bluuebunny/crossref_metadata_2025_split huggingface dataset:
North Oman Tight Gas Development
Authors: Lamers Edwin , Al Siyabi Hisham , Briner Andreas , Elliott David , Weissenbäck Markus , Al-Kindy Fahad 
Published: January 2013

AbstractProduction from conventional non-associated gas fields operated by PDO in North Oman has largely met demand from Oman’s domestic and LNG export requirements to-date. However, with domestic demand growing at around 5% per year and with continuing significant LNG sales contracts to be met, exploration has been stepped up in recent years to meet this demand, especially as new opportunities from conventional gas accumulations become rarer. Exploration successes over the last five years are increasingly restricted to deep, tight Amin sandstone reservoirs with porosities ranging from 2 to 10% and (ambient) permeabilities from 0.001 to 1 mD.Following an extensive exploration campaign including a hunt for Basin Centre Gas during 2009-2011 focus has now shifted to the appraisal and early development of the Khulud cluster of fields, located in the Yibal-Fahud area.Significant challenges exist over and above the tightness of the rock: target reservoirs are deep (4700-5200 m below Ground Level) and have high reservoir temperatures (160 to 190°C). Rock geomechanics are a critical issue: high fracture gradients mean that not all hydraulic fracturing jobs are successful. On top of all this, longer term well production will be impacted by relatively high Condensate Gas Ratios and associated water production.With significant Gas-In-Place, the presence of infrastructure, notably the nearby Yibal gas processing plant, and the proven presence of sweet spots make the Khulud Cluster a prime candidate to provide the 2nd wave of production following conventional reservoirs and a possible working model for future tight and unconventional gas developments.A 1 mln m3/d capacity Early Production System (EPS) is currently being constructed to de-risk and ‘right-size’ a cluster development by assessing Expected UltimateRecovery (EUR) per well.
QI Workflow to Identify Sweet Spots in the Unconventional Tight Gas Amin Play in North Oman
Authors: Scholten-Vissinga Marianne , Busaidi Talal 
Published: January 2013

AbstractAs conventional hydrocarbon plays have become highly mature after more than fifty years of exploration, Petroleum Development Oman LLC (PDO) is increasingly focusing towards unconventional plays. The Amin gas play is an example of such a play. The play concept consists of high pressure and high temperature alluvial sandstone reservoir with a very high netto-gross (N/G) but relatively low porosity and permeability. Due to these properties, the reservoir is classified as a tight reservoir.Several wells in North Oman have encountered Amin reservoir showing low permeability and overpressures. One of the key wells within the area of interest has encountered high overpressures with good porosity and gas pay. These findings have triggered a quantitative interpretation (QI) study to pursue a possible correlation between seismically derived properties such as acoustic impedance or velocity with overpressures and/or good porosity to pinpoint sweet spots for drilling.The QI study was split into two parts: Phase 1 consists of an amplitude versus angle (AVA) forward modelling including cross plotting of the rock properties and Phase 2 comprises an AVA inversion. The purpose of Phase 1 was to assess the feasibility of predicting reservoir quality or/and pore pressure by integrating well log data, VSP's and seismic data. The results from this phase were encouraging and it was decided to proceed with the AVA inversion.The AVA inversion was carried out on the state of the art wide azimuth seismic data that was acquired in 2009. Using the results from the inversion and the knowledge obtained from Phase 1 enables us to identify sweet spots for future exploration drilling. In this paper the QI workflow is described which has been applied to identify sweet spots for this tight gas play. After this study was completed one additional well was drilled and is used as a blind test well.The main conclusions from this study are that porosity variations at Amin level can be related to acoustic impedance at well resolution and at seismic resolution. AVA behavior shows that "higher" porosities in Amin give an increase in amplitude with increasing angle while "low" porosities show a polarity flip. Due to the limited availability of well data and their clustered distribution in the south-east corner of the survey, the inversion results are heavily biased by the derived low frequency model. Hence, only a porosity map and no volume has been calculated and is used to guide the porosity distribution in the static model.
Can Shale-Like Stimulations Unlock the Potential of Extremely Low Permeability Tight Gas Reservoirs?
Authors: Owolabi O. O. , Volz R. F. , Smith P. S. 
Published: January 2013

