bluuebunny/crossref_metadata_2025 huggingface dataset:
Field-Scale Modeling of Tracer Injection in Naturally Fractured Reservoirs Using the Random-Walk Particle-Tracking Simulation
Authors: Stalgorova E.. , Babadagli T..
Published: November 2012

Modeling complex transport processes in naturally fractured reservoirs (NFRs) using classical continuum models may not be practically possible because the algorithms used in this type of modeling approach for the detailed structure of fracture/matrix systems require unreasonable computational time. Also, fractured reservoirs are highly irregular, and finite-difference calculations for such models often cause convergence problems. In addition, an exact representation of a complex fracture network in classical continuum modeling algorithms is highly difficult. An alternative is to use a nonclassical technique known as the random-walk particle-tracking (RWPT) algorithm.

We showed earlier (Stalgorova and Babadagli 2012) that the random-walk (RW) technique can be adapted to model miscible flooding in a fractured porous medium at the laboratory scale. The unknown parameters used to match the model results were only the diffusion coefficients for oil and solvent, as the diffusive/dispersive transport (effective in fracture and matrix) was coupled with viscous (effective in fracture) and gravity (effective in fracture and matrix) displacement. Advantages of this method over classical simulation include a shorter computational time, which allows avoidance of simplifications; the ability to model the matrix/fracture diffusion process without any transfer function; and the representation of a complex and irregular fracture network system.

In this paper, we modified this laboratory-scale RW model for field-scale applications. A series of tracer-test results from the Midale field in Canada was used to test the model. A fracture-network model was constructed on the basis of geological data, and then we used the RWPT model to calibrate the fracture network against tracer-test results. The results were compared to those obtained using continuum (dual-porosity) models, and it was observed that the connectivity and breakthrough times can be captured more correctly with the RWPT model.

We performed a sensitivity analysis to identify the importance of different parameters for the simulation results. The new model and observations can be used to validate and calibrate stochastically generated fracture-network models and to estimate the enhanced-oil-recovery (EOR) performance of NFRs.
History Matching and Production Forecast With Logs as Effective Completion and Reservoir-Managing Tools in Horizontal and Vertical Wells
Authors: Haro Carlos F.
Published: November 2012

Simulation history matching is a daunting, time-consuming task with numerous unknowns and several plausible answers. Scale differences in the data frequently obscure results, limiting its application in completion strategies. Good history matching does not guarantee accurate production forecasts, however. Reliable predictions, required for well planning, depend on the ability of the user to reduce the uncertainties to find consistent and timely solutions. Logs can provide appropriate conditioning data for history matching to enable its use for reservoir management.

Electrofacies, capillary pressure, and absolute and relative permeability, imprinted on logs, can be mathematically linked with irreducible water saturation (Swi). Unlike reservoir simulators, well logs are at the right scale for completion designs. Logs facilitate upscaling, honoring rock and fluid properties and the physics of flow (Haro 2006). Logs are snapshot measurements that are amenable for conversion into dynamic forecasting tools by use of flow and pressure equations. This concept permits creation of synthetic production logs (SPLTs) over time, from which production decline can be calculated.

This method consists of integrating material balance, flow/ pressure algorithms, fluid data, cores, and log data. Thus, the corresponding analytical expressions are required. In this approach, every well represents a finite, gridded tank, capable of producing a measurable volume of fluids, limited by its petrophysical constraints. Superposition, in terms of pressure and flow, combines the various components within and among wells. The quality of the results is ensured because material balance must be honored at every depth at all times under different production scenarios and the prevailing drive mechanism.

This log-handling technique helps when making strategic economic decisions to maximize reserves and optimize the reservoir-development plan. This strategy is used to obtain oil in place (OIP), drainage radii, lateral connectivity, fluid-bank arrival times, productivity indices (PIs), inflow performance relationship (IPR), production allocation, and recovery per zone per well. Current log analyses or simulators generally do not provide these parameters at this detail. This refined use of logs streamlines completion designs and improves conformance, enabling us to comply with an important part of daily reservoir management.
A New Method for the Design and Selection of Premium/Woven Sand Screens
Authors: Mondal Somnath , M. Sharma Mukul , M. Hodge Richard , A. Chanpura Rajesh , Parlar Mehmet , A. Ayoub Joseph
Published: November 2012

Woven-metal-mesh sand screens, commonly known as premium screens, have been used extensively by the industry. Sand-retention testing is often executed to evaluate the performance of these screens and to establish empirical guidelines for screen-size selection. These tests are tedious, however, and the results are prone to artifacts and have been used, at best, to correlate trends in sandretention performance with select sand-size-distribution parameters. A new method incorporating results from numerical modeling, in addition to experimental data, is presented to estimate the mass and size distribution of the produced solids in prepack sandretention tests (SRTs) through premium screens. This method provides a fast, reliable correlation to estimate sand production through premium mesh screens when the size distribution of the formation sand is known.

