ExxonMobil (Canada)

Academic and professional disciplines form societies, associations, groups and networks to grow communities, build culture, create and share knowledge, develop and recruit talent, collaborate and advocate for its members. This article details the creation and initial development of a special interest group for Human Factors, specifically focused on high-risk safety-critical industries in Eastern Canada. The HFC Canada network was conceptualized by recognizing an opportunity for collaboration and Human Factors knowledge sharing among multidisciplinary stakeholders within the offshore energy and maritime sectors in Eastern Canada as they transitioned toward digitalized, remote, and autonomous operations. The impetus and underlying motivation is to foster collaboration and communication across key stakeholders and better understand their processes within these high-risk, safety-critical domains. This article details the initial formation of the network, operational structure and activities, including initial feedback and perspectives from different stakeholders, lessons learned, and future direction.

ABSTRACTRadiometric dating of fault gouges has become a useful tool for regional tectonics studies and for exploring and understanding fault and earthquake processes. Methods to define the absolute age of faults achieved a solid scientific foundation almost 25 years ago when the development and application of illite age analysis for investigating sedimentary burial and thermal histories found a new potential application – defining the age of fold-and-thrust development. Since then, the methods have benefitted from further development and incorporation of the 40Ar/39Ar micro-encapsulation method and quantitative clay mineral evaluation to distinguish polytypes (Wildfire). These refinements to the methods have improved their application in fold-and-thrust terrains and have opened up applications in normal and strike-slip fault environments. Another important development is the use of absolute dating methods in retrograde clay gouges in which clays in a fault develop from igneous or metamorphic wall rocks that contain no clays. In addition, the method has also been shown to be useful at dating folds in fold-and-thrust belts. We think the method is now an established part of the geological toolkit, look forward to future fault structural and tectonic studies that incorporate fault ages and hope that researchers continue to probe and discover ways that the method can assist fault process studies, including earthquake fault studies.

ABSTRACT Analysis of high-resolution three-dimensional seismic data from the Cold Lake Production Project (CLPP) of central Alberta, Canada, has resulted in a new sequence stratigraphic interpretation and depositional model for the upper Albian Clearwater Formation of the Mannville Group. Specifically, we document the presence of one sequence boundary within the Clearwater Formation that (1) separates older, deltaic deposits from a younger fluvial-dominated, terraced incised valley fill succession and (2) ties to a lowstand shoreline approximately 100 km (62 mi) to the north of the CLPP. Although this interpretation is far simpler than previous stratigraphic interpretations of this area, the sedimentologic record within the Clearwater Formation remains very complex because of the vertical stacking of high-energy fluvial to fluvial–estuarine deposits that are scour based. The composite sequence boundary identified here is associated with an extended period of landscape degradation and the formation of a moderately large valley that is complexly defined by a series of terraced fluvial deposits. Because individual channels eroded vertically and migrated laterally during both the fall and ensuing rise of sea level, the resulting valley-shaped stratigraphic sand body is (1) substantially wider than the true topographic valley (i.e., landform that is constrained by subvertical to near-vertical walls, open to the air, and typically resulting from degradation of the landscape via vertical and lateral erosion by a fluvial channel or channels) within which the lowstand channels flowed, (2) formed by both fluvial and marine processes that can be allogenic and/or autogenic in nature, and (3) defined by a composite surface that formed during the descending limb of a base level cycle and was partially modified during the subsequent base level rise and is thus of minor chronologic significance. We attempt to define the time of maximum topographic valley development, but younger erosion has removed much of the record of this valley. However, we estimate that the Clearwater Formation topographic valley had a maximum incision depth of greater than 60 m (>197 ft) and a width of approximately 20 km (12 mi). These dimensions correlate very well to incised valleys observed in the Quaternary. Analysis of core and log results within our seismic stratigraphic framework indicates that a fluviodeltaic model best explains the lithofacies distributions and geometries within the CLPP. Furthermore, finer-scale seismic mapping was used to encapsulate packages of sediment—which we refer to as genetic sedimentary bodies—whose reservoir properties could then be defined using core results. A genetic body approach to defining stratal architectures has resulted in (1) a predictive model for reservoir types and distributions across the CLPP; (2) accurate paleoenvironmental interpretations; and (3) a simple, yet robust sequence stratigraphic model of this area that is aligned with recent results reported from the study of similar systems in the Quaternary, recent morphologic observations from small-scale, physical sand box experiments, and the most up-to-date models of coastal fluvial erosion, deposition, and stratigraphic surface formation.

