bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Nanoparticles on Migrating Fines in Formations
Authors: Petroleum Technology Development Fund (PTDF) Research Group _ , Ogolo Naomi , Olafuyi Olalekan , Onyekonwu Mike
Published: June 2012

Fines migration in reservoirs is a serious problem because it gives rise to several problems in hydrocarbon production. Several methods have been proposed and applied to manage this problem but some have failed, some have been ineffective while others consolidate wellbore formations. Rendering formation fines immobile by attaching them to the formation matrix is the best option in controlling migrating fines in reservoir formations. There are indications that the presence of certain nanoparticles in the formation can prevent fines migration by fixing them to the formation.

This project therefore investigates the fines trapping capacity of nine nanoparticles in sand packs. The ability of nano treated sands to retain the clays they contain at high flow rates of low salinity water capable of moving fines was examined. The effect of hydrocarbons on the performance of these nanoparticles and other conditions that affect ce their performances were studied. The best performing nanoparticles and the ideal dispersing fluids that aids in accomplishing this task were determined. Experimental results show that dispersing the right kind of nanoparticles in reservoir formations can control fines migration thereby preventing the primary and secondary problems caused by unconsolidated reservoir formations. Field application of this technique will in addition optimize hydrocarbon production and flow assurance.
The Trick Is The Surface - Functionalized Nanodiamond PDC Technology
Authors: Chakraborty Soma , Agrawal Gaurav , DiGiovanni Anthony , Scott Dan
Published: June 2012

Nanoparticles have built tremendous interest in recent years. In this regard carbon nanomaterials are extremely interesting because of their unique combination of mechanical, structural, electrical and thermal properties. With down-hole conditions shifting more towards challenging harsher, deeper and hotter conditions we have explored nanoparticles—nanodiamond in this case—for more demanding applications.

As a result of their inherent extremely high surface energy these very small particles tend to attract each other or exist as clusters. Thus a particle which is "nano" can exist as a submicron-or micron-sized cluster, thus overall exhibiting micron features instead of "nano" characteristics.

To derive the true benefits of a nanoparticle it is crucial to exfoliate and derivatize the surface such that the system is not only true "nano" but also so that the surface is activated to optimize the desired structure property relationship. Derivatization or — functionalization" further stabilizes the nanoparticles in different chemical matrices as well as activates them to directly bond/interact with their chemical environment. Thus functionalization is critical to the successful incorporation of nanoparticles into materials for various down-hole applications.

In this context nanodiamonds have been functionalized for polycrystalline diamond applications such as polycrystalline diamond compact (PDC) cutters for drill bits.

Nanodiamond particles have been derivatized or functionalized to give them unique surface characteristics that allow them to integrate homogeneously into PDC synthesis. We have studied the functionalization of nanodiamond, integration into the PDC matrix and subsequent property enhancement in comparison to the base PDC matrix. The performance of PDC cutters produced will be shown and the behaviors and proposed mechanisms will be discussed.
Experimental Investigation of Heavy Oil Recovery from Fractured Reservoirs by Secondary Steam – Gas Assisted Gravity Drainage
Authors: Mohsenzadeh A. , Escrochi M. , Afraz M. V. , Al-Wahaibi Yahya , Ayatollahi Sh.
Published: June 2012

In this study, gas-oil gravity drainage process and steam-gas assisted gravity drainage processes for heavy oil recovery from fractured models were investigated experimentally. For each test, six oil- wet saturated outcrop cores, 8.7 cm in diameter and 15 cm length, were stacked in a long core holder. In the first step, gas injection was started into the model at reservoir condition that results in oil production under gas-oil gravity drainage mechanism. In the second round of tests when no more oil was produced by gas injection, the tests were continued using steam-gas assisted gravity drainage process. In this stage, gas was injected together with specific steam/gas ratio at saturated temperature condition. In the course of experiments, oil and water productions, pressure and temperatures of system were monitored carefully.

The experiments were performed using three different combination of gases consist of pure CO2, pure N2 and mixture of 15 % CO2 and 85% N2 as synthetic flue gas. The results showed that after gas breakthrough and fracture depletion, the ultimate oil recovery for CO2 injection was 58.4 % (14.8% for gas injection and 43.6 % for steam-gas co-injection), in the case of flue gas injection, it was 73.8 % (9.8 % for gas injection and 64% for steam-gas co-injection) and for N2 injection was 47% (13.5 % for gas injection and 33.5% for steam-gas co-injection). The results indicate the high performance of flue gas injection for heavy oil recovery from fractured reservoirs during gas-oil gravity drainage and steam-gas assisted gravity drainage processes.
Thermo-Viscous Fingering in Heterogeneous Media
Authors: Sajjadi Mozhdeh , Azaiez Jalel
Published: June 2012