This paper presents results from a wide range of pre-pack sand-retention experiments. In these tests, which represent complete hole collapse, the mass of sand produced and its size distribution over time are measured. Results of 3D, discrete- element computer simulations of woven-screen geometry placed in contact with granular sandpacks of approximately 100,000 particles are also presented. On the basis of both the simulations and the experiments, a new method for screen selection is presented. This method is based on a correlation that allows one to use the entire sand-size distribution of the formation sand and to estimate the mass and size distribution of the produced sand. The method is validated by comparisons with experimental data.

A new method and new correlations for estimating the mass and size distribution of produced solids in prepack tests through premium screens are presented. Key differences in sand-retention mechanisms between premium screens and wire-wrapped screens (WWSs) have been identified. The method uses the entire-formation sand-size distribution (as opposed to a single design point), and has been validated with laboratory tests. The method also helps in screening anomalous test results.
A Modern Method for Using Databases To Obtain Accurate Solutions to Complex Reservoir-Characterization Problems
Authors: Freedman R.. , Anand V.. , Zhou T.. , Rose D.. , Beekman S..
Published: November 2012

Many problems in reservoir characterization require the formulation and solution of an inverse problem. The definition of the inverse problem is the prediction of reservoir properties from measurements made on the reservoir. The most familiar example of an inverse problem is well-log interpretation. Well logging involves the acquisition of various kinds of data for the purpose of predicting reservoir properties of the earth formations near the borehole.

Conventional inverse methods used in the industry today typically involve the constrained minimization of a weighted sum of the squared deviations between a set of measurements and a forward-model equation or equations. The forward-model equations are either empirically or theoretically derived equations. These equations relate the reservoir property to be predicted (e.g., saturation, permeability) to measurements (e.g., resistivity, T2 distributions, porosity). Adjustable parameters in the forward-model equations are determined using a "calibration database" of laboratory measurements made on a suite of representative samples. This traditional methodology suffers from fundamental limitations that stem from the fact that reservoir rocks and fluids are too complex to be described accurately by the simple idealized equations that are used today as forward models. Additionally, the forward models contain adjustable parameters that can vary over a wide range, thereby leading to additional inaccuracies in reservoir properties.

Our paper discusses a new model-independent inversion method that overcomes the limitations and inaccuracies of the conventional method. The new inversion method predicts reservoir properties without the need to use idealized model equations or to solve minimization problems. The new method divides the calibration database into input measurements (i.e., used for the predictions) and output measurements (i.e., the reservoir properties to be predicted). The outputs are mapped to the inputs using model-independent mapping functions constructed from Gaussian radial-basis functions (RBFs). The RBF mapping functions are accurate representations of the functional relationship between the database inputs and outputs. The coefficients of the mapping function can be determined uniquely using the database. Once the coefficients are determined, there are no adjustable parameters.

The new method is applicable to a wide variety of reservoir-characterization problems. The construction of the mapping functions is presented in detail. We apply the method to a challenging problem in nuclear well logging: accurate predictions of formation thermal neutron-capture cross sections (sigma) from welllogging data. Logs of formation Σ predicted using the conventional regression method and using the new method are compared and discussed.
Simple Engineering Applications Recycled as Effective Training Aids
Authors: Sawaryn S.J.. J.
Published: November 2012

Technical advances have led to both expansion and increased specialization in the engineering skills employed in our industry. In many cases, these specializations involve the use of complex engineering calculations involving a bewildering number of inputs and outputs to match real-world situations. Another problem with high-end applications is that they are costly and their logic is often presented as a "black box"—disclosure may be hampered by intellectual-property concerns. Although such high-fidelity applications may be essential for operations, simpler models with few inputs are better for scoping exercises or training.

The rapid and effective transfer of knowledge and experience to new hires with diverse backgrounds remains a key challenge. Though information technology and richer media have helped standardize delivery methods, accessing appropriate engineering applications for training purposes remains a challenge.

The important requirements are to communicate the fundamentals and build on knowledge gained at university. At the same time, the teaching methods and modules should instill curiosity and encourage critical assessment of the models and methods used. Therefore, the models should not be too far from reality.

Technical progress and refinement of a broad range of topics are inherent in the content and structure of the SPE paper library. The application to training is illustrated using examples including the simple 2D bottomhole-assembly (BHA) algorithm presented by Walker (1973). This paper shows how key refinements have been included by use of simple geometrical constructs and how the model has been used effectively in spreadsheet form to develop an understanding of BHA behavior and directional-survey-sag correction, and to identify and correct programmatic errors.

It is suggested that greater use can be made of the SPE library as a ready source of cost-effective training material and that the descriptions of the simpler engineering applications it contains can be recycled as valuable training aids.
Fracture-Stimulation Diagnostics in Horizontal Wells Through Use of Distributed-Temperature-Sensing Technology
Authors: Tabatabaei M.. , Zhu D..
Published: November 2012

Horizontal wells with hydraulic-fracture treatments have proved to be an effective method for developing unconventional oil and gas reservoirs. During the past several years, fracturing methods have evolved and improved rapidly; however, there still exist many uncertainties in fracture design. Several fracture-diagnostic techniques have been developed to improve the understanding of the fracturing process. In this study, after reviewing the application and limitations of the current fracture-diagnostic techniques, we describe the application of distributed-temperature-sensing (DTS) technology as a complementary tool for real-time fracture diagnostics. DTS technology has enabled us to observe the dynamic-temperature profile along the wellbore during the treatment. However, quantitative interpretation of dynamic-temperature data is very challenging and requires in-depth mathematical modeling of heat and mass transfer during the treatment.