ExxonMobil Canada Properties and its collaborators are building a gravity based structure (GBS) in Newfoundland and Labrador to be installed on the Hebron Field offshore Eastern Canada. The geometry of the Hebron GBS is driven by the design constraints of a long operating life placed on the seafloor in the harsh environments at the Hebron field location. Prior to installation, the GBS encounters a number of significant floating phases — deep-water construction, towage, and installation. In each of these stages the hydrodynamic character of the unique Hebron geometry must be quantified to predict dynamic motions, assess tow performance, and define installation procedures and limitations. For the floating GBS, both heave and roll natural periods are long, and resonant responses due to wind gusting and vertical wave drift take place. Assessing the hydrodynamics by industry standard empirical methods is insufficient as regards capturing the viscous damping generated by eddy formation off the sharp edges of the submerged GBS structure. This paper focuses on the utilization of Computational Fluid Dynamics (CFD) to better understand and quantify this viscous damping. The Hebron GBS work has challenged the traditional methods for model generation and use of CFD for damping estimation, primarily because these techniques are most frequently used for traditional hull shapes. For example, application of the overset mesh technique, as successfully applied for ship-shaped vessels, does not provide the required accuracy in this case. Alternative numerical models are tested and found to work well: morphing techniques and sliding meshes for heave and pitch, respectively. Based on convergence and sensitivity studies, the results are accepted. Ultimately, the CFD work allows the project to quantify the expected increases in hydrodynamic damping and progress in the process of improving predictions of GBS motions and thus optimizing the operational planning of towing and installation.

Abstract This paper discusses an approach used to assess liquid film erosion/corrosion effects in the tubing strings of sour, high-rate, wet gas producers. This was done as an alternative to API RP 14E, which utilises an empirical erosional velocity factor "C" to estimate maximum velocity limits to minimise the potential for tubing metal loss from erosional effects. Many RasGas wells are completed with a full L-80 carbon steel or a combination L-80/Corrosion Resistant Alloy (CRA) production string. Once on production, a thin iron sulfide scale develops on the tubing wall significantly retarding the rate of metal loss due to internal corrosion. However, shear stresses generated from the condensate/water film flowing along the tubing wall could potentially remove this protective iron sulfide coating and expose fresh metal to much higher corrosion rates. This paper describes the approach adopted to assess the magnitude of shear stress created across a range of flow conditions including well production rates, fluid properties, and completion sizes using transient 1D flow simulation and more detailed 3D computational fluid dynamics modelling. The results will be used to design future laboratory experiments to assess the effect of these stresses on the integrity and effectiveness of the iron sulfide scale in reducing corrosion rates. Introduction RasGas Company Limited initiated a study to investigate the potential effect of high flow velocity on the stability of iron sulfide scales formed in carbon steel tubing during late field life when the wells will be required to maintain high rates at low wellhead pressures. Higher flow velocities will generate higher shear stresses that might be capable of stripping iron sulfide scale leading to high general corrosion rate and/or severe localised corrosion. The former will be expected in the case of uniform scale erosion while the latter is expected in the case of non-uniform scale erosion. In order to meet the study objective, the first step is to understand the flow behaviour (wall shear stress, flow regime and temperature distribution) in the tubing string. Four different tubing strings were investigated: a 7-inch monobore-vertical (MB-V) and deviated (MB-D), a 9-5/8 inch x 7 inch bigbore-vertical (BB-V) and deviated (BB-D). The completion schemes for MB and BB wells are illustrated in Figure 1. 1-D flow simulations using a Transient Flow Simulation Software (TFSS) were conducted to determine the flow regime, wall shear stress, and temperature distribution and the portion of liquid flowing as wall film in the tubing strings. 3-D Computational Fluid Dynamics (CFD) simulations were also conducted to determine the wall shear stress at specific locations (X-overs) where there is a change in internal diameter of the tubing string that is greater than 10%. The objective of these simulations was to obtain shear stress predictions that would be utilised in a customised test loop to establish the stability of the iron sulfide film. If this film is not stable at the predicted shear stresses, then the wellbore integrity management programme would have to be focused on corrosion protection since historical well corrosion monitoring data has established high corrosion rate in tubing strings where the iron sulfide film has not been formed.