Adverse mobility ratio at the flood front in displacement processes due to temperature difference between the injected fluid and the medium and/or the inhabitant fluid may result in an instability known as thermo-viscous fingering (TVF). In practice such processes mostly take place in heterogeneous environments where the heterogeneity of the medium alters the preferred path of the flow and interacts with TVF. TVF is encountered in thermal-based enhanced oil recovery processes such as hot water flooding, steam flooding, CSS and SAGD or in fracturing. The fingers growth and development can have either favorable or detrimental impacts on the efficiency of these processes. The effects of adverse thermal or solutal mobility gradients and heterogeneity on the instability are quantified. Concentration, temperature, viscosity, and velocity fields have been generated using nonlinear simulations and studied for a better understanding of the mechanism of fingering at different log mobility ratios, heat exchange rates, and heterogeneity profiles. TVF in fields with wider channels is very similar to that in homogeneous fields and different mechanisms for finger development take place in the highly permeable layers. Heterogeneity works in favor of stability as the number of layers increases. In fields with many layers, the fingers induced by heterogeneity diffuse across the narrow channels and produce a widely diffused front which results in even less instability than in a homogeneous field. Heat exchange with the medium causes the thermal front to lag behind the solutal front and induce backward fingering (for unstable thermal front) or build a stable wall following the solutal front (for stable thermal front) and hence affect the sweep efficiency. The mechanism of TVF in heterogeneous porous media and its interaction with channeling are not well understood. Further studies in this field can illuminate the important factors affecting the displacement of heavy oil in Alberta fields.
A Generic Modeling Approach to Evaluate the Application of Different EOR Techniques for High-Viscous Oil in the Russkoye Field in the Russian Arctic
Authors: Gaviria William , Shmidt Sergey , Magdeyev Igor , Zakirov Iskander , Shayhutdinov Ildar , Gabisiani Georgiy
Published: June 2012

Russkoye oil field with gas cap, discovered in 1968, is one of the biggest high-viscous oil fields in Russia. It is a challenging field to develop commercially because of its geological complexity, unconsolidated formations, permafrost zone, and high heterogeneous compartmentalized reservoir with a large gas cap, active bottom aquifer, and remote location from main infrastructure. Consequently, a "generic modeling" approach was developed to evaluate the feasibility application of the following Enhanced Oil Recovery (EOR) techniques for this field: cold waterflood, hot waterflood, Water Alternating Gas (WAG), polymers and Alkaline-Surfactant-Polymer (ASP) injection.

The generic model consists of two main parts: a simulation model and a response surface model (RSM) equation.

The simulation model was constructed with uncertainty parameters to represent any combination of reservoir properties and any reservoir situation: large and small gas caps and just oil rim with bottom aquifer. Sensitivity analysis performed for selecting the most influencing parameters. Then a reasonably broad variation of the key parameters considered to successfully constructing the RSM equation. The Monte-Carlo technique was applied to get stochastic production profiles, which enable a rapid and reliable forecast of cumulative production, injection and recovery factor ranges.

The five field development technologies selected were analyzed using this generic modeling approach, prior to the commercial field development to maximize the recoverable reserves. Probabilistic profiles were estimated, taking into account the risk associated with the uncertainty in order to compare and rank selected EOR methods.

The generic modeling approach enables to make recommendations for data acquisition strategy in order to mitigate the influence of the key uncertainties on the commercial development. This approach gives to an engineer fast forecasting tool for estimation of production profiles by changing of boundaries of uncertainty parameters which reflects the change of circumstances after new data acquisition process conducted.
Simulation of Miscible Cyclic Injection Flows in Porous Media
Authors: Yuan Qingwang , Azaiez Jalel
Published: June 2012

The present study examines the development of miscible displacements in homogeneous porous media with a non-constant, time-dependent injection velocity. Numerical simulations for a sinusoidal injection velocity model are conducted to determine the effects of different variables on the efficiency of the displacement. The evolutions of nonlinear fingers with time are analyzed by plotting concentration fields, transversely averaged concentration profiles and sweep efficiency curve. Both the displacing process (injection process) and inverse displacing process (production process) are considered. Convection, transverse dispersion mechanisms, magnitude and frequency of the velocity changes are analyzed and the results are compared with those of a constant injection velocity process.
Experimental Study of Wettability Alteration of Limestone Rock from Oil-Wet to Water-Wet using Various Surfactants
Authors: Golabi Elyas , Azad Fakhry Seyedeyn , Ayatollahi Sayed Shahabuddin , Hosseini Sayed Nooroldin , Akhlaghi Naser
Published: June 2012

The water flooding in the carbonate fracture reservoir is low efficiency because of higher permeability in fractures than in matrix, and water will not imbibe spontaneously into the matrix due to a negative capillary pressure. Spontaneous imbibition of water into carbonate fracture reservoir is a very important issue in secondary oil recovery method. However, almost more than 80% of the entire known carbonate reservoir can be categorized as oil wet. It is therefore important to find methods to alter the wettability from oil-wet to water-wet conditions that are effective in order to improve the recovery from carbonate fracture reservoir. So far, two methods have been developed wettability alterations: 1) addition of certain chemical surface active agent to the injection water, and 2) thermally wettability alteration by steam injection.

In this study, an oil sample with 20 API was used to investigate the effect of the understudied surfactants on wettability alteration in the oil-water-limestone system.

