bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-Term Performance of Sand-Control Completions in the Mokoko-Abana Field, Cameroon
Authors: Mason David , Evans Mike , Ekamba Blaise , Jones Colin , Cameron John
Published: June 2007

Choosing the most economic sand-control system from the available options is a central component in field development planning. The choice of sand-control system depends on a number of factors such as production and sand-control performance, reserves recovery, reliability, ease of installation, and life-cycle economics. Logistical and health, safety, and environment (HSE) issues are also important, especially in areas with limited support infrastructure.

A key input to the process of sand-control-system selection is data on how the various systems compare in a given environment. Ideally, this comparison should be made over time to compare properly long-term performance and reliability. These data can be obtained only by analyzing existing installations fairly and objectively.

The Mokoko-Abana field is situated offshore Cameroon. It is a mature heavy-oil field with unconsolidated formations that require sand control from the onset of production. A wide variety of sandcontrol solutions have been used in this field, with varying levels of success and performance. Cased-hole internal gravel packs (IGPs), milled-casing openhole underreamed gravel packs (MCGPs), and cased-hole frac packs (CHFPs) have been used in vertical wells. Prepacked standalone screens (PPSASs), openhole gravel packs (OHGPs), and openhole expandable sand screens (OHESSs) have been used in horizontal and highly deviated wells.

Each of the completion options now has several years of production history. This allows their initial performance and their performance over time to be modeled and compared. The wells chosen for study were in the same sand body with an installation as close to perfect as possible. The MCGP had relatively good performance, as did the CHFP; unfortunately, however, the CHFP fractured into a water-bearing leg and only added water cut. The PPSAS had initially low mechanical skins, but its performance declined quickly. The OHGP had higher initial skins, but the rate of production decline was much slower. The OHESS had a very low initial skin with no impairment over the 5-year production period.

Mason et al. (2005) provide background information on the Mokoko-Abana field and look at the productivity performance of the PPSAS, OHGP, and OHESS techniques on initial completion and after 2 years of production. This paper follows on from that work and examines the operational, productivity, reliability, and economical aspects of the completion techniques over 5 years or more of production.
An Application of Vacuum-Insulation Tubing for Wax Control in an Arctic Environment
Authors: Singh Probjot , Walker Jack , Lee Hyun Su , Gharfeh Samir , Thomason Bill , Blumer David
Published: June 2007

Several options (prevention and mitigation) for controlling wax deposition inside production wells operating in an Arctic environment are evaluated. Preventive measures include improved heat retention using vacuum-insulated tubing (VIT), active heating using electrical heating elements inside the well tubing, jet pumps using water as a power fluid, and downhole injection of paraffin inhibitors. In the field cases studied, none of these measures is 100% effective in preventing wax deposition. Mitigation methods include mechanical scraping using wireline tools and hot oiling. Again, the mitigation methods are not completely effective, and even a method with 99% effectiveness can damage the well seriously after several jobs. Cost of the wax jobs and the production downtime during the jobs are added losses. The current study showed that an optimal combination of appropriate prevention and mitigation measures is needed for adequate wax control and maximization of economic returns. Extensive field data (production rates and flowing wellhead temperatures) were collected to develop and tune the well thermal model. Laboratory flow-loop data were obtained for wax-deposition scaleup and predictions. The wax-deposition model was tuned to match the field data, including a production-rate decline attributable to wax deposition. An economic model was developed to evaluate the benefits of VIT with appropriate polyurethane coupling insulation in achieving higher production rates and lower production downtime during the wax jobs vs. the capital expense of the VIT segment. The results showed that it is highly beneficial to run the VIT, at least in the permafrost layer. Additional length of VIT below the permafrost layer has limited benefits.
Increased Assurance of Drill Cuttings Reinjection: Challenges, Recent Advances, and Case Studies
Authors: Guo Quanxin , Geehan Thomas , Ovalle Adriana
Published: June 2007

The handling of drill cuttings and other wastes generated by drilling operations is both an environmental and economic issue. With ever-tightening environmental regulations and the green operation initiatives of operators, drill cuttings reinjection (CRI) into subsurface geology is often the preferred option, allowing operators to achieve zero discharge because oily cuttings are returned to their place of origin.

When the technology was introduced about a decade ago, injection into a single well had a maximum slurry volume of approximately 30,000 bbl. Now, particularly in very large projects, several million barrels of slurry can be injected into a single well. This represents more than 1,000 times the volume of a typical hydraulic fracturing job, or more than 100 times that of earlier cuttings reinjections. In some cases, the success of the CRI operation is critical, either because there are no backup options or because the economic and environmental impacts are too significant.

This paper describes the challenges faced in CRI projects, along with recent advances and experience gained in tackling these challenges through modeling, cuttings slurry and operational procedure design, monitoring, and verification. For example, much progress has been made recently in slurry rheology design and operational procedure selection such as suspension and displacement to avoid loss of injectivity and to maximize disposal capacity and minimize health, safety, and environment (HSE) issues.

