bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of Production in Reservoirs with Temperature-Dependent Asphaltene Precipitation and Irreversible Flocculation
Authors: Temizel Cenk , Zhang Ming , Balaji Karthik , Ranjith Rahul , Zheng Wei 
Published: September 2016

Abstract
Asphaltene precipitation is caused by numerous factors such as changes in pressure, temperature, and composition. Drilling, completion, acid stimulation, and hydraulic fracturing activities can also induce precipitation in the near-wellbore region. Heavier crudes that contain a larger amount of asphaltene have very few asphaltene precipitation problems because they can dissolve more asphaltene. Thus, it is crucial to understand the significance of each uncertainty and control variables not only theoretically, but also with application to real-life examples such as with this model that uses a 32-degree API South American oil to demonstrate the importance of each variable to shed light in order to efficiently manage such reservoirs.
A commercial optimization and uncertainty tool is coupled with a full-physics commercial simulator that models the phenomenon in order to investigate the significance of major parameters on performance of wells in temperature-dependent asphaltene precipitation and irreversible flocculation. Temperature-dependent asphaltene precipitation and irreversible flocculation are modelled where no precipitation occurs at the original reservoir temperature, and flocculated asphaltene is allowed to deposit via surface adsorption and pore throat plugging. The exponent in the power law relating porosity reduction to the permeability resistance factor is modified to change the effect of asphaltene deposition on permeability reduction.
Lower temperatures are specified around the wellbore causing asphaltene precipitation. Sensitivity and optimization have been done on major reservoir parameters, such as, fluid and rock properties and well operational parameters, and significance of each has been illustrated in tornado diagrams. It is observed that a robust approach on handling of uncertainties in reservoir are as important as management of well operational parameters in the scope of reservoir management.
This study provides an in-depth optimization and uncertainty analysis to outline the significance of each major parameter involved in production performance and ultimately the recovery efficiency in reservoirs with temperature-dependent asphaltene precipitation and irreversible flocculation.
Retrieval of Solvent Injected During Heavy-Oil Recovery from Water - and Oil-Wet Reservoirs: Pore Scale Analysis at Variable Temperature Conditions
Authors: Cui Jingwen , Babadagli Tayfun 
Published: September 2016

Abstract
Solvent injection has been given attention to enhance oil recovery by sole use or in combination with a thermal method to develop light, medium, and heavy-oil fields. To make this process efficient, retrieval of expensive solvent efficiently is required. This can be achieved by alternative injection of water (WAG) if the reservoir is homogeneous. In case of heterogeneous reservoirs (fractured carbonates or sands with wormholes), one needs to develop techniques other than viscous displacement to retrieve the solvent diffused into less permeable matrix portion. A method of injecting steam/hot water to heat the solvent to vaporize and retrieve it was introduced recently (steam-over-solvent injection in fractured reservoirs) and tested through core experiments. Although these tests provide valuable data to design the optimal temperature of injected water to make the process viable, the mechanics of the nucleation of the solvent vapor and its entrapment in the pores at the micro scale requires further research.
A series of experiments using a 2-D etched glass micromodel (sandstone replica with a fracture) were carried out to investigate the mechanics of solvent retrieval and entrapment at variable temperature conditions. The micromodel was saturated with dyed processed oils and different solvents were injected through fracture. After the solvent was diffused into matrix completely to recover the oil, the model was heated mimicking a thermal method to reach the boiling point of the solvent and retrieve it. The wettability of the micromodel was also altered to achieve water-wet and oil-wet conditions as wettability dictates the phase distribution in the pores. Following the heating phase, water was injected to retrieve the remaining solvent in the liquid or vapor phase.
Visual observations of solvent diffusion/dispersion into matrix and its retrieval from the matrix clarified the miscibility process in the presence of an immiscible phase, interaction between different phases in a complex heterogeneous system, and phase distributions as a function of temperature. This information can be used to determine the efficiency of solvent retrieval process and optimal application conditions for EOR applications in heterogeneous sands and carbonates.
The Concept of the Sustainable Oil Field Development Applied to Heavy and Extra Heavy Oil Fields
Authors: Armacanqui J. Samuel 
Published: September 2016