Understudied surfactants were SDBS (sodium dodecylbenzene sulfonate), C12TAB (dodecyl trimethyl ammonium bromide), C16TAB (hexadecyl trimethyl ammonium bromide) and Triton X-100 that were utilized at 0.5, 1.5 and 2.5 wt% concentrations. The experiments were performed several times (0, 1, 6, 12, 24, 48, 72, 96 h) after injection of oil drop under limestone rock sample at reservoir temperature of 80°C. The obtained results showed that the increasing each of the surfactant could cause wettability alteration of the rock from oil-wet towards water-wet situation by passing of time. This alteration was very sharp at the beginning, but it was increases slightly at the time. It was observed that Triton X-100 was more efficient than C16TAB, C12TAB and SDBS to alter the wettability of the rock.
Energy (Heat) Distribution and Transformation in the SAGP Process
Authors: Wang J. Y. , Ezeuko C. C. , Gates I. D.
Published: June 2012

The Steam and Gas Push (SAGP) process was developed to improve the thermal efficiency of SAGD process. In SAGP, non-condensable gas is co-injected with steam into the reservoir. Ideally, the non-condensable gas accumulates at the top of the reservoir and provides insulation which reduces heat losses to the overburden. This means that lower SOR can be achieved at the same recovery factor. It remains unclear how energy is distributed and transformed within the chamber and its edges when non-condensable gas is added to the injected steam. In this work, we compare conduction and convection at edge of the steam chamber during SAGD and SAGP. The results show that both oil production rate and cumulative oil are reduced in SAGP compared to SAGD when 0.8 mole% NCG is co-injected with steam. This is because the injected NCG accumulates at the upper part of the leading edge of the steam chamber and slows down the growth of the steam chamber in that area, which results in lower cSOR but with a reduction of recovery factor. If 0.8 mole% NCG is co-injected at later periods of the operation, lower cSOR results without a significant reduction of oil production rates and cumulative oil production. In this case, the injected NCG migrates directly to the upper part of the reservoir and accumulates at the side edge of the steam chamber, since the steam chamber had already grown to the top of the reservoir. The added gas slows down lateral growth of the steam chamber in the upper part of the reservoir and forces steam chamber growth in the downward direction. From an analysis of energy transport in SAGP and SAGD operations, the results reveal the optimal timing for the onset of NCG co-injection with steam.
Using a New Hybrid Artificial Lift System for Mature Heavy Oil Fields
Authors: López Manríquez Alberto , López Hernández José G.
Published: June 2012

Previous work has been done in depleted carbonated heavy oil fields located in north of Mexico to address the problem of lack or low oil production due to high crude oil viscosity using downhole chemical treatment. In order to make these mature wells economically attractive, this previously acquired experience was combined with venturi technology, resulting in a downhole hybrid system designed as an alternative method to conventional gas lift.

This paper describes an in-depth analysis and the benefits of applying a hybrid artificial lifting system based on the principle of venturi and downhole chemical treatment for improving production in mature heavy crude oil fields. This study also presents various aspects; such as, design, calculations, working principle, and sensitivity analysis. A brief description of the individual components of the system is included as well, showing that this can be modified according to the particular conditions and constrains of a well. A variation of this hybrid system was tested in a pilot project in a shallow well with promising results.

The innovations and technical contributions of this work consist of the following. Firstly, a hybrid lift system such as the one described here is beneficial for depleted reservoirs containing heavy crude oil since it allows for both: reduction of bottom hole pressure and reduction of oil viscosity at down hole conditions. Secondly, since this hybrid system is simple, deploying it into a well using a reduced diameter pipe such as coiled tubing avoids the use of a workover rig, which is crucial form the economical point of view.
Monitoring PPB Levels of Dissolved Oxygen in SAGD Facilities
Authors: Weagle Glenn , Maltman Ron , Archer Andy
Published: June 2012

Many SAGD facilities recycle the produced water for use in steam generation. High opacity, coloured boiler feed water (BFW) from recycled produced water makes dissolved oxygen measurement difficult. New sensing technology using fluorescence decay now permits dissolved oxygen measurement that is unaffected by these conditions. Membrane based dissolved oxygen meters frequently fail in those conditions. Dissolved oxygen levels of 2 ppb were monitored for 6 weeks continuously where it was not previously possible with other techniques. A membrane based instrument was rendered inoperative after 2 days in the same service. In another facility, a 113 ppb oxygen decrease across a heat exchanger from active corrosion was detected. In this presentation several case studies will be used to outline where dissolved oxygen measurement assisted in facility operations, preventing costly maintenance and loss of equipment.
New Thermally Responsive Cement for Heavy Oil Wells
Authors: Tomilina Elena M. , Chougnet-Sirapian Alice , Aboutourkia Wesam
Published: June 2012

Canada’s oil sands are one of the world’s largest hydrocarbon resources. The initial volume of crude bitumen in place is estimated to be approximately 260 billion cubic metres with 11 percent or 28 billion cubic metres recoverable under current economic conditions. Continually improving economics, bolstered by recent higher crude oil prices, has resulted in the International recognition of the vast potential of Canada’s oil sands. Based on publicly announced development plans through to 2015, over C$60 billion could be invested in numerous projects to develop the oil sands.