We have developed a thermal model to simulate the temperature behavior along the wellbore during the treatment, as well as during the shut-in period. This model takes into account the effect of all significant thermal processes involved, including conduction and convection.

Examples are presented to illustrate how this model can be applied for fracture-stimulation diagnostics. Estimation of the fracture-initiation points, number of created fractures, and distribution of stimulation fluid along each isolated zone are the problems for which DTS technology can help obtain answers. The effectiveness of isolation can also be diagnosed by DTS technology because the heat-transfer mechanism changes when convection caused by leaking in isolation occurs. This information can be used for more-accurate fracture modeling and better estimation of fracture conductivity and fracture geometry and, therefore, to optimize future treatments and also to evaluate the well performance.
Wax-Deposition Forecast
Authors: Semenov Andrey
Published: November 2012

In the case of altering the pressure/volume/temperature properties of oil, change of the aggregate state of oil is one of the main issues in oil processing. When oil lifts to the surface, the most advantageous energy state of high-weight components becomes the state in which a portion of the molecules becomes solid. Phase-behavior diagrams could be plotted using a typical compositional simulator, but even if one knows the phase behavior, one still will not be able to understand the wax deposition in the tubing or pipeline and will not forecast this process performance.

As some authors have mentioned, the resin and asphaltene concentrations in the oil affect the wax-deposition velocity. Because of the high complexity of the crystallization mechanism, the high-weight molecules are not taken into consideration in a phase-behavior simulator. Thus, with the intent of qualitatively characterizing the oil tendency to the aggregate, the oil from different reservoirs has been compared.

Because of the temperature gradient between rock (permafrost) and oil, there is a probability of wax deposition in the tubing. The deposition-growth model makes different diffusion assumptions. The equilibrium model and the film-mass-transfer model (as well as solidification and separation) have been applied. Using these models, the wax-growth velocity and tubing-drift diameter have been forecast.

As a result of the harsh northern environment, there is a serious risk of oil solidification in the surface pipeline in the case of a pump stopping. On the basis of the laboratory measurements and with the help of a stepwise approximation, the oil-viscosity dependence on temperature has been derived. By solving the heat-transfer equation (between oil in the pipeline and the environment) and using nodal analysis, the maximum safety time in case of an accident in the pipeline has been determined.
Contemporary Approach Coupled With Traditional Techniques Tackles Extreme Wellbore Environment in Schoonebeek Heavy Oil Field
Authors: Foster Andrew , Pollema Auke , Petitt Ian , Heathman James , Johnson Carl , Schlepers Rudy
Published: November 2012

The Schoonebeek heavy-oil field was first developed by Nederlandse Aardolie Maatschappij B.V. (NAM) in the late 1940s. Because of economics, it was abandoned in 1996. In 2008, the Schoonebeek Redevelopment Project, using a gravity-assisted-steamflood (GASF) design concept, was initiated with 73 wells (44 producers, 25 injectors, and 4 observation wells).

Steam injection and cool-down cycles subject a cement sheath to some of the most severe load conditions in the industry. Wellbore thermal modeling predicted that surface and production sections would experience temperatures in excess of 285°C (545°F) and considerable stress across weak formations. A key design requirement was long-term integrity of the cement sheath over an expected 25- to 30-year field life span. Complicating this requirement was the need for lightweight cementing systems, because lost-circulation issues were expected in both hole sections, particularly in the mechanically weak Bentheim sandstone.

The long-term integrity challenge was divided into chemical and mechanical elements. Prior research on high-temperature cement performance by the operator provided necessary guidance for this project. Laboratory mechanical and analytical tests were conducted to confirm the high-temperature stability of the chosen design.

In addition to using lightweight components, foaming the slurry allowed the density, mechanical, and economic targets to be met. A standardized logistical plan was put in place to allow use of the same base blend for the entire well, adjusted as needed, using liquid additives, and applying the foaming process when necessary. This single-blend approach greatly simplified bulk-handling logistics, allowing use of dedicated bulk-handling equipment.

The first well was constructed in January 2009; all 73 wells have been successfully cemented to surface. The steaming process, initiated in May 2011, has progressed with no well integrity issues to date.
Buckling of Tubing Inside Casing
Authors: Mitchell Robert F.
Published: November 2012

Oil wells typically have multiple concentric casing strings. For a set of two concentric strings, if the inner pipe has a compressive axial force, it will typically buckle within the outer string. The buckling of pipe can be important in the analysis of a well-completion design because the buckled pipe can develop bending stresses that may be significant. Most analyses of this problem assume that the outer casing is rigid. In reality, this external casing is also elastic and would displace owing to the loads generated by contact with the inner pipe. Further, if both strings have compressive axial forces, both strings will buckle, and the resulting buckled configuration must fit together so that contact forces between the two strings are positive and the pipes do not each occupy the same space. If the two strings have an external, cylindrical rigid wellbore, then any contact forces with this wellbore must also be positive, and the buckled pipe system must lie within this wellbore.

