bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unconventional Reservoir Formation Evaluation Challenges Addressed With Deployment-Optimized Open Hole Logging Solutions
Authors: Hameed A. , Bacciarelli M. , Williams P. J. 
Published: October 2014

Abstract
It is estimated that only one third of the remaining worldwide oil and gas reserves are conventional, the remainder being in unconventional reservoirs whose evaluation requires appropriate measurements delivered in a cost-effective way. In the case of shales and other tight reservoirs, the defining characteristics are low matrix porosity and low or ultra-low permeability which requires artificial stimulation to encourage production. The optimum stimulation strategy for a particular reservoir is strongly dependent on the distribution of organic material, and on the mechanical and geometrical properties of the rock, and the associated stress field. It is essential to quantify these to an appropriate level of certainty, and well logs are the primary source of such data. Until recently the options for acquiring appropriate logs in high angle and horizontal wells have been constrained either by the limited available sensors or tool conveyance methods. However, the introduction of memory capable small diameter specialized tools and multiple innovative conveyance options has changed the cost-benefit balance for the better. This paper reviews the current status of open hole log measurements with full spectrum conveyance options, and how they impact the evaluation of these challenging reservoirs.
An Integrated Reservoir Model for Unconventional Resources, Coupling Pressure Dependent Phenomena
Authors: Eshkalak Mohammad O. , Aybar Umut , Sepehrnoori Kamy 
Published: October 2014

Abstract
An integrated unconventional reservoir model that accounts for known mechanisms and nonlinearities affecting modeling of hydraulically fractured wells is developed. In general, modeling and simulation of multi-fractured reservoirs are highly challenging due to the complexity attributed to the flow in this very low permeability and dense structured rock. Pressure- dependent phenomena in reservoir modeling are considered as combined hydraulic and natural fracture conductivity losses, desorption, Klinkenberg gas slippage effect and non-Darcy flow. Integrating these phenomena and analyzing the importance of each parameter in a reservoir model are essential.
The proposed model includes three zones, Rock Matrix (I), Induced-Fracture (II) and Hydraulic Fracture (III) that are defined with different characteristics. Pressure dependent permeability is considered for zone II and III, with an exponential relationship between permeability and reservoir pressure. Governing equations of gas flow are non-linear partial differential equations, for all three zones, due to incorporated pressure-dependent phenomena that are solved using the finite difference method. A synthetic case is defined in order to investigate the effect of each individual phenomenon on long-term production. Moreover, a history matching process with Marcellus Shale field production data is performed in order to obtain the most uncertain parameters in the model.
Results showed that combined effect of permeability losses of hydraulic and induced-fracture zones results in 15 percent gas production drop in 30 years. Also, it is observed that Klinkenberg effect and non-Darcy flow have insignificant effect on the modeling of shale gas reservoirs, whereas desorption has great contribution on long-term production. It is concluded that the minimum ingredients for an accurate shale reservoir modeling are considering gas desorption phenomena alongside with pressure-dependent permeability for the hydraulic and induced-fractures network. Our simple reservoir modeling approach helps in understanding complex behavior of flow mechanisms in shale plays. Also, this integrated model can be used during optimization of key factors in hydraulic fracturing process and fracture characterization by history matching of production.
Scaling from an Unexpected Source: Proppants
Authors: Luo Hongyu 
Published: October 2014

