bluuebunny/crossref_metadata_2025_split huggingface dataset:
Construction Activities Inside of Air Structures Protected From the Arctic Environment
Authors: Mangus A. R. 
Published: December 2007

ABSTRACT
A very brief overview of the seventy year history of air structures will trace the evolution to encapsulating arctic worksites. Its desirable working under controllable conditions inside an air structure because it results in higher quality of work, year-round work, and improving worker safety.
A encapsulated worksite allows the personnel to use lighter work clothing and move more effectively. Additionally, wind chill effects on people are eliminated plus problem of drifting snow over work and the tools will not occur. The lightness of an air structure allows mobility plus remote site installations by air cargo aircraft.
The manufactured air structure will last for decades like most construction equipment. Air structures can be utilized each winter to construct project after project by an active organization or sold to another firm to recover a majority of the initial cost of the facility.
An Alaskan case history of a three acre (1.21 ha) column free air structure used to shelter construction of one project during the winter of 1985 and another facility during the winter of 1986 will demonstrate these advantages. The author will relate lessons learned and successful use of this facility by two different contractors. Carbon monoxide and carbon dioxide from equipment operating inside the air-structure is the major safety issue. Unique safety concerns and worker protection will be discussed.
Arctic foundation systems for anchoring the air-structures will be presented, plus untested conceptual solutions.
Technology improvements continue to be made and the author will discuss trends in the air-structure industry that will result in more desirable product for use in the arctic.
A list of manufacturers and an extensive bibliography will be provided to assist the practicing professional or researcher.
Kuparuk River Module Crossing Case History: A Critical Arctic Oilfield Transportation Link Is Protected by a Refrigerated Foundation
Authors: Christopherson A. B. , Nottingham D. 
Published: December 2007

ABSTRACT
A case history and design review of the Kuparuk River Module Crossing and its refrigerated foundation are presented. The Kuparuk Crossing incorporated a number of design and construction innovations to meet the challenges of bridging a major Alaskan North Slope river. Among these challenges was the need for a foundation system--to be placed in a continuous permafrost bed--which could support a 2,500-ton (2.26 × 103 Mg) live load on the bridge deck. A temporary mechanical refrigeration system was provided to refreeze subgrade soil disturbed during construction of this foundation. After the removal of the temporary mechanical refrigeration, a passive thermosyphon system was employed as part of the foundation design to maintain the long-term integrity of the frozen soils. A special procedure was used to install and monitor the passive systems in the foundation piles.
The predictions of the thermodynamic design model are compared to five years of post-construction field measurements. General trends of both future performance and foundation stability are discussed and compared to design assumptions. The performance of ground temperature monitoring equipment is also reviewed.
OTH-Backscatter Power Plant Foundation Design for Warm, Ice-Rich Permafrost Soils
Authors: Foster M. L. , Washburn D. S. , Foote D. S. 
Published: December 2007

ABSTRACT
An actively refrigerated, slab on grade foundation was designed for a coal-fired electric generating facility with a total capacity of 11 megawatts. The facility was constructed to supply power to the Over-the-Horizon Backscatter site near Gakona, Alaska. The soil on which the foundation was placed consisted of relatively warm (30°F [−1°C]) permafrost consisting of ice-rich clay averaging 25%-50% total moisture. A 8.5 foot (2.6 m) thick insulated gravel pad was designed for the power plant foundation. A stress analysis for the foundation indicated that a stress of over 2900 psf (139 kPa) would be observed at the permafrost/gravel depth under the power plant boiler. Because of the temperature, properties of the soil matrix, and loading configuration, it was determined that excessive long-term creep settlement could occur. The final foundation design consisted of 55 near-horizontal thermosyphons to remove the heat transferred through the floor of the approximately 80°F (27°C) power plant. In order to add strength to the native permafrost, and thereby minimize the creep settlement, an active refrigeration system incorporating the 55 near-horizontal thermosyphons and over 30 near-vertical thermosyphons was designed to lower the temperature of the permafrost. The excess electricity generated by the power plant made active refrigeration an economically feasible solution to the creep settlement problem. The system was designed to refrigerate the permafrost from the original temperature of approximately 30°F (−1°C) to a temperature of approximately 20°F (−7°C) to a depth of 50 feet (15.2 m) below the existing natural ground level. The lower temperature will significantly increase the strength of the in situ soil, and thus reduce the amount of creep settlement. After the desired temperature is reached, the system will be operated passively to maintain the 20°F (−7°C) temperature. Eight thermistors were installed for weekly monitoring of the subgrade temperature, and weekly settlement monitoring of the foundation was recommended.
Developments in the Application of Fiber Optic Technology to Pipeline Structural Integrity Monitoring
Authors: Griffiths R. W. , Rizkalla M. , Colquhoun I. R. 
Published: December 2007