The authors will also present a risk-based approach that integrates deterministic software and tools, available data, knowledge, and experience, for modeling of geological and operational uncertainties and potential risks to increase quality assurance. Case examples will be presented to illustrate the value of this integrated approach. Best-practice guidelines and recommendations will be provided for data collection, design and engineering, operation, and monitoring.
A Comparative Study of Mechanical Properties of Density-Reduced Cement Compositions
Authors: Ravi Kris , McMechan David E. , Reddy B. R. , Crook Ron
Published: June 2007

This paper discusses the tests conducted to determine the mechanical properties and the integrity of the cement sheath when subjected to cyclic loads. In addition, the effects of well operation on cement sheaths of different mechanical properties are analyzed, and the results are discussed. The results clearly demonstrate the importance of both laboratory measurements of cement-sheath mechanical properties and engineering analysis of the effect of well operations on the integrity of the cement sheath.

Lower-density cement systems are discussed in this paper, along with how the density was lowered by incorporating conventional additives such as

Pozzolanic beads (cenospheres) Hollow glass beads Gas bubbles Water-binding additives Silica fume Fly ash

Primary cementing compositions for oilwell applications are becoming increasingly complex and challenging because of the extreme well operating conditions encountered. The stresses exerted on the cement sheath during well operations could be severe enough to damage the cement sheath and negatively affect the safety and the economics of the well.

The results discussed in this paper should help operators design a cement sheath that can withstand the stresses from well operations, thus improving the safety and economics of the wells.
Effect of IFT Variation and Wettability on Three-Phase Relative Permeability
Authors: Cinar Y. , Marquez S. , Orr F. M.
Published: June 2007

In this paper, we report experimental results that demonstrate the combined effects of variations in interfacial tension (IFT) between one pair of three phases and wettability of a porous medium on three-phase relative permeabilities. We used two analog three-phase systems, in which the IFT between two of the phases could be varied systematically while holding the IFTs between the other pairs of phases approximately constant. We report measured three-phase relative permeabilities for systems with IFTs between two of the three phases varying from 0.005 to 2 mN/m. Phase-recovery and pressure-drop data were interpreted by the combined Welge/ Johnson-Bossler-Naumann (JBN) method to yield relative permeability curves. The results obtained indicate that as IFT between the analog gas/oil pair of phases decreases, relative permeabilities for those phases increase at a given saturation. The relative permeability for the analog water phase remains nearly unchanged for water-wet porous systems, but it decreases especially at low phase saturations for oil-wet porous systems.
Spatial Error and Convergence in Streamline Simulation
Authors: Jimenez Eduardo , Sabir Kamran , Datta-Gupta Akhil , King Michael J.
Published: June 2007

Streamline models are routinely used for waterflood optimization and management and are being extended to more complex processes (e.g., compositional simulation). Despite these new developments, no systematic study has examined the underlying numerical spatial and temporal discretization errors in streamline simulation and their convergence. Such studies are a prerequisite to determining the optimal density of streamlines during simulation and ensuring the resulting accuracy of the solution.

In this paper, we first examine transverse spatial errors (e.g., errors resulting from the number or placement of streamlines). We provide an analytic proof and a numeric demonstration of the order of spatial convergence of the mass-balance discretization error. Both global and local calculations are performed, and they demonstrate the impact of stagnation regions on the order of convergence. A second transverse error arises for faulted grids, where lack of flux continuity at cell faces can lead to incorrect trajectories. These trajectory errors are of zeroth order and can be resolved only by introducing additional degrees of freedom into the streamline velocity model. Longitudinal spatial errors also arise and are associated with the inaccurate calculation of time of flight across cells.

We show that the commonly used algorithm for corner-point cells leads to inaccurate time-of-flight calculations for stratigraphic grids, depending upon aspect ratio. We provide a simple and exact means of calculating the time of flight for arbitrary corner-point cells, or unstructured grids, in two or three dimensions, for either compressible or incompressible flow. Finally, using this new time-of-flight formulation, we analyze a series of cross-sectional finite-difference simulations to identify grid-orientation errors in the numerical calculation of flux and spatial error.
Real-Time Downhole pH Measurement Using Optical Spectroscopy
Authors: Raghuraman B. , O'Keefe M. , Eriksen K. O. , Tau L. A. , Vikane O. , Gustavson G. , Indo K.
Published: June 2007

A new downhole pH sensor has been developed to provide an in-situ pH measurement of formation water at reservoir conditions, and results are presented for two wells in the Norwegian Sea. The measurement technique, for use with wireline formation-sampling tools, uses pH-sensitive dyes that change color according to the pH of the formation water. To make a real-time pH measurement, the dye is injected into the formation fluid being pumped through the tool flowline, and the relevant visible wavelengths in an optical detector are used to record the dye signal and calculate pH with 0.1-unit accuracy.