Various factors have to be considered to select the proper cement for zonal isolation of thermal recovery heavy-oil wells. First the cement should be flexible enough to withstand the stresses which occur when casing expands during the heating up of the well. To reduce these stresses, the cement thermal expansion coefficient should be similar to the thermal expansion coefficient of the casing. Finally, cement mechanical properties should not degrade during the whole steam injection process, i.e. when it is subjected to extremely high temperatures (up to 350 degC) for extended periods of time.

Specifically in Canada, the majority of the steam injection wells are drilled in shallow sandstone formations. This requires the cement to have high flexibility to resist the stresses. Moreover, during steam injection, a reaction between the sandstone formation and the cement sheath may occur, impacting the cement matrix and hence changing its properties.

This paper describes the application of a new thermally responsive cement for zonal isolation of heavy oil wells in Canada. This system is designed to have excellent strength, flexibility and thermal properties even upon interaction with sandstone formations. It minimizes the mechanical stresses exerted on the cement sheath during steam injection, thus reducing the risk of loss of well integrity. The numerical simulations performed with these long-term material properties (six months of exposure to 350 degC) for typical Canadian heavy oil wells conditions predict reliable and durable zonal isolation under these extreme conditions. These simulation results are confirmed by several field applications in wells which have not leaked after months of steam injection.
The Benefits of Multiphase Flow Meters in SAGD for Production Optimization and Allocation Measurements
Authors: Graham John , Olson Jeff , Pinguet Bruno , Abraham Anson
Published: June 2012

Steam Assisted Gravity Drainage (SAGD) production is a challenging environment where the economics are driven by optimization of the steam injection and oil production. An accurate metering system coupled with downhole pump information is required as is the reduction in physical intervention and operating expenditures.

Suncor’s Firebag team engaged themselves in this challenging endeavor over the last 4 years to build a strategy using multiphase flowmeter (MPFM) to (1) provide a compact and versatile solution for new wells, (2) comply with regulations, and (3) validate the metering performances of the MPFM against the conventional separator.

The goal of this paper is to address the learnings and challenges faced in the MPFM deployment under these high temperature and harsh line conditions. This knowledge sharing is expected to serve as a guideline for future users of this MPFM technology in SAGD applications particularly with Cold Weather Operations, Multiphase Sampling and High H2S environment, also considering Pressure-Volume-Temperature (PVT) Modeling.

From a practical point of view, the qualification, application and benefits of MPFMs in field conditions will be highlighted versus the conventional solution. A particular focus will be placed on the production optimization and reservoir management.

Additionally, the synergy between the downhole pump information and instantaneous MPFM flow rate measurements will be reviewed along with the positive impact on the production optimization. The benefit of the MPFM accuracy and continuous measurement is expected to improve the allocation factors applied to all wells and pads.
Horizontal Well Placement for Heavy Oil Production in Colombia
Authors: Cuadros Jaime , Salamanca Andrey , Amado Nestor , Cuadros Guillermo , Rojas Esteban , Viramonte Jose Maria
Published: June 2012

The success of a horizontal drilling campaign highly depends on the implementation of appropriate well placement procedures to manage the constraints, risks, and uncertainties that may have a negative impact on the overall economy of the project. The magnitude of the uncertainties associated with the horizontal well trajectory and the geology is usually higher than the magnitude of that particular target within the reservoir that would maximize the production. The risk and uncertainty factors can be handled with the use of particular well placement techniques during the planning and execution phases.

In the planning phase, these techniques include proper geological modeling methods and flexible well planning to allow room for changes if unexpected events arise while drilling. During the well execution, procedures should include the use of appropriate technologies to understand in real time the rock properties, the reservoir geometry, and horizontal well position, and, based on this information, to steer the well within the desired geological target.

Girasol field, located in the Middle Magdalena Valley basin in Colombia, is composed of a sequence of sandstone channels that contain heavy oil with gravity ranging from 11 to 13° API. The main targets are five stacked sandstone reservoirs, from 10 to 35 ft thick, located 1,100 to 1,500 ft true vertical depth below surface. The field development included cyclic steam injection applied in horizontal wells to improve the heavy oil mobility. To maximize oil production and improve the cumulative steam/oil ratio, the objective was to place horizontal wells of up to 2,500 ft lateral extension within 3 to10 ft distance from the bottom shale of each reservoir.

The horizontal well placement under this type of scenario required the use of precise horizontal well placement techniques and drilling practices to avoid exits from the predefined geological targets. These techniques relied on the use of deep directional electromagnetic measurements that enabled real-time bed boundary mapping.

This paper presents the main challenges and uncertainties faced for well placement in the Girasol field horizontal drilling campaign, the technical solutions implemented, and the lessons learned in more than 80 horizontal wells drilled.
Study of Thermal Recovery Method of Steam and Flue Gas Combined with Gel Injection
Authors: Feng Qihong , Guo Longfei , Zhang Xianmin , Gao Sunhua , Shi Hongfu , Wu Shuhong
Published: June 2012

Since the production of China offshore heavy oil field, cold production is mainly used for oil recovery. However, it has faced great challenge including declination of oil production, rapid-increasing water cut and sharp cutoff of reservoir pressure. Conventional heavy oil recovery, such as steam stimulation, steam drive, in-situ combustion and SAGD, is not entirely suitable for offshore platform condition (platform space is small). Based on a new portable and convenient gas generator that can produce high-temperature steam, CO2 and N2, a new stimulation treatment is discussed in this paper, which aimed at the characteristic of sharp cutoff of reservoir pressure, combining steam and flue gas stimulation in production well together with injecting weak gel formed by polymer and cross linker in injection well, thus to keep the reservoir pressure to the utmost extent, and obtain maximal recovery.

