bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prescription patterns of enzyme-containing products in South Africa over a 2-year period
Authors: Truter Ilse 
Published: September 2014

Enzymes are traded in five categories, namely medical (intervention), diagnostic (detection and quantification), molecular biology, biofuel and industrial. Therapeutic enzymes have been investigated for different uses, for example, for the treatment of genetic disorders, blood clotting disorders, cancer and infectious diseases and for burn debridement. No studies on the prescription of enzyme-containing products in South Africa could be found. Enzymes are classified in the Monthly Index of Medical Specialities under digestants, enzymes and fibrinolytics. The primary aim of this study was to investigate the prescription patterns and cost of enzyme-containing products in South Africa. A private health-care medicines claims database for 2010 and 2011 of approximately 4.5 million records was analysed retrospectively. Enzyme-containing products constituted a small percentage of medical insurance claims (only 0.02% of approximately 4.5 million claims for products and procedures), yet they were relatively expensive. A total of 906 products was prescribed at a cost of almost ZAR2 million over the 2 years. Hyaluronidase was the most frequently prescribed (60.04%), followed by pancreatin-containing products (34.66%). Pancreatin (lipase/ protease/amylase) is primarily used in the management of pancreatic exocrine insufficiency. The average cost per hyaluronidase prescription paid by the medical insurance schemes was ZAR280. Other enzyme-containing products prescribed were imiglucerase, alteplase and tenecteplase. Imiglucerase was overall the most expensive. Alteplase, tenecteplase and streptokinase are antithrombotic enzymes that are used in the treatment of acute myocardial infarction or ischaemic stroke. Streptokinase, regarded as the most affordable antithrombotic enzyme, was not prescribed during the period under study. With the growing opportunities for enzymes for therapeutics, the use of enzyme-containing products which are comparatively expensive require cost-effectiveness studies.
Enhanced Fluid Flow: An Improved Method for Estimating Stimulated Reservoir Volume
Authors: Preiksaitis Mike , Bowman Sheri , Urbancic Ted , Baig Adam 
Published: September 2014

Abstract
In hydraulic fracture treatment programs microseismic imaging is often used to determine geometrical dimensions of the fracture network. The geometrical dimensions can be measured using fracture lengths, widths, and heights, or as an estimation of the potential volume that will contribute to production typically referred to as the stimulated reservoir volume (SRV). These SRV values are often used in reservoir models to plan and optimize a completion plan. Most techniques involve simply fitting a volume to these events. However, microseismic events also provide information on the deformation, energy and stress release and other seismic parameters that can possibly be used to constrain and provide realistic SRV estimates. In this paper, we investigate how SRV values vary by comparing standard approaches, with values as calculated based on seismic deformation and by taking into account the source types and fracture orientations derived from Seismic Moment Tensor Inversion (SMTI) to define regions of Enhanced Fluid Flow (EFF), akin to SRV estimates for fracture networks with propped or opening components of failure. By using a representative microseismic dataset from a shale gas play in North America, differences in approach are considered, and we conclude that EFF derived SRV estimates are likely a better reflection and more accurate representation of potential yields and estimates of reservoir volume.
Effect of Formation Stimulation Order in the Marcellus Shale
Authors: Kocon Ken , Urbancic Ted , Baig Adam 
Published: September 2014

Abstract
For vertically stacked wells undergoing hydraulic fracture stimulation, the order in which wells are stimulated can affect the achieved fracture length, width, height and intensity. We examine the effect of stimulation order for the plug-and-perf completion of two pairs of vertically stacked wells in the Marcellus Shale. Each pair of lateral wells hosts one well targeting the Lower Marcellus Formation, and one well targeting the Upper Marcellus Formation. All stages are completed in one well before moving to the next. For one pair of laterals, the Lower Marcellus is simulated before the Upper Marcellus. In this case, the cumulative seismic moment, and by extension the reservoir deformation, is much greater for the well which is completed second. In the next pair of laterals the stimulation order reverses and the Upper Marcellus Formation is stimulated before the Lower Marcellus. In this case, the cumulative seismic moment, and by extension total reservoir deformation, is again much greater for the well that is completed second. For the wells targeting both the Upper and Lower Marcellus, the achieved fracture length and width is independent of which Formation is simulated first. However, for both formations the kurtosis of the depth distribution is greater for whichever Formation is stimulated second. These observations demonstrate that in situ stress changes induced by hydraulic fracturing effect achieved fracture length and fracture intensity in the Marcellus Formation.
Wettability of the Montney Tight Gas Formation
Authors: Lan Qing , Dehghanpour Hassan , Wood James , Sanei Hamed 
Published: September 2014