The pH of a formation fluid alters as the sample is brought to surface from the high-temperature and high-pressure conditions downhole, owing to acid gases and salts coming out of solution and changes in water-chemistry equilibria. To obtain an accurate pH, the measurement must be made downhole at reservoir conditions. Unlike potentiometric methods in which fouling of electrode surfaces by oil and mud is a potential problem, the dye technique is robust because the dye is isolated from the formation fluid and is injected into the sample only when a measurement is made. The technique has been applied successfully to both oil-based and water-based drilling muds, with successful measurements even in mixed oil/water flows. Multiple measurements of pH at a single sampling station demonstrate that the method is robust and repeatable. These measurements have been compared with numerical simulations using a multiphase chemical-equilibrium model that uses laboratory analysis of collected water samples as input.

pH is a key parameter in water chemistry and is critical for corrosion and scale studies. Accurate downhole pH measurement allows a more-accurate selection of appropriate completion materials and more-effective planning for scale treatment and inhibition.
Development, Verification, and Improvement of a Sediment-Toxicity Test for Regulatory Compliance
Authors: Dorn P. B. , Rabke S. , Glickman A. , Nguyen K. , MacGregor R. , Candler J. , Wong D. C. L. , Hood C. , Hall J. , Purcell T.
Published: June 2007

The offshore oil and gas industry has moved toward the use of synthetic-based drilling fluids (SBFs), changing potential exposure scenarios for discharged cuttings when compared to those of water-based drilling fluids (WBFs). Unlike WBFs, SBFs sorb predominately to particles in the cuttings and are not dispersed extensively into the water column; therefore, a sediment-toxicity test was required by the US Environmental Protection Agency (EPA) in addition to the existing water-column test to define a bestavailable-technology (BAT) limit. Inclusion of a sediment-toxicity test for National Pollutant Discharge Elimination System (NPDES) compliance was precedent-setting and unique. To fulfill the US EPA requirements, an interindustry research group worked with the EPA to develop a suitable test that met the technology-based discharge standard. Toxicity of discharged field drilling fluid is compared to a reference SBF (C16–C18 internal olefin), and, for compliance, the ratio of the reference-drilling-fluid median lethal concentration (LC50) to the field-mud LC50 must be ≤1.0. Before the use of this test, there were concerns that false positive results could lead to incorrectly identified noncompliance events, limiting the use of SBF technology. Consequently, initial application allowed the use of a variability factor (K-factor) in determining the ratio. After use of the compliance test was initiated, research was continued to reduce test variability and minimize false positives. This research included (1) analysis of NPDES-compliance data (500+tests), (2) two interlaboratory testing programs, (3) analysis of reference-fluid data from one commercial laboratory, and (4) refinements to test sediment type and effects on animal health. The results of these efforts to date are reviewed in this paper and are used to identify potential improvements in the application of the test as a regulatory tool.
The Power of Real-Time Monitoring and Interpretation in Wireline Formation Testing—Case Studies
Authors: Elshahawi H. , Hashem M. , McKinney D. , Ardila M. , Ayan C.
Published: June 2007

Modern wireline formation testers (WFTs) are able to collect a massive amount of data at multiple depths, thus helping to quantify changes in rock and fluid properties along the wellbore, to define hydraulic flow units, and to understand the reservoir architecture. They are being used routinely in a wide range of applications spanning pressure and mobility profiling vs. depth, fluid sampling, downhole fluid analysis (DFA), interval pressure-transient testing (IPTT), and microfracturing. Because of the complex tool strings and the elaborate operational aspects involved in wireline formation testing, success requires detailed upfront planning and procedural design as well as real-time operational and interpretational support.

It is becoming increasingly critical for operating and service company experts to remotely monitor and interpret WFT surveys in real time through Web-based systems. The importance of meeting all rock and fluid data-acquisition objectives cannot be overstated, given the high cost of offshore operations and the implications of obtaining false or misleading information. The main objective of real-time monitoring remains to assure that the planned data are acquired according to pre-established procedures and contingency plans. However, even in developed reservoirs, unexpected circumstances arise, requiring immediate response and modifications to the preplanned job procedures. Unexpectedly low or high mobilities, probe plugging, unanticipated fluid types, the presence of multiple phases, and excessive fluid contamination are but a few examples of such circumstances that would require real-time decision making and procedural modifications. Real-time decisions may include acquiring more pressure data points, extending sampling depths to several zones, extending or shortening sampling times, and repeating microhydraulic fracture reopening/closure cycles, as well as real-time permeability, composition, or anisotropy interpretation to determine optimum transient durations.

