bluuebunny/crossref_metadata_2025_split huggingface dataset:
Petrophysical Modeling Based on Porosity Partitioning, a Case Study in Thamama Formation
Authors: Menon Pradeep , Ali Abdulla , Guergour Mohamed N. , Ebeid Mahmoud , Jeong Jaehoon , Darous Christophe 
Published: November 2016

Abstract
What makes a petrophysical model robust is the understanding of the relationships between its petrophysical properties, typically porosity, permeability, and saturation. In carbonates, and particularly in limestones, the pore geometry and connectivity are often not uniform which can lead to lack of correlation between porosity, permeability, and saturation.
This study explains how the combination of core analyses, Nuclear Magnetic Resonance (NMR), and borehole image logs was used to build a permeability transform that considers the pore size distribution and connectivity. The permeability model is based on a dual medium pore network concept that combines the macro pore network with the micro and meso pore network according to their relative pore volume. The saturation height functions are defined based on the rock characteristics that honor the capillary pressure (Pc) core data behavior.
The comparison of the pore size partitioning from NMR logs or borehole image processing with the core description and digital core photos provided important information on how to process and interpret both log and core data. The pore size distribution was associated with depositional and diagenetic processes that were used during the 3D modeling of the macro porosity. After the porosity and the macro-porosity were modelled using geological concepts and geostatistics, the permeability in the 3D static model is directly computed using the function defined from core and logs. The saturation height functions (SHF) are defined from routine and capillary pressure (Pc) core data to be consistent with the pore size classification used to define the permeability model. The saturation height modeling is ultimately adjusted by combining the free water level (FWL) from pressure data, SHF from Pc data, and log-derived water saturation.
All the properties of the model are consistent between each other and can be updated with new wells very easily since only porosity and its macro porosity volume need to be re-populated with the data from the new wells.
The construction of empirical permeability models in particular in carbonates that use the pore size distribution has been established in the past generally at the core to log level. This work revisits the construction of those analytical permeability models by using a dual-media pore network concept and illustrates the advantages to use those functions directly in the 3D modeling construction and update.
Estimating Ultimate Recovery and Economic Analysis of Shale Oil Wells in Eagle Ford and Bakken
Authors: Darugar Qusai , Heinisch Dennis , Lundy Brian J. , Witte Pascal , Wu Weiwei , Zhou Songsheng 
Published: November 2016

Abstract
Estimated ultimate recovery (EUR) and well economics are two subjects of high interest for unconventional wells, especially during the downturn of the market when the profitability of unconventional oil/gas becomes marginal. In this work, the authors investigated a few models that are commercially available for EUR assessment and developed a mathematical model for evaluating shale oil economics.
EUR is typically assessed by a Decline Curve Analysis (DCA). The authors applied different models (including Arps’ and multi-segment) to estimate EURs. The influence of the length of production data on EUR is also analyzed. A comprehensive approach was taken to analyze all major costs that occur in every phase from leasing to well abandonment. Eventually, a mathematical model is established which enables the estimation of well economics by use of publicly available data, e.g., production data, well total depth, and stimulation treatment.
By applying the estimated EURs in the newly developed model, the authors analyzed the economics of more than 3900 shale oil wells in Eagle Ford and Bakken. Results show that the mean breakeven oil prices in Eagle Ford and Bakken are, respectively, $69/bbl and $63/bbl. At an oil price of $50/bbl, more than 60% of the wells in those two shale plays are not profitable.
Oxygen Enrichment in Sulphur Plants to Reduce the Life Cycle Costs of New-Build, Large Gas Plants
Authors: Borraccia Adriano , Roux Adriaan , Street Robin , Pollitt Steve , Guzmann Dr. Marcus , Neuhaus Oliver , Puetz Thomas , Pirard Jolien 
Published: November 2016