Abstract
The Concept of the Sustainable Oil and Gas Field involves a Preventive Approach and the use of New Technologies, Innovations and Best Practices to avoid or reduce the risks of occurrence of environmental incidents and accidents achieved in a cost effective manner. This novel approach focuses on the root causes of the current gaps proposing a practical solution demonstrated on real example cases. Further it contributes to bridge the gap between non Oil and Gas Professionals evaluating the potential impact on the Environment of the core business processes related to the Exploration, Development and Field Abandonment of Oil and Gas fields.
In the present Paper a method is described that supports a sustainable development and operation of Oil and Gas Fields. Further the most common reasons for the current dysfunctional procedures are analyzed as well as practical examples of the proposed approach are shown on executed projects in four continents. The proposed method builds on a preventive approach that starts with the focus of the Environmental Impact Assessment of the activities foreseen for the early project phase, as it is at this stage where the entire project can more effectively be influenced. Further the Use of fit for purpose Innovations, Technologies and Best Practices that strive to remove the risk before it happens, supports a preventive approach. The involved technologies deliver the same outcome than traditional means in a more efficient way. The mindset that the use of those Technologies comes at a higher price is challenged by the latest developments showing that those enable both an environmental friendly workflow and economical advantages to the E & P Companies. Further the above Technologies can be applied at any stage of the field life, be it at the early field development, the operational plateau or later on at the decline and abandonment phase.
Several specific examples from executed Oil and Gas Projects following key elements of the presented Concept of the Sustainable Oil and Gas Field carried out in four continents are provided, showing that operating Oil and Gas fields with Zero Gas Flare, Zero Oil Spill, small footprint, no process effluents to the environment and energy efficiency can be reflected in low oil/gas unit production costs, technical and operational excellence as well as full environmental compliance.
In the present paper a preventive approach to avoid and reduce environmental incidents and accidents by means of an Environmental Impact Assessment that focuses on the early project phases and the aid of fit for purpose Technical Innovations, Technologies and Best Practices is presented. This supports the goal of achieving a more Sustainable Oil and Gas Field to safely achieve production peak and increase recoverable Reserves.
Robust Characterization of Naturally Fractured Carbonate Reservoirs Through Sensitivity Analysis and Noise Propagation Reduction
Authors: Minutti C.. , Ramos G.. , Gomez S.. , Camacho R.. , Vázquez M.. , Castillo N. del 
Published: September 2016

Abstract
Well testing is today a main procedure for verifying reservoir, well and fluid properties such as permeability, skin effect, average reservoir pressure, heterogeneities, boundaries and hydraulic connectivity. We present in this work a methodology based on numerical optimization and statistical methods to get an accurate and reliable Naturally Fractured Carbonate Vuggy Reservoir Characterization, using a Triple Porosity-Double Permeability Model. A sensitivity analysis is performed to identify the effect and magnitude on the pressure of each parameter involved in the model to reduce the error estimation and to eliminate multiple interpretations due to numerical precision. We also introduce a robust regularization method to control noise propagation contained in pressure data for improving well test analysis. The efficiency and accuracy of the proposed approach is demonstrated by implementing the triple porosity-double permeability model as compared with the traditional double-porosity model used in commercial software. Furthermore, not only the accuracy of the fit is compared but also the amount of reservoir information obtained when using the Triple Porosity-Double Permeability model, as we identify nine parameters in the case of totally penetrated wells and eleven parameters in the case of partially penetrated wells. Results are illustrated with transient well tests of real carbonate fractured vuggy reservoirs from Mexico.
Pore-Level Simulation of Heavy Oil Reservoirs; Competition of Capillary, Viscous, and Gravity Forces
Authors: Goudarzi B.. , Mohammadmoradi P.. , Kantzas A.. 
Published: September 2016

Abstract
The advancing high resolution scanning technology has formed a concrete basis for simulation of pore events within microstructures. Interactions between capillary, gravity, and viscous forces result in complex flow phenomena affecting pore-scale physics and phase distributions during different displacement scenarios. Consequently, a myriad of techniques has been proposed to deal with all effective forces and dynamically simulate pore scale multi-phase flow physics. In this regard, the significance of each force, particularly viscous forces, on pore-level flow morphology is not yet well studied. Here, the Navier-Stokes equation along with a VOF volume tracking advection equation is applied for simulation of two-phase displacement scenarios considering gravity, capillary, and viscous forces. A pore-throat pair is used as a simple pore-level geometry to conduct a comprehensive sensitivity analysis and investigate the effect of viscosity, IFT, contact angle and velocity on the trapping amount of non-wetting phase. The results are in good agreement with available experimental data and confirm that in pore-level transport phenomena, the amount of residual trapping is a function of pore-throat geometry and wettability and is not affected greatly by interfacial tension or differences of viscosity. The analysis also demonstrates that within microscale porous media images the gravity role is negligible due to low Bond number values. A pore morphology-based quasi-static approach is then applied to a multi-pore micro-tomographic sandstone image to simulate drainage, and imbibition processes and investigate the effect of geometry, contact angle, and IFT on the amount of heavy oil residual trapping.
Evaluation of Heavy Oil Recovery Factor by Water Flooding and Polymer Flooding at Different Temperatures
Authors: Bento Hernandes de , Moreno Rosângela Barros 
Published: September 2016