ABSTRACT
Increasingly, pipelines in unstable terrain are being monitored as a supplement to design stage integrity measures. The quantities monitored most often in this case are strains and displacements. A variety of techniques are being used and considered to assure the monitored quantities are kept within allowable limits.
This paper reviews the potential use of distributed fiber optic sensor technology for direct strain measurement in long, lineal structures such as newly constructed pipeline systems. The components of an opto-electronic system are described. Methods of attaching the fiber optic sensors to pipelines are reviewed. Data from large scale laboratory pipeline-deflection tests are presented.
Utilizing the inherent low loss of optical fibres and "optical radar" techniques, the passive distributed optical system described in this paper is shown to hold promise for high cost effectiveness in practical applications.
Dynamics of Subsurface and Geocryological Conditions in Foundations for Power Structures in the Northeast Region, USSR
Authors: Krivonogova N. F. , Kagan A. 
Published: December 2007

ABSTRACT
Subsurface and geocryological conditions impacting the construction of power structures in northeast USSR are reviewed. The sites are characterized by nonhomogeneous geological structure, cryogenic texture in the foundation rock or soil, and sharp differences in temperature conditions of the rock or soil within the foundation area. Large temperature variation is exhibited by the presence of talik zones composed of highly permeable rock confined by ice-saturated, ice-rich ground. A. significant loss of the bearing capacity and an increase in permeability of rock or soil that would endanger the stability of the structures were predicted upon thawing. However, geocryological factors were of paramount importance in adopting design solutions.
Examples of design solutions and modifications during construction included: (l) the foundation rock or soil was kept frozen; (2) talik zones, both natural or those formed during the construction, were frozen; (3) impervious elements of the storage dams were installed using refri gerating units of different types.
Effective Unconsolidated Core Preservation in the Arctic Environment: An Aid to Accurate Reservoir Evaluation
Authors: MacGregor K. W. , Park E. I. , Sincock K. J. , Piekenbrock E. J. 
Published: December 2007

ABSTRACT
Accurate data from undamaged core is key to evaluating the substantial reserves of moderate to highly viscous oil held in Arctic unconsolidated formations.
This paper describes a laboratory technique which can be used to design trip schedules to reduce gas-in-viscous-oil expansion core damage. This technique, based on X-ray CT core structure visualisation, indicates the majority of core dilation due to retrieval occurs during the last 500 psi (3.45 MPa) of decompression. Reducing the trip rate over the latter stages of the trip will therefore result in better quality core.
Improved fibretube core processing systems compact enough for Arctic enclosed rigs; and methods of preserving core structure through the rigours of Arctic transportation are also described in this paper.
Peculiarities of Rock Massif Behavior in a Zone of Transition From Subzero to Above Zero Temperatures
Authors: Chislov A. I. 
Published: December 2007