The only known solution to the multiple concentric pipe-buckling problem is that of Christman (1976), who proposed a composite pipe based on the summed properties of the individual pipes. This analysis does not conform to the requirements posed in the preceding paragraph.

This paper presents the various ways that two concentric pipes can interact when one or both pipes are in compression and would then have a tendency to buckle. The contact forces between the pipes and with the external wellbore are explicitly calculated, and contact or noncontact conditions are determined. All results are analytical so that they can easily be used in spreadsheets or hand calculations. Several examples of calculations are presented to illustrate how these results might be used.
Measurements of Hydraulic-Fracture-Induced Seismicity in Gas Shales
Authors: Warpinski N.R.. R. , Du J.. , Zimmer U..
Published: November 2012

Hydraulic fracturing is an essential technology for hydrocarbon extraction from both conventional and unconventional reservoirs. Recently, concern has developed regarding induced seismicity generated in association with multistage fracturing of horizontal wells in shale reservoirs. Microseismic monitoring of hydraulic fractures, which has been a routine service for over a decade, can provide information about the levels of seismic activity commonly found during fracturing. A review of thousands of fracture treatments that have been microseismically monitored shows that the induced seismicity associated with hydraulic fracturing is very small and not a problem under any normal circumstances. Results are presented for six major shale basins in North America in which hundreds to thousands of fracture treatments have been conducted in predominatly gas reservoirs. This paper reviews the methodology, the data, and the interpretation of the microseismicity.
Surface and Subsurface Requirements for Successful Implementation of Offshore Chemical Enhanced Oil Recovery
Authors: Raney Kirk , Ayirala Subhash , Chin Robert , Verbeek Paul
Published: November 2012

Chemical enhanced oil recovery (EOR), including polymer and surfactant-based processes, is a method that operators consider to maximize oil recovery from onshore and offshore reservoirs. Because of the logistical, operational, and environmental differences and the footprint and required weight needed for additional injection and production equipment, offshore chemical EOR processes are challenged by greater complexity and costs as compared with onshore applications of the same technologies.

Chemical EOR commonly requires large volumes of injection chemicals, as well as demulsifiers to break produced-water/oil emulsions and inhibitors to control scale, resulting in high shipment and storage costs. The use of seawater and/or produced water for injection of the chemicals into offshore fields mandates stringent processing of both streams to allow optimal injectivity, sweep efficiency, and chemical effectiveness in the reservoir. Offshore production of saleable oil and clean water requires space- and weight-efficient oil/water-separation equipment. Currently, conventional methods for processing produced fluids fall short in both efficiency and compactness. High offshore drilling costs lead to relatively large well spacing and more difficulty in monitoring the EOR subsurface process, and lead to restrictions on the number of disposal wells. Finally, environmental restrictions limit the overboarding of toxic or poorly biodegradable EOR chemicals.

The industry is currently investigating the limiting factors pertinent to offshore chemical EOR. As a result of these efforts, new enabling chemistries and technologies are being examined for improving surface operations to allow cost-effective offshore chemical EOR to be performed in an environmentally sound and safe manner. Some of these recent chemical- and fluids-processing developments are described in this paper. Subsurface challenges to implementing offshore chemical EOR are also highlighted, along with potential solutions.
Introducing a New Correlation for Multiphase Flow Through Surface Chokes With Newly Incorporated Parameters
Authors: Safar Beiranvand Mahmoud , Babaei Khorzoughi Mohammad
Published: November 2012

Flow-rate prediction of oil production wells is of prime importance to effectively confront high-water-cut and separator problems. (Semi-) empirical multiphase-flow correlations are proved quite useful for this purpose. This work presents new generalized multiphase flow choke correlation, derived on the basis of actual production data from horizontal and vertical wells from an oil field in Iran. The newly established correlation predicts liquid flow rates as a function of flowing wellhead pressure, gas/liquid ratio, surface wellhead choke size, and the newly incorporated parameters: basic sediment and water (BS&W) and temperature. To evaluate the influence of these two new parameters, a parameter-sensitivity analysis was performed and the results are shown. This proposed correlation exhibited an average error of roughly 2.89%, which is superior to those previous correlations in the literature that did not use these two newly incorporated parameters (BS&W and temperature). These new parameters can be added to the previous correlations when the water cut and temperature become important in the production history of the wells.
Study on the FOG-Based Well-Trajectory-Logging Tool
Authors: Ren C.. , Li M.. , Li L.. , Duan Y.. , Weng H..
Published: November 2012