AbstractHorizontal drilling and multi-stage fracturing has sky-rocketed the economic development of ultra-low permeability shale gas resources in North America. The same technology has the potential to be applied to extremely low permeability tight gas (sandstone) reservoirs.In this paper, we discuss the results of evaluating if we can successfully apply shale-like stimulations in developing and improving the performance of extremely low permeability tight gas reservoirs. The focus of the study is on doing sensitivity model runs to investigate the effects of reservoir permeability, drainage area, fracture surface area, and fracture conductivity on both initial and long term gas production rates, using single well simulation models for a generic tight, dry gas reservoir. The study compared transverse multiple fractures in a horizontal well with 40, 20, 10, and 5 hydraulic fractures, for permeabilities from 1 mD down to 1 nD, and for drainage areas of 80 to 1,275 acres. The impact of fracture conductivities and fracture half-lengths on gas production was also assessed.A typical horizontal tight gas completion has a lateral length of 2,500 ft to 3,500 ft with 5 to 7 fracture stimulation stages using open-hole completion style system. The results from this study show that there is potential for improving well economics by targeting more fracture initiation points similar to that of shale gas wells, when permeability of the tight gas reservoir is between 0.1 µD to 10 µD. The findings can be used not only to design better tight gas wells, but also helps in understanding the fundamental behavior of the low quality tight gas production system. In conclusion, this paper clearly illustrates that in extremely low permeability tight gas reservoirs, horizontal wellbores with shale-like stimulation programs may be the only robust option for achieving commercial gas production rates.
Adopting North American, Multi-stage Fracturing and Horizontal Completion Technologies Starts to Unlock the Amin Tight Gas Formation in the Sultanate of Oman
Authors: Robert Clark , Kevin Mullen , Stevanus Kurniadi 
Published: January 2013

AbstractThe careful planning and successful execution of a multi-stage fracture stimulation completion in one of the first horizontal wells drilled in the Amin Formation instigated a step change in initial production rate and long term deliverability from this tight gas sandstone reservoir in North Central Oman.The field was discovered in 1993 but remained undeveloped due to low deliverability from single-stage hydraulic fracturing treatments. Previous vertical Amin completions, though intriguing, failed to deliver satisfactory production rates. Hydraulic fracturing stimulation technology is critical to achieving commercial rates in tight gas formations. The operator and service company worked as a team, modeling the fracturing program after North American practices, prescribing a novel approach for the Sultanate of Oman.The vertical completion profile was changed to horizontal multi-stage fracturing, to increase reservoir contact. North American unconventional reservoir stimulations were investigated by pumping cross-linked gel, slick water, and hybrid fracs across six stages along the horizontal section. Several reservoir access options were tested to evaluate fracture initiation points including sliding sleeve, jet perforating, and abrasive jetting. Various well intervention strategies and zonal isolation techniques were also deployed. Extensive cased-hole logging was employed to evaluate the effectiveness of each stage.A full range of integrated surveillance, including open-hole characterization, production logs, and BHP monitoring was used to evaluate formation behavior, fracturing effectiveness, and intervention activities, achieving optimum operational and production results for potential application to full field development.Adopting best practices from other regions and integrating comprehensive surveillance data is helping to unlock the potential of the Amin tight gas reservoir. The KZN-F well is used as a case study throughout this paper.
Field Cases of Hydraulic Fracture Stimulation Diagnostics Using Fiber Optic Distributed Acoustic Sensing (DAS) Measurements and Analyses
Authors: Molenaar Mathieu M. , Cox Barbara E. 
Published: January 2013

