bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Stimulation Technique: High Strength Crosslinked Acid
Authors: Pabley Avtar S. , Holcomb David L.
Published: December 2007

A new revolutionary crosslinked high strength hydrochloric acid system (patent pending) has been developed which provides much better retardation of acid activity on the formation than the existing retarded acid systems1,2. The retardation effect has been established by laboratory testing up to temperatures of 350°F (176.7°C).

Now, the acid gel having hydrochloric acid concentrations of 14% to 28% and a pH less than one can be crosslinked for effective retardation. This new crosslinked acid has high viscosity with shear stability providing perfect support for proppants. Additionally, this new system has excellent clay stabilization and emulsion prevention properties.

Field treatments using this new crosslinked acid system for the Greater Aneth, San Juan County, Utah, will be discussed.
Preliminary Estimation of The Reservoir Capacity and the Longevity of the Baca Geothermal Field, New Mexico
Authors: Bödvarsson Gudmundur S. , Vonder Haar Stephen P. , Wilt Michael J. , Tsang Chin Fu
Published: December 2007

A 50 MW geothermal power plant is currently under development at the Baca site in the Valles Caldera, New Mexico, as a joint venture of the Department of Energy (DOE), Union Oil Company of California and the Public Service Company of New Mexico (PNM). To date, over 20 wells have been drilled on the prospect, and the data from these wells indicate the presence of a high-temperature liquid dominated reservoir. In this paper, data from open literature on the field are used to estimate the amount of hot water in place (reservoir capacity) and the length of time the reservoir can supply steam for a 50 MW power plant (reservoir longevity).

The reservoir capacity is estimated by volumetric calculations using existing geological, geophysical and well data. The criteria used are described and the sensitivity of the results discussed.

The longevity of the field is studied using a two-phase numerical simulator (SHAFT79). A number of cases are studied based upon different boundary conditions, and injection and production criteria. Constant or variable mass production is employed in the simulations with closed, semi-infinite or infinite reservoir boundaries. In one of the cases, a fault zone feeding the production region is modeled. The injection strategy depends on the available waste water. The results of these simulations are discussed and the sensitivity of the results, with respect to mesh size and the relative permeability curves used, are briefly studied.
Pressure Transient Analysis of Geothermal Wells with Phase Boundaries
Authors: Home Roland N. , Satman Abdurrahman , Grant Malcolm A.
Published: December 2007

The analysis of pressure tests in geothermal reservoirs is often complicated by two-phase effects. This paper investigates the effect of a phase boundary at a constant radial distance from the well, produced, for example, by the flashing of a water reservoir during production or by the injection of water into a steam or two-phase reservoir. This configuration may be recognized from a time shift in the buildup (or falloff) semilog straight line, and, in some cases, the distance to the phase boundary can be estimated by plotting the transition pressure response against time on cartesian coordinates. Field data from the Broad-lands geothermal field in New Zealand confirms the applicability of the technique and demonstrates that the injected volume (which is known) may be used with the buildup data to calculate porosity and "swept" volume.

The analysis also indicates the possibility of determining compressibility and permeability contrasts across the phase boundary. This enables estimation of the reservoir porosity and relative permeabilities in the two-phase region. In a few cases, wellbore storage effects can disguise the pressure response and make parameter determination more difficult. These cases are discussed.
Economic Sand Control and Stimulation Strategy for Marginal Wells with Limited Reserves
Authors: Morrison T. L. , Smith K. C.
Published: December 2007

This paper presents a detailed case history showing the practical use of monobore and vent-screen completions to produce from reservoirs that are marginally commercial.

Marginal well completions can become a viable economic possibility through (1) advancements using monobore and vent-screen completions, (2) innovative application of sand control products, and (3) 3-D modeling. The three-part completion strategy presented below shows that a sand-control fracture treatment can be economically efficient in marginal wells that would not have historically justified such completion.

Perform the completion process without a rig on location. All elements of the strategy must have this element as a primary consideration. Plan and prepare for the delivery of the completion in a manner that is practical, economic, and timely, so that job quality and safety are not compromised. Integrate new and existing technologies to create a fresh approach to provide economic solutions for both sand control and stimulation of the well.
Rheological Evaluation of Cement Slurries: Methods and Models
Authors: Bannister Charles E.
Published: December 2007

The determination of the rheological behavior of cement slurries is essential for the proper evaluation of displacement pressures and flow rates for optimum cement placement. Several cement slurries have been examined, using pipe flow and concentric cylinder viscometers, in an effort to determine which method is better suited for determining such flow characteristics. Comparative analysis of the data indicates that the concentric cylinder viscometer may be inadequate for measurement of the rheological properties of cement slurries.

Studies using a pipe-flow rheometer indicate that an apparent "slip" at the pipe surface occurs during rheological evaluation of cement slurries. This wall "slip" is attributed to particle migration when cement slurries are sheared. Field evaluation of the rheological properties of cement slurries flowing in large diameter pipes confirm the results of the pipe-flow rheometer.