Abstract
The abundant hydrocarbon resources in low-permeability formations are now technically accessible due to advances in drilling and completion of multi-lateral/multi-fractured horizontal wells. However, measurement and modeling of petrophysical properties, required for reserve estimation and reservoir-engineering calculations are the remaining challenges for the development of tight formations. In particular, characterizing wettability (wetting affinity) of tight rocks is challenging due to their complex pore structure, which can be either in hydrophobic organic materials or in hydrophilic inorganic materials.
We conduct comparative and systematic imbibition experiments on ten binary core plugs from the Montney tight gas formation, which is an enormous tight gas fairway in the Western Canadian Sedimentary Basin. Both contact angle and imbibition data indicate that the formation has a stronger affinity to oil than to water. However, the ratio between oil and water uptake of these samples is usually higher than what capillary-driven imbibition models predict. This discrepancy can be explained by the strong adsorption of oil on the surface of a well-connected organic pore-network that is partly composed of degraded bitumen. We also define a wettability index based on the equilibrium oil and water uptake of the binary samples. Oil wettability index is positively correlated with Total Organic Carbon (TOC) and clay content of the rocks which increase with depth from the Upper Montney to the Lower Montney.
Adding Value to the Kerrobert, Viking Oil Formation via Emerging Completion Methodologies of Horizontal Multi-Stage Wells – A Case Study
Authors: Toyad G. 
Published: September 2014

Abstract
Horizontal multistage fracture stimulation techniques have strategically advanced the completion and stimulation development in the Viking formation. Conventional Viking plays were vertically drilled, produced and thought to be depleted, but are now resurfacing with new opportunities.
The combination of being able to reach further with wellbore lengths and increase stimulation intensity has contributed to the viability of unconventional resources. As a direct result, various stimulation technologies have emerged and evolved, such as coiled tubing straddle systems, ball drop systems, and sliding sleeves with a resettable frac-isolation tool. These completion technologies have revived and renewed interest in challenging plays and have made it possible to economically stimulate portions of the reservoir that were previously bypassed. Implementing multistage technologies in the Halkirk, Provost and Dodsland fields have created positive and noticeable production results. Operators have begun to explore and revisit areas that may have been overlooked or less obvious. With improvements in technology and techniques for horizontal multistage stimulation treatments, areas like Prairiedale, Kerrobert, Lucky Hills, Plato and Forgan are capturing attention.
This case study seeks to investigate and discuss stimulation treatments, technology, and completion efficiency, which includes a case history describing how an operator completed in excess of 100 wells in the Kerrobert Viking play. It is located in southwest Saskatchewan, Canada, and lies below the Base of Fish Scales and above the Joli Fou. It will highlight key foreseen and unexpected challenges that arose in this play. Despite the challenging average 6 m pay thickness and interbedded layers of sandstone, siltstone and shale, production continues to proliferate within the Kerrobert Viking pool. Contributions of strategic horizontal drilling and multistage stimulations have improved efficiencies and reduced completion cycle time. This play has relatively low completion costs, is predictable, and therefore demonstrates repeatable economic results.
Dependence of Stress-Induced Micro-Seismicity on Natural Fracture Properties and In-Situ Stress
Authors: Garcia-Teijeiro Xavier , Rodriguez-Herrera Adrian 
Published: September 2014

Abstract
The opening and propagation of a hydraulic fracture introduces stress and pressure changes around it that could potentially lead to slippages of natural fractures. If detected, the associated microseismicity is commonly used to indirectly measure the geometry of the hydraulic fracture and the stimulated rock volume. One source of microseismicity is the fluid leakoff and pressure increase into the natural fractures. As pressure increases, the effective stress is reduced and shear failure of the natural fractures can be triggered. The natural fractures can also be reactivated in absence of leakoff due to the stress changes induced in the rock due to the opening of the hydraulic fracture itself and due to the inflation of the natural fractures intersected by the main hydraulic fracture. The volume in which stress changes alone can reactivate natural fractures is commonly thought to be small and localized near the hydraulic fracture tips. Yet, this paper shows that when the presence of natural fractures is explicitly taken into account, together with the potential propagation of further stress changes as the natural fractures slip, then such reactivated volume can be substantially larger. The results presented here demonstrate the importance of local stress heterogeneities in the potential generation of microseismicity and highlight how the local stress heterogeneity directly depends on the mechanical properties of the natural fractures.
Back to the Future: Shale 2.0 - Returning Back to Engineering and Modelling Hydraulic Fractures in Unconventionals With New Seismic to Stimulation Workflows
Authors: Ramanathan V. , Boskovic D. , Zhmodik A. , Li Q. , Ansarizadeh M. 
Published: September 2014