Abstract
This paper compares the effiency of heavy oil recovery factor by water and polymer flooding under different level of temperature (26°, 50° and 75°C). The performances of both methods were assessed by analyzing the fractional flow curves and the oil recovery factor (%OOIP) for the same temperature. Rheological measurements were carried out to characterize and to select the fluids. Buckley-Leverett model was applied to evalute the effectiveness of the recovery method after the injected fluid breakthrough. Due to the high oil viscosity, the displacement for water flooding is unfavarable. However, the polymer addition improves the viscosity ratio injected/displaced fluids, making the displacement front more sharp. The fractional flow curves showed that the polymer flooding reduces the amount of the remaining oil more than water flooding and the oil recovery are greatly influenced by the test temperature. As the temperature increases, the oil recovery increases, for both methods. At the same temperature, the final oil recovery is equal for water and polymer flooding, showing that the used polymer has not affected the residual oil saturation. However, the polymer flooding was able to anticipate the oil production and the anticipation was more pronounced for higher temperatures. The mobility ratio reduction with temperature rising turned the displacement more piston-like, highlighting the anticipation of the produced oil by polymer flooding.
New Material Technologies Reduce PDC Drill Bit Body and Cutter Erosion in Heavy Oil Drilling Environments
Authors: Wong Alex , Bell Andy , Williams Michael , Isnor Sid , Herman J. J. 
Published: September 2016

Abstract
In heavy oil applications, drill bit body and PDC cutter erosion are frequently encountered challenges that can significantly affect the durability and overall drilling performance of the bit. Abrasive formations such as unconsolidated sands, drilling fluids with high solids content, and high hydraulic flow rates are all factors that limit the life of the drill bit, and consequently, there exists an opportunity to improve the economics of heavy oil wells through the development of more abrasion and erosion resistant body materials and PDC cutter substrates.
This paper will discuss the various stages of research and development performed on drill bit hardfacing and PDC cutter substrate materials to improve durability and minimize repair costs in Canadian Oil Sands applications. Hardfacing development was accomplished through microstructural analysis, experimentation with various carbide compositions and particle sizes, and the incorporation of superhard abrasives (hardness values in excess of 5800 ksi) dispersed throughout the hard metal matrix. Moreover, the development of erosion resistant PDC cutter substrates was achieved through novel manufacturing processes and material research. Close cooperation with operators and the ability for rapid field testing of new technologies has enabled the collection of valuable feedback and performance comparisons between close offset wells.
To date, a significant improvement in wear resistance has been achieved in hundreds of runs in the Canadian Oil Sands. These runs consisted predominantly of 10.625 in. and 8.750 in. diameter horizontal intervals, in which the operators typically observed a positive impact on drilling economics. For instance, reduced gage pad wear has resulted in fewer bits falling under-gage, thereby preventing the subsequent bit from having to ream the under-gage section to the correct diameter. Enhanced hardfacing life has reduced bit body erosion surrounding PDC cutters and other brazed components, thus decreasing the number of lost components due to the erosion of supporting material. Furthermore, PDC cutter substrate improvements have reduced the amount of observed carbide loss behind the diamond table in order to mitigate cutter breakage and preserve their formation shearing efficiency.
Additional efforts are currently underway to further develop wear resistant materials tailored to abrasive and erosive drilling environments. These technologies have potential to enhance drilling efficiency and repairability of drill bits in heavy oil applications including, but not limited to, the Canadian Oil Sands.
Evaluation of a Polymer Injection Pilot in Argentina
Authors: Hryc A.. , Hochenfellner F.. , Best R. Ortiz , Maler S.. , Puliti R.. 
Published: September 2016

Abstract
The present article is based on the enhaced recovery pilot in Argentina presented in SPE 160078 ("Desing and Execution of a Polymer Injection Pilot in Argentina").
A polymer injection pilot is being conducted since January 2012 in El Corcobo Norte field, in Neuquén Basin, Argentina. The project intends to evaluate the incremental volumetric efficiency for Lower Centenario formation, unconsolidated, strongly water-wet sandstone that has been under waterflood since the beginning of the field's production in 2006.
El Corcobo Norte field produces medium-heavy oil and, due to its unconsolidated nature, production strategy involves massive sand production all along the well's productive life. Although waterflooding efficiency has allowed achieving an important oil recovery, wormholing and chanelling issues represent a challenge to the field's development strategy of increased injection and fluid production. A polymer injection project would help increasing ultimate recovery factor, through enhacing injected fluid's efficiency to displace the oil. Along the past four years of experience operating this pilot, many lessons learnt regarding process, operational, logistic and chemical issues, became extremely valuable for the company's know how in operating this technology. Pilot surveillance has proven to be a key factor for understanding how the process is working in the reservoir.
This work will present the updated results of the polymer injection pilot, which is still under evaluation but already showing promising results that could lead to an attractive expansion project.
VARIABLE STARS AND STELLAR POPULATIONS IN ANDROMEDA XXV. III. A CENTRAL CLUSTER OR THE GALAXY NUCLEUS?*
Authors: Cusano Felice , Garofalo Alessia , Clementini Gisella , Cignoni Michele , Federici Luciana , Marconi Marcella , Ripepi Vincenzo , Musella Ilaria , Testa Vincenzo , Carini Roberta , Faccini Marco 
Published: September 2016

