bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal EOR in Oman Heavy Oil Fractured Portfolio: Learning from Aquifer Communication and Offtake Management
Authors: Al-Aulaqi Talal , Soleimani Arash , Bellmann Lars , Attalla Hassan , Al-Azri Nasser 
Published: March 2016

Abstract
Thermal EOR is one of the success stories in the fractured carbonate portfolio in Sultanate of Oman. This paper summaries the challenges, learning and best practices in executing field developments plans in one of the complex reservoirs in Oman.
In Thermally Assisted Gas-Oil Gravity Drainage (TA-GOGD), steam injected into the top of the reservoir to achieve two important phenomena: first to apply a gas gradient across matrix blocks so that the oil in the matrix drains down by gravity and secondly to heat up carbonate matrix blocks to initiates various mechanisms including solution gas drive, thermal expansion and viscosity reduction of oil to drain oil faster.
The selected field candidate is a fractured carbonate that structurally segmented into two distinctive blocks: Crest block and Sub-crest block which they contain of 25% and 75% of STOIP respectively. It has been produced with cold production mode over 40 years of heavy oil (~ 700 cp) and ultimate recovery 2% of initial STOIIP. This field shared a common aquifer with other nearby developed fields. This paper intended to discuss a suggested development plan for a combination of challenging environment including: the heavy nature of the oil, the fractured nature of the rock, the offtake fluids requirements and the pressure management given aquifer communication with nearby fields.
The development strategy of oil rim is driven by steam injection rate optimization into Carbonate field. Two strategies are designed: (i) full steam injection in crest and sub-crest blocks and (ii) phase steam injection (starting by crest block and then followed by sub-crest). The following conclusions can be drawn: –Aquifer communication impact the gross evacuation decision and lowering pressure strategy.–The reservoir simulation model can be used to optimize the oil rim management in the fractures.
Determination of Optimal Conditions for Addition of Foam to Steam for Conformance Control
Authors: Etminan S. Reza , Goldman Jon , Wassmuth Fred 
Published: March 2016

Abstract
Heat is transferred into the heavy oil reservoirs through steam injection. It reduces the viscosity of the heavy oil and bitumen and makes them mobile for production. Steam oil ratio (SOR) directly affects the cost of operation and is an index of the process efficiency. Steam processes could be optimized through addition of chemical additives to steam to selectively prohibit unfavorable channeling, gravity override and steam loss to the high permeable thief zones. Injection of foam with steam for conformance control is considered as a solution for increasing steam flooding efficiency and optimizing reservoir performance.
In this experimental study, a candidate surfactant is used to evaluate the optimal conditions for steam- foam application. Through a separate dedicated screening study at steam condition, one surfactant was identified which passed the required tests on solubility in injecting brine, foam generation, foam stability, surfactant thermal stability and its loss to reservoir rock surface, due to adsorption. This surfactant was co-injected in aqueous phase with steam to produce foam in porous medium. Core flooding tests were conducted at 260°C to evaluate the performance of foam with steam. The focus of this study was on determination of the optimal foam performance in different steam qualities and injection rates using steam (not non-condensable gases). Our tests were conducted in absence of oil and in a 30-cm core of less than 5 mD. Foam performance was monitored through differential pressures along the core as well as analysis of the foam in the effluent. Mobility Reduction Factor (MRF) allowed us to compare the performance of foam steam with steam-only process.
Shear velocities of as high as velocity at well perforations and as low as one meter per day were considered and tested at different steam qualities. The range of steam qualities tested was from 3 5% all the way to 100%, which was a slug-format test. Our candidate surfactant produced most foam around 50% quality which seems to be a good balance between the proportion of gas and liquid that produce stable foam texture. Higher qualities leads to drying out the lamella and lower qualities do not introduce sufficient gas to liquid for foam generation. Our tests reveal that there is a critical velocity beyond which foam generation starts and the foam and surfactant fronts are moving separately. MRFs of larger than 10 was determined in our optimal conditions.
Different steam qualities are tested in this study using real steam which condenses due to pressure rise along the core. Through these tests, operators could add significantly to their knowledge on how to best operate in adding foam to steam for a better reservoir performance.
Methodology of Foam-Surfactant EOR for Pilot Design Studies in Naturally Fractured Reservoirs
Authors: Abbaszadeh M. , Rodriguez De-La Garza F. , Villavicencio A.E. 
Published: March 2016