Numerical simulation study was conducted on the basis of the conceptual model aimed at the recovering mechanism of weak gel injection and steam and flue gas thermal recovery, the mechanism including dwelling and displacement of weak gel, heating and visbreaking of thermal water or steam, solution and miscible visbreaking of CO2, and thermal fluid heating radius enlarging and gas driving effort improvement of N2. On the foundation of mature mechanism, the optimal injection-production technological parameters fit for reservoir development can be estimated by numerical stimulation of several development programs designed for certain reservoir and orthogonal optimizing method. And injection time and rate for weak gel injection preserving pressure are also discussed in this paper.
Enhanced CHOPS Using SuperSump to Reduce Environmental Footprint and Increase Oil Recovery
Authors: Arnold W. A. , Graham R. E. , Wagg B. T.
Published: June 2012

The two key challenges of primary heavy oil production using the process of Cold Heavy Oil Production with Sand (CHOPS) are limited recovery and the environmental footprint. With estimated remaining heavy oil in Western Canada of up to 300 billion barrels there is a significant opportunity for industry. Recovery of this oil using CHOPS is generally limited to 15% maximum brought on by high operating costs due to sand handling and interruption of the reservoir production process due to sand related workovers. The large CHOPS environmental footprint is driven by the significant surface disturbance due to close well spacing, greenhouse gas emissions from the use of heated lease tanks and handling and the long term disposal of produced sand.

Ongoing evaluations show that the SuperSump System has the potential to reduce the environmental footprint and increase recovery of typical CHOPS operations both in new heavy oil fields and in revitalizing existing fields. The technology uses a gravity stable process to drain oil through multiple wells from an upper viscous oil reservoir into a small fit for purpose cavern washed from underlying salt formations. Oil, water, and sand separate in the cavern and clean oil is produced from a single wellbore to surface. The environmental footprint is reduced by eliminating sand handling, reducing lease sizes, and reducing fluid storage and processing on surface. The SuperSump technology also has the potential to reduce operating costs, allowing increased recovery by prolonging the economic well life as production rates decline. In addition, early well failures due to sudden, massive sand influx may be virtually eliminated, encouraging the uninterrupted development of the sand production mechanism in the reservoir. Plugging problems and pump failures may also be eliminated as the wells mature because sand, oil and water are allowed to drain into the cavern below, where sand settles, water separates and sandfree, clean oil is produced to surface.

Simulation work has demonstrated that the SuperSump System could improve CHOPS operations in the following ways: Recovery factors are 50% higher; Operating costs are 30% lower; Energy efficiency is better by 75%; and Greenhouse Gas Emissions are lower by 95%. Estimated costs indicate very favourable economics compared to conventional CHOPS operations.

The analysis of SuperSump System currently focuses on CHOPS operations in the Western Canadian Sedimentary Basin, but could be used anywhere CHOPS is applied. It appears to be especially effective for developing new small fields where the cost of surface facilities constitute a significant portion of the field development cost. SuperSump could also be beneficial in applications where high density drilling is required but there are sensitivities to surface footprint. SuperSump could also be a cost effective precursor to EOR/IOR.
To Start up Extra-heavy Oil or Bitumen Wells by Solvents after Drilling
Authors: Zhang Jie , Li Cuinan , Zeng Fanhua , Chen Ping , Zhang Zhen , Zhou Chenghua , Zhang Wenlong
Published: June 2012

Extra-heavy oil or bitumen wells are very difficult to start up and recover because of the high oil viscosity in cold production. It is necessary to get initial mobility by reducing the viscosity of oil or bitumen when the wells are drilled. Although there are mechanical ultrasonic stimulation technologies, the penetration of ultrasonic wave in the formation is very limited and their efficiency is not very good. Hot water or steam circulation is another option. However the heat loss in the wellbore is too significant to send enough heat to the targeted interval, specifically for deep reservoirs. Solvent could be a better option from both oil viscosity reduction and operation points of view. It can be injected into the well immediately after drilling for soaking, which is a convenient method to reduce viscosity without many complicated procedure as thermal methods. The concern for using solvent to reduce viscosity is selecting the optimal solvent. This paper studied the mixture of some typical extra-heavy oil and bitumen with solvent. After fully mixed with each other, viscosity reduction and potential precipitation have been investigated. Different solvents are discussed and recommended to reduce viscosity for new well start up and work-over.