Abstract
Scales such as aluminum silicates are commonly believed to come from reservoir rocks such as shale and/or their interaction with injected chemicals from EOR (enhanced oil recovery) methods. In hydraulic fractured wells, scales could be a major source of damage to fracture conductivity, which is usually less than 5% of their desired value by fracturing design. Despite much research on conductivity loss, few efforts have been directed at proppants, the number one material by quantity (except for water) used in fracturing operations.
In this research, a brief review is conducted on how proppants might be an active agent in scale-generating reactions. Using a ceramic proppant sample from the Bakken shale oil field as an example, a new method is proposed for characterizing proppant strength and interaction with fracturing fluids, rock, and formation and production fluids under realistic down-hole conditions. It was found that certain ceramic proppants widely used in the Bakken field are vulnerable in weakly acidic fluids (i.e. pH=4). Temperature increases expedite the proppant weakening process. Estimated conductivity loss could be ~50% compared with that treated at neutral pH. This is alarming because many wells produce sweet (carbon dioxide CO2) and/or sour (hydrogen sulfite H2S) gas along with production fluids. Common scale inhibitors such as phosphonate-based acids and polycarboxylic acids (PAA) could also lower the pH of fluids in propped fractures to 3~4, break the ceramic proppant and generate fines and scales.
The first lesson learned is that proppants could be a source of scale. Proppants, especially ceramic ones, should be treated as a chemical and potential source of scale when implementing designs for hydraulic fracturing or gravel packing. Not only will poor quality proppants crush easily, but also they may generate migrating scales, a double inhibition for flow assurance. Extreme care should be exercised when choosing proppants for sour wells. Tighter specification on acid resistance of proppants is proposed. Field quality control and scale management in fractured wells will also be discussed.
Effect of Saturation Dependent Capillary Pressure on Production in Tight Rocks and Shales: A Compositionally-Extended Black Oil Formulation
Authors: Nojabaei B. , Siripatrachai N. , Johns R. T. , Ertekin T. 
Published: October 2014

Abstract
Pore sizes are typically on the order of nanometers for many shale and tight rock oil reservoirs. Such small pores can affect the phase behavior of in situ oil and gas owing to large capillary pressure. Current simulation practice is to alter the unconfined black-oil data for a fixed mean pore size to generate confined black-oil data with a depressed bubble-point pressure. This approach ignores compositional effects on interfacial tension and the impact of pore-size distribution (PSD) with variable phase saturations on capillary pressure and phase behavior.
In this paper, we develop a compositionally-extended black-oil model where we solve the compositional equations (gas, oil, and water components) directly so that black-oil data are a function of gas content in the oleic phase and gas-oil capillary pressure. The principle unknowns in the variable bubble-point fully-implicit formulation are oil pressure, overall gas composition, and water saturation. Flash calculations in the model are noniterative and are based on K-values calculated explicitly from the black-oil data. The advantage of solving the black-oil model using the compositional equations is to increase robustness of the simulations owing to a variable bubble-point pressure that is a function of two parameters; gas content and capillary pressure. Leverett J-functions measured for the Bakken reservoir are used to establish the effective pore size-Pc-saturation relationship, where the effective pore size depends on gas saturation. The input fluid data to the simulator, e.g. interfacial tension (IFT), phase densities and viscosities, are pre-calculated as functions of pressure from the Peng-Robinson equation of state (PREOS) for three fixed pore sizes. During the simulation, at any pressure and saturation, fluid properties are calculated at the effective pore radius by using linear interpolation between these three data sets. In the current simulator, the reservoir permeability is enhanced to allow for opening of the fracture network by hydraulic fractures. We compare the results of the compositionally-extended black oil model with those of a fully-implicit eight-component compositional model that we have also developed. The results for the Bakken reservoir show that including PSD in the model can increase estimated recoveries by nearly 10%. We also examine the sensitivities of production to various parameters, such as wettability and critical gas saturation.
Identifying the Ideal Stimulation Design via Quantitative Multivariate Analysis – Second Bone Springs Sand, New Mexico
Authors: Rice Ryan 
Published: October 2014

Abstract
One of the major challenges associated with economic exploitation of unconventional hydrocarbon accumulations in shale resource development is determining the optimal stimulation design. This work employs quantitative multivariate analysis to determine the efficacy and efficiency of different hydraulic fracturing designs. If the analysis is done correctly, it allows for accelerated delineation of unconventional plays, minimizes excessively long learning curves, and increases well productivity. It is important to recognize that previously published work, such as SPE 152531, SPE 163852, and SPE 1355223, propose alternative methods for identifying optimal completion designs. However, these methods require access to expensive and/or complex neural networking and proxy modeling software, as well as an advanced statistics background. Alternatively, this research proposes a simple, novel, and effective approach for ascertaining the most ideal completion design using the most basic software packages and statistical analysis. Most importantly, this method focuses not on finding statistical averages for each stimulation variable but instead finding inherent trends in real data.
Fracture Conductivity Damage by Water in Shale Formations
Authors: Zhang Junjing 
Published: October 2014