Based on data obtained with a pipe-flow rheometer, a recommendation is offered as to which mathematical model most accurately describes the flow characteristics of cement slurries.
Multi-Well Operational Optimization for Maximum Production
Authors: Kappos L. , Economides M. J.
Published: December 2007

A typical oil and gas surface production scheme consists of gathering systems where individual wells are connected en route to a common separator. These wells are invariably at differing distances and may also be connected with different size pipelines and other pressure-reducing devices. However, they do have some overriding commonalities: they are all expected to be culminating into a common pressure at the separator and, often, at the other end they also start at a common pressure, that of the reservoir. The latter is time dependent, reflecting reservoir depletion. The production rate greatly depends on the well "plumbing", the surface network and, of course, the fluid properties. The pressure drop depends on the flow rate and the inlet pressure and the system temperature. In such a situation, production engineers have a number of tools at their disposal to maximize the production rate: a more drastic approach is to change the production tubing and/or the surface pipelines, add pumps etc. A more benign approach is to optimize the choke sizes and, especially, anticipate, the time of such choke changes or work in the system a schedule for variable choke adjustments.

We have developed a multi-well network optimization scheme that uses a mathematical solver, which employs a large number of equations, which, when solved simultaneously, allow the finding of the system optimum rate, points towards the appropriate choke sizes (as the reservoir pressure declines) and re-sizes the diameter of the surface network tubulars. We present here both the methodology and example applications for natural gas gathering systems.
Numerical Simulation of the Imbibition Process in Fractured Reservoirs
Authors: Menouar Habib , Knapp Roy M.
Published: December 2007

This paper describes an algorithm for simulating matrix fractured reservoirs. Response curves for individual matrix blocks developed by numerically simulating the inhibition processes in individual blocks for several sets of boundary conditions are coupled in an iterative process to describe vertical water movement and oil production in the simulator. This simulator can be used to estimate the efficiency of water-flooding in matrix fractured reservoirs as a function of reservoir and matrix block description and planned waterflooding rates.

The simulator has been used on an example reservoir to develop some general results and conclusions. For matrix fractured reservoirs, ultimate recoveries will be greater if there are relative few blocks in the vertical direction and flooding rates are kept low. If individual blocks are tall and flooding rates are high low recoveries can be expected. The water oil ratio increases more rapidly in matrix fractured reservoirs after water breakthrough than in homogeneous reservoirs.
An Experimental Investigation of the Effect of the Conductive Matrix on the Physical and Electrical Properties of Saudi Sandstone Reservoir Rocks
Authors: Zaafran Zaher M. , Totonji Ahmad M.
Published: December 2007

Laboratory studies of saturated sandstone samples collected from Saudi Oil Fields showed that the sandstone exhibits conductive matrix. Formation Factor of the reservoir rocks is measured under different water salinities and correlated with rock porosities. A relationship between the Formation Factor and the corresponding water quality is also determined.

The study has its merit not only in electric log interpretation but also in the Study of Fundamental rock Parameters which are of great use in reservoir engineering.
Application of Build-Up Transient Pressure Analysis to Well Deliverability Forecasting in Gas Condensate Reservoirs Using Single-Phase and Two-Phase Pseudo-Pressures
Authors: Bozorgzadeh M. , Gringarten A. C.
Published: December 2007

The ability to predict well deliverability is a key issue for the development of gas condensate reservoirs. We show in this paper that well deliverability depends mainly on the gas relative permeabilities at both the end point and the near-wellbore saturations, and on the reservoir permeability. We then demonstrate how these parameters and the base capillary number can be obtained from pressure build-up data by using single-phase and two-phase pseudo-pressures simultaneously. These parameters can in turn be used to generate gas pseudo-relative permeability curves. Finally, we illustrate this approach with simulated build-up pressure data before applying it to an actual field case.
Deep Ocean Coring - Recent Operational Experiences of the Deep Sea Drilling Project
Authors: Larson Valdemar F. , Robson V. Barry , Foss Glen N.
Published: December 2007

During recent years, many changes and innovations in deep sea drilling techniques and equipment have been required to meet the objectives of an increasingly sophisticated and diversified scientific program. These include such developments as a deep-penetrating hydraulic piston corer, drill string design improvements and a bit releasing mechanism. Methods of deploying instrumentation for specialized geophysical investigations were devised. An additional challenge lay in maintaining the efficiency of the drilling vessel in the face of a research schedule with an increasing amount of on-site time and rising operating costs.
Adding Value through Integrated Research to Unlock the Tight Gas Potential in the Rotliegendes Formation of North-Germany
Authors: Gaupp R. , Liermann N. , Pusch G.
Published: December 2007

The deep Rotliegendes sandstone deposits in North-Germany are estimated to carry natural gas resources of some 300-500 billion cubic meters. The distribution of the diagenetically altered Permian Basin deposits was identified by 3-D seismic survey of 200 square kilometers, well log analyses of 46 exploratory and production wells and of approximately 1200 meters of cores. A scientific analysis and interpretation of this data was achieved in a joint-industry, university and research institutes-project, co-ordinated by DGMK. The most important geologic and geophysical findings can be summarized: Diagenetic patterns correlate with reservoir properties in tectonically controlled compartments. Seismic facies classes distinguish major reservoir characteristics. Early oil (and other HC) migration appears to be a dominant factor in the reservoir quality evolution of the later tight gas reservoirs. Best perme-abilities are encountered in settings with late stage dissolution porosities adjacent to former oil accumulations and migration paths.

