WP2 final report

This document summarises the significant results in work package 2 of the DigiMon project. Detailed descriptions and results from each task can be found in the referenced deliverables and publications

The modified arterial reservoir: An update with consideration of asymptotic pressure (P∞) and zero-flow pressure (Pzf)

This article describes the modified arterial reservoir in detail. The modified arterial reservoir makes explicit the wave nature of both reservoir (Pres) and excess pressure (Pxs). The mathematical derivation and methods for estimating Pres in the absence of flow velocity data are described. There is also discussion of zero-flow pressure (Pzf), the pressure at which flow through the circulation ceases; its relationship to asymptotic pressure (P∞) estimated by the reservoir model; and the physiological interpretation of Pzf . A systematic review and meta-analysis provides evidence that Pzf differs from mean circulatory filling pressure

Project Execution and Offshore Field Development in the Current Oil Market Downturn

This Record of Study presents the author’s experience in the capacity of riser lead and technical advisor working on multiple engineering and management project assignments by Cuneiform Offshore Consulting (Cuneiform). Cuneiform is a consulting firm based in Houston, Texas, specialized in providing engineering, technical advisory and project management services to the offshore energy industry. The author provided direct technical and managerial support to several of Noble Energy’s field developments in Gulf of Mexico (GOM) and Eastern Mediterranean; and, performed CVA (Certified Verification Agent) duties on behalf of BSEE (Bureau of Safety and Environmental Enforcement) by conducting riser design, fabrication and installation verification for risers intended for operation in two different GOM developments. The author’s assignments were comprised of different technical and managerial challenges related to design, engineering, fabrication and installation of offshore risers. A fundamental goal and imperative challenge was to minimize project execution and operational risks and costs. The author emphasizes the importance of correct hazard identification, appropriate risk assessments, good decision making and judgement to ensure the health, safety and protection of the offshore personnel, the public and the environment, as well as the avoidance of incidents through proper riser design and proper execution to help safeguard the offshore asset and the interest of all stakeholders. The engineering and execution of offshore dynamic risers require a detailed understanding of the internal and external environment and interfaces. Early assessment of key design considerations during feasibility and concept selection phases was of utmost importance as it allowed for the identification of technical gaps and risk evaluation. Indeed, particular attention was given to the riser type selection philosophy with respect to host floater types, field configurations, environmental conditions, and fluid properties amongst primary parameters. Moreover, the author’s experience highlights the importance of staffing, teamwork, communication, planning, management, leadership and decision making as key factors and challenges to the overall project execution success. Furthermore, organizational elements such as talent identification, retention and acquisition; continuous investment into innovation and R&D; risk assessment and minimization; ability to adapt to changing market demands; cost control; and maintaining a cash flow positive organization with access to capital are found to contribute to an enhanced operational efficiency. The thorough assessment of outcomes for each project provided valuable technical and managerial lessons. The acquired experience and proper implementation of the gathered lessons from past projects enables better execution of future projects. Finally, the overall outcome and success of any project can be judged by assessing its technical rigor and robustness as well as the efficacy in its managerial decisions, approaches, processes, priorities and execution

Project Execution and Offshore Field Development in the Current Oil Market Downturn