Abstract
Deciding on the optimum spacing between fractures and selecting the optimum fracture treatment parameters is a key challenge in designing the hydraulic fracture stimulations of Unconventional Gas and Liquid Rich Shale (UGLRS) wells.
To make those decisions more effectively and more rapidly, (downhole) hydraulic fracture diagnostic tools can be used which provide a better understanding of how and where fractures initiate and what the distribution of fluid and proppant volume is downhole. One emerging technology, fiber optic distributed acoustic sensing (DAS) has the potential of providing such key diagnostic insights during hydraulic fracturing operations in real-time.
This paper describes some of the background technology and presents the results of several hydraulic fracture stimulation (HFS) diagnostic case studies. The results illustrate how DAS has been used to perform real-time monitoring for both open-hole multi-stage fracturing and "Cemented Plug & Perf Completions". DAS has provided valuable insight as to the stimulation effectiveness. The technique has also provided insights into effective zonal isolation when using mechanical isolation during the hydraulic-fracturing process that would otherwise not have been possible. It also complements other HFS diagnostic technologies (e.g. tracers, micro-seismic, distributed temperature sensing (DTS), production logs (PLT)).
DAS monitoring of hydraulic fracture stimulation can help accelerate the learning curve and drive performance improvements. Installation of fiber optic cables early in a field's life or when entering a new geological/geo-mechanical situation can allow for accelerated optimization of future wells.
A Cost Effective Way to Boost Production from Tight Oil and Gas Fields Using Surface Jet Pump Systems
Authors: Sarshar Sacha , Beg Najam 
Published: January 2013

Abstract
Tight oil and gas fields suffer from poor permeability and in most cases fragmentation of reservoir. As the reservoir pressure drops and water-cut increases, production from these fields becomes even more restricted. There are a number of techniques under IOR and EOR to maintain production and increase total recovery from these fields. These techniques involve major capital investments and involve some risks on the extent of benefits gained.
The use of surface jet pumps (SJPs) is a simple and cost effective way to maintain or boost production from many low pressure (LP) wells. This paper describes the key features of the SJP systems and their wide range of applications. A number of field examples, worldwide, are presented and in each case the benefits are highlighted. Payback period for the SJPs is short, a matter of a few weeks to a few months from the added revenue.
SJPs can operate cost effectively in conjunction with IOR and EOR techniques and artificial lift solutions in both oil and gas production applications. The use of SJPs is the simplest and least costly solution to maintain production and to extend the life of many wells. They are particularly beneficial for stranded satellite wells where other solutions are not cost effective because of their complexity, or the need for electric power, or continuous manning of the station. They offer other benefits such as de-bottlenecking compressors, eliminating intermediate compressors and prevention of flaring LP gas.
Aging obviates sex‐specific physiological responses to exercise
Authors: Deschenes Michael R. , Taylor Jessica L. , Mangis Katherine A. 
Published: January 2013

ObjectivesBoth sex and aging have been shown to affect physiological responses to exercise. The aim of the present investigation was to determine whether aging impacted the sex‐specific nature of physiological responses to exercise commonly noted among young adults.MethodsTen aged men (69.0 ± 1.7 years; mean ± SE) and 10 aged women (71.6 ± 1.3 years) reporting similar levels of habitual physical activity performed a 30‐min exercise session at 60–65% of their predetermined peak oxygen uptake. Cardiovascular, thermoregulatory, and metabolic variables were assessed before exercise, at the 15th and 30th min of exercise, and at 5 and 15 min into a passive postexercise recovery period. Variables of interest were statistically analyzed via two‐way analysis of variance with repeated measures; significance was set at P < 0.05.ResultsSignificant effects of time (i.e., exercise) for each physiological variable of interest were identified, but not once was a significant effect of group (i.e., sex) detected.ConclusionsExercise‐induced physiological responses to prolonged, moderate intensity exercise were similar among aged men and aged women. This evidence that the sexually dimorphic nature of physiological responses to exercise is obviated with age should be taken into account when prescribing health‐related exercise training programs for older individuals. Am. J. Hum. Biol. 25:215–221, 2013. © 2013 Wiley Periodicals, Inc.
Endocrinological issues and hormonal manipulation in children and men with Klinefelter syndrome
Authors: Wosnitzer Matthew S. , Paduch Darius A. 
Published: January 2013