No presently open natural fracture systems have been identified in the tight formation. The extremely low permeability of less than 600 micro-Darcies of the rock matrix under in-situ stress conditions requires the application of horizontal well technology combined with multiple hydraulic fracturing, which could be used successfully in many cases, although less successful tests have been reported.

The water sensitive rock can entrap fracture fluid filtrate, which damages the potential productivity of the fractured wells (hydraulic skin). The key parameters of this rock-liquid inter-action-the interfacial tension and the liquid mobility-have been identified by numerical simulation as being responsible for sustaining hydraulic skin effects. Solid production in form of illite fines as well as broken quartz grains in the early production phase of the fractured wells indicates a further potential form of productivity damagea mechanical skin, induced by the disintegration of the rock during the dilatant deformation in the fracture pressure build-up phase.
Evaluating Uranium Deposits for Solution Mining
Authors: Stover Dennis E.
Published: December 2007

In situ leaching of uranium has rapidly developed into a commercial technology. The extent of this development is typified by the fact that many mining feasibility studies now routinely examine in situ leaching as well as the conventional shaft and open pit options.

A methodology for evaluating the leachability of a uranium ore body is presented. Extensive coring of the ore body and testing of ore samples are necessary to establish the quality, quantity, and leachability of the ore. A testing program which provides the necessary data in a rapid, yet thorough fashion, is discussed.
Pumping Well Analysis
Authors: Alexander Lloyd G.
Published: December 2007

This paper presents a new, patented1,2 approach to the testing and evaluation of a pumping oil well.3 For an actively pumping well, the test provides the flowing bottom-hole pressure, the flow rate at which gas is liberated up the annulus, and the pumping rate of the bottom-hole pump.

When the well is shut in, the technique can be used to determine the bottom-hole pressure as a function of time. This information can be used in conventional pressure-buildup analysis for damage, transmissibility, and static pressures.
Regulatory Impacts on Major Energy Projects
Authors: Barton Hugh B. , Hester Carl T.
Published: December 2007

Environmental laws and other regulatory restraints have seriously hampered progress toward achieving national objectives of greater energy self-sufficiency. Significant energy projects have been stymied by the instability of regulations and erosion of economic liberties. Although there are encouraging signals of a move toward a more practical regulatory climate for the energy industry, advocates of this movement must support it strongly while the momentum is building. Several definitive methods are suggested as potential avenues to re-establish a greater degree of economic freedom so important to the long-term strength of our nation.
Development of Technology for Downhole Steam Production
Authors: Fox Ronald L. , Donaldson A. Burl , Mulac Anthony J.
Published: December 2007

Two concepts for downhole production of steam for drive operations have been selected for comparative development. The two designs differ in method of transferring heat from hot combustion gases to produce steam. A low pressure combustion design transfers energy to water through a heat exchanger thus enabling the combustion process to be conducted at a pressure less than the injection pressure; a high pressure combustion design mixes the combustion gases directly with water, resulting in the injection of steam and combustion gases into the reservoir.

The comparative development program has included analysis of energy efficiency, computational examination of recovery, core recovery experiments, and field evaluation.

Field tests have been conducted under low reservoir injection pressure (2.76 MPa). The tests were carried out in a 260 m (800 ft) deep reservoir utilizing a 2.5 acre five spot pattern. Data collected from injection and production wells included fluid flow rates, fluid compositions, and energy content. The reservoir conditions were monitored by a combination of global flow measurements and simultaneous core flow tests. Test results have demonstrated that the recovery with the high pressure combustion design is equivalent to the low pressure design at low reservoir pressure. The injection of combustion gases with steam have reduced the quantity of air contaminents released to the atmosphere.
Sloss Micellar/Polymer Flood Post Test Evaluation Well
Authors: Taggart Davis L. , Russell George C.
Published: December 2007

A successful post-test evaluation well was drilled in the Sloss Field, Kimball County, Nebraska, following a micellar-polymer flood. Drilling and sampling procedures are discussed which help insure valid data. Sulfonate loss, adsorption plus partitioning, was determined to be 0.4 of a pound per barrel (1.1 Kg/m3) of pore space. From core analysis and logging survey, oil was displaced over the entire pay interval from the average post waterflood residual of 30%, although some of the lower permeability zones had a final oil saturation of up to 16% compared to the average of 8%. The polyacrylamide polymer used in the mobility control bank was severely degraded causing the loss of mobility control. The degradation was not caused by a simple thermally induced hydrolysis. Limited tests indicate well workover fluids may have contributed to the degradation.
A Laboratory Study to Determine Physical Characteristics of Heavy Oil After CO2 Saturation
Authors: Miller John S. , Jones Ray A.
Published: December 2007

Petroleum recovery techniques are being developed by laboratory experimentation by personnel at the Bartlesville (Okla.) Energy Technology Center, U. S. Department of Energy. These techniques are being studied and developed to aid production from shallow, low productivity, heavy oil sand deposits in southeastern Kansas, southwestern Missouri and northeastern Oklahoma.