Abstract
Stimulating Shale Gas Wells has become a mundane activity with very little or no engineering. The industry has focused heavily on reducing costs and increasing efficiencies of operations that there is seldom any time for engineering. The lack of any horizontal logging information, assumptions that rock quality does not change have led to excel driven spreadsheets doing glorified mass balances which are considered as the fracture designs of today. In addition to this the same fracture treatment is pumped stage after stage well after well. Needless to say the industry's lack of ability to model these complex fractures has also contributed to the exercise of moving away from fundamental fracture design. This trend has resulted in productivities of wells being all over the place that mostly are unexplained. The industry is beginning to realize that a significant % of the wells drilled in unconventionals are not profitable.
Refracturing is also gaining prominence because of a single important factor that primary initial completions are ineffective. Shale 2.0 is all about integrating seismic to stimulation information to provide better answers and ultimately better productivity via simple measurements in the lateral. These measurements are ultimately used to engineer the completion, design and understand the science behind fracturing than just merely pumping the job.
This paper details the planning, design and evaluation processes in the application of a new workflow called the Unconventional Reservoir Optimized Completion workflow. This revolutionary Seismic to Stimulation workflow demonstrates with examples how we have migrated, a dominant well centric process to a reservoir centric process. A significant step change in fracture modelling has been applied using unconventional fracture models which have the ability to model complex fractures using discrete fracture networks. These models can be validated using microseismic and when calibrated with production can become a powerful prediction tool. Experiences and lessons learned in the Canadian Montney will be presented.
Utilizing Fit-For-Purpose Decision Analysis Techniques to Maximize Value From Unconventionals: Case Studies from the Wolfcamp Play, Permian Basin
Authors: Rexilius Jarrad , Prochnow Shane , Morgan Michael , Fields Michael 
Published: September 2014

Abstract
In any petroleum industry application, it is important that sound decision making techniques are applied to maximize value of investments and generate optimal returns from execution of these decisions. This is especially critical for lower margin unconventional resource plays, where cost reduction is of upmost concern. Whilst significant attention is placed on minimizing costs to improve economics for unconventional projects, there are often opportunities with potential to yield substantial incremental value creation, despite some outlay of additional capital. This paper will discuss the application of fit-for-purpose decision analysis (DA) and value of information (VOI) techniques to evaluate various opportunities to enable data driven decisions to be made, and maximize value from unconventionals.
The Wolfcamp Play in Permian Basin is one of the most active unconventional oil plays in North America, and is widely considered a statistical play requiring a manufacturing approach, whereby many wells are drilled and completed in the same fashion to develop the field with optimal operational efficiency. However, this paper will discuss several case studies where more detailed study and analysis have led to opportunities to optimize the development and increase economic viability, by adopting a more scientific and DA based approach. Final results suggest that these opportunities have generated significant value creation and highly favorable economic returns, and should serve as examples for other tight rock plays.
This paper provides a robust workflow of fit-for-purpose DA techniques for application to various decision points for unconventional projects. The paper also presents case studies that convey the complexities and challenges faced in unconventional resource plays, and how making data driven decisions that provide value creation can enhance the value of the assets. Case studies discussed include 1) Open hole logging decisions, 2) Proppant selection for hydraulic fracturing, and 3) The use of mud logs as a completion selection tool. To evaluate these opportunities, a series of VOI and DA techniques were employed, including decision trees, investment efficiency charts, sensitivity to probability calculations, and other net present value (NPV) and profitability analyses.
The subject matter discussed in this paper has relevance and application to other unconventional plays in the industry that seek to maximize value of the resource base and capital investment employed.
A Rock and Fluid Study of Middle Bakken Formation: Key to Enhanced Oil Recovery
Authors: Kurtoglu Basak , Kazemi Hossein , Rosen Richard , Mickelson William , Kosanke Tobi 
Published: September 2014

Abstract
The discovery of significant reserves in the Middle Bakken of the Elm Coulee Field in 2000 changed the development of Bakken Formation in the Williston Basin. In 2006 the Elm Coulee success led to the exploration of other fields in the Williston Basin, such as Parshall and Sanish fields in North Dakota. Thousands of Middle Bakken wells have been drilled and produced in the primary production mode, yet there is likely significant potential for enhanced oil recovery, which prompted this multi-facetted research study.
First, the physical properties of the reservoir brine, oil, and gas of fluid samples from different Middle Bakken geographic locations are presented to emphasize significant physical property differences across North Dakota. This information is essential to understand the impact of fluid properties on primary production and potential for oil recovery at different locations.
Second, we identified reservoir connectivity by combining petrographic analysis, scanning electron microscopy, and permeability measurements. The permeability measurements included core-based steady-state permeability and unsteady-state water-oil relative permeability. The selected cores were characterized using X-ray diffraction mineralogy, thin section petrology, and scanning electron microscopy (SEM) to correlate flow capacity to the petrophysical properties. The conclusion is that interconnected microfractures make current production possible in successful wells.
Finally, the high salinity formation water compared to the low salinity of fracturing and IOR fluids was investigated by performing spontaneous imbibition using both low and high salinity brines. It was concluded that in the oil-wet environment of the Bakken, the low salinity injection fluids can enter part of the reservoir because of osmotic pressure while high salinity makes the clay surface extremely hydrophobic and causes local oil-wetness.
Bilinear Flow in Shale Gas Wells: Fact or Fiction?
Authors: Kanfar M. S. , Alkouh A. B. , Wattenbarger R. A. 
Published: September 2014