This paper describes several examples of formation tester surveys that have been remotely monitored in real time to ensure that all WFT evaluation objectives are met. The power of real-time monitoring and interpretation will be illustrated through these case studies.
Decision Making With Uncertainty While Developing Multiple Gas/Condensate Reservoirs: Well Count and Pipeline Optimization
Authors: Kabir C. S. , Gorell S. B. , Portillo M. E. , Cullick A. S.
Published: June 2007

Well-developed methodology exists for handling uncertainty for a single reservoir. However, development of multiple fields presents a significant challenge when uncertainty in a large number of variables, such as gas in place and liquid yield, occur in each reservoir. Some of the challenges stem from our need to forecast the system behavior involving a coupled reservoir/wellbore/surface (CRWS) network for the entire spectrum of variables so that facilities can be designed for the range of fluid composition and throughput. Of course, assessing well count and sequencing well drills are some of the important objectives.

This paper describes probabilistic production forecasting with a compositional CRWS network model for nine reservoirs involved in delivering gas supply to a liquefied natural gas (LNG) plant in Nigeria. Our main objective was to use an economic indicator to select the optimal design of two main pipelines, each transporting 200 and 300 MMscf/D from the two production platforms, located 15 and 5 km, respectively, from the processing platform.

Rate and cumulative profiles showed that sustained deliverability of gas could be realized for approximately 11 years before the decline occurred in high-permeability reservoirs. In other words, uncertainty in gas in place did not surface during the plateau period, only during the decline period lasting another 5 years after the first 11. In contrast, the liquid rates exhibited a large uncertainty band throughout, a direct manifestation of the condensate yield issue. The uncertainty band among each of the 12 components aided facilities design. Differences in net present value (NPV) and discounted profitability index (DPI) were used as discriminators for discerning optimal pipe size from the standpoint of project economics.
Modeling Laboratory Permeability in Coal Using Sorption-Induced-Strain Data
Authors: Robertson Eric P. , Christiansen Richard L.
Published: June 2007

Sorption-induced strain and permeability were measured as a function of pore pressure using subbituminous coal from the Powder River basin of Wyoming, USA, and high-volatile bituminous coal from the Uinta-Piceance basin of Utah, USA. We found that for these coal samples, cleat compressibility was not constant, but variable. Calculated variable cleat-compressibility constants were found to correlate well with previously published data for other coals. Sorption-induced matrix strain (shrinkage/swelling) was measured on unconstrained samples for different gases: carbon dioxide (CO2), methane (CH4), and nitrogen (N2). During permeability tests, sorption-induced matrix shrinkage was demonstrated clearly by higher-permeability values at lower pore pressures while holding overburden pressure constant; this effect was more pronounced when gases with higher adsorption isotherms such as CO2 were used. Measured permeability data were modeled using three different permeability models that take into account sorption-induced matrix strain. We found that when the measured strain data were applied, all three models matched the measured permeability results poorly. However, by applying an experimentally derived expression to the strain data that accounts for the constraining stress of overburden pressure, pore pressure, coal type, and gas type, two of the models were greatly improved.
Fundamental PVT Calculations for Associated and Gas/Condensate Natural-Gas Systems
Authors: Sutton Robert P.
Published: June 2007

Problems with existing procedures used to estimate gas pressure/volume/temperature (PVT) properties are identified. The situation is reviewed, and methods are proposed to alleviate these problems. Natural gases are derived from two basic sources: associated gas, which is liberated from oil, and gas condensates, where hydrocarbon liquid, if present, is vaporized in the gas phase. The two gases are fundamentally different in that a high-gravity associated gas is typically rich in ethane through pentane, while gas condensates are rich in heptanes-plus. Additionally, either type of gas may contain nonhydrocarbon impurities such as hydrogen sulfide, carbon dioxide, and nitrogen. Failure to distinguish properly between the two types of gases can result in calculation errors in excess of those allowable for technical work. Sutton (1985) investigated high-gravity gas/condensate gases and developed methods for estimating pseudocritical properties that resulted in more-accurate Z factors. The method is suitable for all light natural gases and the heavier gas/condensate gases. It should not be used for high-gravity hydrocarbon gases that do not contain a significant heptanes-plus component. The original Sutton database of gas/condensate PVT properties has been expanded to 2,264 gas compositions with more than 10,000 gas-compressibility-factor measurements. A database of associated-gas compositions containing more than 3,200 compositions has been created to evaluate suitable methods for estimating PVT properties for this category of gas. Pure-component data for methane (CH4), methane-propane, methane-n-butane, methane-n-decane, and methane-propane-n-decane have been compiled to determine the suitability of the derived methods. The Wichert (1970) database of sour-gas-compressibility factors has been supplemented with additional field and pure-component data to investigate suitable adjustments to pseudocritical properties that ensure accurate estimates of compressibility factors. Mathematical representations of compressibility-factor charts commonly used by the engineering community and methods used by the geophysics community are investigated. Generally, these representations/methods are robust and have been found suitable for ranges beyond those recommended originally. Natural-gas viscosity, typically estimated through correlation, has been found to be inadequate for high-gravity gas condensates, requiring revised procedures for accurate calculations.
Fiber-Optic Distributed-Temperature-Sensing Technology Used for Reservoir Monitoring in an Indonesia Steam Flood
Authors: Nath D. K. , Sugianto Riki , Finley Doug
Published: June 2007