Heavy oil samples ranging from 10 to 17° API gravity (1.000 to 0.953 g/cm3) were tested to determine physical characteristics of heavy oils before and after CO2 saturation. The experimentation was conducted using a modified PVT apparatus designed and constructed at BETC.

Viscosity, density, saturation and swelling factor were determined at temperatures of 75°, 140° and 200°F (24°, 60° and 93° C) and at eleven pressures ranging from 200 to 5,000 psi (1400 to 34,500 KPa) at each temperature.
Results of a Micellar-Polymer Flood in a Flooded-Out, Low Gravity Reservoir
Authors: Staub Harrison L.
Published: December 2007

This paper presents the early results of a micellar-polymer demonstration project in the Wilmington Field, California. This project is a joint venture between the City of Long Beach and the U. S. Department of Energy, designed to establish a tertiary oil recovery technique applicable to unconsolidated low-gravity oil sands typical of many in the California Coastal Province. The pilot area is located on the flank of an essentially watered-out reservoir and contains about 10 acres with an average net thickness of 58 feet.

This paper briefly describes some of the early problems encountered in initiating the project, how they were solved, and their possible effect on the final outcome of the flood. The results of a tracer test program are reviewed and related to the initial response to the chemical chemical injection. Some operational difficulties relating to breakthrough of the chemical constituents are revealed. The current response to micellar-polymer injection is presented and analyzed.
Performance of Deutsche Texaco AG's Oerrel and Hankensbuettel Polymer Floods
Authors: Maitin Balram K. , Volz Hartwig
Published: December 2007

In 1975 Deutsche Texaco AG initiated a polymer pilot flood in a part of the Oerrel field. The main objective was to plug off a zone of high permeability in the reservoir and hereby improve the areal sweep efficiency of flood operations. A second polymer project was brought into operation in a part of the homogeneous Hankensbuettel field in 1977.

In this paper flood performance is described. Both floods are considered successful and polymer application was extended to larger parts of both fields.
Immiscible Displacement Of Oil By Simultaneous Injection Of Water And Nitrogen
Authors: Slack William W. , Ehrlich Robert
Published: December 2007

Mobilization of waterflood residual oil by simultaneous injection of water and nitrogen is possible in some cases even where nitrogen and oil are immiscible and no swelling, viscosity reduction or vaporization of oil occurs. Residual oil saturation reduction is found to depend very strongly on three-phase relative permeability characteristics. For Berea sandstone, reductions of up to 18% PV were measured.

Numerical simulation of water-nitrogen flooding was used to predict process performance in real reservoir geometries and to study the effects of water-nitrogen ratio, kv/kh and permeability profile. Results show that despite gravity segregation, immiscible water-nitrogen flooding is capable of recovering an appreciable fraction of waterflood residual oil at reasonable nitrogen-oil ratios and in reasonable times.
Calcium Effects in the DOE Surfactant-Polymer Pilot Test
Authors: Lorenz Philip B. , Tham Min K.
Published: December 2007

The surfactant and polymer slugs for the chemical recovery pilot test operated by DOE were designed to be effective at the divalent ion concentration of the injection water. Laboratory tests indicated that even if there were no intrusion by the formation brine, the slugs would experience an increase in divalent ion content on contact with the rock. It was found that with calcium present, optimal salinity of the surfactant system was reduced by 4 to 7 times the amount of calcium on an equivalent basis. The minimum IFT was raised 4-fold by 8 eq/m3(meq/L) of calcium, but the valley was much broader. The distribution of calcium indicated that it occurred primarily in the surfactant phase. Empirical equations were developed for calculating the effect on polymer viscosity of polymer concentration, salinity, and calcium. Over a range of polymer concentrations and salinities, calcium had close to 10 times more effect on viscosity than an equivalent increase in salinity. It was found that calcium from the rock played a major role in surfactant behavior, but affected polymer behavior in only a minor way.
Enhanced Oil Recovery Incentives (And Dis-Incentives) From a Producer's Standpoint
Authors: Goldburg Arnold , Morgenthaler Charles
Published: December 2007

Enhanced Oil Recovery (EOR) as a group of producing techniques -- here we will restrict ourselves to the four (4) high EOR technologies of micellar-polymer (microemulsion), carbon dioxide, fireflood and deep steam (>2500′ or <10° API) — have had two special economic problems:

1. Rate of Return (ROR) when balanced against technical risk; and

2. Front-End Capital formation for independent oil operators.

To illustrate these two problems, and the impact of various past and possible future incentives and disincentives upon them, we use here as a typical example, tertiary micellar-polymer flooding of the Bell Creek Field in southeastern Montana. The reservoir parameters of this field are well suited to the micellar-polymer technique; and, starting in 1976, a micellar-polymer pilot for Bell Creek Unit ‘A’ reservoir (cost-shared with DOE, Contract No. DE-AC03-78SF01802) was carefully designed, deployed and executed, Refs. 1–11. The economics of a full field micellar-polymer flood in Unit ‘A’, based upon this pilot experience, have been developed extensively during the past 3 years and placed in the public domain, Refs. 12 – 16, in order to address the two designated financial problems of ROR vs. risk and capital formation.