This Record of Study presents the author’s experience in the capacity of riser lead and technical advisor working on multiple engineering and management project assignments by Cuneiform Offshore Consulting (Cuneiform). Cuneiform is a consulting firm based in Houston, Texas, specialized in providing engineering, technical advisory and project management services to the offshore energy industry. The author provided direct technical and managerial support to several of Noble Energy’s field developments in Gulf of Mexico (GOM) and Eastern Mediterranean; and, performed CVA (Certified Verification Agent) duties on behalf of BSEE (Bureau of Safety and Environmental Enforcement) by conducting riser design, fabrication and installation verification for risers intended for operation in two different GOM developments. The author’s assignments were comprised of different technical and managerial challenges related to design, engineering, fabrication and installation of offshore risers. A fundamental goal and imperative challenge was to minimize project execution and operational risks and costs. The author emphasizes the importance of correct hazard identification, appropriate risk assessments, good decision making and judgement to ensure the health, safety and protection of the offshore personnel, the public and the environment, as well as the avoidance of incidents through proper riser design and proper execution to help safeguard the offshore asset and the interest of all stakeholders. The engineering and execution of offshore dynamic risers require a detailed understanding of the internal and external environment and interfaces. Early assessment of key design considerations during feasibility and concept selection phases was of utmost importance as it allowed for the identification of technical gaps and risk evaluation. Indeed, particular attention was given to the riser type selection philosophy with respect to host floater types, field configurations, environmental conditions, and fluid properties amongst primary parameters. Moreover, the author’s experience highlights the importance of staffing, teamwork, communication, planning, management, leadership and decision making as key factors and challenges to the overall project execution success. Furthermore, organizational elements such as talent identification, retention and acquisition; continuous investment into innovation and R&D; risk assessment and minimization; ability to adapt to changing market demands; cost control; and maintaining a cash flow positive organization with access to capital are found to contribute to an enhanced operational efficiency. The thorough assessment of outcomes for each project provided valuable technical and managerial lessons. The acquired experience and proper implementation of the gathered lessons from past projects enables better execution of future projects. Finally, the overall outcome and success of any project can be judged by assessing its technical rigor and robustness as well as the efficacy in its managerial decisions, approaches, processes, priorities and execution

Seismic chronostratigraphy for reservoir characterization : modeling and applications

The assumption of the chronostratigraphic significance of seismic reflections serves as a fundamental premise in interpreting stratigraphy from seismic images. This hypothesis proposed in 1977 was initially applied to delineate depositional sequences as the basic interpretive unit, and then to reconstruct Wheeler Diagram and regional sea level curves. After a further comparison against with global eustatic events, these regional curves can further facilitate predicting the age, distribution, and facies of depositional sequence before drilling in a seismic-covered area during petroleum exploration. With a boom in reservoir-level seismic applications, for obtaining significant high frequency sequence (HFS) surfaces as the bounding surfaces in static reservoir model construction, this fundamental assumption was inevitably extended to characterize HFS and even high-frequency cycles (HFC) during seismic reservoir characterization. For an ultimate improvement in constructing reservoir-bounding surfaces, the author targeted at evaluating the validity of this fundamental assumption as applied to high-order seismic stratigraphy. The author conducted the entire project via the forward seismic modeling upon geologic models with known chronostratigraphic relationship. Besides, these input models carefully honor the reservoir geology for meaningful discussions on (1) shallow marine siliciclastic reservoirs in Starfak Field, GoM, (2) shallow-water mixed carbonate/clastic Upper San Andres-Grayburg reservoirs in Permian Basin, and (3) shallow-water carbonate Abo shelf margin-Clear Fork platform in Permian Basin. This study has achieved three-fold contributions. On the aspect of realistic geocellular, property and seismic modeling at the reservoir scale, the author integrated high-resolution sequence stratigraphic framework, published 3D depositional model, intra-facies heterogeneity in 3D modeling to selectively apply advanced geostatistical methods to model hierarchical heterogeneity. Subsequently, the author proposed an evaluation scheme with a defined parameter ('time-correlation error/TCE') to assess HFS-scale reservoir-bounding surfaces. These assessments revealed an interactive influence from (1) stratal geometry, (2) lateral lithofacies variation, (3) lithofacies-sonic velocity relationship in pure- versus mixed-lithology successions, (4) intra-facies heterogeneity, and (5) seismic frequency. Finally, based on these forward modeling results, the author proposed a decision tree to determine valid interpretation strategy in seismic chronostratigraphic correlation in scenarios with geoscientists’ expert knowledge and recommended an attribute-driven volumetric picking scheme to improve published algorithms for scenarios without prior knowledge.Geological Science

Modeling USA stream temperatures for stream biodiversity and climate change assessments