The commonly used technology in well-trajectory logging, for both the oil and the gas well, is the magnetometer. However, it cannot work well in the magnetic-interfered or nonmagnetic environment, such as in a cased well or an iron mine. This paper presents a new trajectory-logging tool with a small diameter. Configured by a three-axis FOG unit and three quartz accelerometers, the logging tool allows for continuous attitude and trajectory measurement. High-temperature-caused accuracy degradation is the major error source for the underground environment. To diminish the thermal-related error, a flask stuffed with thermal-insulation material was embedded in the tool body; meanwhile, a wavelet neural network was used for identification of and compensation for the temperature drift. The system configuration, trajectory-resolution algorithm, and temperature-compensation algorithm are presented in this paper. Testing results show that the inclination accuracy is better than ±0.1°, with a range of 0 to 180°, and the azimuth accuracy is better than ±2°, with a range of 0 to 360°. The new logging tool resolves continuous trajectory-measurement problems in a magnetic-interfered or a nonmagnetic environment. Moreover, the capability of all-attitude measuring facilitates horizontal-well logging. Therefore, broad applications and good marketing could be anticipated for this new logging tool.
Experimental Study of Two-Phase Performance of an Electric-Submersible-Pump Stage
Authors: Gamboa Jose , Prado Mauricio
Published: November 2012

This paper presents electric-submersible-pump (ESP) -stage performance handling air and water in a laboratory setup. Experimental data gathered shows the effect of volumetric gas flow rate and intake-stage pressure for different rotational speeds. The presence of gas mildly deteriorates the stage performance at low volumetric gas flow rates. A sudden reduction in the stage-pressure increment is observed at this operation condition for a certain critical liquid flow rate, which marks the initiation of surging on the stage performance as mentioned by Lea and Bearden (1982). The surging initiates at lower liquid flow rates as the volumetric gas flow rate increases, which demonstrates the relationship between the surging initiation and liquid flow rate. It is also observed that the initiation of the surging moves toward lower liquid flow rates by increasing the rotational speed or the stage intake pressure.

A two-phase stage-performance map was recently introduced, defining boundaries for five pump-performance regimes: homogenous, mild-performance deterioration, performance reverse slop, server performance deterioration, and nil performance (Gamboa and Prado 2011b). The current work shows that these performance regime boundaries are affected by rotational speed and intake-stage pressure.
A Modified Thermal Time Model to Predict Germination Rate of Ryegrass and Tall Fescue at Constant Temperatures
Authors: Zhang Hongxiang , McGill Craig R. , Irving Louis J. , Kemp Peter D. , Zhou Daowei
Published: November 2012

The thermal time model is widely used to describe the relationship between germination and temperature. However, the model breaks the germination curve into two parts and ignores the possibility that germination rate is constant at optimal temperatures. The purposes of this study were to investigate the relationship between temperature and germination rate within the context that optimum temperature (To) may be better defined as a range rather than a single point and to test for variation in minimum temperature (Tb) and the thermal time constant of a given subpopulation g at suboptimal temperatures [θ1(g)] among subpopulations. Seeds of two ryegrass cultivars, perennial ryegrass (Lolium perenne L.) ‘Bronsyn’ and annual ryegrass (Lolium multiflorum Lam.) ‘Archie’, and two tall fescue cultivars (Festuca arundinacea Schreb.) ‘Flecha AR542’ and ‘Advance’ were germinated at constant temperatures ranging from 6 to 43°C at 3°C intervals and monitored for subpopulation variability from the 10th to 80th germination percentiles. Linear regression was used to estimate the parameters of the modified thermal time model at suboptimal, optimal, and supraoptimal temperatures. The tall fescue and ryegrass cultivars all exhibited an To range over which the germination rate was constant, although the magnitude of the To range depended on cultivar and/or species and subpopulations. Therefore, a modified thermal time model incorporating upper limit of optimum temperature range (Tou) and lower limit of optimum temperature range (Tol) was proposed. This modified thermal time model can better predict the germination rate and temperature relationship in some circumstances.
Doubled Haploids versus Conventional Breeding in CIMMYT Wheat Breeding Programs
Authors: Li Huihui , Singh Ravi P. , Braun Hans‐Joachim , Pfeiffer Wolfgang H. , Wang Jiankang
Published: November 2012

Doubled haploid (DH) technology has been used in breeding programs for several decades and is currently the method of choice in a number of crop species, including barley (Hordeum vulgare L.), rapeseed (Brassica napus L.), maize (Zea mays L.), and wheat (Triticum aestivum L.). In this study we investigated via computer simulation the benefit of using DHs compared with the conventional wheat breeding strategy used at CIMMYT. Two strategies using DHs were considered: DH lines directly derived from F1 hybrids (F1–DH), and DH lines derived from F3 individuals that are retained following selection for agronomic traits in the F2 generation (F3–DH). Genetic gains per cycle, per year, and per dollar spent were consistently higher for conventional breeding than for DH breeding strategies, especially gains per dollar. Though the F1–DH strategy saved 1 yr in completing a breeding cycle, genetic gains per year for the adaptation trait from F1–DH were much lower than those from conventional breeding, where two growing seasons are used per year. Though the DH breeding strategy showed no significant advantages over the conventional wheat shuttle‐breeding regime of CIMMYT, we did not exclude the possibility that the DH breeding strategy may have advantages when genetic gains per unit of time are considered, and only one generation is grown per year. The conventional shuttle regime will continue to be the major wheat breeding strategy at CIMMYT, where two cycles can be grown per year and breeders can do selection in large populations in both cycles.
Herbicide‐Resistant Tall Fescue with Cytoplasmic Male Sterility Selected by a Mutated Rice Acetolactate Synthase Gene
Authors: Sato Hiroko , Shimizu Tsutomu , Kawai Kiyoshi , Kaku Koichiro , Arakawa Akira , Tachibana Tadashi , Takamizo Tadashi
Published: November 2012