A series of viscosity tests is conducted in the paper for heavy oil-solvent mixture under different temperatures to discuss the effect of three different solvents (diesel, ligarine and toluene) on viscosity reduction. Through these viscosity tests, the optimal solvent, temperature and solvent concentration for viscosity reduction are recommended. And it is found that after a solvent is placed in contact with heavy oil samples at any temperature in the range of 20 – 80C the reduction of viscosity can be significant. However, considering the economical effectiveness, diesel is not recommended. And 60–90 ligarine and toluene are better choices for starting up super heavy oil or bitumen wells. In addition, as to bitumen, due to its extremely high viscosity, using several times volume of solvent as the bitumen volume still can’t have the viscosity reduce to a desired value. So these solvents tested in the experiments are not recommended for bitumen well starting up after drilling.
Response to Early Generation Selection for Resistance to Rice Kernel Fissuring
Authors: Pinson Shannon R. M. , Jia Yulin , Gibbons James
Published: June 2012

The value of milled rice (Oryza sativa L.) depends on the percent whole versus broken kernels after milling. Kernel fissures caused by pre‐ or postharvest stresses are the leading cause of breakage on milling. ‘Cypress’ is known to be more fissure resistant (FR) than most cultivars, but breeding success has been limited by a lack of ability to identify FR among F2 and F3 progeny. An induced‐fissuring method wherein small samples of seed are evaluated for fissure rates after controlled exposure to humid laboratory conditions can distinguish FR among pure‐breeding rice cultivars. To measure the efficacy of the induced‐fissuring system for evaluating FR among segregating breeding progeny, we applied divergent selection for FR and fissure susceptibility (FS) on seed harvested from ∼300 Cypress (FR) × ‘LaGrue’ (FS) F2 plants and evaluated selection success using seed from F2:3 plants grown in Arkansas and Texas. A second round of divergent selection was made among F3 progeny followed by F3:4 progeny testing. Fissure susceptible F2:3 progeny fissured twice as much as FR progeny, with an average response to selection of 13.5%. Response to F3 selection was smaller (averaging 2.6%), suggesting some fixation of alleles due to the F2 selections. Narrow‐sense heritabilities (h2) were 0.54 and 0.73 for the FR and FS F2 selections, respectively. This study documented successful early‐generation selection for FR, opening new opportunity for breeders to develop rice cultivars improved for this important trait.
Generation and Characterization of Interspecific Hybrids of Lotus uliginosus × Lotus corniculatus
Authors: Castillo A. , Rebuffo M. , Rizza M. Dalla , Folle G. , Santiñaque F. , Borsani O. , Monza J.
Published: June 2012

A method is described for obtaining interspecific hybrids between commercial lines of Lotus uliginosus Schkuhr and Lotus corniculatus L. Hybridization was possible between these species using embryo rescue. Two strategies were used to confirm 40 F1 hybrids, that is, flow cytometry and microsatellite simple sequence repeats (SSRs). The L. uliginosus and L. corniculatus parents have significantly different genome size (2.5 ± 0.02 and 2.22 ± 0.02 pg, respectively) and the offspring from the cross had intermediate values. Two SSR primers were polymorphic between the genotypes tested, TM1150 and EH380069. Maternal effect was detected in L. uliginosus genotypes, as determined by greater frequency of F1 hybrids. Recombinant traits were observed in the F1 hybrid progeny. Ninety F1 hybrids resulting from L. uliginosus × L. corniculatus crosses showed different levels of fertility in the polycross; <3% F1 plants produced more than 1000 seeds without embryo rescue while 10% of plants did not flower the first year. The F1 hybrid plants grown under greenhouse conditions exhibited shoot phenotypes similar to L. uliginosus (maternal) whereas F2 phenotypes were similar to L. corniculatus (paternal) in field trials. Rhizome presence was observed in 60% of F2 hybrid plants. The diameters of the root crowns of these plants, however, were similar to that of L. corniculatus.
An Assessment of Raffinose Family Oligosaccharides and Sucrose Concentration in Genus Lens
Authors: Tahir Mohammad , Båga Monica , Vandenberg Albert , Chibbar Ravindra N.
Published: June 2012

To determine the natural variation for sucrose and raffinose family oligosaccharides (RFO) concentration in lentils (Lens culinaris Medik. ssp. culinaris), we analyzed a subset of 168 Lens germplasm lines from the ICARDA collection. Significant (P ≤ 0.05) variations were found for sucrose, total RFO concentrations, and composition of the three main RFO (specifically raffinose, stachyose, and verbascose). Sucrose concentration in domesticated genotypes ranged from 0.5 to 2.7 g 100 g−1 flour dry matter (DM) and was higher overall than the concentrations observed in wild genotypes (0.1 to 1.7 g 100 g−1 flour DM). Similarly, the RFO concentration in domesticated genotypes (4.0 to 6.1 mmoles 100 g−1 flour DM) was generally higher than in wild lentil genotypes (1.7 to 5.2 mmoles 100 g−1 flour DM). The verbascose, stachyose, and raffinose concentrations in domesticated genotypes ranged from 1.1 to 1.6 g, 1.5 to 3.5 g, and 1.5 to 3.0 g 100 g−1 flour DM, respectively, and were similar to concentrations measured in wild genotypes. Lens ervoides genotypes tended to have higher verbascose and lower stachyose concentrations than other genotypes. High raffinose and low verbascose concentrations were observed in Lens nigricans genotypes. The diversity in RFO, raffinose, and verbascose concentrations was higher in wild genotypes than domesticated lentils. Utilization of this natural variation in RFO concentration in genus Lens provides opportunities for the improvement of lentil seed quality.
Potential and Optimization of Genomic Selection for Fusarium Head Blight Resistance in Six‐Row Barley
Authors: Lorenz A. J. , Smith K.P. , Jannink J.‐L.
Published: June 2012