Abstract
Oxygen enrichment is a well-known economic and reliable method of debottlenecking existing Sulphur Recovery Units (SRU) with minimal capital investment. It can also eliminate the need for fuel gas co-firing in the reaction furnace, required to maintain the correct temperature for contaminant destruction, for example for destruction of benzene, toluene and xylenes (BTX) in the acid gas.
The concept of oxygen enrichment is simple: by replacing air with enriched air or pure oxygen the volumetric flow through the SRU decreases allowing more acid gas to be fed to the system – resulting in increased sulphur production capacity without the need for significant modifications to existing equipment or major changes to the process plant pressure profile.
This paper specifically considers the application of oxygen enrichment to the design of new-build large gas plants where the feed acid gas is lean (has low H2S content) and contains BTX. Such plants typically require feed gas and/or combustion air preheating and the use of fuel gas co-firing and have not, historically, been considered for oxygen enriched operation. The effects of oxygen enrichment in such cases are presented and the resulting benefits in capital cost and operating cost reductions.
An important part of the economic assessment is the supply of oxygen and the paper will provide guidance on the selection of the oxygen production technology - including cost indications depending on required oxygen volumes and oxygen-enrichment levels to be applied in the desulfurization process.
The analysis focuses on a number of areas which include: –Equipment size: due to the smaller volumetric gas flowrate processed in oxygen enriched plants SRU and Tail Gas Treatment Unit (TGTU) equipment will be smaller compared to conventional air design and in the case of multiple trains it can even reduce the number of trains required.–Oxygen supply: The additional cost of the oxygen production; oxygen supply costs are considered as OPEX being supplied by industrial gas company, thus not requiring CAPEX.–Fuel Gas consumption: When fuel gas co-firing is required in the Reaction Furnace for contaminant destruction, the use of oxygen enrichment reduces or eliminates co-firing requirements. There are also savings in fuel gas consumption in the thermal oxidiser downstream of the TGTU.–Power consumption: this is reduced due to the smaller equipment required for the same sulphur capacity. Savings are also seen due to the reduced air demand and size of the combustion air blower.
Over-Design Bias - Pitfalls and Recourses
Authors: Al-Ghanem F. A. , Singhal V. 
Published: November 2016

Abstract
All good equipment & system designs include certain margins to deliver operational flexibility, mechanical integrity and high availability under unforeseen variations in operating conditions. However, the adequacy & veracity of these margins has long been an issue of discussion. Project facility design goes through many cycles of reviews & updating during which, margins are added resulting in equipment or facilities that are difficult and expensive to operate & maintain. Reasons for over-design include working in silos, incorrect input-data, inappropriate simulation correlations and/or assumptions, non-linear incremental cost for upsizing, large project-cycle-time, lack of precedence, avoiding penalties etc. and last but not least, regional culture. This paper discusses the problems & root-causes associated with over-design, its evolution through various project stages & possible opportunities to limit over-design in up-stream oil & gas industry through real-life examples. This philosophy was utilized in recent projects and led to capex & opex savings besides delivering technically efficient systems. As majority of over-design cases relate to green-field projects, brown-field projects will not be discussed. Though over-design bias & its pitfalls apply globally to all sectors of the oil & gas industry, discussion will be focused around surface gas handling facilities (compressors mainly & brief references to pipelines, gas treatment units).
End of Linear Flow Time Picking in Long Transient Hydraulically Fractured Wells to Correctly Estimate the Permeability, Fracture Half-Length and Original Gas in Place in Liquid Rich Shales
Authors: Dahraj Naeem Ul. , Ali Muhammad , Khan Muhammad Noman 
Published: November 2016