Abstract
This paper presents a novel foam-assisted surfactant Chemical Enhanced Oil Recovery (CEOR) of the matrix oil in naturally fractured reservoirs. Foam reduces fluid mobility within fractures and diverts the injected surfactant solution into matrix for wettability alteration and IFT reduction. Single–well cyclic huff-n-puff and dual completion pilots are modeled to evaluate the effectiveness of this envisioned CEOR, assess process mechanisms and demonstrate recovery conformance. In order to perform these foam-surfactant injection studies, a dual porosity-dual permeability 3-D sector model of the gas cap in a fractured reservoir is constructed, and co-injections of foaming surfactant in the nitrogen gas stream are simulated. These pilot simulations implement a laboratory-based surfactant phase behavior and foam model along with a compositional technique that captures surfactant-oil-brine phase behavior and tracks IFT and rheology of microemulsion phases. Sensitivity studies to various CEOR process mechanisms, injectivity characteristics, reservoir parameters and conformance are explored to guide an optimized pilot design scheme within operational constraints to evaluate and monitor the extent of oil recovery efficiency. The results show that while only a fraction of the released matrix oil is captured in the pilot arrangements due to conformance, considerable volumes of oil drain from the gas cap matrix blocks down to the oil column, thus substantiating the applicability of this envisioned foam-surfactant CEOR for naturally fractured reservoirs. Cyclic huff-n-puff injection is shown to be a more appropriate configuration for single-well pilot testing.
The Chronology of Steam Piloting in the Rubble Heavy Oil Reservoir, Awali Field, Bahrain
Authors: Al Balushi Aamer , Mohamed Ali , Stearns Stanley 
Published: March 2016

Abstract
Due to the complex geological nature of naturally fractured reservoirs (NFRs), their development is often associated with a lot of challenges, especially when it comes to improved oil recovery (IOR)/enhanced oil recovery (EOR) processes, where certain fluids are injected into the reservoir with the aim of increasing the recovery factor. If a large enough contrast in permeability between the rock's matrix and the fractures exists, which is often the case, fractures will dominate the flow, leading to a poorly processed matrix and eventually a poor recovery factor. The Rubble reservoir is one of the shallowest reservoirs in the long-producing Bahrain field that was discovered in 1932 as the first oil discovery in the Gulf Cooperation Council (GCC) region. With the majority of oil in place categorized as heavy oil, it was decided that a steam pilot would be implemented in 2011. Steam piloting in the Rubble reservoir has gone through multiple stages since 2011, and different thermal recovery processes have been tested using vertical, deviated, and horizontal wells.
The initial pilot tested cyclic steam stimulation (CSS) using high-pressure steam injection and low-pressure production in vertical wells, which was successful in mobilizing oil from the low-permeability Rubble reservoir. Based on the initial technical success, the CSS pilot was expanded to 17 additional wells drilled on three well pads in different parts of the field with different reservoir properties. The CSS expansion pilot also mobilized oil from the reservoir. Subsequently, continuous steam injection and offset oil production were attempted in two of the steam pilot pads. CSS was also attempted in horizontal wells; however, although oil was mobilized, the produced rates and volumes were not enough to have a low steam/oil ratio (SOR). These efforts ultimately led to the forced imbibition (FIM) pilot. In this current pilot, steam is simultaneously injected into three parallel, closely spaced horizontal wells and then produced simultaneously using large pumping units to reduce the bottomhole pressure to a minimum.
Results have been encouraging, with SORs of less than 4 barrels of steam per barrel of oil (bs/bo). FIM has proved to be the most promising steam EOR process attempted in the Rubble reservoir.
This paper examines the results of the Rubble steam pilot stages, highlights the challenges faced in each stage, and presents our evolved understanding of the physical processes involved as the pilot progressed.
Foam Propagation in Rock Samples: Impact of Oil and Flow Caracterization
Authors: Batôt G. , Fleury M. , Rosenberg E. , Nabzar L. , Chabert M. 
Published: March 2016