Abstract The problem cased by wax deposition during production and transportation of waxy oil has been receiving an increasing attention from the industry, especially with the off-shore projects expansion recently. Due to the high cost of those projects, an accurate modelling on wax precipitation and deposition is imperatively required to facilitate the design, development, and operation of those projects. While the wax precipitation models depict the thermodynamic behaviour of waxy oil, the modelling of wax deposition in production facilities and pipelines focuses on how soon wax would accumulate. The wax deposition simulation appears to be a more challenging task due to the high complexity and limited measured data available in the open literature. In this work, a compositional simulator is introduced to simulate the wax deposition in a pipeline. This model is founded on a thermodynamics model from our previous work and equipped with major wax deposition mechanisms as well as tuning function. Through four case studies, the model, with its prediction and tuning capability, has demonstrated a practical tool in flow assurance simulation. The results also suggest that a promising methodology can be applied in flow assurance study when the simulator is tuned with measurements from the high pressure deposition cell.

Abstract Asset performance can often be improved through continuous monitoring and/or through better utilization of information extracted from the high frequency data that are becoming more readily available in today's digital world. ExxonMobil has a long history of applying advanced technologies in asset management. Today, we continue to use new hardware, integrated software, and improved data infrastructure to enhance asset management workflows. ExxonMobil is taking an enterprise-wide approach (Reece et. al. 2008) to implementing digital technology in asset management. This paper presents four examples where ExxonMobil has taken advantage of high frequency data for timely asset management decisions. These four examples represent implementation at four different operational scales: for reservoir management, for well management, for facility management, and for plant management. The four examples are: (1) For a West African reservoir: Permanent downhole pressure gauge data have added value in reservoir modeling that in turn provided a method for calculating reservoir rates; (2) For South Texas gas wells: Real-time data access and charting capabilities were implemented and advanced data analysis explored to identify well events and manage well work-over activities aided by artificial intelligence; (3) For Norwegian oil fields: An integrated facility model was developed and tuned for surveillance and operation of a network of wells and production facilities that are shared by multiple fields; (4) For an Australian production plant complex: Production from offshore platforms, a gas plant, a crude stabilization plant, a fractionation plant, and a tank farm was optimized with high frequency data and automatic process control.

A five-stage strategy is suggested for conducting an exposure assessment of mixtures that may contain numerous chemical components. The stages are: (1) determination of mixture composition and variability, (2) selection of component groups within the mixture and documentation of criteria used for this selection, (3) compilation of relevant property data for each group, (4) assessment of environmental fate of each group, and (5) assessment of environmental and human exposure to each group and to the mixture as a whole. A subsequent step is the assessment of environmental and/or human risk associated with the individual and aggregate exposure to each group. The approach is illustrated by application to gasoline, which is treated as 24 component groups or hydrocarbon blocks. Focusing on stages 2-4, the illustration shows that the groups display widely different environmental fates as a result of their different physicochemical properties, degradation half-lives, and mode-of-entry into the environment. As a result, the relative proportions of groups in each environmental medium (such as air and water) differ greatly from that of the original mixture. It is thus important to treat gasoline and similar mixtures as a number of component groups instead of as a single substance. A generic procedure is suggested in which the model is run for unit emissions of each component group to air, water, and soil. These results are compiled into matrices that can then be conveniently scaled to actual emission rates without rerunning the model. Methods for determining subsequent exposure and risk are also briefly outlined.

Abstract The term "Real-Time Optimization" (RTO) has rapidly found its way into common usage in the oil and gas industry, as it already has in many others. However, RTO in the oil and gas industry is usually used more as a slogan rather than describing a system or process that truly optimizes anything at all, let alone does so in real-time. In this paper, we describe what RTO means in the exploitation of hydrocarbons and what technologies are available now and are likely to be available in the future. We discuss how it is misunderstood and what real financial benefits await those who adopt it. Furthermore, we are working toward developing a method of classification to allow us to establish where a field operation lies on the RTO ladder, and to help plan a strategy to generate the benefits that moving up the RTO ladder can offer on specific fields and assets. The paper also describes a new SPE Technical Interest Group (TIG), explaining why it has been formed, and outlining its objectives and some planned deliverables.