Abstract
Many shale wells undergo a gradual production decline before reaching a linear flow decline. This gradual decline lasts for several days and often matches a quarter-slope. Some authors attribute this gradual decline to bilinear flow, which occurs as a result of simultaneous linear flow in natural fractures and matrix (Al-Ahmadi and Wattenbarger 2011; Tivayanond et al 2012). In this paper, we show that bilinear flow in natural fractures and matrix is short and, therefore, it cannot explain the sustainable gradual decline observed in shale wells. Instead, we provide two alternative explanations. Bilinear flow caused by low-conductive hydraulic fractures is one explanation. Another one is an artificial shift in data caused by ignoring flowback.
First, we use analytical solutions and show that bilinear flow is short unless matrix permeability is extremely low or natural-fracture spacing is very large. Second, we show that analytical solutions are unrealistic when natural fracture spacing is large. Third, we use reservoir simulation to obtain more realistic results and show that bilinear flow in matrix and natural fractures is not sustainable. In conclusion, we show that ignoring flowblack data results in a fictitious quarter-slope and demonstrate the concept with field examples.
This work shows the importance of including flowback data into rate transient analysis. In addition, it describes a procedure to accurately analyze production data and avoid misleading bilinear flows. Several sensitivity studies are also shown to define the geometrical and petrophysical conditions under which the bilinear flow regime is not expected. Concepts presented in this paper provide engineers with better tools for analyzing and forecasting production from shale gas wells.
Estimating the reliable residential water substitution from household rainwater tanks
Authors: Mukheibir P. , Boyle T. , Moy C. , White S. 
Published: September 2014

In Australia, household rainwater tanks have come to be considered as one of the broad potential supply options for meeting household water demands. It has been viewed as an effective way of reducing the supply requirements by water businesses and can potentially defer future capital supply investments. With likely variability of future supplies and demands due to climate change impacts, rainwater tanks also have an important role in building future resilience to shifts in historical trends, and also can potentially play a role in mitigating stormwater damage.
The substitution of mains supplied water by rainwater can vary significantly, with the major factors influencing yields being the roof size to capture the rain, water usage regime (having some level of internal water use) and tank size. Tank performance, with respect to reduced substitution as a result of functionality failure, is seldom included in yield calculations however. A review of a number of studies in Australia has illustrated that the vast majority of field studies have produced qualitative responses on the perceptions of the use of rainwater, the structural integrity of their rainwater capture infrastructure and the end-uses connected to the system.
It was found that the data required to inform the impact of functionality on substitution is currently largely limited to qualitative responses on the perceptions of the use of rainwater tanks, the structural integrity of their rainwater capture infrastructure and the end-uses connected to the system. There is very little in the way of quantitative assessments. This paper offers an interim approach for overcoming this quantitative information gap on the role and extent of functionality failure.
Conditional Conservatism and Audit Fees
Authors: Lee Hye Seung (Grace) , Li Xu , Sami Heibatollah 
Published: September 2014

SYNOPSIS
In this study, we examine the impact of conditional conservatism on audit fees and, more importantly, the influence of corporate governance on this relationship. Prior literature presents evidence regarding explanations for the existence and pervasiveness of accounting conservatism such as compensation and debt contracting, shareholder litigation, taxation, and accounting regulation. However, there is very limited evidence or discussion of the potential benefit of accounting conservatism on audit risk and thus audit fees, and how the potential benefit can be attenuated by corporate governance quality. Using a sample of firm-year observations over the period of 2004–2009, we provide evidence consistent with conditional conservatism and firms' commitment to such conservatism reducing their audit fees. However, our evidence shows that this reduction in audit fees is moderated by higher corporate governance quality. These results have implications for auditors, regulators, standard setters, and firms' managers. In addition, our study extends the literature on the determinants of audit fees.
JEL Classifications: M41; M42; D81; D22.