Abstract
Foams are among the most promising and cost effective means to alleviate the drawbacks associated with gas-based EOR-processes. The objective of this work is to probe the impact of residual oil saturation on CO2-foam generation and on their flow behavior in porous media
Designing a foam-EOR process requires its evaluation and optimisation at laboratory scale using coreflood tests. However, such coreflood tests are usually performed on relatively long core sample, this lead to long time-consuming experiments. In this study are presented results using both long and short coreflood systems. Short coreflood systems (allowing short-duration test) are coupled to a NMR apparatus and to an CT-scanner that allow live and non-invasive measurements of the fluids saturation.
In a first part of this work, the efficiencies of two proprietary formulations to generate stable foam in porous media under reservoir conditions and in absence of oil have been compared. We used a coreflood set-up equipped with X-Ray detection to monitor gas propagation inside relatively long core samples. Then, their ability to resist the oil (Dodecane) have been evaluated and compared. The results evidenced two largely different behaviors. One of the two formulations resists the presence of oil up to an oil saturation of 35-40% while the second is destabilized as soon as the oil saturation exceeds 20%. Both formulations were insensitive to oil bellow an oil saturation of 15%. Depending on the application targeted, this laboratory evaluation should be coupled with a detailed economic evaluation to select the formulation to be used.
In a second part, we performed co-injection tests using NMR small coreflood set-up and IRM-scanner in absence of oil. They brought more detailed information regarding fluid saturations that help interpreting foam characteristics and flow behavior in porous media.
Steam Piloting in the Aruma Reservoir, Awali Field, Bahrain
Authors: Stearns Stanley , Mohamed Ali , Al Balushi Aamer 
Published: March 2016

Abstract
The Aruma formation is the shallowest hydrocarbon-bearing reservoir in the Bahrain field. It contains heavy oil and bitumen irregularly distributed in fractured and vuggy carbonate rocks, making reservoir characterization and hydrocarbon production particularly challenging. The best analog for the Aruma accumulation is the Grosmont bitumen accumulation in Canada, where bitumen is also present in fractures and vugs in carbonate rocks. A field test of cyclic steam stimulation (CSS) in the Aruma formation was implemented in November 2014. The primary objective of the Aruma CSS pilot was to prove that it is possible to mobilize heavy oil and bitumen in the Aruma reservoir and produce it to the surface. This pilot objective was achieved.
Qualitative and Quantitative Analysis of Microbial Communities in Household Dishwashers in Germany
Authors: Brands Britta , Honisch Marlitt , Merettig Nadine , Bichler Sandra , Stamminger Rainer , Kinnius Jörg , Seifert Monika , Hardacker Ingo , Kessler Arnd , Weide Mirko , Wrubbel Noelle , Bockmühl Dirk P. 
Published: March 2016

AbstractThe proper cleaning of used dishes provides an essential means to maintain a sufficient hygiene level on food contact surfaces. However, little is known on the microbiological quality of domestic dishwashers themselves, especially in relation to consumer habits. This study investigated dishwashers in German households to analyse the number and composition of microbial colonisers and their putative impact on dishwashing hygiene. Although the microbiological status of dishwashers appeared to depend on multiple factors, data suggest that a trend towards lower temperatures might effect in a decreased hygiene.
Synthesis, Surface Activity and Application Properties of a Novel Ethoxylated Gemini Trisiloxane Surfactant
Authors: Peng Zhongli , Zeng Hui 
Published: March 2016