Abstract
Multi-stage hydraulic fracturing is the key to the success of many shale gas and shale oil reservoirs. The main objective of hydraulic fracturing in shale is to create fracture networks with sufficient fracture conductivity. Due to the variation in shale mineralogical and mechanical properties, mechanisms of fracture conductivity damage in shale formations are complicated. Standard fracture conductivity measurement procedures were developed for high concentration propped fractures and need to be modified to measure the conductivity of the low concentration proppant packs. Water-based fracturing fluids can interact with the clay minerals in shale and eventually impact shale fracture conductivity. All these challenges require more studies to elevate our understanding of realistic fracture conductivity in shale formations.
The aims of this work were to design an experimental framework to measure fracture conductivity created by low concentration proppants and to investigate the mechanisms of conductivity damage by water. We first presented the laboratory procedures and experimental design that can accurately measure fracture conductivity of shale fractures at low concentrations of proppants. Then we measured the undamaged shale fracture conductivity by dry nitrogen. Water with similar flowback water compositions was injected to simulate the damage process followed by the second gas flow to measure the recovered fracture conductivity after the water damage.
From this study, we find that laboratory procedures developed in this study can be utilized to reproducibly measure shale fracture conductivity by both gas and liquid. The conductivity measurement of propped fractures by small size proppants at low concentrations requires strict control on gas flow bypassing the fracture both parallel and perpendicular to the fracture length direction. Shale fracture surface softening is identified as the dominant cause for the significant conductivity reduction after water flow.
Accounting Information Quality, Interbank Competition, and Bank Risk-Taking
Authors: Corona Carlos , Nan Lin , Zhang Gaoqing 
Published: October 2014

ABSTRACT
We study the interaction between interbank competition and accounting information quality and their effects on banks' risk-taking behavior. We identify an endogenous false-alarm cost that banks incur when forced to sell assets to meet capital requirements. We find that when the interbank competition is less intense, an improvement in the quality of accounting information encourages banks to take more risk. Keeping the banks' investments in loans constant, the provision of high-quality accounting information reduces the false-alarm cost of assets sales and improves the discriminating efficiency of the capital requirement policy. When considering the banks' endogenous investment decisions, however, this improvement in discriminating efficiency causes excessive risk-taking, because banks respond by competing more aggressively in the deposit market, and the increase in deposit costs motivates banks to take more risk. Our paper shows that improving information quality increases risk-taking with mild competition, but has no effect under fierce competition.
Do Industry-Specialist Auditors Influence Stock Price Crash Risk?
Authors: Robin Ashok J. , Zhang Hao 
Published: October 2014

SUMMARY
Francis (2011) calls for more research on “the effect of audit quality on economic outcomes.” We respond by examining whether high-quality auditors reduce stock price crash risk, an important consideration for stock investors. We argue that high-quality auditors reduce crash risk because of their information intermediary and corporate governance roles. Using a large sample of U.S. stocks spanning the period 1990–2009, we examine the issue empirically by using auditor industry specialization as our proxy for auditor quality. Our main finding is a statistically significant and negative association between auditor industry specialization and stock price crash risk, implying that high-quality auditors can directly benefit investors by reducing tail risk. In addition, we provide evidence that industry-specialist auditors moderate the effects of opacity, accounting conservatism, and tax avoidance on crash risk. Finally, our main finding of a negative relation between auditor industry specialization and crash risk is robust to using city-level industry specialization as an alternate measure.
JEL Classifications: G19; G32; M42.
The Relation between Business Property Values and Local Property Taxes
Authors: Key Kimberly G. , Lightner Teresa A. 
Published: October 2014

