bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integration of Fracture, Reservoir, and Geomechanics Modeling for Shale Gas Reservoir Development
Authors: Gupta Jugal K. , Albert Richard A. , Zielonka Matias G. , Yao Yao , Templeton-Barrett Elizabeth , Jackson Shalawn K. , El-Rabaa Wadood , Burnham Heather A. , Choi Nancy H. 
Published: January 2013

AbstractFracture nucleation and propagation are controlled by in-situ stresses, fracture treatment design, presence of existing fractures (natural or induced), and geological history. In addition, production-driven depletion and offset completions may alter stresses and hence the nature of fracture growth. For unconventional oil and gas assets the complexity resulting from the interplay of fracture characteristics, pressure depletion, and stress distribution on well performance remains one of the foremost hurdles in their optimal development, impacting infill well and refracturing programs.ExxonMobil has undertaken a multi-disciplinary approach that integrates fracture characteristics, reservoir production, and stress field evolution to design and optimize the development of unconventional assets. In this approach, fracture modeling and advanced rate transient techniques are employed to constrain fracture geometry and depletion characteristics of existing wells. This knowledge is used in finite element geomechanical modeling (coupling stresses and fluid flow) to predict fracture orientation in nearby wells.In this paper, an integrated methodology is described and applied to a shale gas pad as a case study. The work reveals a strong connection between reservoir depletion and the spatial and temporal distribution of stresses. These models predict that principal stresses are influenced far beyond the drainage area of a horizontal well and hence can play a critical role in fracture orientation and performance of neighboring wells. Strategies for manipulating stresses were evaluated to control fracture propagation by injecting, shutting-in, and producing offset wells. In addition, we present diagnostic data obtained from the pad that demonstrates inter-well connectivity and hydraulic communication within the pad. The workflow presented herein can be used to develop strategies for (1) optimal infill design, (2) controlling propagation of fractures in new neighboring wells, and (3) refracturing of existing wells.
Case Studies for the Fracturing of Highly Diverse Gas Reservoirs
Authors: Ajao Omobola , Iwu Chijioke F. , Economides Michael J. 
Published: January 2013

Abstract
Hydraulic fracturing, which has emerged as the premier well completion technology in the petroleum industry, is applied to almost all natural gas wells, worldwide, but for different reasons. It may sound trite but all gas fields should be considered as "unconventional, compared to oil wells." In higher-permeability reservoirs (&gt; 5 md) the remediation of reservoir-to-well turbulence is the main motivation. In lower-permeability reservoirs the main rationale is similar to oil- stimulation- but with significant adjustments. In much tighter reservoirs, including shales, the purpose is to inundate the formation with a very large number of parallel fractures, executed transversely from horizontal wells. This would lead to the effective draining of the Stimulated Reservoir Volume (SRV).
We present here two complete field studies, one in a 17 md dry gas well in Siberia, and the second from a 0.0001 md shale formation in the United States. The shale formation is assumed to have a number of similar properties with the field data from the 17md gas well. The first study shows the impact of turbulence and its removal via hydraulic fracturing. We also show the management of inside-the-fracture turbulence through the adjustment of fracture geometry and the selection of higher permeability proppant. The design approach uses the Unified Fracture Design (UFD), which is the only way to adjust fracture geometry based on expected flow performances. The drainage shape and the irregular ratio between reservoir length and fracture spacing are important considerations in SRV.
We also conduct a parametric study on the turbulence effects inside the fractures for a range of reservoir permeabilities. Which design/execution constraints are necessary at very low or very high permeabilities?
For the shale reservoir, while turbulence effects appear to be inconsequential, the length of the fracture, the spacing among fractures and the actual number of fractures are the critical variables for the physical production optimization. Such a study is also presented in this paper.
Extended Well Test Facility Unlocks Tight gas Resources in The Sultanate of Oman
Authors: Adil Imtiaz , Husain Ali , Al Shidhani Ruqia , Al Lawati Hussain , Chowdhury Ahmed 
Published: January 2013