Fusarium head blight (FHB),is a devastating disease of barley (Hordeum vulgare L.), causing reductions in yield and quality. Marker‐based selection for resistance to FHB and lowered deoxynivalenol (DON) grain concentration would save considerable costs and time associated with phenotyping. A marker‐based selection approach called genomic selection (GS) uses genomewide marker information to predict genetic value. We used a cross‐validation approach that separated training sets from validation sets by both entry and environment. We used this framework to test the potential of GS for genetic improvement of FHB and DON as well as test the effect of different factors on prediction accuracy. Prediction accuracy for FHB was found to be as high as 0.72 and that for DON was found to be as high as 0.68. Little difference was found between marker effect estimation methods in terms of prediction of entry genetic value. The extensive linkage disequilibrium (LD) present in this population allowed the marker set to be reduced to 384 markers and training population (TP) size to be reduced 200 with little effect on prediction accuracy. We found little to no advantage to combining subpopulations that correspond to neighboring breeding programs to increase TP size. Apparently, little genetic information is shared between subpopulations, either because of different marker–quantitative trait loci (QTL) linkage phases, different segregating QTL, or nonadditive gene action.
Genetic Yield Gains of the CIMMYT International Semi‐Arid Wheat Yield Trials from 1994 to 2010
Authors: Manès Y. , Gomez H. F. , Puhl L. , Reynolds M. , Braun H. J. , Trethowan R.
Published: June 2012

Genetic progress for yield has been assessed globally in the semi‐arid wheat yield trials (SAWYTs) of the International Maize and Wheat Improvement Center (CIMMYT) over a 17‐yr period. Grain yield expressed as a percentage of the long‐term check cultivar Dharwar Dry has increased at approximately 1% yr−1 between 1994 and 2010. In real terms, yield has been increased at a rate of 31 kg ha−1 yr−1. The rate of yield increase in high‐yielding environments was twice that of low‐yielding environments. The average yield of low‐yielding sites are significantly correlated with the average yield of high‐yielding sites (p < 0.001), and many of the highest‐yielding lines of the various SAWYT performed well at both low‐ and high‐yielding sites. The key parents Attila and Pastor were consistently high yielding in several of the early SAWYT. In later trials their derivatives were also high yielding. The line Vorobey, developed by crossing Pastor with a synthetic derivative, showed outstanding yield in SAWYT 11 and 12. The performance of CIMMYT lines compared to local check cultivars was relatively stable over time. A success rate was calculated as the ratio of the number of sites where a given line is superior to the local check divided by the total number of sites. On average, the success rate of the 10% best lines was 61% in low‐yielding sites and 62% in high‐yielding sites.
Persistence of Triticale Seed in the Soil Seed Bank
Authors: Raatz Lisa L. , Yang Rong‐Cai , Beres Brian L. , Hall Linda M.
Published: June 2012

Spring triticale (×Triticosecale Wittm. ex A. Camus) is being developed as a bio‐product crop for the Canadian prairies and may involve the use of genetic modification. Seed loss before or during harvest from genetically modified (GM) triticale could impact its ability to coexist with conventional crops. Experiments were conducted in Alberta, Canada, to determine if spring triticale exhibits primary dormancy relative to wheat (Triticum aestivum L.) and whether seeds persist in the seed bank. Primary dormancy was assessed for four triticale cultivars, AC Alta, Blue Aleurone, Tyndal, and AC Ultima, and AC Barrie wheat by quantifying germination weekly from anthesis to postharvest. Seed persistence was assessed for the same cultivars by placing seed‐filled mesh bags on the soil surface (0 cm) and at 2 and 12 cm burial depths. Before harvest in 2009, germinations were less than 56% for all cultivars. After harvest, AC Barrie and Blue Aleurone exhibited a short period of primary dormancy. In 2010, wet conditions were conducive to preharvest sprouting. Germinations ranged from 46 to 85% preharvest with no lingering primary dormancy postharvest. Seeds buried to 12 cm germinated readily, removing them from the seed bank within 7 mo, while 99% of seeds buried to 2 cm were nonviable 11 mo after burial. Seeds on the soil surface persisted longest; however, 99% were nonviable after 26 mo. Like wheat, triticale has little or no primary dormancy, and results from this study suggest triticale seed does not persist in the seed bank.
Development of Leaf Spectral Models for Evaluating Large Numbers of Sugarcane Genotypes
Authors: Zhao Duli , Glynn Neil C. , Glaz Barry , Comstock Jack C. , Johnson Richard M.
Published: June 2012