ABSTRACT
This paper reveals the results of the studies relating to a rock massif behaviour in a zone of transition from subzero to above - zero temperatures. Distribution of rock areas having above - and sub - zero temperatures and various aggregate moisture condition had been established within one horizon. For the first time underpermafrost waters had been found in the areas with tectonic disturbances and high rock jointing. While opening water - bearing areas a water inflow totalled 3-8 m3ph (up to 25m3ph), and in 4-5 months of flowing by itself it lowered to 0.6 - 1 m3 ph. Maximum rock temperature ( +0.6 °C ) was fixed during opening driving with its temperature further lowering by total the negative temperature balance of the air fed to a mine. Rock strength characteristics considerably changed for the worse comparing to the upper horizons. At was established that by rizing the temperatures from −2.2 °C to above - zero ones rock strength lowered by 18 - 20%, and by water - soaking compressive rock strength decreased by 9-55%, tensile strength by 7 - 40%, cohesion by 19 - 49%, an angle of internal friction by 6-15%, Poisson's ratio by 18-25%. The rocks of a transition temperature zone tend to freezing and partially to packing, the compressive strength of frozen together samples reaching 0.6 MPa. As a result of a pressure waters inpact washing - out of binding material from cracks takes place, what lowers the stability of mine workings.
Frequent roof and wall caving at a horizon of transition temperatures made it necessary to provide a metal arch support with tight wall and roof lagging (with a support lagging behind the face not more than 2.5 m) for mine workings.
The instability of mining workings made it necessary to change from one method of rock pressure control (pillars) to another (caving).
The conducted investigations allow to predict the behaviour of rock massif of metamorphic rocks when reaching a zone of transition from subzero to above - zero rock temperatures.
Drilling and Sampling of Permafrost for Site Investigation Purposes: A Review
Authors: Riddle C. H. , Hardcastle P. K. 
Published: December 2007

ABSTRACT
The methods used for drilling and sampling of permafrost for site investigation purposes have evolved significantly during recent years. These changes are due in part to the development of new technology and equipment. A review of the applicability of current drilling and sampling methods in various frozen subsurface materials is presented.
Effects of Total Water Content on Dynamic Properties of Frozen Soils
Authors: Fukuda M. , Huang S. L. 
Published: December 2007

ABSTRACT
A series of laboratory tests on frozen soils were conducted to investigate the variability of ultrasonic velocities passing through frozen soils in relation to changes of sample temperatures. Frozen soil samples were placed in a kerosene bath, between the transmitter and receiver of an ultrasonic device which was operated in a frequency range of 0.5 to 2.0 MHz with the dominant frequency at 1.0 MHz. The velocity of an ultrasonic wave was determined based on the differences in delay time of the first-arrival waves passing through the samples and kerosene.
Statistical analysis revealed strong correlations between the measured velocity and temperature as well as total and volumetric unfrozen water contents. The ultrasonic velocity was found to be highly temperature dependent in a range of 0°C to -10°C. At a temperature near the thawing point of ice the velocity was considerably lower than the velocity measured at a lower temperature due to an increase in unfrozen water content. A general power model was presented in this paper to describe these relationships. Three ranges of velocities were categorized in accordance with the types of soils, namely, sand, silt, and clay. Among the soils tested, sandy soil had the highest velocity at -1°C and the clayey soil had the lowest. The clayey soil was, however, more subject to temperature variation and the silty and sandy soils were less responsive. Total water content was noted to have influence on the velocity of soils as well. In general, a soil with a higher total water content has a larger velocity at -1°C, and is, however, less variable over the temperature range tested.
Slope Stability Problems in Open Pit Coal Mines in Permafrost Regions
Authors: Vakili J. 
Published: December 2007

ABSTRACT
The instability of highwall slopes, exposed to thawing, in open-pit coal mines in permafrost regions is described. Remedial measures are proposed to prevent shallow as well as deep slope failures in these regions. It is shown that by introducing a wide bench in the highwall at the bottom of the permafrost layer and by proper designing of interbench slope angles, and equipment distance from slope crest, such failure can be avoided or minimized.
Vertical Support Member Design in Areas of Ponded Water Over Permafrost
Authors: Wineland John , Yarmak Edward , Ganguly Partha 
Published: December 2007