Thus, there is a body of data for micellar-polymer project economics in Bell Creek Unit ‘A’ and a history of the Working Interest Owner (W.I.O.) group deployment decisions in the light of such economic information. This empirical information -- of what set of economic factors did motivate and (more importantly) what set did not motivate the W.I.O. to move forward with proposed tertiary recovery projects -- will be used to examine the likely impact of future incentives and dis-incentives on the deployment of the high EOR technologies by managements and owners.
Application of New Well Logs and Geology to Fracturing and Producibility in Tight Gas Sands, Cotton Valley Group
Authors: Hunt Ercill R. , Raymond Dean H. , Haskett Carl E. , Pirie Robert G.
Published: December 2007

A combination of new tools, the Digital Sonic and the Induced Gamma-Ray Spectroscopy (GST*) with the High Resolution Dipmeter (HDT*), a SARABAND* suite of logs, and a rock core study provided a unique opportunity to re-examine fracturing (fracing) procedures and producibility in the "tight gas sands" of the Cotton Valley Group in East Texas.

The depositional paleoenvironment of the Cotton Valley tight gas sandstones is interpreted as a sequence of shallow, marine, organically-burrowed, shoreface deposits which, with the HDT, can be separated into sedimentation units–barrier bars or tidal deltas. This separation is important because the local feature, the tidal delta, may have a more limited reservoir than the massive sand unit, the barrier bar.

The Digital Sonic tool measures values of shear and compressional velocities from which Poisson's ratio is determined. These velocities in combination with bulk density yield Young's Modulus which is commonly used to calculate fracture width. Combining Poisson's ratio with SARABAND provides answers needed to determine the vertical containment boundaries of the hydraulic fracture.

The GST provides a lithological description which identifies hydrated shales and well-developed intergranular pore-filling cements such as quartz, calcite, and clay minerals which, in some cases, are containment boundaries.

Producibility is then estimated as a function of the fracture surface area (fracture length x height) and the hydrocarbon pore volume (calculated from the SARABAND listing). This estimate of producibility is compared to flowmeter results. In several studies, the comparison is good; however, some significant, yet foreseeable, exceptions occur.
Impact of Job-Specific New-Hire Functional Testing
Authors: Kalkan S. , Bunch R.
Published: December 2007

Ergonomic injuries in the oil industry can occur when there is a gap between employee physical capacities and the physical demands of the job. Improper matching of the employee to the job can be prevented with job-specific functional testing. This paper describes the effect of new-hire functional capacity testing on injury reduction and wellness in an oilfield services company after 2 years of program implementation.

Data analysis revealed a 96% pass rate among a random sample population. A detailed investigation was conducted among the 4% of the sample who failed to meet the essential functional demands because of insufficient physical capacities or existing medical conditions. The results of the analysis of safe maximum lift capacities were used to develop ergonomic and behavioral-based intervention strategies to reduce the gap between the worker's physical capacities and the required job demands. Estimates related to direct and indirect costs for each applicant who failed were analyzed and compared to the program administration cost. The return on investment was 13:1.

The results show that improper matching of the employee to the job can be effectively prevented with job-specific functional testing. Post-offer new-hire functional testing is shown to be highly effective in preventing injuries, avoiding aggravation of preexisting medical conditions, educating new hires about specific needs for improved wellness, improving productivity, and reducing medical costs.

Discussion will include how some medical conditions can be identified effectively in the functional capacity examination. Data concerning human performance capacities is important in developing strategies that further reduce the risk of ergonomic injuries among an aging work force plagued by a growing epidemic of obesity and reduced fitness capacities.
The Analysis and Control of Hydraulic Fracturing Problems
Authors: Osborne M. W. , McLeod Harry O. , Schroeder Herbert D.
Published: December 2007

Fracturing formations deeper than 10,000 feet at temperatures greater than 200°F with crosslinked gels created a variety of special problems in South Texas and Anadarko Basin wells. Engineering analysis of these problems resulted in modifications of fluids systems, treatment design, and fracturing operations. These changes eliminated premature shut-downs of fracturing treatments and improved stimulation ratios.
The Department of Energy’s Western Gas Sands Project Multi-Well Experiment
Authors: Atkinson Charles H. , Crawley Alex B. , Northrop David A. , Sattler Allan R. , Mann Robert L. , Schillo John C.
Published: December 2007

The Department of Energy has initiated a Multi-well Experiment with the objectives: (1) characterization of low permeability, lenticular gas sands and (2) evaluation of state-of-the-art and developing technology for their production. The location is in the Rulison Field in the Piceance Basin, Garfield County, Colorado where the lenticular Mesaverde sequence and the underlying blanket Corcoran-Cozzette are the formations of interest and lie at depths between 4,000 and 8,600 ft.