ABSTRACT
This study examines the relation between commercial and industrial property values and local property taxes using 1999 to 2009 data for the state of Georgia. Results show a negative relation between commercial values and property taxes, consistent with the new view of capital tax prediction that these taxes are borne, at least in part, by property owners. Incidence estimates show very high to full capitalization. There is little evidence of a relation between industrial property values and property taxes, contrary to prior research. This study is the first to provide empirical evidence of differences in commercial and industrial property tax incidence. The study contributes to the understanding of the capitalization of business taxes, which has been the subject of very little prior research. The results can inform policymakers who consider trade-offs in tax revenue needs, economic development, and issues of fairness in their localities.
The Effect of Tax-Related Material Weakness in Internal Controls on the Market Valuation of Unrecognized Tax Benefits
Authors: Koester Allison , Lim Steve C. , Vigeland Robert L. 
Published: October 2014

ABSTRACT
This paper examines the effect of tax-related material weakness in internal controls (MWIC) over financial reporting investors' valuation of unrecognized tax benefits (UTBs). Firms are required to record a UTB when their uncertain tax positions are unlikely to be sustained upon tax return audit. While Koester (2012) finds that investors positively value UTBs, we posit that a tax-related MWIC represents information risk in the tax account, reducing the value-relevance of UTBs. We predict that the positive relation between market value of equity and UTBs is attenuated when firms report a tax-related MWIC, and our empirical tests reveal that the relation is completely mitigated in the presence of a tax-related MWIC. Falsification tests confirm that non-tax-related MWICs do not attenuate the positive relation between market value of equity and UTBs, consistent with tax-related MWICs capturing low information quality specific to the tax account.
“The Daughter of Fu Manchu”
Authors: Rajgopal Shoba Sharad 
Published: October 2014

Abstract
Courses regarding race, gender, and representation are not easy to teach under any circumstances, but even more so in predominantly white classrooms in the post 9/11 U.S. where the masses have been fed a diet of xenophobic, anti-Asian propaganda inculcating an “us” versus “them” mentality. I analyze the discourse of empire, a metaphor that has been used time after time to construct a mythical and menacing Other. In contrast, the portrait of Asian women in cinema and television news as traditional, veiled, and inhabiting a separate sphere adds to this representation of Asian cultures as premodern and irrevocably opposed to the West, much as portrayed in Samuel Huntington's “clash of civilizations” theory (Huntington 1996). I illustrate this transnational feminist critique with a documentary used in Women's Studies classes: Deborah Gee's landmark film Slaying the Dragon (1988).
What is Reproductive Justice? How Women of Color Activists Are Redefining the Pro-Choice Paradigm
Authors: Price Kimala 
Published: October 2014

Abstract
Frustrated by the individualist approach of the “choice” paradigm used by the mainstream reproductive rights movement in the U.S., a growing coalition of women of color organizations and their allies have sought to redefine and broaden the scope of reproductive rights by using a human rights framework. Dubbing itself “the movement for reproductive justice,” this coalition connects reproductive rights to other social justice issues such as economic justice, education, immigrant rights, environmental justice, sexual right, and globalization, and believes that this new framework will encourage more women of color and other marginalized groups to become more involved in the political movement for reproductive freedom. Using narrative analysis, this essay explores what reproductive justice means to this movement, while placing it within the political, social, and cultural context from which it emerged.
Detection of protein glycation inhibitory potential of nine antidiabetic plants using a novel method
Authors: Perera H. K.I. , Handuwalage C. S. 
Published: October 2014