AbstractA novel ethoxylated gemini trisiloxane surfactant B whose general formula is of RO(CH2CH2O)8.7R [R = Me3SiOSiMe(CH2)3 · OSiMe3] has been synthesized using polyethylene glycol 400, 3-chloropropylene and 1,1,1,3,5,5,5-heptamethyltrisiloxane as main raw materials. This compound was structurally characterized by ESI-MS, 1H-NMR and 13C-NMR spectroscopy. Its surface activity and application properties containing spreading performance and hydrolysis resistance were also measured. The critical aggregation concentration (CAC) and the surface tension of surfactant B solution at CAC (γCAC) of are 2.63 × 10−6 mol L−1 and 20.7 mN m−1, respectively. This CAC is only one-tenth of the CAC of the Υ-shaped ethoxylated double-tail trisiloxane surfactant 1P, where CAC was replaced with critical micelle concentration (CMC), indicating that surfactant B has an extremely high surface activity. The spreading ability (SA) of its solution (5 × 10−3 mol L−1) within 1 min over Parafilm, PE film and ficus microcarpa leaves is 23.9, 45.7 and 59.8, respectively, suggesting that this surfactant has a better SA than 1P and possesses superspreading. This surfactant also possesses a stronger hydrolysis resistance than 1P; for instance, in pH 10.0 environment for 86 days. The surface tension of surfactant B solution has been no more than 6 percent of its initial value. It is suggested that the excellent interfacial properties of surfactant B is related to its U-shaped conformation in water.
Synthesis and Surface Active Properties of Novel Oligomer Betaine Surfactants
Authors: Zhou Ming , Huang Zhou , Yu Shuang , Yang Yan , Huang Yongsheng , Qiu Dan , Zhao Jinzhou 
Published: March 2016

AbstractA new type of oligomer betaine surfactants pentasodium N,N′,N″-alkyl diethylene triamine pentaacetic acid containing five carboxylate groups, three quaternary ammonium groups and three hydrophobic groups was synthesized by alkaline neutralization reaction and quaternization with diethylene triamine pentaacetic acid, sodium hydroxide and long chain alkyl bromide as main raw materials. The chemical structures of the prepared compounds were confirmed by FTIR, 1H NMR, MS spectroscopy and elementary analysis. With the increasing length of the carbon chain, the CMC of the synthesized compounds initially decreased. The surface active properties of these compounds were superior to that of the single chain betaine surfactants rich as decyl dimethyl betaine. The efficiency of adsorption at the water/air interface (pC20) of these surfactants was very high. It is found that the shorter hydrocarbon chain length of oligomer betaine surfactants, the faster the rate of reduction of surface tension, and the bigger the aggregation number of oligomer betaine surfactants are. Their foaming properties and wetting ability toward a felt chip, and lime-soap dispersing ability were investigated.
Preparation of a Multifunctional Terpolymer Inhibitor for CaCO3 and BaSO4 in Oil Fields
Authors: Liu Yanmei , Zhou Yuming , Yao Qingzhao , Wang Huchuan , Wu Zhen , Chen Yiyi , Liu Liu , Yang Chongyang , Wu Wendao , Sun Wei 
Published: March 2016

AbstractThe aim of this paper is to inhibit the formation of calcium carbonate and barium sulfate scales which are common but unwanted crystalline products in the production of oil from off-shore rigs. A multifunctional antiscalant APES/AA/AMPS was prepared by reaction of acrylic acid, ammonium allylpolyethoxy sulphate and 2-acrylamido-2-methyl-propanesulfonic acid with different molar ratios. The experimental results showed that the polymer has high performance towards scales, nearly 90 % for CaCO3 and 87 % for BaSO4 respectively by static scale inhibition tests. The crystals of scales were characterized by using scanning electron microscopy and X-ray powder diffraction. According to the changes of the crystal shape, size and morphology, the inhibition mechanisms of complexation and adsorption between the inhibitor and the crystal surface were proposed.
Interactions of Cellulase and Oleic Acid Solution Mixtures
Authors: Yehia Ahmed , El-Halim Sawsan Abd , Sharada Hayat , Khalek Mohamed Abdel , Ammar Mayar 
Published: March 2016

AbstractThe interaction of oleic acid, as an anionic detergent, with cellulase has been investigated using different techniques (surface tension, turbidity and FTIR). The surface tension measurements show that the CMC of the oleic acid-cellulase mixture is lower than that of the individual components. The interaction in this case is defined as attractive and the mixture exhibits synergism. Also, it is found that the area per molecule for the oleic acid/cellulase mixed isotherm is lower than area of the pure oleic acid. This decrease in the area/molecule is due to the arrangement of cellulase molecules in-between the oleic acid chains. Turbidity measurements indicate the formation of two complexes. Complex 1 is obtained at low oleic concentrations (< 10−4 M) with compact size giving a high turbidity. Complex 2 is formed at higher oleic concentrations (> 10−4 M) where the formed aggregates were precipitated and the turbidity was decreased. The changes in the FTIR spectrum features of cellulase after oleic acid addition indicate an interaction between cellulase and oleic acid in their mixture.
Experimental studies in a single-phase parallel channel natural circulation system: preliminary results
Authors: Bodkha K. , Pilkhwal D. S. , Jana S. S. , Vijayan P. K. 
Published: March 2016