Features of this research-oriented field experiment include: (1) three close-spaced wells (100 to 500 ft) for reservoir characterization, conventional well tests, interference testing, well-to-well geophysical profiling, and placement of diagnostic instrumentation adjacent to fracture treatments; (2) complete core taken through the formations of interest; (3) a comprehensive core analysis program; (4) an extensive logging program featuring conventional and experimental logs; (5) determination of in situ stress in sand lenses and bounding shales; (6) application of geophysical techniques to determine sand lens orientation; (7) use of seismic, electrical potential and tilt diagnostic methods for hydraulic fracture characterization; and (8) a series of stimulation experiments.

Analysis of data from these activities will yield the following kinds of information: (1) geologic characterization emphasizing the morphology, properties and variability of lenticular sands; (2) a reservoir model for lenticular sand production; (3) a fracture model including correlations between stress, geometry and lens orientation; (4) core-log-well test correlations for improved formation evaluation, and (5) economic assessments.
Gas Compressor Design & Operation
Authors: Littlefield Robert G.
Published: December 2007

Oil and gas production requires compression of gases involving considerable range of initial inlet and final discharge pressures as well as widely varying volumes. Frequently the applications are further complicated by the gas containing H2S or entrained liquids and equipment space/weight limitations imposed by offshore platform designs or semi-portability due to future relocation plans onshore.

The manufacturers of compressors, engines and gas turbines have responded to these requirements with a broad selection of power and compressor machinery to make possible an optimum selection for any given installation.
Design of Gas Conditioning and Processing Facilities
Authors: Campbell John M.
Published: December 2007

The proper planning and choice of such facilities depends on a number of non-process factors--market/economic, geographical, climate, cultural, political, etc. These determine the optimum output of the facility. The input is determined by the characteristics of the reservoirs supplying raw material for conditioning and processing. These establish boundary conditions within which the process must conform. The engineering calculations therefore must find the optimum path between input and output … and are not independent of these considerations.

This paper presents the state of the art of gas plant design and how this relates to the non-process factors. It is necessarily an overview but outlines a plan of attack that should provide maximum profitability.
Multistage stochastic linear programming model for daily coordinated multi-reservoir operation
Authors: Lee Yongdae , Kim Sheung-Kown , Ko Ick Hwan
Published: December 2007

Operation planning for a coordinated multi-reservoir is a complex and challenging task due to the inherent uncertainty in inflow. In this study, we suggest the use of a new, multi-stage and scenario-based stochastic linear program with a recourse model incorporating the meteorological weather prediction information for daily, coordinated, multi-reservoir operation planning. Stages are defined as prediction lead-time spans of the weather prediction system. The multi-stage scenarios of the stochastic model are formed considering the reliability of rainfall prediction for each lead-time span. Future inflow scenarios are generated by a rainfall–runoff model based on the rainfall forecast. For short-term stage (2 days) scenarios, the regional data assimilation and prediction system (RDAPS) information is employed, and for mid-term stage (more than 2 days) scenarios, precipitation from the global data assimilation and prediction system (GDAPS) is used as an input for the rainfall–runoff model. After the 10th day (third stage), the daily historical rainfall data are used following the ensemble streamflow prediction (ESP) procedure. The model is applied to simulate the daily reservoir operation of the Nakdong River basin in Korea in a real-time operational environment. The expected benefit of the stochastic model is markedly superior to that of the deterministic model with average rainfall information. Our study results confirm the effectiveness of the stochastic model in real-time operation with meteorological forecasts and the presence of inflow uncertainty.
Flooding probability of urban area estimated by decision tree and artificial neural networks
Authors: Chen Jeng-Chung , Shu Ching-Sung , Ning Shu-Kuang , Chen Ho-Wen
Published: December 2007

Remote sensing, such as from satellite, has been recognized as useful for monitoring the changes in hydrology. In this study, we propose a way that is able to estimate flooding probability based on satellite data from the observation network of the World Meteorological Organization. Through a two-stage probability analysis, we can depict the area with high flooding potential in near-real time. In the first stage, decision trees offered a prompt and rough estimation of the flooding probability; in the second stage, artificial neural networks handle the rainfall forecast in a small-scale area. Case studies, simulating two rainfall events on 20 May 2004 and 11 July 2001, proved that our proposed method is promising for mitigating the flooding damage along urban drainage within the downtown area of Kaohsiung city.
Strategies to close water supply and demand gap
Authors: Olsson Gustaf
Published: December 2007