Abstract
Formation permeability (k) and fracture half-length (Xf) determination provides the ability to economically optimize well and fracture spacing. For wellbores completed in the gas-condensate and oil window (producing below saturation pressure) two-phase flow occurs from the fracture face increasing in distance until it reaches the no flow boundary from the adjacent fracture face along a horizontal wellbore. Thereafter the flow becomes boundary dominated. It becomes challenging to precisely pick the end of linear flow time and the start of boundary dominated flow regime due to long transient region in shales (low permeability nature).
End of linear flow time is used to calculate both the permeability and original gas in place (OGIP) using production data. Existing practices in the literature suggest to pick the end of linear flow time implicitly from the plot of reciprocal rate vs cumulative production. The deviation on the line is termed as typically the time at which linear flow has ended. However, considering the lengthy transition regions in shales, this involves a great deal of error as the end of linear flow time is not calculated mathematically but picked on the analyst's eyeballing practices. Thus, a small mispick of end of linear flow time could result in substantially misleading permeability and OGIP.
The primary work presented in this paper resolves the selection of end of linear flow time by proposing a technique which involves production data analysis equations and statistical methods along with graphical techniques to calculate and rightly pick the end of linear flow time. Since gas condensate ratio (GCR) remains constant during the linear flow regime, our methodology also involves reverification of the end of linear flow time. This is done by picking the increase in GCR which happens at the end of linear flow on the plot of cumulative production versus the GCR.
While the procedure involved laboratory fluids, special core analysis, and numerical simulation, the methodology lends to a wide range of liquid-rich reservoirs where linear flow analysis is appropriate.
CO2 Wettability of Shales and Coals as a Function of Pressure, Temperature and Rank: Implications for CO2 Sequestration and Enhanced Methane Recovery
Authors: Arif Muhammad , Barifcani Ahmed , Zubair Talha , Lebedev Maxim , Iglauer Stefan 
Published: November 2016

Abstract
The underground geological CO2 storage into oil and gas reservoirs and/or saline aquifers is a promosing technique to reduce anthropogenic greenhouse gas emissions which thus ensures clean environment. CO2 can also be injected into coal beds and shale formations where it gets trapped by means of adsorption trapping with additional benefits of enhanced methane recovery. In this context, wettability of CO2/coal/brine and CO2/shale/brine systems plays an important role in governing the suitable storage conditions. Wettability of a given system is a function of injection pressure, reservoir temperature and type of the coal or shale. Despite the vital benefits, relatively less attention has been given to CO2 injection in coals and shales for storage and enhanced methane recovery purposes. Therefore, in order to access the storage potential in coals and shales, we experimentally tested CO2-wettability by advancing and receding contact angles measurement using a drop-pendant titled plate technique for coals of high, medium and low ranks (data taken from previous work) and three organic-rich shale samples of varying TOC at in-situ pressure and temparture conditions. We found that both advancing and receding contact angles increased with increase in pressure and decreased with increase in temperature irrespective of the type of sample analysed. Moreover, at any given pressure and temperature, high rank coals exhibited higher values of contact angles (more CO2-wet surfaces) in comparison to low rank coals. Similarly, high-TOC shales were more non-wetting as compared to low TOC shales. In summary, higher the organic carbon content of coal/shale, higher were the CO2-wettability of the system under investigation. The increased CO2-wettability of coals and shales implies that the injected CO2 will be distributed rather uniformly in organic material of the coal or shale formation thus resulting in better adsorption of CO2 into the micropores. Moreover, since it is experimentally proven by previous studies that adsorption capacity of CO2 is up to ~9 times higher than that of CH4, therefore, higher CO2-wettablity will result in improved displacement of methane towards production wells due to preferential adsorption of CO2 over CH4. We finally conclude that high rank coals and high-TOC shales are better for CO2 storage and methane gas prodcution due to better CO2-wetting and that the benefits are further improved if formation temperature is low and injection pressure is high. The results of this study, therefore, lead to a guideline for optimum coal and shale formation selection for CO2 injection.
Enhancing Recoveries from a Low Permeable Gas-Condensate Reservoir through Hydraulic-Fracturing & EOR Technologies
Authors: Ahmed Sheraz , Khakwani Atta M. , Ahmed Ijaz , Khan Osama H. 
Published: November 2016