Abstract
BP installed an extended well testing (EWT) facility to perform extended flow tests for appraisal of the tight gas reservoirs in the Sultanate of Oman. The EWT facility is a "mini-gas-plant" that processes appraisal well gas and delivers it into the national grid. It helps avoid excessive flaring of significant volumes of gas while providing valuable long term history matching data used to predict full field production profiles.
Middle East tight gas reservoirs are typically Pre-Cambrian to Ordivician in age situated in a high pressure and high temperature environment. A comparatively complex diagenetic history makes prediction of rock quality and fluid distribution very challenging. Key depletion planning uncertainties identified at the outset of appraisal were: the long term decline in gas production rates, the connected hydrocarbon volumes, the impact of condensate banking and the long term trends in water gas ratios. The EWT data gathering is helping to reduce these uncertainties to a level sufficient to inform an investment decision.
Four appraisal wells, ranging from good to poor quality, were tied into the EWT for long term testing for up to 2 years to date. The combination of this production history and downhole pressure data has markedly improves confidence in predictions of production profiles for the range of full field development wells.
The EWT operations have also revealed several potential full field development design and startup concerns. These were related to formation of hydrates due to gas expansion at the wellhead along with other potential integrity risks due to high chlorides content and the presence of minor H2S levels. The changing fluid chemistry was also identified which helped in redefining the fluid basis of surface facilities design to optimize operability of the full field development.
Multiscale finite element coarse spaces for the application to linear elasticity
Authors: Buck Marco , Iliev Oleg , Andrä Heiko 
Published: January 2013

Abstract
We extend the multiscale finite element method (MsFEM) as formulated by Hou and Wu in [Hou T.Y., Wu X.-H., A multiscale finite element method for elliptic problems in composite materials and porous media, J. Comput. Phys., 1997, 134(1), 169–189] to the PDE system of linear elasticity. The application, motivated by the multiscale analysis of highly heterogeneous composite materials, is twofold. Resolving the heterogeneities on the finest scale, we utilize the linear MsFEM basis for the construction of robust coarse spaces in the context of two-level overlapping domain decomposition preconditioners. We motivate and explain the construction and show that the constructed multiscale coarse space contains all the rigid body modes. Under the assumption that the material jumps are isolated, that is they occur only in the interior of the coarse grid elements, our numerical experiments show uniform convergence rates independent of the contrast in Young’s modulus within the heterogeneous material. Elsewise, if no restrictions on the position of the high coefficient inclusions are imposed, robustness cannot be guaranteed any more. These results justify expectations to obtain coefficient-explicit condition number bounds for the PDE system of linear elasticity similar to existing ones for scalar elliptic PDEs as given in the work of Graham, Lechner and Scheichl [Graham I.G., Lechner P.O., Scheichl R., Domain decomposition for multiscale PDEs, Numer. Math., 2007, 106(4), 589–626]. Furthermore, we numerically observe the properties of the MsFEM coarse space for linear elasticity in an upscaling framework. Therefore, we present experimental results showing the approximation errors of the multiscale coarse space w.r.t. the fine-scale solution.
An extended Stickelberger ideal of the compositum of a bicyclic field and an imaginary quadratic field
Authors: Trnková Veronika 
Published: January 2013

Abstract
We consider certain extension of the Stickelberger ideal of the compositum of a bicyclic field and a quadratic imaginary field, obtained by adding new annihilators to the Stickelberger ideal. We compute the index of this extension, from which we get some divisibility properties for the relative class number of the compositum.
Influence of In<sub>2</sub>O<sub>3</sub> Addition On The Magnetic And Electrical Properties of Iron  Deficient Ni-Zn Ferrite
Authors: Akhter Shireen , Choudhury Md Amanullah , Rahman J 
Published: January 2013

