bed materials occur in the steep reaches of the bedrock and moraine breach channels. Discharge hydrographs and flow-duration curves reveal a division into two flow regimes with a hiatus at about 1 m3/s. The modern channel form and pattern and distribution of bed materials may be related to these flow regimes. Channel-in-channel features, berms, overspill channels, and longitudinal bars are related to flow characteristics. The evolution of the river and its terraces is discussed in terms of changes in discharge and sediment supply. Prominent terraces are explained in terms of relative contributions of water and sediment from Wright Lower Glacier and from other glaciers. The terraces reflect climatic changes and their chronology is related to recent glacier activity and changes in level of Lak...

Astract Previous hypotheses to explain the origin of the Labyrinth have invoked floods, glacial erosion, and uniformitarian arguments of salt weathering and deflation. The landscape is one of reticulate troughs, deeper to the east than west, with irregular long profiles and enclosed depressions. The troughs are shown to belong to a hierarchy and display curvilinear form. Their origin is related to glacial plucking along joints and subsequent deepening by ice-marginal and proglacial meltwater systems. Periglacial alteration of the primary form, particularly asymmetric infill by solifluction and scree, is largely a result of debris supplied by freeze-thaw processes. Intertrough blocks initially formed upstanding masses between reticulate, joint-controlled depressions, and were subject to subglacial abrasion by a glacier sliding over its bed. The required wet-based ice conditions imply either extremely thick ice or a warmer climate than present. Landform is used to deduce a complex origin for the Labyrinth w...

Rectilinear slopes in the Olympus Range, Southern Victoria Land, Antarctica were termed Richter slopes and attributed to formation by salt weathering and deflation. Existing theoretical models for Richter slope development are invalid when the processes of salt weathering and deflation act without scree movement. Removal of all slope debris by salt weathering and deflation corresponds to the solution y = 0 in Lehmann's differential equation of slope retreat form. An alternative process of slope retreat is based on undercutting of the free face under the influence of wind drifted snow. Bedrock slope forms measured in the field correspond to observed snow configuration. The stepped microrelief profile is as expected under the nivation hypothesis. Compound slopes with a range of declivities are related to variations in form of debris accumulation and snow conditions under changing climate.

Many authors have presented photographs illustrating coarse-grained deposits within the otherwise fine-grained, winter components of glaciolacustrine varves. Few have realized the significance of these coarse units and in several cases they have been misinterpreted as summer deposits. Examples of such coarse units are given in a literature review. Conclusive examples of deposition of coarse-grained sediments during winter are presented from a modern environment at Lillooet Lake, British Columbia, and from Pleistocene glaciolacustrine deposits in central British Columbia, and in Sweden. Low sediment concentrations in the lake water, winter storms, failure of deltaic deposits, and possibly jikulhlaups are shown to be potential controls on the occurrence of underflows which deposit the coarse-grained, winter sediments. Misinterpretation of coarse-grained deposits leads to overestimation of the time represented by glaciolacustrine sedimentary sequences.

A brief review of the possible mechanisms of drumlin formation leads to the conclusion that several are plausible. The universality of the generally accepted assumptions that drumlins are formed by...