Background: Protein glycation is a major cause of chronic diabetic complications. Medicinal plants with protein glycation inhibitory potential will be benefi cial to prevent or delay diabetic complications. Objective: The objective of the study was to analyze protein glycation inhibitory potential of ten plants among which nine are well known for their antidiabetic effects.Methods: Methanol extracts were prepared using parts from nine plants namely, Coccinia grandis, Ficus racemosa, Gymnema lactiferum, Gymnema sylvestre, Musa paradisiaca, Phyllanthus debilis, Phyllanthus emblica, Strychnos potatorum and Tinospora cordifolia. Dried latex of Pterocarpus marsupium was used without further extraction. Glycation inhibitory potential of the extracts was analyzed using bovine serum albumin (BSA) and fructose, incubated in the presence or absence of plant extracts for 4 week. Appropriate controls and blanks and the standard inhibitor aminoguanidine were included. A novel native polyacrylamide gel electrophoresis (PAGE) method established recently was used to detect the effect of plant extracts on the BSA glycation. Results: Previously we have demonstrated that the BSA migration towards the anode is increased proportionate to the degree of glycation. This increase was comparatively less when the glycation was inhibited. Accordingly, most promising antiglycation effects were observed with P. debilis (whole plant), P. emblica (fruit) and P. marsupium (latex). F. racemosa (stem bark) showed the highest inhibition among the remaining extracts. G. sylvestre (leaf), M. paradisiaca (yam) and T. cordifolia (leaf) also showed promising inhibition. C. grandis (leaf) and S. potatorum (seed) showed lower inhibition. Lowest inhibition was observed with G. lactiferum (leaf).Conclusion: We have demonstrated the antiglycation potential of some antidiabetic plants, using a novel method developed by us recently. Extracts of P. debilis, P. emblica and P. marsupium showed a strong protein glycation inhibitory potential.DOI: http://dx.doi.org/10.3126/ajms.v6i2.10584Asian Journal of Medical Sciences Vol.6(2) 2015 1-7
Gender based EEG before and after acute bout of aerobic exercise
Authors: Limbu Nirmala , Sinha Ramanjan , Sinha Meenakshi , Paudel Bishnu Hari 
Published: October 2014

Objective: We aimed to investigate how EEG frequency bands change in females in response to acute exercise compared to males.Methods: Consenting healthy adult females (n=15) & males (n=15) bicycled an ergometer at 50% HRmax for 20 min. EEG was recorded using 10-20 system from mid-frontal (F4 & F3), central (C4 & C3), parietal (P4 & P3), temporal (T4 & T3) & occipital (O2 & O1) regions. Exercise-induced EEG changes were compared between two sexes by Mann Whitney test. EEG power (μV2) is presented as median & interquartile range.Results: In females, as compared to males, resting right side delta, alpha, and beta activities were more in almost all recorded sites [delta: F4= 49.82 (44.23-63.56) vs. 35.5 (32.70-44.44), p < 0.001; etc], [alpha F4: 127.62 (112.89-149.03) vs. 49.36 (46.37-52.98), p < 0.001; etc], [beta F4= 18.96 (15.83-25.38) vs. 14.77 (10.34-17.55), p < 0.05; C4= 21.16 (18.4-25.9) vs. 15.48 (9.66-19.40), p < 0.01; etc]. Similarly, females resting right theta activity was more in parietal [P4= 33.04 (25.1-42.41) vs. 22.3 (18.36-34.33), p < 0.05] & occipital [O2= 50.81 (30.64-66.8) vs. 26.85 (22.18-34.42), p < 0.001] regions than in males. They had similar picture on the left side also. The delta values of right alpha power was less in female in frontal [F4= -11.61 (-45.24 -3.64) vs. 9.48 (1.05-16.58), p < 0.01] and central [C4= -72 (-32.98-9.48) vs. 22.69 (13.03-33.05), p < 0.01] regions compared to males. Also, they had less delta values of left central alpha [C3= -8.32 (-32.65-6.1) vs. 16.5 (0.36-36.36), p < 0.01] and temporal beta [T3= -6.29 (-10.09- -1.49) vs. 1.24 (-0.84- 2.8), p < 0.001] power compared to males.Conclusion: At rest females may have high EEG powers in different bands. In response to acute exercise, they respond in reverse way as compared to males.DOI: http://dx.doi.org/10.3126/ajms.v6i2.11116Asian Journal of Medical Sciences Vol.6(2) 2015 30-35