ABSTRACT
We present B and V time series photometry of Andromeda XXV, the third galaxy in our program on the Andromeda’s satellites, which we have imaged with the Large Binocular Cameras of the Large Binocular Telescope. The field of Andromeda XXV is found to contain 62 variable stars, for which we present light curves and characteristics of the light variation (period, amplitudes, variability type, mean magnitudes, etc.). The sample includes 57 RR Lyrae variables (46 fundamental-mode—RRab, and 11 first-overtone—RRc, pulsators), 3 anomalous Cepheids, 1 eclipsing binary system, and 1 unclassified variable. The average period of the RRab stars (

σ = 0.04 days) and the period–amplitude diagram place Andromeda XXV in the class of the Oosterhoff-Intermediate objects. From the average luminosity of the RR Lyrae stars we derive for the galaxy a distance modulus of (m–M)0 = 24.63 ± 0.17 mag. The color–magnitude diagram reveals the presence in Andromeda XXV of a single, metal-poor ([Fe/H] = −1.8 dex) stellar population as old as ∼10–12 Gyr, traced by a conspicuous red giant branch and the large population of RR Lyrae stars. We discovered a spherically shaped high density of stars near the galaxy center. This structure appears to be at a distance consistent with Andromeda XXV and we suggest it could either be a star cluster or the nucleus of Andromeda XXV. We provide a summary and compare the number and characteristics of the pulsating stars in the M31 satellites analyzed so far for variability.
Reliability of Entry-Level Athletic Trainers' Palpation Skills of Bony Anatomical Landmarks in the Lumbopelvic Region
Authors: Schultz Sarah M. , Jacobs Michelle M. , Gorgos Kara S. , Wasylyk Nicole T. , Hanrahan Sean , Van Lunen Bonnie L. 
Published: September 2016

Context
Accuracy of locating various lumbopelvic landmarks for novice athletic trainers has not been examined.

Objective
To examine reliability of novice athletic trainers for identification of the L4 spinous process and right and left posterior superior iliac spine (PSIS).

Design
Cross-sectional reliability.

Setting
Laboratory.

Patients or Other Participants
Sixteen physically active volunteers participated (age = 22.56 ± 2.67 years, height = 172.0 ± 9.38 cm, mass = 67.39 ± 9.73 kg, body mass index = 22.8 ± 1.97). Four novice athletic trainers (certified &lt; 2 years) served as the testers of interest.

Intervention(s)
Subjects were placed prone and 2 expert athletic trainers (certified &gt; 12 years) agreed upon each bony landmark and transferred the palpation markings to contact paper. Each novice athletic trainer palpated the landmarks twice within the same test session and used the same method as the experts for transfer and recording. Novice athletic trainers rotated between subjects after 1 marking trial. Expert marks were transposed over the tester marks to assess distance and agreement.

Main Outcome Measure(s)
Independent variables were novice athletic trainer (AT1, AT2, AT3, AT4) and time (Trial 1, Trial 2); dependent variables included distance from the expert marking in millimeters for L4 and PSIS palpations, and agreement within or outside of a designated area for the L4 spinous process. Intraclass correlation coefficients (ICC [2,1]), standard error of measurement, and percent agreement were calculated.

Results
Intratester reliability for L4 ranged from 0.370 to 0.833, right PSIS (RPSIS) ranged from 0.371 to 0.771, and left PSIS (LPSIS) ranged from −0.173 to 0.760. Intertester ICC (2,1) for Trial 1 and Trial 2 were, respectively, 0.319 and 0.466 (L4), 0.213 and 0.002 (RPSIS), and 0.96 and 0.073 (LPSIS). Percent agreement between expert and testers ranged from 18.75%–81.3% for L4 spinous process.

Conclusions
Our results indicate novice athletic trainers are generally poor at reliably locating lumbopelvic anatomical landmarks, and this should be addressed within educational programming.