The world's largest steamflood operation is conducted on the island of Sumatra in Indonesia. Fiber-optic distributed-temperaturesensing (DTS) surveys are used in the Sumatra fields to provide valuable data for reservoir management. The DTS profile data can determine the temperature and extent of a "steam chest," a phenomenon that occurs when steam injected into a steam-injection well moves away from the perforations until it encounters an impermeable barrier in the formation. The steam then extends laterally until breakthrough occurs at the producing well. Because oil is produced by gravity drainage, the steam chest (also known as a steam-saturated volume) grows downward. DTS surveys also have the capacity to determine the temperature gradient for either overburden or underburden reservoirs. This information is vital for properly setting steam-injection target rates. The information is also used to mitigate steam breakthroughs and eruptions, as well as to identify bypass oil.

Steamflood operations experience many types of problems, including inefficient injection rates, wasted heat to the casing, sanding in producers, liner failures, and pump failures. There is also an ongoing need to improve the efficiencies of vapor collection systems, well-test stations, and central gathering stations. Based on these challenging problems, periodic wellbore temperature surveys are required to improve heat management and, ultimately, profitability. Conventional temperature logs cannot be run in these wells without first pulling the pumps from the completion. Therefore, a fiber-optic DTS system attached to the production tubing was suggested.

This paper will present case histories of successful applications of fiber-optic DTS surveys that improved steamflood management in this steamflood field in Indonesia.

The benefits from fiber-optic DTS monitoring were

Significant improvement in the understanding of steam breakthrough zones along the pay-zone interval of production wells Improved understanding of the steam path in steam-injector wells Improvement of the real-time temperature profile in observation wells to identify steam-zone development and unswept or bypassed oil zones in the steamflood patterns
Recent Advances in Aphron Drilling-Fluid Technology
Authors: Growcock F. B. , Belkin A. , Fosdick M. , Irving M. , O'Connor B. , Brookey T.
Published: June 2007

Aphron drilling fluids are being used globally to drill depleted reservoirs and other underpressured zones. The primary features of these fluids are their unique low-shear rheology and the presence of aphrons, which are specially designed pressure-resistant microbubbles of air. However, how aphron drilling fluids work is not well understood, which limits acceptance of this technology. Recently, a study was undertaken under the auspices of the US Department of Energy (DOE) to gain some understanding of aphron drilling fluids and provide guidance about running these fluids in the filed to optimize performance.

Various laboratory techniques were applied to determine the physicochemical properties of aphrons and other components in the fluid and how they affect flow through permeable and fractured media. These included wettability and surface tension, bubble stability, radial and dynamic flow visualization, and fluid displacement tests.

One key discovery was that aphrons can survive compression to at least 4,000 psig, whereas conventional bubbles do not survive pressures much higher than a few hundred psig. When drilling fluid migrates into a loss zone under the drill bit, aphrons move faster than the surrounding liquid phase and quickly form a layer of bubbles at the fluid front. The bubble barrier and radial-flow pattern of the fluid rapidly reduce the shear rate and raise the fluid viscosity, severely curtailing fluid invasion.

Another key finding is that aphrons show little affinity for each other or for the mineral surfaces of the pore or fracture. Consequently, the seal they form is soft, and their lack of adhesion enables them to be flushed out easily during production. Equally important, the interfacial tension between the base fluid and produced oils or gases is quite low, so that produced fluids do not create a formation-damaging high-viscosity emulsion; instead, they channel through the drilling fluid with relative ease.

Depleted wells, which are very expensive to drill underbalanced or with other remediation techniques, have been drilled overbalanced with the aid of aphron drilling fluids.
Generalized Functional Models for Drilling Cost Estimation
Authors: Kaiser Mark J. , Pulsipher Allan G.
Published: June 2007

A new approach to drilling cost estimation is presented that establishes a general framework for cost estimation using a formalized systems perspective. A generalized functional approach is developed that combines regression-based techniques, as used in the Joint Association Survey (JAS), with the multidimensional attributes of drilling, as incorporated in the Mechanical Risk Index (MRI), Directional Difficulty Index (DDI), and Difficulty Index (DFI) models. A generalized methodology for framing the drilling cost estimation problem is presented and illustrated using a stylized example.
The Effect of Friction on Initial Buckling of Tubing and Flowlines
Authors: Mitchell Robert F.
Published: June 2007

The introduction of friction into the analysis of buckling stability causes problems. For sliding friction, the friction force is fully developed for small lateral motion, while the destabilizing effect of the axial force is proportional to the lateral motion. Because the sliding-friction force develops so rapidly and destabilizing effects develop so slowly, buckling is essentially impossible.

