Hydraulic fracturing design for horizontal wells in the Bakken formation, Williston Basin

Unconventional hydrocarbon reservoirs have proved to be challenging in terms of reservoir characterization, predicting production potential, estimating ultimate recovery, and optimizing hydraulic fracture stimulations. The methods by which these resources are extracted use progressive, or unconventional, technologies. Today, through the use of hydraulic fracturing and horizontal drilling, extraordinary amounts of oil and natural gas from deep shale formations across the United States and around the world are being safely produced. Performing a hydraulic fracture design requires modeling of fracture propagation and tracking the fluid front in the created fracture. In this dissertation, the roles of all effective parameters and properties on the design and performance of hydraulic fracturing in the Bakken Formation, Williston Basin, are examined. To accomplish the above objectives, this dissertation is divided into four major sections that include: 1) basic principles of geology, lithology, and reservoir aspects of the Bakken Formation, 2) the fundamental concepts of hydraulic fracturing, 3) technology aspects are integrated into one cohesive unit to model and optimize the entire hydraulic fracture treatments, and 4) a comprehensive approach to the uncertainty assessment of the complex numerical simulations is described. In this research by integrating reservoir and hydraulic fracture simulations, a robust workflow was used to evaluate several combinations of fracturing materials (i.e. fluids and proppants) and well/fracture parameters (i.e. lateral length, fracture spacing, and fracture half-length) to identify the best candidate(s) for well stimulation planning. Using an automated history matching procedure, the reservoir properties of the Bakken Formation were estimated that can be used in future reservoir simulation projects. The fully 3D/FEM* fracture simulation showed that a fracturing treatment with injecting slickwater as the pad followed by crosslinked gel together with ceramic or resin-coated sand would guarantee that most proppants would stay within the Bakken Formation. The results from this research also suggest that in a Bakken well with a long lateral length (e.g. 10,000 ft), a fracturing strategy that leads to a relatively high fracture half-length (e.g. 1000 ft) with a high number of fractures (36 or more) would return an efficient balance between the operating charges, fracture treatment costs, drilling expenses, and the benefits earned from the incremental oil production. The pump schedule developed for the optimal fracture treatment, obtained from the fully 3D fracture modeling, would also guarantee fracture confinement within the Bakken Formation

Quality data assessment and improvement in pre-processing pipeline to minimize impact of spurious signals in functional magnetic imaging (fMRI)

In the recent years, the field of quality data assessment and signal denoising in functional magnetic resonance imaging (fMRI) is rapidly evolving and the identification and reduction of spurious signal with pre-processing pipeline is one of the most discussed topic. In particular, subject motion or physiological signals, such as respiratory or/and cardiac pulsatility, were showed to introduce false-positive activations in subsequent statistical analyses. Different measures for the evaluation of the impact of motion related artefacts, such as frame-wise displacement and root mean square of movement parameters, and the reduction of these artefacts with different approaches, such as linear regression of nuisance signals and scrubbing or censoring procedure, were introduced. However, we identify two main drawbacks: i) the different measures used for the evaluation of motion artefacts were based on user-dependent thresholds, and ii) each study described and applied their own pre-processing pipeline. Few studies analysed the effect of these different pipelines on subsequent analyses methods in task-based fMRI.The first aim of the study is to obtain a tool for motion fMRI data assessment, based on auto-calibrated procedures, to detect outlier subjects and outliers volumes, targeted on each investigated sample to ensure homogeneity of data for motion. The second aim is to compare the impact of different pre-processing pipelines on task-based fMRI using GLM based on recent advances in resting state fMRI preprocessing pipelines. Different output measures based on signal variability and task strength were used for the assessment

Realising Global Water Futures: a Summary of Progress in Delivering Solutions to Water Threats in an Era of Global Change

Canada First Research Excellence FundNon-Peer ReviewedOver the past six years the Global Water Futures program has produced a wide range of scientific findings and engagements with multiple types of potential users of the research. This briefing book provides a snapshot of some of the science advancements and user engagement that have taken place to date. Annual reports to the funding agency are the most up to date source of information: this compilation has been created from reports submitted by projects in 2022, representing both completed and current project work. The briefing book aims to provide quick access to information about GWF projects in a single place for GWF’s User Advisory Panel: we hope that knowing more about the research being produced will spark conversations about how to make the best use of the new knowledge in both policy and practice

Introducing the connected reservoir storage concept for reservoir characterization and production forecast