The growing water and sanitation crisis in the world calls for enormous efforts from water professionals as well as economic and political leaders. The climate change contributes to the acuteness of the problem, with dryer areas in some parts of the world and severe floods and rains in other parts. The European Water Supply and Sanitation Technology Platform (WSSTP) is an industry driven organisation aiming to strengthen the potential for technological innovation and the competitiveness of the European Water Industry but is also a response to global challenges and regional demands to ensure safe, secure and sustainable water and sanitation services for the benefit of industry, the society and the environment. The supply of electrical energy has to be carefully considered as a pre-requisite for water supply and sanitation. The production of biogas can be significantly increased by using instrumentation and control. The use of monitoring and control has wide consequences for safe and reliable water supply and sanitation.
“They suffered with us and should be compensated”: Entitling Caregivers of Canada's Veterans
Authors: Struthers James
Published: December 2007

This article examines the struggle to win lifetime eligibility for selected home care benefits provided through the Veterans Independence Program (VIP) for veterans' widows in recognition of their years of unpaid caregiving – a policy change eventually implemented between 2003 and 2004. It explores how arguments on their behalf shifted from discourses of dependency, cost-saving, and compassion to ones of entitlement and commemoration between 1981 and 2004 as the large cohort of Second World War veterans and their wives moved towards the end of their lives. This policy victory for veterans' widows marked a historic shift in mandate for Veterans Affairs Canada and an important recognition by the state of unpaid caregiving as a form of national service. If Canadians are to learn from this example, however, it must be through seeing all caregiving labour – not just that of veterans' wives – as equally heroic and worthy of compensation.
French Immersion and At-Risk Students: A Review of Research Evidence
Authors: Genesee Fred
Published: December 2007

Abstract:

This report reviews results of research on the outcomes of French immersion students with special educational needs related to low levels of general academic ability and low levels of first language ability (and possibly impairment), as well as those of students with difficulty or who are at risk for difficulty in learning to read. Studies of the effectiveness of interventions for such students are also reviewed and analyzed. The report ends with suggestions for future research and educational policy.
Les élèves allophones dans les programmes de français seconde langue officielle: revue de la littérature
Authors: Mady Callie
Published: December 2007

Abstract:

In Canada, education in French as a second language (FSL) offers students the opportunity to learn a second official language. Is such an opportunity appropriate for allophone students who are still in the process of learning English? This literature review provides a four-fold consideration of the issue. Section 1 examines the political response by investigating whether Canadian federal policies provide for the inclusion of allophone students in FSL programs. Section 2 provides an overview of provincial policies, specifically examining allophone students’ access to FSL. A review of the literature regarding the motivation of allophone students is found in Section 3. Finally, Section 4 details the research on the achievement of allophone students studying French.
Synthesis of Microscale Raft‐shaped Zinc(II)–Phenylalanine Complexes and Zinc(II)–Phenylalanine/dye Hybrid Bundles with New Optical Properties
Authors: Cong H.‐P. , Yu S. H.
Published: December 2007

Novel raft‐like zinc(II)–phenylalanine complexes and zinc(II)–phenylalanine/acid green 27 (AG27) hybrid radial bundles have been successfully synthesized by a simple refluxing reaction. The formation processes of the morphologies and the superstructures of the hybrid bundles were proposed based on the time‐dependent evolution process. The AG27 molecules act as both the inclusion compound and the controller of the morphologies and the superstructures of the final hybrid. The combination of the zinc(II)–phenylalanine complex and AG27 leads to distinct optical properties compared with the individual component materials. This approach opens a new and effective way for the fabrication of amino acid/dye hybrid materials with unique optical properties and is expected to allow access to other organic/organic hybrid materials with structural specificity and functional novelty.
Rational Design of Chelating Phosphine Functionalized Os(II) Emitters and Fabrication of Orange Polymer Light‐Emitting Diodes Using Solution Process
Authors: Cheng Y. M. , Lee G. H. , Chou P. T. , Chen L. S. , Chi Y. , Yang C. H. , Song Y. H. , Chang S. Y. , Shih P. I. , Shu C. F.
Published: December 2007

A new series of charge neutral Os(II) pyridyl azolate complexes with either bis(diphenylphosphino)methane (dppm) or cis‐1,2‐bis(diphenylphosphino)ethene (dppee) chelates were synthesized, and their structural, electrochemical, photophysical properties and thermodynamic relationship were established. For the dppm derivatives 3a and 4a, the pyridyl azolate chromophores adopt an eclipse orientation with both azolate segments aligned trans to each other, and with the pyridyl groups resided the sites that are opposite to the phosphorus atoms. In sharp contrast, the reactions with dppee ligand gave rise to the formation of two structural isomers for all three kind of azole chromophores, with both azolate or neutral heterocycles (i.e., pyridyl or isoquinolinyl fragments) located at the mutual trans‐disposition around the Os metal (denoted as series of a and b complexes). These chelating phosphines Os(II) complexes show remarkably high thermal stability, among which and several exhibit nearly unitary phosphorescence yield in deaerated solution at RT. A polymer light‐emitting device (PLED) prepared using 0.4 mol % of 5a as dopant in a blend of poly(vinylcarbazole) (PVK) and 30 wt % of 2‐tert‐butylphenyl‐5‐biphenyl‐1,3,4‐oxadiazole (PBD) exhibits yellow emission with brightness of 7208 cd m–2, an external quantum efficiency of 10.4 % and luminous efficiency of 36.1 cd A–1 at current density of 20 mA cm–2. Upon changing to 1.6 mol % of 6a, the result showed even better brightness of 9212 cd m–2, external quantum efficiency of 12.5 % and luminous efficiency of 46.1 cd A–1 at 20 mA cm–2, while the max. external quantum efficiency of both devices reaches as high as 11.7 % and 13.3 %, respectively. The high PL quantum efficiency, non‐ionic nature, and short radiative lifetime are believed to be the determining factors for this unprecedented achievement.
Hepatogenic differentiation of mesenchymal stem cells using microfluidic chips
Authors: Ju Xiuli , Li Dong , Gao Ning , Shi Qing , Hou Huaishui
Published: December 2007