Abstract47, XXY or Klinefelter syndrome (KS), the most common chromosomal aberration in males, is characterized by either absolute or relative hypogonadism with frequent decline in serum testosterone (T) following the onset of puberty. Decreased T levels are the result of testicular dysfunction with decrease in size of Leydig cells, and loss of germs and Sertoli cells leading to tubular hyalinization. Increase in estradiol results from over‐expression of aromatase CYP19. Deficient androgen production and observed varied response of end‐organs to T leads to delayed progression of puberty with decreased facial/body hair, poor muscle development, osteoporosis, and gynecomastia. It is possible that hypogonadism and excessive estradiol production contribute to emotional and social immaturity, and specific learning disabilities in KS. Based on the authors' experience and literature review, early fertility preservation and hormonal supplementation may normalize pubertal development, prevent metabolic sequelae of hypogonadism, and have a positive effect on academic and social development. No randomized clinical trials are available studying the effects of T supplementation on reproductive or cognitive issues in KS. Aggressive T supplementation (topical gel) and selective use of aromatase inhibitors may be considered at the onset of puberty with careful follow‐up and titration to reach age‐specific high‐normal physiologic serum values. The decision to institute hormonal therapy should be part of a multidisciplinary approach including physical, speech, behavioral, and occupational therapy. © 2013 Wiley Periodicals, Inc.
Sexual differentiation of the brain in man and animals: Of relevance to Klinefelter syndrome?
Authors: McCarthy Margaret M. 
Published: January 2013

AbstractThe developing brain is highly sensitive to the organizing effects of steroids of gonadal origin in a process referred to as sexual differentiation. Early hormone effects prime the brain for adult sensitivity to the appropriate hormonal milieu, maximizing reproductive fitness via coordinated physiology and behavior. Animal models, in particular rodents, have provided insight into general principles and the cellular and molecular mechanisms of brain differentiation. Cellular endpoints influenced by steroids in the developing brain include neurogenesis, migration, apoptosis, dendritic growth, and synaptic patterning. Important roles for prostaglandins, endocanabinoids, and epigenetics are among the many cellular mediators of hormonal organization. Transference of general principles of brain sexual differentiation to humans relies on observations of individuals with genetic anomalies that either increase or decrease hormone exposure and sensitivity. The physiology and behavior of individuals with XXY (Klinefelter syndrome) has not been considered in the context of sexual differentiation of the brain, most likely due to the delay in diagnoses and highly variable presentation. The behavioral phenotype and impairments in the domains of speech and language that are characteristic of individuals with XXY is consistent with the reduced androgen production associated with the syndrome. Hormone replacement appears effective in restoring some deficits and impact may be further improved by increased understanding of the hormonally mediated sexual differentiation of the brain. © 2013 Wiley Periodicals, Inc.
Neurocognitive variance and neurological underpinnings of the X and Y chromosomal variations
Authors: Gropman Andrea , Samango‐Sprouse Carole A. 
Published: January 2013

AbstractX and Y chromosomal variations including tetrasomy and pentasomy conditions are rare and occur in 1:18,000–1:100,000 male births. The most common sex chromosome aneuploidy is 47, XXY for which there is a rich literature delineating the physical and neurobehavioral phenotype. Although the more complex chromosome aneuploidies 48, XXYY, 48, XXXY, and 49, XXXXY are often compared with 47, XXY (Klinefelter syndrome) because of shared features including tall stature and hypergonadotropic hypogonadism, there is a wider spectrum of physical and cognitive abilities that have recently been delineated. The phenotypic presentation of the boys with more severe aneuploidy shares some characteristics with 47, XXY, but there are also other unique and distinctive features. Previously unappreciated intact nonverbal skills have been demonstrated in association with severe developmental dyspraxia. MRI findings of white matter hyperintensities may underlie cognitive deficits and deserve further study. This report discusses what is known about clinical variability in the XY syndromes collectively evaluated through careful multidisciplinary clinical evaluation including the clinical and neurobehavioral aspects of these conditions. Variability in clinical and cognitive functioning may reflect skewed X inactivation, mosaicism, or epigenetic factors that warrant further investigation. © 2013 Wiley Periodicals, Inc.
The vascular collar of the ilium— Three‐dimensional evaluation of the dominant nutrient foramen
Authors: Cunningham Craig A. , Black Sue M. 
Published: January 2013