Abstract
Natural circulation systems find extensive applications in industrial engineering systems. One of the applications is in nuclear reactor where the decay heat is removed by natural circulation of the fluid under off-normal conditions. The upcoming reactor designs make use of natural circulation in order to remove the heat from core under normal operating conditions also. These reactors employ multiple vertical fuel channels with provision of on-power refueling/defueling. Natural circulation systems are relatively simple, safe and reliable when compared to forced circulation systems. However, natural circulation systems are prone to encounter flow instabilities which are highly undesirable for various reasons. Presence of parallel channels under natural circulation makes the system more complicated. To examine the behavior of parallel channel system, studies were carried out for single-phase natural circulation flow in a multiple vertical channel system. The objective of the present work is to study the flow behavior of the parallel heated channel system under natural circulation for different operating conditions. Steady state and transient studies have been carried out in a parallel channel natural circulation system with three heated channels. The paper brings out the details of the system considered, different cases analyzed and preliminary results of studies carried out on a single-phase parallel channel system.
Protactinium-231 as a new fissionable material for nuclear reactors that can produce nuclear fuel with stable neutron-multiplying properties
Authors: Shmelev A. N. , Kulikov G. G. , Kulikov E. G. , Apse V. A. 
Published: March 2016

Abstract
Main purpose of the study is justifying doping of protactinium-231 into fuel compositions of advanced nuclear reactors with the ultimate aim to improve their operation safety and economic efficiency. Protactinium-231 could be generated in thorium blankets of hybrid thermonuclear facilities. The following results were obtained: 1. Protactinium-231 has some favorable features for its doping into nuclear fuel; 2. Protactinium containing fuel compositions can be characterized by the higher values of fuel burn-up, the longer values of fuel lifetime and the better proliferation resistance; 3. as protactinium-231 is the stronger neutron absorber than uranium-238, remarkably lower amounts of protactinium-231 may be doped into fuel compositions. The free space could be occupied by materials which are able to improve heat conductivity and refractoriness of fuel. As a consequence, operation safety of nuclear reactors could be upgraded.
Structural and mechanical study on Mg–xLM (x = 0–5 wt.%, LM = Sn, Ga) alloys
Authors: Kubásek Jiří , Vojtěch Dalibor , Dvorský Drahomír 
Published: March 2016

Abstract
Low-melting point metals, such as Sn and Ga, can improve both the mechanical and corrosion properties of pure Mg. Currently, Mg–Sn based alloys are being considered for high-temperature applications, and both Mg–Sn and Mg–Ga based alloys are also being considered as possible candidates for biodegradable materials. Although these binary systems have already been the subject of research, only limited information on their characteristics has been published. Therefore, as-cast Mg–Sn and Mg–Ga alloys containing 1, 3.5 and 5 wt.% of alloying elements were studied in the present work. Moreover, the effect of extrusion on Mg–Sn and Mg–Ga alloys containing 3.5 wt.% of the alloying element was studied. Structural and chemical analyses of the alloys were performed by using light and scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction. The mechanical properties were determined by Vickers hardness measurements and tensile and compressive testing. The as-cast alloys were characterized by a dendritic morphology with the presence of secondary eutectic phases. Both Sn and Ga exhibited hardening and strengthening effects on magnesium. The extruded alloys were characterized by fine-grained microstructures with a grain size of approximately 3 and 6 μm for Mg-3.5Sn and Mg-3.5Ga alloys, respectively, and significantly improved mechanical properties compared with the as-cast state. The ultimate tensile strength reached almost 250 MPa for both extruded alloys compared with 120–150 MPa for the as-cast condition. The results indicate that Mg–Sn- and Mg–Ga-based alloys appear to be suitable candidates for both engineering and medical applications.