Stream temperature (ST) is a primary determinant of individual stream species distributions and community composition. Moreover, thermal modifications associated with urbanization, agriculture, reservoirs, and climate change can significantly alter stream ecosystem structure and function. Despite its importance, we lack ST measurements for the vast majority of USA streams. To effectively manage these important systems, we need to understand how STs vary geographically, what the natural (reference) thermal condition of altered streams was, and how STs will respond to climate change. Empirical ST models, if calibrated with physically meaningful predictors, could provide this information. My dissertation objectives were to: (1) develop empirical models that predict reference- and nonreference-condition STs for the conterminous USA, (2) assess how well modeled STs represent measured STs for predicting stream biotic communities, and (3) predict potential climate-related alterations to STs. For objective 1, I used random forest modeling with environmental data from several thousand US Geological Survey sites to model geographic variation in nonreference mean summer, mean winter, and mean annual STs. I used these models to identify thresholds of watershed alteration below which there were negligible effects on ST. With these reference-condition sites, I then built ST models to predict summer, winter, and annual STs that should occur in the absence of human-related alteration (r2 = 0.87, 0.89, 0.95, respectively). To meet objective 2, I compared how well modeled and measured ST predicted stream benthic invertebrate composition across 92 streams. I also compared predicted and measured STs for estimating taxon-specific thermal optima. Modeled and measured STs performed equally well in both predicting invertebrate composition and estimating taxon-specific thermal optima (r2 between observation and model-derived optima = 0.97). For objective 3, I first showed that predicted and measured ST responded similarly to historical variation in air temperatures. I then used downscaled climate projections to predict that summer, winter, and annual STs will warm by 1.6 °C - 1.7 °C on average by 2099. Finally, I used additional modeling to identify initial stream and watershed conditions (i.e., low heat loss rates and small base-flow index) most strongly associated with ST vulnerability to climate change

First-principles kinetic modeling in heterogeneous catalysis: an industrial perspective on best-practice, gaps and needs

Electronic structure calculations have emerged as a key contributor in modern heterogeneous catalysis research, though their application in chemical reaction engineering remains largely limited to academia. This perspective aims at encouraging the judicious use of first-principles kinetic models in industrial settings based on a critical discussion of present-day best practices, identifying existing gaps, and defining where further progress is needed

DigiMon Final Report

"DigiMon Final Report” summarizes the ACT DigiMon project. The overall objective of the DigiMon project was to “accelerate the implementation of CCS by developing and demonstrating an affordable, flexible, societally embedded and smart Digital Monitoring early-warning system”, for monitoring any CO2 storage reservoir and subsurface barrier system, receiving CO2 from fossil fuel power plants, oil refineries, process plants and other industries.DigiMon Final ReportpublishedVersio