AbstractNutrient arteries are the predominant blood supply to endochondral bones and are particularly important during the early stages of endochondral ossification and the active growth period. These nutrient vessels traverse the periosteal shell of a developing bone to invade the disintegrating cartilage matrix and bring about endochondral bone formation. This results in the formation of a nutrient foramen which is retained as the vascular conduit between the exterior and interior of the bone. This study examined the dominant nutrient foramen of the neonatal ilium using high resolution micro‐computed (micro‐CT) tomography. Three‐dimensional reconstruction of micro‐CT data consistently demonstrated the presence of a distinctive, yet poorly reported, collar of bone extending into the trabecular cavity beyond the endosteum. This study proposes that this collar of bone may have formed in response to osteogenic signaling from approximated arterial vasculature. Additionally, it is suggested that the formation of this collar may act as a protective mechanism to the dominant nutrient vessel and as a potential biomechanical anchor for surrounding trabeculae, aiding to increase the biomechanical competency around the area of the foramen. The documentation of this osteological structure is important from a clinical perspective to prevent the misinterpretation of fracturing and pathology on plain plate radiographs and clinical computed tomography scans. Clin. Anat., 2013. © 2013 Wiley Periodicals, Inc.
Synthesis and Characterization of Conformationally Rigid Chiral Pyridine–N‐Heterocyclic Carbene‐Based Palladacycles with an Unexpected Pd–N Bond Cleavage
Authors: Ng Kim Hong , Li Yongxin , Tan Wei Xian , Chiang Minyi , Pullarkat Sumod A. 
Published: January 2013

ABSTRACTThe versatility of a previously developed method for the synthesis of chiral carbene‐based palladacycles is demonstrated through the synthesis of two new chiral pyridine‐functionalized N‐heterocyclic carbene palladacycles with different wingtip groups. The efficiency in their resolution with different counter anions and different chiral amino acid salt auxiliaries has been studied. The absolute stereochemistries of all the chiral compounds were confirmed by single crystal X‐ray crystallography. An unexpected Pd–N bond cleavage that resulted in the racemization of the α‐carbon center in these complexes has also been investigated. Chirality 25:149–159, 2013. © 2013 Wiley Periodicals, Inc.
Studies of Enantiomeric Degradation of the Triazole Fungicide Hexaconazole in Tomato, Cucumber, and Field Soil by Chiral Liquid Chromatography–Tandem Mass Spectrometry
Authors: Li Yuanbo , Dong Fengshou , Liu Xingang , Xu Jun , Chen Xiu , Han Yongtao , Liang Xuyang , Zheng Yongquan 
Published: January 2013

ABSTRACTChiral pesticide enantiomers often show different bioactivity and toxicity; however, this property is usually ignored when evaluating their environmental and public health risks. Hexaconazole is a chiral fungicide used on a variety of crops for the control of many fungal diseases. This use provides opportunities for the pollution of food and soil. In this study, a sensitive and convenient chiral liquid chromatography coupled with tandem mass spectrometry (LC‐MS/MS) method was developed and validated for measuring hexaconazole enantiomers in tomato, cucumber, and soil. Separation was by a reversed‐phase Chiralcel OD‐RH column, under isocratic conditions using a mixture of acetonitrile‐2 mM ammonium acetate in water (60/40, v/v) as the mobile phase at a flow rate of 0.4 mL/min. Parameters including the matrix effect, linearity, precision, accuracy and stability were undertaken. Then the proposed method was successfully applied to investigate the possible enantioselective degradation of rac‐hexaconazole in plants (tomato and cucumber) and soil under field conditions. The degradation of the two enantiomers of hexaconazole proved to be enantioselective and dependent on the media: The (+)‐enantiomer showed a faster degradation in plants, while the (−)‐enantiomer dissipated faster than the (+)‐form in field soil, resulting in relative enrichment of the opposite enantiomer. The results of this work demonstrate that both the environmental media and environmental conditions influenced the direction and rate of enantioselective degradation of hexaconazole.Chirality 25:160–169, 2013. © 2013 Wiley Periodicals, Inc.