Yet we know that pipe buckles with friction. In conventional analysis, the only possible way for buckling to occur is to have an initial nonzero lateral displacement, so that the axial-force contribution can exceed the fully mobilized friction force. This initial displacement cannot normally be estimated accurately, so the force needed to buckle pipe with sliding friction is essentially unknown.

A cylindrical pipe has another possible mode of lateral displacement. Instead of sliding, the pipe can roll. In this case, the friction force developed is static friction. Static friction may take on any value between zero and the peak static-friction value, where the value of the static friction usually is determined from a balance of known forces in the problem of interest. Here, the magnitude of the static friction is determined from a balance of torsional forces on the pipe. The key fact is that the friction force develops gradually, so a critical buckling force can be determined in the traditional sense.

The introduction of axial torque adds further complications to the buckling analysis. This paper develops a comprehensive model for pipe undergoing axial forces and torque and then develops the critical buckling loads for three cases of interest. The first case corresponds to the pipe in the wellbore, as investigated by Dawson and Paslay (1984). The second problem looks at a pipe lying on a flat plane, for example a pipeline on the seabed. In both cases, a critical buckling load is determined for pipe in which lateral motion is constrained by friction. The third case involves a rotating pipe and determines its critical buckling load. Several sample calculations are performed to illustrate the importance of friction forces in ensuring the stability of tubing and of seafloor flowlines.
Limited Capacity for Contour Curvature in Iconic Memory
Authors: Sakai Koji
Published: June 2007

We measured the difference threshold for contour curvature in iconic memory by using the cued discrimination method. The study stimulus consisting of 2 to 6 curved contours was briefly presented in the fovea, followed by two lines as cues. Subjects discriminated the curvature of two cued curves. The cue delays were 0 msec. and 300 msec. in Exps. 1 and 2, respectively, and 50 msec. before the study offset in Exp. 3. Analysis of data from Exps. 1 and 2 showed that the Weber fraction rose monotonically with the increase in set size. Clear set-size effects indicate that iconic memory has a limited capacity. Moreover, clear set-size effect in Exp. 3 indicates that perception itself has a limited capacity. Larger set-size effects in Exp. 1 than in Exp. 3 suggest that iconic memory after perceptual process has limited capacity. These properties of iconic memory at threshold level are contradictory to the traditional view that iconic memory has a high capacity both at suprathreshold and categorical levels.
Effects of Part-Set Cuing on Experienced and Novice Chess Players' Reconstruction of a Typical Chess Midgame Position
Authors: Drinkwater Kenneth , Dagnall Neil , Parker Andrew
Published: June 2007

A typical midgame chess position was presented to participants for 30 sec. Participants then reconstructed the presented position on a second board from memory. Following a brief distraction phase, participants were asked to reconstruct the position a second time with 0, 6, or 12 of the original pieces present. It was hypothesized that cue presentation during second reconstruction would be more disruptive to experienced players' recall than to novices'. Recall was measured in terms of correct pieces placed, new items generated (reminiscence), and previously recalled items omitted (forgetting). Analysis indicated that cues neither facilitated nor inhibited recall: experienced players performed better than novice players across recall indices, with the exception of reminiscence at which both groups performed similarly.
Motion Sickness History, Food Neophobia, and Sensation Seeking
Authors: Alley Thomas R. , Willet Kathleen A. , Muth Eric R.
Published: June 2007

Motion sickness is believed to be caused by conflicting sensory signals, a situation that mimics the effects of ingesting certain toxins. Thus, one might suspect that individuals who have experienced a relatively high frequency of motion sickness may be particularly vigilant about avoiding anything that produces nausea, including potentially nauseating toxins. Consequently, they may be more resistant to trying new foods, i.e., be more food neophobic, since unfamiliar foods can have unexpected adverse effects due to toxins or allergens. Likewise, many highly stimulating experiences can trigger motion sickness, so individuals who are more susceptible may be more prone to avoid such experiences, i.e., be less sensation seeking. Finally, it was expected that food neophobia would be more frequent in individuals low on sensation seeking tendencies. Self-reported motion sickness history in 308 adults ( M=18.8 yr.; SD=1.6) was correlated with scores on the Arnett Inventory of Sensation Seeking and the Food Neophobia Scale. As predicted, greater history of motion sickness was associated with lower Sensation Seeking scores. Food Neophobia was not correlated with motion sickness history but, as expected, was negatively correlated ( r = –.42) with scores on Sensation Seeking. Further research is recommended that measures actual sensitivity to motion sickness.
Hand and Eye Preference and Their Association with Task Approach by Preschoolers
Authors: Mahone E. Mark , Wodka Ericka L. , Hiemenz Jennifer R.
Published: June 2007