The influence of low melting In2O3 addition on the magnetic and electrical properties of irondeficient ferrites of composition. Ni0.65Zn0.35Fe1.96O4 + xIn2O3(x = 0, 0.005, 0.01, 0.015, 0.02, 0.025, 0.03 and 0.035) was investigated. Single phase spinel structure of all sintered samples were confirmed by X-ray diffraction. The lattice parameter of the samples increased with the increment of In2O3. The effect of In2O3 (melting point 680°C) can be explained by the formation of liquid phase on the grain surface due to reaction of In2O3 with the spinel phase at 1250°C sintering temperature. Saturation magnetization decreased almost linearly and Curie temperature linearly with the increasing addition of In2O3. The decrease in magnetization was possibly due to diamagnetic In3+ ions occupy B-sublattice ( octahedral sites) and replace Fe3+ ions keeping the magnetization of A-sublattice (tetrahedral sites) unchanged. When indium ions occupy B-sites and replace Fe3+ ions, the magnetization of B-sublattice (MB) decreases keeping the magnetization of A-sublattice (MA) constant which in turn weakens A-B exchange interaction (M = MB-MA). The dc resistivity of the samples increased almost linearly with the addition of In2O3. With the increasing addition of In2O3, In3+ ions occupy B-sites which reduces Fe2+ to Fe3+ electron hoping conduction in octahedral sites and contributes to increase in resistivity. DOI: http://dx.doi.org/10.3329/jbas.v36i2.12957 Journal of Bangladesh Academy of Sciences, Vol. 36, No. 2, 153-158, 2012
A Chaotic Three Dimensional Non-Linear Autonomous System Beyond Lorenz Type Systems
Authors: Khan Md Shariful Islam , Islam Md Shahidul 
Published: January 2013

Some fundamental properties of a chaotic three-dimensional non-linear system of the Lorenz type systems were studied. The invariance, dissipation, bifurcation and the strange attractors were investigated and analyzed one 1-scroll, two 2-scroll and two 4-scroll attractors by adding control parameters to this system. The relationship and connecting function for the 2-scroll attractor of this system were also explored. DOI: http://dx.doi.org/10.3329/jbas.v36i2.12959 Journal of Bangladesh Academy of Sciences, Vol. 36, No. 2, 159-170, 2012
A Comparison of Outcomes and Dislocation Rates Using Dual Articulation Cups and THA for Intracapsular Femoral Neck Fractures
Authors: Tarasevičius Sarunas , Robertsson Otto , Dobozinskas Paulius , Wingstrand Hans 
Published: January 2013

Total hip arthroplasty for intracapsular femoral neck fractures (FNF) is associated with a greater risk of dislocation. Dual articulation systems in this group of patients may provide better implant stability and a reduced dislocation rate. The aim of our study was to investigate FNF patients treated with dual articulation cups (DAC) and conventional THA and compare their clinical results at four months and one year after surgery. Our study compared femoral neck fracture patients treated with either DAC or conventional THA during two different time periods. Before surgery and during follow-up, the patients answered questions regarding their mobility, pain and usage of walking aids. Additionally at four-month and one-year follow-ups EQ-5D and HOOS questionnaires were applied for those patients qualifying for functional and quality of life analysis. Out of 125 femoral neck fracture patients 58 were treated with DAC and 67 with conventional THA. At four months and one year follow-up the HOOS and EQ-5D results did not differ significantly between DAC and conventional THA. Five hips in the THA group were revised for recurrent dislocation and two had a single dislocation. One year after surgery, the functional result of DAC and conventional THA are comparable but DAC have a lower risk of dislocation.
Solvent‐Responsive Behavior of Polymer‐Brush‐Modified Amphiphilic Gold Nanoparticles
Authors: Dong Jiaqi , Zhou Jian 
Published: January 2013