ABSTRACT
Elevated pipelines are the norm in the North Slope oilfields. Problems were observed with tilting, settling, or frost-jacking of Vertical Support Members (VSMs) supporting portions of the abovegrade piping. Further observation showed that the majority of the problems existed where the VSMs were installed in, or adjacent to, the numerous shallow ponds or lakes that dot the tundra. Ponded water causes a condition where the local permafrost is warmer than the surrounding permafrost because much of the winter's cooling is absorbed by the phase change from water to ice and then lost during the summer due to the high solar absorbance of the water surface. To further understand the magnitude of the warming condition, a drilling program was undertaken to determine subsurface soils and groundwater conditions and temperatures. From this data, a correlation was developed between the ponded water depth and the subsurface temperature profile. Subsequently, a procedure was developed to design adfreeze (standard) VSMs, Helix VSMs, and Thermo Helix VSMs in areas of ponded fresh water. This paper presents the temperature profile of the permafrost beneath ponded water and addresses the development of design procedures for these conditions.
The Instantaneous Strain of Frozen Sand
Authors: Soo S. , Adams L. T. 
Published: December 2007

ABSTRACT
In engineering application, creep strain of frozen soil was modelled by a pseudoinstantaneous strain and a secondary creep law. The pseudo-instantaneous strain was often neglected by researchers because it is usually less than 10% of the total strain in a long term situation. Nevertheless, many cases of frozen soil structural analysis require computation of pseudo-instantaneous strain. There are two ways to determine the pseudo-instantaneous strain: (1) after separating the pseudo-instantaneous strain into an elastic strain and a plastic strain, compute the elastic strain by dividing the stress by an elastic modulus, and compute the plastic strain with a power law; (2) use a simplified approach to obtain the pseudoinstantaneous strain by dividing the stress by a secant modulus.
This project investigated the pseudoinstantaneous strain of frozen sand through a serious of uniaxial compressive tests including both constant stress (creep) and constant strain rate tests. These experiments were conducted in two large size freezers. A front-end loading machine with dead weight was used to conduct creep tests. An uniaxial compression machine with constant displacement rate control was used to conduct constant strain rate tests. Two sample sizes, 2.94 in. (74.7 mm) diameter by 7.25 in. (184.2 mm) in length and 1.45 in. (36.8 mm) in diameter by 4.375 in. (111.1 mm) in length were used. Ottawa sand passing #30 sieve and retained on #140 sieve was used. The coefficient of uniformity was approximately 1.5. Distilled water was used to mix the. samples. Sand concentration were 64 and 70 percents by volume. The sand volume fraction was determined by preweighing the amount of sand and water. Samples were frozen to desired temperature before testing. A temperature probe was embedded at the top portion of each specimen to monitor its temperature during testing. A thin membrane was used to protect the specimen from evaporating. Specimen temperature were from −5 to −11 degree C. Temperature variation during each test was within 0.5 degree C.
In creep test, specimens were loaded until the straight line portion of creep curves (secondary creep) was reached.; Then, the straight line portion of the curve was projected back to vertical axis at time zero to obtain the pseudoinstantaneous strain. The secant modulus was obtained by dividing the applied stress by the pseudo-instantaneous strain. The relation between the secant 'modulus and temperature is shown in figure 1. The secant moduli were found not sensitive to sand concentration. In constant strain rate tests, a deformation rate 0.113 inches per minute was used. Elastic-modulus was obtained from the initial slope of the stress-strain curve. The elastic modulus was shown in Table 1. The secant modulus was about 1 to 3 percent of the elastic modulus. The plastic strain was set equal to the pseudo-elastic strain since the elastic strain is negletable. Relation between the applied stress, the plastic strain, and temperature is shown in figure 2.
Acid Stimulation of Endicott Kekiktuk Formation, North Slope, Alaska
Authors: Hsi C-K. D. , Strassner J. E. , Blosser W. R. 
Published: December 2007