Hand preference, eye preference, and the concordance of hand-eye preference were assessed in 99 healthy preschool-age children (46 boys: Mage = 55.4 mo., SD = 10.5 and 53 girls: Mage = 53.6 mo., SD = 11.8). Children were also administered neuropsychological measures requiring attention and reaching to both sides of midline including the Peabody Picture Vocabulary Test, Third Edition, Multiple Boxes Test, Developmental Neuropsychological Assessment Visual Attention, and Imitating Hand Positions. All groups performed in the average range using standard administration and scoring of the neuropsychological tests, and no significant differences were found in performance between those with left- versus right-hand preference, left-versus right-eye preference, or concordant versus discordant hand/eye preference. In contrast, significant differences were noted in task approach to neuropsychological measures depending on hand preference. Rate of left-hand preference in this sample was consistent with that seen for adults; and rate of left-eye preference, and hand/eye concordance remained stable across age groups 3 to 6 years. While the presence of left-hand or -eye preference or discordance in the preschool years appears to be a benign characteristic in relation to standardized test performance, some aspects of test-taking efficiency may be affected.
Relationship of Dysfunctional Sport Fandom with Dislike for Rivals in a Sample of College Students
Authors: Smith Jana , Wann Daniel L.
Published: June 2007

The relationships among sport-fandom dysfunctionality (tendencies toward complaining and confrontation as assessed via the Dysfunctional Sport Fandom Scale) and items assessing team identification (assessed via the Sport Spectator Identification Scale) were examined with 87 college students (24 men, 63 women, M age = 20.2 yr.). Although positive associations of dysfunction and identification were found, contrary to expectations, the relationship between dysfunction and dislike for rivals was not particularly strong.
Spontaneous Eye Blink Rates Vary According to Individual Differences in Generalized Control Perception
Authors: Declerck Carolyn H. , De Brabander Bert , Boone Christophe
Published: June 2007

This study tested the hypothesis that individual differences in generalized control perception for 43 undergraduate adults may be reflected in Spontaneous Eye Blink Rates during conversation in an interview. Control perception was assessed by means of Rotter's internal-external Locus of Control questionnaires, while Spontaneous Eye Blink Rates were computed from filmed videos of interviews consisting of a series of questions which could presumably have triggered different mental states. Pearson correlations and linear regression analyses indicated that the individual differences in Spontaneous Eye Blink Rates did not differ significantly across different questions, but that Spontaneous Eye Blink Rates measured over the entire interview correlated positively and significantly with an internal Locus of Control ( r = .26). This could be interpreted as modest but corroborative evidence that a personality trait reflecting control perception may have a biological component. The possible roles of dopamine neurotransmission and frontal cortex involvement in higher cognition and Locus of Control are discussed.
Contingent Muscular Tension during a Choice Reaction Task
Authors: Araki Masanobu , Choshi Koji
Published: June 2007

This study examined the effects of contingent muscular tension on a choice reaction task, and especially, the effects various amounts of muscular tension have on the information processing of choice reaction time. The reactive movement task included a choice reaction task. Ten right-handed healthy men (ages 18 to 19 years) underwent trials with stimulus presentation probabilities of 50% and 20% on the muscular tension task and choice reaction tasks. The conditions for the muscular tension tasks were divided into seven different conditions: 0%, 10%, 20%, 30%, 40%, 50%, and 60% of maximum voluntary contraction. On these tasks, subjects performed isometric contraction of the biceps brachii. The choice reaction task was a rapid extension of the left or right knee as a choice reaction. Measures were choice reaction time, movement time, and total reaction time. Analysis indicated that shortening choice reaction time of the left and right feet was observed under 10% muscular tension of maximum strength. Muscular tension appreciably influenced information processing, including choice reaction time. Muscular tension did not affect movement time. Results are discussed with respect to previous research and the optimal muscular tension for best performance.
Sensitivity to Sensoriprocessing, Self-Discrepancy, and Emotional Reactivity of Collegiate Athletes
Authors: Kemler David S.
Published: June 2007

This study investigated how differences between athletes who scored low and high on sensoriprocessing sensitivity apply self-discrepancies and emotional reactions to competitive sporting events. Two hypotheses were proposed: The High Sensitivity group ( n = 33) would score higher for anxiety, guilt, and shame, and lower on pride and report more stress attributed to self-discrepancies than the Low Sensitivity group ( n = 32) following competitive sports events. Collegiate varsity athletes were administered the High Sensitivity Scale prior to competition and completed the Selves Questionnaire and the Goal Congruent and Incongruent Emotion Scale immediately after competition. Scores for the High Sensitivity Scale were used to separate athletes into high and low sensitivity groups. A multivariate analysis of variance and subsequent univariate analyses indicated that the High Sensitivity group reported higher scores on anxiety, shame, and stress than the Low Sensitivity group. This was interpreted as reflecting differences between both ideal and ought self-discrepancies.
Social Ecology of Intelligence and Suicide in the United States
Authors: Voracek Martin
Published: June 2007