Abstract
The Retrograde Gas-condensate systems have always been found unique both in their flow behavior and their ultimate recovery. This is mainly because of the process of condensation that takes place around the wellbore creating a region of condensate drop out resulting in flow impedance. In addition to it, the dependency of relative permeabilities on positive and negative velocities due to coupling and inertia respectively, further complicates the flow performance. These factors, thus, make an optimum production from these systems a very challenging and difficult task. Therefore, the main aim of this paper is to present a systematic approach towards the recovery optimization of such a low permeable gas condensate reservoir in Pakistan.
There are different production enhancement techniques that are applied to retrograde systems, among which Hydraulic Fracturing (HF) is a very common exercise. This Fracturing, however, also needs the optimization of geometry (i.e. width and length) and flow (i.e. rate) parameters to make it of high value. But, in some instances, despite of the enhanced flow behavior by HF, considerable amount of valuable gas and liquid might still be lost. Therefore, the recovery can be further optimized through techniques such as Water Flood (to increase the pressure back above the dew point), Miscible Gas or CO2 flooding etc.
This study first illustrates the impact of coupling and inertia on hydraulically fractured wells, using 3D reservoir simulation on real time data. A one well sector model is initially developed after validating the history match of the whole field model. Afterwards, the data from the Hydraulic Fracturing jobs, is incorporated to evaluate the positive and negative effects of the gas velocity, along with the recommendations on frac-geometry optimization for such gas condensate reservoirs.
The paper then illustrates the application of different Enhanced Oil Recovery methods on the whole field, using detailed compositional simulation, keeping in view the limitations of hydraulic fracture – as it may not be the answer to optimized recovery. Eventually, a comprehensive strategy has been presented, summarizing all the factors having maximum influence on the ultimate recovery and illustrate the operational and economic aspects of such technologies, to increase the overall gas and condensate production from the field.
Perawatan Maloklusi Klas II Divisi 1 Dentoskeletal Disertai Retrusi Mandibula Dengan Alat Fungsional Bionator
Authors: Luthfianty Afini Putri , Suparwitri Sri , Hardjono Soekarsono 
Published: November 2016

Maloklusi klas II divisi 1 dentoskeletal disertai dengan retrusi mandibula dan lengkung rahang yang sempit dapat terjadi akibat dari faktor keturunan dan diperparah oleh kebiasaan buruk. Kondisi maloklusi tersebut ditandai dengan adanya palatal bite dan overjet yang besar. Perawatan maloklusi klas II divisi 1 pada masa pertumbuhan dan perkembangan dapat dilakukan dengan menggunakan alat ortodontik fungsional, salah satunya adalah Bionator. Pemilihan bionator bertujuan untuk menuntun rahang bawah untuk bergerak ke posisi yang diinginkan dan memperlebar lengkung rahang. Tujuan dari penulisan laporan kasus ini adalah menyajikan hasil kemajuan perawatan maloklusi klas II divisi 1 dengan menggunakan alat ortodontik fungsional Bionator. Pasien perempuan berumur 12 tahun mengeluhkan gigi depan atas maju sehingga mengganggu penampilan. Diagnosa kasus adalah maloklusi klas II divisi 1 dentoskeletal disertai dengan retrusi mandibula, bidental protrusif, palatal bite, kontraksi lengkung rahang dan malposisi gigi individual. Pasien dirawat dengan menggunakan alat ortodontik fungsional Bionator. Perawatan setelah tiga bulan, secara klinis terlihat profil pasien terkoreksi, overjet berkurang, palatal bite hilang, dan open bite posterior. Treatment of dentoskeletal class II division I with mandibula retrussion using Bionator appliance. Malocclusion Class II division 1 dentosceletal followed with mandibular retrusion and contraction of arch could be happened by genetic and bad habit. It was showed with severe palatal bite and overjet. In the development and growth phase, the treatment for that condition is fuctional appliance, such as Bionator. Bionator arranged lower jaw to the good position and distraction the arch. The purpose of this case report is to present the treatment of malocclusion dentosceletal Class II division 1 with fuctional appliance Bionator. A 12 years old female patient complained of front upper teeth are protrusive. Diagnosis is malocclusion Class II division 1 dentosceletal followed with mandibular retrusion, bidental protrusive, palatal bite, contraction of jaw and malposition individual teeth. The patient treated with fuctional appliance Bionator. After 3 months treatment, patient`s profile corrected, decreased overjet, no palatal bite, and open bite posterior.
Comparative Effectiveness of Second-Line Agents for the Treatment of Diabetes Type 2 in Preventing Kidney Function Decline
Authors: Hung Adriana M. , Roumie Christianne L. , Greevy Robert A. , Grijalva Carlos G. , Liu Xulei , Murff Harvey J. , Ikizler T. Alp , Griffin Marie R. 
Published: November 2016

Background and objectives
Diabetes is the leading cause of ESRD. Glucose control improves kidney outcomes. Most patients eventually require treatment intensification with second-line medications; however, the differential effects of those therapies on kidney function are unknown.