This research presents a novel concept of the connected reservoir storage (CRSM) with which we can characterize the reservoir and accurately predict the production performance of hydrocarbon reservoirs, which have a complex reservoir geometry and have a considerable uncertainty of reservoir energy support. Based on the deconvolution of measured pressures and rate data from a well, both a liquid and gas reservoir performance can be modeled using a group of normalized quantities with which the behavior of the well can be accurately predicted in all flow regimes. No foreknowledge of reservoir geometries, petro-physical properties, or fluid properties is required to develop this analysis. Reservoir storage is a time function defined as the product of the total compressibility and the reservoir volume at a particular time. Unlike with classical or curve fitting decline curve analysis, the CRSM is based on the pressure diffusivity theory by the normalized production rate and normalized cumulative production volume through deconvolution methods. With the knowledge of reservoir volumes, the long term well performance of liquid or gas reservoirs can be predicted. Through the development of the CRSM, three profiles can be ascertained and are interrelated to shed valuable insight into the production potential and health of a liquid or gas reservoir that exhibits complex formation geometries. The three curves are the reservoir response curve (RPC), normalized decline curve (NDC), and connected reservoir storage curve (CRSC). Utilizing the three curves stated above embodies a more powerful reservoir performance analysis technique for predicting the production potential of complex reservoirs. The CRSM will be presented from the fundamental material balance approach and mathematical equations will be derived for the model related to both liquid and gas reservoir production. The CRSM concept will be validated through the development of numerical simulation models, conventional well application, with varying permeabilities, porosities and well geometries through the use of a reservoir simulation suite with known reservoir parameters and the utilization of deconvolution techniques to develop the CRSM. The CRSM will then be used to evaluate the reservoir response behavior to better approximate and characterize the flow and pressure behavior utilizing simulated production data of a bi-wing hydraulically fractured undersaturated oil reservoir, tight well application, and compare the CRSM to two classical forecasting methods. Additional studies using the CRSM will be applied to shale gas well performance comprised of a formation where the matrix is made up of very low permeable media (Kim and Lee, 2015). Moreover, this research will conclude by applying the CRSM to evaluate the reservoir response behavior to characterize the fracture network system in a shale gas reservoir with multi-stage hydraulic fracturing along the horizontal segment. The application ability of the CRSM allows for the bridging of the production decline and reservoir pressure response from production data found in the public domain. This concept enables one to evaluate and forecast current and future volume production, reservoir pressure behavior, average reservoir pressure and determine original fluids in place with no prior knowledge of reservoir geometries, petro-physical or fluid properties. With the development of this model, decline curve analysis (DCA) can be extended into the transient regime of the production period

Estimating Suspended Solids and Phosphorus Loading in Urban Stormwater Systems Using High-Frequency, Continuous Data

The introduction of pavement, buildings, and other impervious surfaces to urban landscapes greatly influences the quantity and quality of urban stormwater runoff. In this study, we designed and implemented modern stormwater monitoring technologies to establish a “smart” stormwater sensor network within the Northwest Field Canal (NWFC), an urban water conveyance located in Logan, Utah, USA. This network was designed to collect flow and water quality data at high frequencies and simultaneously at multiple locations. The observatory’s innovative method of inter-site communication and changing sampling frequencies during storm events was able to capture short duration events at the upstream and downstream ends of the NWFC and at multiple outfalls in the canal simultaneously without human intervention. We then investigated statistical regression models between turbidity and TSS so as to predict TSS at high frequencies. Finally, the addition of the high-frequency discharge data in the calibration procedure for a stormwater simulation model developed using the Environmental Protection Agency’s Stormwater Management Model did little to improve model performance at the downstream end of the canal, but did provide important insight into the overall contribution of discharge from individual stormwater outfalls to the NWFC. The results of this study inform water professionals on how to build and operate automated monitoring systems and how to create high-frequency estimates of TSS and TP loads in urban water systems

Heat Transfer in Energy Conversion Systems

In recent years, the scientific community’s interest towards efficient energy conversion systems has significantly increased. One of the reasons is certainly related to the change in the temperature of the planet, which appears to have increased by 0.76 °C with respect to pre-industrial levels, according to the Intergovernmental Panel on Climate Change (IPCC), and this trend has not yet been stopped. The European Union considers it vital to prevent global warming from exceeding 2 °C with respect to pre-industrial levels, since this phenomenon has been proven to result in irreversible and potentially catastrophic changes. These climate changes are mainly caused by the emissions of greenhouse gasses related to human activities, and can be drastically reduced by employing energy systems, for both heating and cooling of buildings and for power production, characterized by high efficiency levels and/or based on renewable energy sources. This Special Issue, published in the journal Energies, includes 12 contributions from across the world, including a wide range of applications, such as HT-PEMFC, district heating systems, a thermoelectric generator for industrial waste, artificial ground freezing, nanofluids, and others