Visual Techniques for Geological Fieldwork Using Mobile Devices

Visual techniques in general and 3D visualisation in particular have seen considerable adoption within the last 30 years in the geosciences and geology. Techniques such as volume visualisation, for analysing subsurface processes, and photo-coloured LiDAR point-based rendering, to digitally explore rock exposures at the earth’s surface, were applied within geology as one of the first adopting branches of science. A large amount of digital, geological surface- and volume data is nowadays available to desktop-based workflows for geological applications such as hydrocarbon reservoir exploration, groundwater modelling, CO2 sequestration and, in the future, geothermal energy planning. On the other hand, the analysis and data collection during fieldwork has yet to embrace this ”digital revolution”: sedimentary logs, geological maps and stratigraphic sketches are still captured in each geologist’s individual fieldbook, and physical rocks samples are still transported to the lab for subsequent analysis. Is this still necessary, or are there extended digital means of data collection and exploration in the field ? Are modern digital interpretation techniques accurate and intuitive enough to relevantly support fieldwork in geology and other geoscience disciplines ? This dissertation aims to address these questions and, by doing so, close the technological gap between geological fieldwork and office workflows in geology. The emergence of mobile devices and their vast array of physical sensors, combined with touch-based user interfaces, high-resolution screens and digital cameras provide a possible digital platform that can be used by field geologists. Their ubiquitous availability increases the chances to adopt digital workflows in the field without additional, expensive equipment. The use of 3D data on mobile devices in the field is furthered by the availability of 3D digital outcrop models and the increasing ease of their acquisition. This dissertation assesses the prospects of adopting 3D visual techniques and mobile devices within field geology. The research of this dissertation uses previously acquired and processed digital outcrop models in the form of textured surfaces from optical remote sensing and photogrammetry. The scientific papers in this thesis present visual techniques and algorithms to map outcrop photographs in the field directly onto the surface models. Automatic mapping allows the projection of photo interpretations of stratigraphy and sedimentary facies on the 3D textured surface while providing the domain expert with simple-touse, intuitive tools for the photo interpretation itself. The developed visual approach, combining insight from all across the computer sciences dealing with visual information, merits into the mobile device Geological Registration and Interpretation Toolset (GRIT) app, which is assessed on an outcrop analogue study of the Saltwick Formation exposed at Whitby, North Yorkshire, UK. Although being applicable to a diversity of study scenarios within petroleum geology and the geosciences, the particular target application of the visual techniques is to easily provide field-based outcrop interpretations for subsequent construction of training images for multiple point statistics reservoir modelling, as envisaged within the VOM2MPS project. Despite the success and applicability of the visual approach, numerous drawbacks and probable future extensions are discussed in the thesis based on the conducted studies. Apart from elaborating on more obvious limitations originating from the use of mobile devices and their limited computing capabilities and sensor accuracies, a major contribution of this thesis is the careful analysis of conceptual drawbacks of established procedures in modelling, representing, constructing and disseminating the available surface geometry. A more mathematically-accurate geometric description of the underlying algebraic surfaces yields improvements and future applications unaddressed within the literature of geology and the computational geosciences to this date. Also, future extensions to the visual techniques proposed in this thesis allow for expanded analysis, 3D exploration and improved geological subsurface modelling in general.publishedVersio

Stratigraphy, sedimentology and petrophysics of transgressive tight gas sandstones, Almond Formation, Wyoming

With the recent increase in development of unconventional reservoirs, the ability to predict rock quality from sedimentary and petrophysical models has become paramount to the development of tight gas sandstones. In this way, a refined understanding of the primary sedimentary, stratigraphic and diagenetic controls on rock quality permits more reliable hydrocarbon distribution prediction and more economical drilling programs. The Almond Formation in southwest Wyoming is characterized by three depositional facies associations (DFA); shoreface, delta and fluvial/coastal plain, which present three distinctive porosity-permeability trends. Differences between petrophysical facies are primarily driven by diagenetic (cementation and grain dissolution) effects on different framework grain compositions. Depositional textural variation, such as grain size and sorting is minimal in all DFAs. This research focuses on building an understanding of the transgressive deposits by studying the variability of sandbody types, comparing and contrasting their reservoir architecture in a setting with a well-documented back-stepping stacking pattern. Construction of a high-resolution chronostratigraphic framework, in 1,450 wells over 6,200 km², revealed the evolution of fundamental fine-scale architectural elements. Detailed analysis and integration of cores and well logs along a spectrum of sandbodies document stratigraphic evolution from longshore accretion to seaward progradation associated with progressively increased infill of a shrinking lagoon. End members sandstone geometries include: 1) narrow, finger-like sandstone morphologies with well-developed lagoonal facies and; 2) broad, strandplain-type sandbodies with coastal plain-dominated back-barrier. This research also addresses a problematic aspect of tight gas reservoirs: the prediction of rock-quality-dependent water saturation (SW) models with depth. Primary drainage and imbibition saturation-height models (SHM) were developed from special core analysis and integrated with porosity and permeability logs to verify the SW state of reservoirs. Assuming that reservoirs were fully charged with hydrocarbons, the drainage SHM is key for flagging departures from the expected rock-quality-dependent water saturation. Observations in tens of wells show that the reference resistivity-derived saturation can be predominantly fitted by primary drainage SHM. However, some upper Almond shoreface bars that have anomalously high SW can be fitted with primary imbibition saturation functions. These fitting exercises indicate that some Upper Almond reservoirs imbibed due to trap tilting or leaking through outcrops.Geological Science