AbstractAmphiphilic polymer brushes grafted onto gold nanoparticles impart distinct solvent‐responsive behavior via the change to particle size and surface chemistry and, therefore, wide application prospects can be expected. Coarse‐grained simulations are performed for block and/or mixed polystyrene (PS)/poly(ethylene oxide) (PEO)‐modified amphiphilic gold nanoparticles (AuNP) to investigate their responsive behavior in five different solvents by analyzing their morphology, distribution density profiles, and gyration radii. Typical core–shell, Janus‐type, buckle‐like, ring‐like, jellyfish‐like, and octopus‐like morphologies are formed. Influence of block sequence, mixing mode, and several other effects are discussed. Responsive particle size and surface hydrophilicity can be successfully reproduced by altering solvents. magnified image
Nanoinfusion of ZnO and ZnS nanoparticles into ethylene vinyl acetate in situ for improved optical properties
Authors: Bachus Matthew J. , Spendel Wolfgang U. , Steinecker William H. , Prybyla Stanley G. , Pacey Gilbert E. 
Published: January 2013

AbstractZnO nanoparticles were successfully synthesized within the free volume of an ethylene vinyl acetate (EVA) polymer sheet. Using a process termed “nanoinfusion,” nanoparticles are created in situ. Vapor phase nanoparticle precursors first filled the polymer free volume. Nucleated components of the precursor molecule within the free volume enabled nanoparticle formation and immobilization within the polymer. Trapped nanoparticles were accessible to gas diffusion and can be modified as was demonstrated by the successful conversion of nanoinfused ZnO to ZnS nanoparticles. Successful nanoparticle formation was confirmed through fluorescence spectroscopy and the amount of material nanoinfused was obtained through thermal gravimetric analysis. The nanoinfused ZnO and ZnS exhibited unexpectedly high fluorescent quantum yields, significantly higher than that observed for comparable materials. © 2013 Society of Plastics Engineers
Optimization of the Surimi Production from Mechanically Recovered Fish Meat (MRFM) Using Response Surface Methodology
Authors: Fogaça Fabíola H S. , Trinca Luzia Aparecida , Bombo Áurea Juliana , Silvia Sant'Ana Léa 
Published: January 2013

AbstractThe by‐products generated from industrial filleting of tilapia surimi can be used for the manufacture of surimi. The surimi production uses large amounts of water, which generates a wastewater rich in organic compounds (lipids, soluble proteins and blood). Optimizing the number of washing cycles will contribute to a more sustainable production. A mathematical model of mechanically recovered tilapia meat (Oreochromis niloticus) for the processing of surimi (minced fish washing cycles and tapioca starch addition) based on two quality parameters (texture and moisture) was constructed by applying the response surface methodology (RSM). Each factor had an important effect on the moisture and texture of surimi. This study found that the optimal formulation for producing the best surimi using the by‐products of tilapia filleting in manufacturing fish burger were the addition of 10% tapioca starch and three minced fish washing cycles. A microstructural evaluation supported the findings of the mathematical model.Practical ApplicationsThe use of mechanically recovered fish meat (MRFM) for the production of surimi enables the utilization of the by‐products of filleting fish. However, the inferior quality of the surimi produced from MRFM in relation to that produced with fillets necessitates the addition of starch; secondly, surimi production consumes a large volume of water. RSM provides a valuable means for optimizing the number of washing cycles and starch amounts utilized in fish burger production. Tapioca starch, widely produced in Brazil, has desirable characteristics (surface sheen, smooth texture, neutral taste and clarity in solution) for use in MRFM‐produced surimi.
Synonymous codon usage bias is correlative to intron number and shows disequilibrium among exons in plants
Authors: Qin Zhen , Cai Zhengqiu , Xia Guangmin , Wang Mengcheng 
Published: January 2013

Abstract

Background
Evidence has been assembled to suggest synonymous codon usage bias (SCUB) has close relationship with intron. However, the relationship (if any) between SCUB and intron number as well as exon position is at present rather unclear.

Results
To explore this relationship, the sequences of a set of genes containing between zero and nine introns was extracted from the published genome sequences of three algal species, one moss, one fern and six angiosperms (three monocotyledonous species and three dicotyledonous species). In the algal genomes, the frequency of synonymous codons of the form NNG/NNC (codons with G and C at the third position) was positively related to intron number, but that of NNA/NNT was inversely correlated; the opposite was the case in the land plant genomes. The frequency of NNC/NNG was higher and that of NNA/NNT lower in two terminal exons than in the interstitial exons in the land plant genes, but the rule showed to be opposite in the algal genes. SCUB patterns in the interstitial and two terminal exons mirror the different evolutionary relationships between these plant species, while the first exon shows the highest level of conservation is therefore concluded to be the one which experiences the heaviest selection pressure. The phenomenon of SCUB may also be related to DNA methylation induced conversion of CG to AT.