Cryomedicine Laboratory, Qilu Hospital of Shandong University, Jinan, Shandong, China Directional induction and differentiation of mesenchymal stem cells (MSCs) is very important to clinical therapy, but the mechanisms that govern differentiation are not well understood. However, traditional plate culture cannot precisely control cellular behavior because cells take up substances while secreting cytokines and wastes. Here, we used a microfluidic device to culture MSCs inside a microchamber. Hepatic differentiation medium was perfused to evaluate the ability of MSCs to differentiate toward hepatic cells on the chip. Parallel differentiation on 96‐well plates was used to provide a detailed comparison of the differences between the two culturing methods. After treatment for 4 weeks, differentiated cells from both groups could express hepatocyte‐specific markers, including α‐fetoprotein, tyrosine aminotransferase, and albumin. The bioactivity assays revealed that these hepatocyte‐like cells could uptake lipoprotein, but cells that differentiated on the chip showed more positive signals than the cells cultured on plates. Our results indicated that a microfluidic platform might be a potential tool for cost‐effective and automated cell culture, and have potential applications in reliable cell‐based screens and assays.
Effects of net charge and the number of positively charged residues on the biological activity of amphipathic α‐helical cationic antimicrobial peptides
Authors: Jiang Ziqing , Vasil Adriana I. , Hale John D. , Hancock Robert E. W. , Vasil Michael L. , Hodges Robert S.
Published: December 2007

In our previous study, we utilized a 26‐residue amphipathic α‐helical antimicrobial peptide L‐V13K (Chen et al., Antimicrob Agents Chemother 2007, 51, 1398–1406) as the framework to study the effects of peptide hydrophobicity on the mechanism of its antimicrobial action. In this study, we explored the effects of net charge and the number of positively charged residues on the hydrophilic/polar face of L‐V13K on its biological activity (antimicrobial and hemolytic) and biophysical properties (hydrophobicity, amphipathicity, helicity, and peptide self‐association). The net charge of V13K analogs at pH 7 varied between −5 and +10 and the number of positively charged residues varied from 1 to 10. The minimal inhibitory concentrations (MIC) against six strains of Pseudomonas aeruginosa as well as other gram‐negative and gram‐positive bacteria were determined along with the maximal peptide concentration that produces no hemolysis of human red blood cells (MHC). Our results show that the number of positively charged residues on the polar face and net charge are both important for both antimicrobial activity and hemolytic activity. The most dramatic observation is the sharp transition of hemolytic activity on increasing one positive charge on the polar face of V13K i.e., the change from +8 to +9 resulted in greater than 32‐fold increase in hemolytic activity (250 μg/ml to <7.8 μg/ml, respectively). © 2007 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 90: 369–383, 2008.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Influence of ammonium chloride feeding time and light intensity on the cultivation of Spirulina (Arthrospira) platensis
Authors: Bezerra Raquel Pedrosa , Matsudo Marcelo Chuei , Converti Attilio , Sato Sunao , de Carvalho João Carlos Monteiro
Published: December 2007

This study dealt with the influence of both the feeding time and light intensity on the fed‐batch culture of the cyanobacterium Spirulina (Arthrospira) platensis using ammonium chloride as a nitrogen source. For this purpose, a 22 plus star central composite experimental design combined with response surface methodology was employed, and the maximum cell concentration (Xm), the cell productivity (PX), and the yield of biomass on nitrogen (YX/N) were selected as the response variables. The optimum values of Xm (1,833 mg L−1) and YX/N (5.9 g g−1) estimated by the model at light intensity of 13 klux and feeding time of 17.2 days were very close to those obtained experimentally under these conditions (Xm = 1,771 ± 41 mg L−1; YX/N = 5.7 ± 0.17 g g−1). The cell productivity was a decreasing function of the ammonium chloride feeding time and a quadratic function of the light intensity. The protein and lipid contents of dry biomass collected at the end of cultivations were shown to decrease with increasing light intensity. Biotechnol. Bioeng. 2008;100: 297–305. © 2007 Wiley Periodicals, Inc.