Selectable markers are important in selecting transgenic cells from nontransgenic cells in genetic transformation. A rice (Oryza sativa L.) acetolactate synthase (ALS) gene containing a single point mutation [OsALS (sm)] can confer resistance to pyriminobac (PM) herbicide. We produced transgenic tall fescue (Festuca arundinacea Schreb.) using the OsALS (sm) gene as a selectable marker and evaluated its herbicide resistance. Calluses were selected by incubation with PM. All regenerated plants had the OsALS (sm) gene. Transgenic plants sprayed with PM were unaffected whereas wild‐type plants stopped growing and eventually died in part. Acetolactate synthase activity in transgenic plants treated with PM was lower than that in wild‐type plants without PM but higher than that of wild‐type plants with PM. These results indicate that the transgenic plants produced OsALS (sm) protein, which conferred PM resistance. One of the transgenic plants was crossed with a cytoplasmic male‐sterile plant to prevent the flow of transgenic pollen into the environment. All F1 plants were male‐sterile. The F1 plants that inherited the OsALS (sm) gene were resistant to PM. Therefore, we used the OsALS (sm) gene not only as a plant‐derived selectable marker but also for the production of herbicide‐resistant plants. Introducing other agronomically important genes with the OsALS (sm) gene as a selectable marker into tall fescue and crossing with male‐sterile plants should improve public acceptance of transgenic tall fescue.
Marker‐Assisted Selection for Elevated Concentrations of the α′ Subunit of β‐Conglycinin and Its Influence on Agronomic and Seed Traits of Soybean
Authors: Oltmans‐Deardorff Sheilah E. , Fehr Walter R. , Shoemaker Randy C.
Published: November 2012

Soybean [Glycine max (L.) Merr.] cultivars with elevated concentrations of the α′ subunit of β‐conglycinin (BC) may provide health benefits to soy protein consumers. Two Monsanto single nucleotide polymorphism markers were used to classify F2 plants in four segregating populations as having elevated α′ concentration (EAP) or normal α′ concentration (NAP). Seeds from one F3 progeny of each F2 plant were analyzed for protein composition by sodium dodecyl‐sulfate polyacrylamide gel electrophoresis. Of the 800 plants in the four populations evaluated with the two markers, 82% were correctly classified for the EAP trait and 80% for the NAP trait. The EAP and NAP traits were evaluated in combination with the four glycinin genotypes gy1,2, Gy3, gy4, Gy5; gy1,2, Gy3, gy4, gy5; gy1,2, gy3, gy4, Gy5; and gy1,2, gy3, gy4, gy5. The seed yield, time of maturity, and protein and oil concentration were evaluated for 18 F3:5 lines in each of the eight genotypic classes of the four populations at three environments in 2011. The EAP trait resulted in a significant increase in the α′ and β subunits of BC and a decrease in the α subunit, with no consistent impact on total BC, total glycinin, seed yield, maturity, and protein and oil concentrations. It should be possible to develop acceptable soybean cultivars that have the EAP trait in combination with the glycinin genotype gy1,2, gy3, gy4, gy5 to obtain a high concentration of the α′ subunit and total BC with no glycinin for soy‐based food products.
Effects of Cytokinin and Potassium on Stomatal and Photosynthetic Recovery of Kentucky Bluegrass from Drought Stress
Authors: Hu Longxing , Wang Zhaolong , Huang Bingru
Published: November 2012

Drought‐induced stomatal closure may limit resumption of photosynthesis and plant growth if stomata do not quickly reopened when plants are later rehydrated. Cytokinins (CK) and K are known to regulate stomatal opening and closure. The objective of this study was to investigate whether foliar application of CK and K would enhance stomatal reopening and photosynthetic recovery in leaves of perennial grass after water deficit is alleviated. Kentucky bluegrass (Poa pratensis L. ‘Brilliant’) plants were subjected to drought stress by withholding irrigation for 15 d and then rewatered for 6 d in growth chambers. A synthetic CK (6‐benzylaminopurine [6‐BA]) and KCl with the concentration of 10 μM and 50 mM, respectively, were foliar sprayed on drought‐stressed plants. The experiment consisted of well‐watered control, drought stress followed by rewatering, drought stress followed by rewatering and foliar spray of 6‐BA (10 μM), and drought stress followed by rewatering and foliar spray of KCl (50 mM). Treatments were arranged as a completely randomized block design with four replicates for each treatment. Soil volumetric water content (SWC), leaf relative water content (RWC), net photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate (Tr), and stomatal aperture decreased with the progression of drought stress. The RWC, Pn, gs, Tr, and stomatal aperture increased after rewatering, to a greater extent in 6‐BA‐ or KCl‐treated plants than plants sprayed with water only. A positive correlation between stomatal aperture and Pn (r2 = 0.79) and between stomatal aperture and gs (r2 = 0.87) were detected under drought stress and during rewatering. Our results indicate that exogenous application of 6‐BA and KCl promoted stomatal reopening following drought‐induced closure, leading to enhanced gs and rapid postdrought resumption of photosynthesis on rewatering.
Soybean Aphid Injury Effects on Shoot Nitrogen Components in Glycine max
Authors: Riedell Walter E. , Beckendorf Eric A. , Catangui Michael A.
Published: November 2012