Two proxy variables for regional intelligence, state-level mean scores of 1994–2004 on the American College Test and of 1982, 1993, 1994, and 1998–2004 on the Scholastic Assessment Test, were consistently positively correlated with the averaged regional U.S. suicide rates of 1990–1994. The effects observed in these ecological (group-level) analyses were of small size, with correlation coefficients ranging from .05 to .25, thus mostly falling below the nominal statistical significance level. The present evidence nevertheless adds to several recent findings from international geographical studies by Lester and by Voracek of a positive association of intelligence and suicide mortality by indicating that this pattern may also exist on the within-nation level.
Multidimensional Comparison of Anxiety Direction and Burnout over Time
Authors: Wiggins Matthew S. , Cremades J. Gualberto , Lai Christopher , Lee Jonguck , Erdmann Jeremy B.
Published: June 2007

The purpose of this study was to assess if athletes who perceived their trait anxiety to be debilitative to performance also experienced higher burnout over a competitive season. Volunteers were 53 NCAA Division I and II male ( n = 14) and female ( n = 39) athletes, ages 18 to 23 years. Participants completed a trait version of the Competitive State Anxiety Inventory-2D once and the Athlete Burnout Questionnaire three times during the season. A 2 (anxiety direction group) x 3 (time of season) multivariate analysis of variance indicated no significant interaction and no main effect for time of season. A significant main effect for anxiety direction group did emerge, with the Facilitative group reporting significantly lower Burnout scores overall on the Reduced Sense of Accomplishment scale than the Debilitative group. There were no differences found on the other two subscales, Emotional/Physical Exhaustion and Devaluation.
Field Dependence—Independence and Participation in Physical Activity by College Students
Authors: Liu Wenhao
Published: June 2007

Field-independent individuals, compared with field-dependent individuals, have higher sports potential and advantages in sport-related settings. Little research, however, has been conducted on the association of field dependence–independence and participation in physical activity. The study examined this association for college students who participated in physical activities in and beyond physical education classes. The Group Embedded Figures Test distinguished 40 field-dependent from 40 field-independent participants. Activity logs during one semester showed that field-independent participants were significantly more physically active and their physical activity behaviors were more sport-related than those of field-dependent participants.
Theory of Mind and Executive Function: Working-Memory Capacity and Inhibitory Control as Predictors of False-Belief Task Performance
Authors: Mutter Brigitte , Alcorn Mark B. , Welsh Marilyn
Published: June 2007

This study of the relationship between theory of mind and executive function examined whether on the false-belief task age differences between 3 and 5 years of age are related to development of working-memory capacity and inhibitory processes. 72 children completed tasks measuring false belief, working memory, and inhibition. Significant age effects were observed for false-belief and working-memory performance, as well as for the false-alarm and perseveration measures of inhibition. A simultaneous multiple linear regression specified the contribution of age, inhibition, and working memory to the prediction of false-belief performance. This model was significant, explaining a total of 36% of the variance. To examine the independent contributions of the working-memory and inhibition variables, after controlling for age, two hierarchical multiple linear regressions were conducted. These multiple regression analyses indicate that working memory and inhibition make small, overlapping contributions to false-belief performance after accounting for age, but that working memory, as measured in this study, is a somewhat better predictor of false-belief understanding than is inhibition.
Order of a ‘Uniform Random’ Presentation on Contextual Interference in a Serial Tracking Task
Authors: Sugiyama Masato , Araki Masanobu , Choshi Koji
Published: June 2007

The purpose of the present study was to examine the effect of order of a ‘uniform random‘ presentation on contextual interference in a serial tracking task. Subjects ( N = 48) were randomly assigned to either a random condition or a blocked condition in the acquisition phase, in which they learned three patterns of serial tracking tasks. Subjects performed retention and transfer trials either in a blocked or a ‘uniform random’ order. Analysis indicated, in comparisons of performance among conditions, ‘uniform random’ presentation in the acquisition phase did not improve learning in retention and transfer phases. The results are discussed with regard to both theoretical significance to contextual interference and the nature of ‘uniform random’ presentation.
Judgments of Grammaticality of Japanese Simple Sentences Involving Two Arguments in a Whole-Part Relation: A Further Examination of Chomsky's Principle of Full Interpretation
Authors: Nagata Hiroshi
Published: June 2007

Adult Japanese speakers judged the grammaticality of simple ungrammatical sentences involving two arguments, each related with a single verb. The arguments were attached to the same case marker playing the same thematic role in the sentences. Thus the sentences violated Chomsky's principle of Full Interpretation. The two arguments were manipulated such that, on the one hand, one argument (the part-argument) constituted a part of the other argument (the whole-argument) and that, on the other, a part-argument either preceded or followed a whole-argument. Participants rated the sentences using either a conventional 7-point rating scale or magnitude estimation. Findings showed that irrespective of rating method sentences in which the whole-argument preceded the part-argument were judged more grammatical than sentences in which the part-argument preceded the whole-argument. Such an empirical phenomenon is inconsistent with the prediction derived from Chomsky's principle of Full Interpretation, while interestingly it is consistent with the grammar of classical Japanese used about 900 years ago.