ABSTRACT
A combined laboratory and field study was conducted to evaluate the susceptibility of Endicott Kekiktuk formation to acid stimulation treatments and to optimize treatment performance.
Endicott crude oil causes severe sludging and emulsion problems when mixed with concentrated acids. Iron concentration aggravates emulsion and sludging problems, especially ferric ion. However, the associated permeability damage can be effectively reduced with the addition of proper antisludge/demulsification chemicals in acids and by reduction in acid strength and complexation or reduction of ferric ion. Laboratory geological analyses, acid solubility tests, and acid core flow tests further indicated that half strength mud acid gives similar stimulation performance than full strength mud acid with less weakening of rock strength and fewer fines migration problems following acid treatments.
Actual field acidizing treatments conducted at Endicott Field using 80 gal/ft half strength mud acid with proper additives have shown good productivity increases with better balanced production profiles. No evidence of fines migration has been observed in the post treatment production well testing.
Selection of the acid treatment compatible with reservoir fluids and lithology will minimize formation damage and lead to increases in production.
An Evolving Description of a Fractured Carbonate Reservoir: The Lisburne Field, Prudhoe Bay, Alaska
Authors: Missman R. A. , Jameson J. 
Published: December 2007

ABSTRACTThis paper traces the evolution in models of the Lisburne carbonate reservoir from early wildcat days, through the decision to fund primary development, to waterflood assessment. This work is an integration of geologic and reservoir studies based on nearly ten years of extensive data collection (well test, core, log, pressure and field performance data). Early reservoir descriptions assumed uniform enhancement of continuous pay layers resulting from small-scale fractures. Additional recovery over solution gas drive was expected by gravity drainage and waterflood. Integration of performance and geological data after field start-up reveal greater heterogeneity than originally thought: faults and irregularly distributed fractures dominate performance; much of the porosity is ineffective; and the producing oil-water contact (OWC) varies by as much as 300 ft [90 m]. The evolution in simulation techniques reflects the evolution in geologic models toward increased recognition of heterogeneities.The complexity of the Lisburne reservoir is a result of faulting, two periods of uplift and erosion, and three distinct phases of porosity development. Particularly important among these diagenetic events is the youngest phase of porosity development, which post-dates significant faulting. As a result, many faults are open and conductive. An additional complexity is a high permeability layer created by a laterally extensive set of small open fractures beneath an unconformity at the top of the reservoir.Initial development was based on models with limited data which understated the impact of these heterogeneities. In retrospect, several important clues and their implications were not fully appreciated. Despite extensive data collection, the unpredictable influence of fractures still creates uncertainties in reservoir description (e.g. well performance cannot be accurately predicted pre-drill).Recommendations for evaluating potentially complex carbonates include: give full weight to known uncertainties, conduct inter-well tests early in the evaluation, and minimize risk by proceeding gradually with field development.
Gas Measurement with Large Venturi Tubes at Prudhoe Bay, Alaska
Authors: Metz W. P. , Bruchie J. D. , Fritz R. H. 
Published: December 2007

Summary
Ten large diameter (24 and 30 inch) venturi tubes have been calibrated at flow rates of 40 - 220 MMscfd (10-12 million Reynolds Numbers (NRe)) and have exhibited meter flow coefficients exceeding 1.0. A check calibration was made with one of the 24-inch meters at another calibration lab at expected operating conditions of 500-900 MMscfd (30-60 million Reynolds Numbers (NRe)). This meter calibration also exhibited a meter flow coefficient exceeding 1.0 and varied from the extrapolated initial calibration data by almost 2% in the expected operating range. This check meter flow coefficient, when plotted against NRe, exhibited a non-classical shape.
Adverse Telluric Effects on Northern Pipelines
Authors: Seager W. H. 
Published: December 2007

ABSTRACT
New information regarding the effects of tellurics has been discovered by the use of special equipment to measure the true polarized pipe-to-soil potential even in the midst of a severe geomagnetic disturbance. [The Aurora Borealis (northern lights) is a manifestation of this occurrence.] Heretofore such information was not available and indeed the effect of the often observed tellurics was strictly a matter of conjecture and speculation.
We have now discovered that tellurics can and do pose a serious threat to coated pipelines in the auroral zone, extending from Northern Montana to Great Bear Lake, and of course elsewhere at similar (geomagnetic) latitudes.
The paper discusses tellurics, their origin, magnitude and frequency of occurrence, the equipment utilized to determine their effect on cathodic protection levels and more importantly, their ability to depolarize apparently well protected pipelines.
Means for successfully controlling the adverse telluric effect are also discussed.