Knowledge of soybean aphid (Aphis glycines Matsumura) effects on soybean [Glycine max (L.) Merr.] shoot N components may improve understanding of how plants are injured by this invasive pest. This 2‐yr field study was conducted to measure soybean aphid effects (initial infestation of 0, 10, 50, or 100 aphids plant−1 at the fifth node [V5] stage) on cumulative aphid‐days as well as resulting soybean aphid populations plant−1, shoot dry weight (DW), nitrate N, and ureide N measured at full bloom (R2), beginning pod (R4), full pod (R5), and beginning seed (R6). Cumulative aphid‐days, which quantifies both the number of aphids present on plants and the duration of their feeding time, were similar across initial aphid infestation treatments. Compared with control plants, aphid feeding injury reduced shoot DW by about 40% and increased shoot nitrate N concentrations by about 45% across all initial infestation rates tested. Shoot nitrate N accumulation was increased about 20% by the 10 aphids plant−1 treatment. In contrast, shoot ureide N concentrations in aphid‐injured plants were similar to levels observed for uninjured plants. This lack of a concentration effect resulted in about a 36% decrease in ureide N accumulation in aphid‐injured plants. These differential responses may result because nitrate N can be absorbed directly from the soil solution while ureide N biosynthesis has a higher energy requirement that cannot be met under severe aphid infestations.
TheimMutant Gene Negatively Affects Many Aspects of Fiber Quality traits and Lint Percentage in Cotton
Authors: Wang Cheng , Zhang Tianzhen , Guo Wangzhen
Published: November 2012

Immature fiber(im) is a cotton (Gossypium hirsutumL.) fiber recessive mutant on chromosome 3 that causes abnormal fiber characteristics, fineness, and a low fiber weight. Here, theimmutant and five cotton lines, two fromG. hirsutumaccession TM‐1 and I4005 and three from different chromosome segment introgression lines (CSILs) from chromosome 3 ofGossypium barbadenseL. ‘Hai7124’ in the background ofG. hirsutumaccession TM‐1, were compared for differences in fiber characteristics, fiber quality traits, and lint percentage. Combined F2and F2:3mapping populations were produced by crossingimwith the five lines, which further confirmed the negative effect ofimon fiber quality traits and lint percentage. Except for short fiber index, other fiber traits showed a significant correlation with each other in the five mapping populations. Three traits in particular, micronaire, maturity, and lint percentage, showed a correlation coefficient of >0.8 (P< 0.001). Theimmapping and quantitative trait locus (QTL) analyses revealed QTLs responsible for various measured characteristics in each population. The integration of QTLs from the different populations showed that most QTLs related to multitraits from different populations were clustered near theimlocus with a high percentage of phenotypic variance. Theimmutant significantly affected the phenotypic value of these traits, which indicated thatimplayed an important role in fiber development, and it had a great impact on fiber quality traits and lint percentage.
Phenotypic Effects of the Flowering Gene Complex in Canadian Spring Wheat Germplasm
Authors: Kamran Atif , Randhawa Harpinder Singh , Pozniak Curtis , Spaner Dean
Published: November 2012

Wheat (Triticum aestivum L.) has inherent genetic potential to synchronize its flowering and maturity to a broad growing period and is therefore one of the most widely adapted and grown food crops. Vernalization and photoperiod response genes are of primary importance to this adaptability. We screened 102 Canadian spring wheat cultivars and/or lines, developed between 1885 and 2008, from the Canada Western Red Spring (CWRS), Canada Prairie Spring Red (CPSR), and Canada Western Soft White Spring (CWSWS) classes and studied their phenotypic response both in the field and the greenhouse. Almost all the hard red cultivars possessed the Vrn‐A1a gene either alone or in combination with the dominant Vrn‐B1 while 74% of the higher yielding soft white lines possessed the Vrn‐B1 gene alone or in combination with other Vrn genes. The Vrn‐A1a alone or in combination with the Vrn‐B1 gene was the most potent gene conferring early maturity. Ppd‐D1a did not alter flowering and maturity in the hard red cultivars tested in the field but did in the greenhouse. Ppd‐D1a reduced days to flowering for soft white spring wheat but did not alter maturity. The photoperiod sensitive gene (Ppd‐D1b) is being replaced with the insensitive gene, Ppd‐D1a, in most modern Canadian germplasm, suggesting its adaptive advantages in the prairies. An overall analysis of the data for the hard red class revealed a declining trend of 0.04 d yr−1 in days to maturity in cultivars released from 1885 to 2008 and an increase of 8 kg ha−1 yr−1 in grain yield. The findings of this study may aid wheat breeders selecting parents with appropriate vernalization and photoperiod gene complexes.
Reduction in Saturated and Unsaturated Hydraulic Conductivities of an Andisol by Vinasse Application
Authors: Miyamoto Teruhito , Kameyama Koji , Nakajima Toru
Published: November 2012