Conclusions
These data provide some evidence of linkage between SCUB, the evolution of introns and DNA methylation, which brings about a new perspective for understanding how genomic variation is created during plant evolution.
Thermoelectric Nanomaterial: A Demiurgic Approach towards Improvement of Shale Stability
Authors: Pandey Prateek , Kapadnis Pratik Prakash , Ghansar Bilal Hameed , Mandan Sagar Pralhad 
Published: January 2013

Abstract
Shale has presence of large amount of clay minerals and thus its instability is a major problem while drilling. The main factors contributing to this are the hydrostatic Pressure, Chemical and Thermal. The Thermal factor deals with difference in temperature of drilling fluid and reservoir and contributes mainly to the cause of instability. The use of mud at normal temperature results in high temperature difference between the reservoir and drilling fluid hence adding to the instability of shale.Wellbore stability is very critical for a successful drilling operation. Heating can enhance tensile failure in shale while cooling lowers its tensile stresses. This paper adduces a novel idea to ameliorate the shale stability by using low temperature drilling fluid and a cost effective thermoelectric nanomaterials and Ni-Fe nanomaterial to alter the mud temperature. Thermoelectric nanomaterial reduces the mud temperature as electricity is applied while Ni-Fe nanomaterial helps in increasing the mud temperature. While drilling, mud temperature becomes greater than formation temperature due to which stress on wellbore increases and therefore wellbore stability reduces. Apart from this the pore pressure increases and the fracture pressure decreases. Improved shale stability can be achieved if the difference between temperature of mud and formation temperature is reduced to an optimum value. This optimum temperature difference is found by considering values of pore pressure, stresses on formation and fracturing pressure for different temperatures. In case of practical purposes, stress test can be carried out at different temperatures which help in deciding the optimum temperature difference. It has been discovered that the less expensive and readily available thermoelectric nanomaterials can be used to reduce the mud temperature. The upper hand of this technique is the low dosage requirements. Moreover the nanoparticles used are innocuous and environmentally safe.
Increasing Drilling Performance Using Hydro-Mechanical Hole Cleaning Devices
Authors: VAN PUYMBROECK Luc 
Published: January 2013

Abstract
While hole cleaning is generally considered to be well understood in drilling deviated and horizontal wells, drillers still have difficulty properly managing the entire process. Experience reveals that less-than optimal hole cleaning can lead to non-productive time, poor bore-hole quality, and loss of drill string or even the well.
Efficient cuttings transport and keeping the well clean enough for trouble–free operations are challenges predominantly associated with drilling complex wells. Cuttings tend to accumulate on the low side of the hole forming thick beds causing the flow velocity to become insufficient to keep the hole clean. Large boreholes drilled at high ROPs will usually require additional rig time for cleanup. Time spent on hole cleaning operations can be significant, but essential. A more in-depth analysis of performance drilling in certain directional well profiles reveals a more efficient approach using Mechanical Hole Cleaning Devices (MCD) when economically justifiable.
This paper addresses a new drill pipe design integrating hydro-mechanical features in each tool joint has been developed to overcome limitations of MCDs in smaller diameter holes, and to extend the application of Hydroclean drill pipe to ERD (Extended Reach Drilling) wells. This innovation enables drilling with safer ECD (Equivalent Circulating Density) margins and reducing time spent on hole cleaning operations. Short of a full analysis with Key Performance Indicators, performance improvements compared with standard drill pipe are expected as a result of efficiency gains achieved by the three main principles of hole cleaning; scooping and eroding cutting beds at each tool joint, keeping cuttings continuously flowing on the high side of the hole, and maintaining the conveyor belts effect along the drill string while rotating.