Design, setting, participants & measurements
We studied a retrospective cohort of veterans on metformin monotherapy from 2001 to 2008 who added either insulin or sulfonylurea and were followed through September of 2011. We used propensity score matching 1:4 for those who intensified with insulin versus sulfonylurea, respectively. The primary composite outcome was persistent decline in eGFR≥35% from baseline (GFR event) or a diagnosis of ESRD. The secondary outcome was a GFR event, ESRD, or death. Outcome risks were compared using marginal structural models to account for time-varying covariates. The primary analysis required persistence with the intensified regimen. An effect modification of baseline eGFR and the intervention on both outcomes was evaluated.

Results
There were 1989 patients on metformin and insulin and 7956 patients on metformin and sulfonylurea. Median patient age was 60 years old (interquartile range, 54–67), median hemoglobin A1c was 8.1% (interquartile range, 7.1%–9.9%), and median creatinine was 1.0 mg/dl (interquartile range, 0.9–1.1). The rate of GFR event or ESRD (primary outcome) was 31 versus 26 per 1000 person-years for those who added insulin versus sulfonylureas, respectively (adjusted hazard ratio, 1.27; 95% confidence interval, 0.99 to 1.63). The rate of GFR event, ESRD, or death was 64 versus 49 per 1000 person-years, respectively (adjusted hazard ratio, 1.33; 95% confidence interval, 1.11 to 1.59). Tests for a therapy by baseline eGFR interaction for both the primary and secondary outcomes were not significant (P=0.39 and P=0.12, respectively).

Conclusions
Among patients who intensified metformin monotherapy, the addition of insulin compared with a sulfonylurea was not associated with a higher rate of kidney outcomes but was associated with a higher rate of the composite outcome that included death. These risks were not modified by baseline eGFR.
Neuroplasticity Associated With Anterior Cruciate Ligament Reconstruction
Authors: Grooms Dustin R. , Page Stephen J. , Nichols-Larsen Deborah S. , Chaudhari Ajit M.W. , White Susan E. , Onate James A. 
Published: November 2016

Study Design Controlled laboratory study. Background Anterior cruciate ligament (ACL) injury may result in neuroplastic changes due to lost mechanoreceptors of the ACL and compensations in neuromuscular control. These alterations are not completely understood. Assessing brain function after ACL injury and anterior cruciate ligament reconstruction (ACLR) with functional magnetic resonance imaging provides a means to address this gap in knowledge. Objective To compare differences in brain activation during knee flexion/extension in persons who have undergone ACLR and in matched controls. Methods Fifteen participants who had undergone left ACLR (38.13 ± 27.16 months postsurgery) and 15 healthy controls matched on age, sex, height, mass, extremity dominance, education level, sport participation, and physical activity level participated. Functional magnetic resonance imaging data were obtained during a unilateral knee motor task consisting of repeated cycles of knee flexion and extension. Results Participants who had undergone ACLR had increased activation in the contralateral motor cortex, lingual gyrus, and ipsilateral secondary somatosensory area and diminished activation in the ipsilateral motor cortex and cerebellum when compared to healthy matched controls. Conclusion Brain activation for knee flexion/extension motion may be altered following ACLR. The ACLR brain activation profile may indicate a shift toward a visual-motor strategy as opposed to a sensory-motor strategy to engage in knee movement. Level of Evidence Cohort, level 3. J Orthop Sports Phys Ther 2017;47(3):180–189. Epub 5 Nov 2016. doi:10.2519/jospt.2017.7003