With the increase in the production of bioethanol, it has become urgent to establish a sustainable system for recycling vinasse that includes its application to land. The purpose of this study was to determine the impact of vinasse application on the hydraulic properties of the soil. An incubation experiment was conducted to investigate the biological effects. Temporal changes in both saturated and unsaturated hydraulic conductivities [Ks and K(ψ), respectively] after applying vinasse were measured by the falling‐head method and the steady‐state flux control method, respectively. After vinasse application, the number of bacteria increased by one order of magnitude, whereas the number of fungi increased by two orders of magnitude compared with a test with deionized water. A remarkable reduction in Ks was observed within the fourth day after vinasse was applied instead of deionized water. The reduction in Ks was due to both biological and physical clogging. We attempted to determine what factors contributed to these effects on the Ks reduction and found that 73 to 92% of the Ks reduction was caused by physical clogging due to suspended solids. The temporal reduction in K(ψ) was within one order of magnitude; however, the values of K(ψ) dropped by two orders of magnitude for the same matric potential (ψ) value at the end of each column experiment. Moreover, 91% of the increase in the total amount of organic matter came from vinasse. From the experimental results, we concluded that the reductions in both Ks and K(ψ) occurred during vinasse application and the main reason for the reductions was the physical clogging due to suspended solids.
Implementing Anisotropy Ratio to Modeling of Water Flow in Layered Soil
Authors: Widomski Marcin K. , Iwanek Małgorzata , Stepniewski Witold
Published: November 2012

Anisotropy of saturated hydraulic conductivity (Ks, m s‐1) is a major input datum required for the modeling of saturated and unsaturated water flow in soils, significantly improving the reliability of the models. But, there are several known literature reports presenting positively verified examples of modeling of infiltration in horizontally layered small‐scale soil profiles without taking anisotropy into consideration. The objective of this paper is to analyze the influence of implementing the anisotropy ratio to the two‐dimensional mathematical model of unsaturated flow in a selected small‐scale multilayered soil profile on the possible improvement of calculations results. Two methods of soil sampling for anisotropy measurement were considered—small cylinder and cubic sampling. Our numerical model reflected the profile of a single bench terrace equipped additionally with draining sand ditch, located in Olszanka, Poland. The simple regression analysis indicated that implementing the ratio of anisotropy of saturated hydraulic conductivity to the mathematical model of variably saturated water flow in the studied horizontally layered soil profiles did not result in more precise effects of time‐variable soil moisture calculations (R2 = 0.773–0.883, P = 0.05). Moreover, results of the statistical calculations for volumetric water content and vertical flow velocity, assuming isotropic and anisotropic medium with anisotropy coefficient obtained on the basis of cylindrical and cubic samples, appeared to be comparable; the notable differences were observed only in the case of calculated horizontal flow velocity.
Calibrating Canopy Reflectance Sensors to Predict Optimal Mid‐Season Nitrogen Rate for Cotton
Authors: Oliveira Luciane F. , Scharf Peter C. , Vories Earl D. , Drummond Scott T. , Dunn David , Stevens W. Gene , Bronson Kevin F. , Benson N. Ray , Hubbard Victoria C. , Jones Andrea S.
Published: November 2012

Inadequate N supply can limit yield of cotton (Gossypium hirsutum L.), while too much N can cause excessive vegetative growth and delayed maturity. Reflectance sensors offer the potential to diagnose N need and to translate this diagnosis into a variable‐rate application of N in real time. Our objective was to calibrate canopy reflectance sensors to predict economically optimal N rate (EONR) in support of variable‐rate fertilization. Nitrogen rate experiments were conducted on three soils in 2006 and 2007. Reflectance was measured with three sensors (Crop Circle, GreenSeeker, and Cropscan) at three growth stages (early square, mid‐square, and early flower) and at three heights above the canopy (25, 50, and 100 cm). Economically optimal N rate ranged from 0 to 220 kg N ha−1, suggesting that the need to diagnose EONR is great. Relative reflectance for all three sensors was weakly related to EONR at the early square stage but was related more strongly at the mid‐square and early flower stages. Regression equations were not significantly different between mid‐square and early flower stages, suggesting that a single equation could be used to translate reflectance measurements to N rates over this period. Relationship to EONR was best for all sensors when placed 50 cm above the canopy. For these stages and height, all three sensors were similarly related to EONR (r2 = 0.59 to 0.62). These relationships could feasibly support successful variable‐rate N applications to cotton.