Leaf reflectance has been used to estimate crop leaf chemical and physiological characteristics. Sugarcane (Saccharum spp.) leaf N, C, and chlorophyll levels are important traits for high yields and perhaps useful for genotype evaluation. The objectives of this study were to identify sugarcane genotypic variation in leaf hyperspectral reflectance, leaf chemical (chlorophyll, N, and C), and yield (juice sucrose content, commercial recoverable sucrose [CRS], cane yield in tonnes of cane per hectare [TCH], and sucrose yield in tonnes of sucrose per hectare [TSH]) traits and to determine relationships between leaf reflectance and these chemical and yield traits. In Stage II of the Canal Point, FL, sugarcane cultivar development program, we measured spectral reflectance and chemical traits on three leaves of the top visible dewlap from each of 87 genotypes in December 2008 and 208 and 124 genotypes in May, July, September, and October 2009 and 2010, respectively. Yield traits were determined on mature plants. Genotypic variation of leaf reflectance mainly occurred in 540 to 1200 nm. Leaf relative chlorophyll, N, C, and C to N ratio varied among genotypes and during the growing season. Highly significant calibrations were developed for leaf chemical traits using leaf reflectance (P < 0.0001). Correlations of juice sucrose, CRS, TCH, and TSH with leaf reflectance were poor. Measurement of leaf reflectance is a promising tool for estimating leaf chemical traits but not for predicting yield traits across a large number of diverse genotypes in early selection stages of a sugarcane breeding program.
Generalized Lagrange-D’Alembert principle
Authors: Djukic Djordje
Published: June 2012

The major issues in the analysis of the motion of a constrained dynamic
system are to determine this motion and calculate constraint forces. In the
analytical mechanics, only the first of the two problems is analyzed. Here,
the problem is solved simultaneously using: 1) Principle of liberation of
constraints; 2) Principle of generalized virtual displacement; 3) Idea of
ideal constraints; 4) Concept of generalized and ?supplementary" generalized
coordinates. The Lagrange-D?Alembert principle of virtual work is generalized
introducing virtual displacement as vectorial sum of the classical virtual
displacement and virtual displacement in the ?supplementary" directions. From
such principle of virtual work we derived Lagrange equations of the second
kind and equations of dynamical equilibrium in the ?supplementary"
directions. Constrained forces are calculated from the equations of dynamic
equilibrium. At the same time, this principle can be used for consideration
of equilibrium of system of material particles. This principle simultaneously
gives the connection between applied forces at equilibrium state and the
constrained forces. Finally, the principle is applied to a few particular
problems.
The exact analytical solution for the gas lubricated bearing in the slip and continuum flow regime
Authors: Stevanovic Nevena , Djordjevic Vladan
Published: June 2012

The exact analytical solution for the compressible two-dimensional gas flow
in the microbearing is presented. The general slip-corrected Reynolds
lubrication equation is derived and it is shown that it possesses an exact
analytical solution. It is obtained by a suitable transformation of the
independent variable, and it provides the pressure distribution in the
bearing as well as the mass flow rate through it. By neglecting the
rarefaction effect, this solution is also applicable to the continuum gas
flow in the bearing, which also does not exist in the open literature. The
obtained analytical solution can be usefully applied for testing the other,
experimental or numerical results.
Domain decomposition schemes for the stokes equation
Authors: Vabishchevich Petr
Published: June 2012

Numerical algorithms for solving problems of mathematical physics on modern
parallel computers employ various domain decomposition techniques. Domain
decomposition schemes are developed here to solve numerically
initial/boundary value problems for the Stokes system of equations in the
primitive variables pressure-velocity. Unconditionally stable schemes of
domain decomposition are based on the partition of unit for a computational
domain and the corresponding Hilbert spaces of grid functions.
Adipocytes Secrete Leukotrienes
Authors: Mothe-Satney Isabelle , Filloux Chantal , Amghar Hind , Pons Catherine , Bourlier Virginie , Galitzky Jean , Grimaldi Paul A. , Féral Chloé C. , Bouloumié Anne , Van Obberghen Emmanuel , Neels Jaap G.
Published: June 2012

Leukotrienes (LTs) are potent proinflammatory mediators, and many important aspects of innate and adaptive immune responses are regulated by LTs. Key members of the LT synthesis pathway are overexpressed in adipose tissue (AT) during obesity, resulting in increased LT levels in this tissue. We observed that several mouse adipocyte cell lines and primary adipocytes from mice and humans both can secrete large amounts of LTs. Furthermore, this production increases with a high-fat diet (HFD) and positively correlates with adipocyte size. LTs produced by adipocytes play an important role in attracting macrophages and T cells in in vitro chemotaxis assays. Mice that are deficient for the enzyme 5-lipoxygenase (5-LO), and therefore lack LTs, exhibit a decrease in HFD-induced AT macrophage and T-cell infiltration and are partially protected from HFD-induced insulin resistance. Similarly, treatment of HFD-fed wild-type mice with the 5-LO inhibitor Zileuton also results in a reduction of AT macrophages and T cells, accompanied by a decrease in insulin resistance. Together, these findings suggest that LTs represent a novel target in the prevention or treatment of obesity-associated inflammation and insulin resistance.