bluuebunny/crossref_metadata_2025 huggingface dataset:
FPSO Environmental-Risk Management
Authors: Metzger B.H.. H. , Salmond D.. , Tilstone A..
Published: June 2010

Oil companies planning to locate floating production storage, and offloading vessels (FPSOs) [or floating storage and offloading vessels (FSOs)] in shallow water need to consider the performance of such operations relative to environmentally sensitive coastal habitats. This paper is based on a global study Battelle performed on FPSO safety performance and, in particular, with respect to risk management of nearshore operations. The study provides environmental best-practices benchmarks. It examines the international safety performance of FPSOs operating in various geographies and environmental conditions. To this end, it reviews risk analyses published over the past 10 years on the subject of FPSO failure hazards, such as collision, offloading failure, equipment failure, and tanker spills. The study then examines eight cases of FPSOs operating in nearshore locations around the globe identifying proven risk-mitigation and -management practices and lessons learned that might benefit future FPSO projects.

The study confirms that there is a strong safety record available on more than 1,000 years of FPSO operation around the globe. Extensive research conducted by agencies and researchers in the UK, Norway, the US, and elsewhere on FPSO design, operation, and performance offers a rich body of information on FPSO safety guidance. In addition, detailed review of the eight case studies confirms what the literature suggests: The FPSOs that have been operated to date have had a strong safety record. Very few incidents of consequence have been reported. No major incident or loss of cargo has occurred. None of the minor touches and collisions has resulted in the release of cargo. Virtually all recorded and reported releases have been small, and most of them were less than 1 bbl. Robust management systems combined with strong design and operating practices are capable of avoiding theoretical failure risks, or reducing them to very low and acceptable levels.

The results of this study suggest that there is an arsenal of measures operators can consider to ensure high safety performance of any planned FPSO. Failure and spill risks summarized in this study may be extrapolated for planned systems and proven risk reduction and mitigation measures adopted.
Gas Production System From Methane Hydrate Layers by Hot Water Injection Using Dual Horizontal Wells
Authors: Sasaki K. , Ono S. , Sugai Y. , Ebinuma T. , Narita H. , Yamaguchi T.
Published: June 2010

In this study, we investigate a system of gas production from methane hydrate layers involving hot water injection using dual horizontal wells. Physical and numerical models simulating the gas production process from methane hydrate layers within a hot water chamber are proposed.

Experiments with scaled two-dimensional physical models using an imitated hydrate layer (NaHCO3 ice formation) were performed to investigate fluid flow characteristics and production performance. The thermal simulator was used to simulate experimental chamber growth and field production. Numerical simulations for the processes were successfully performed with a two-component (water and oil or methane hydrates), three-phase (water, methane hydrates and methane gas) and three-dimensional model, matching the physical model. Results of the history-matched numerical simulations were in good agreement with data on production and chamber shapes obtained using the Intermediate3-Stone1 wettability model. Simulations of field production using dual horizontal wells 500 m in length were performed to evaluate cumulative gas production over 3 years of injection with 500 × 103 kg/day of hot water, which varied from 5 × 106 to 9 × 106 std m3. The production process appears economical, in view of the expected convective heat transfer from the chamber boundary and buoyancy force on dissociated methane gas.

Introduction

Recent studies confirm that conserved methane hydrate deposits in sedimentation layers at a depth of more than 200 to 300 m from the bottom of the sea floor can be utilized as novel natural gas resources. In-situ hydrate decomposition into water and gas is required to produce methane gas economically from these layers, since methane hydrate is a type of non-mobile solid energy resource. To trigger methane hydrate decomposition, decompression or temperature increase out of the equilibrium zone is necessary, while heat should be supplied for continuous dissociation. Accordingly, new gas production systems that supply heat continuously into the methane hydrate layers have been reported. The conventional methods of gas production to date include depressurization, inhibitor injection and thermal recovery.
Effects of SO2 and pH Concentration on CO2 Adsorption Capacity in Coal Seams for CO2 Sequestration With Considerations for Flue Gas From Coal-Fired Power Plants
Authors: Huy P.Q. , Sasaki K. , Sugai Y. , Kiga T. , Fujioka M. , Adachi T.
Published: June 2010

Coal-fired power plants produce flue gas consisting mainly of nitrogen (around 79%), followed by CO2 (around 10 - 15%), and small amounts of other gases such as H2, NOx and SO2. One of the promising methods for reducing CO2 emission is CO2 sequestration into deep, unminable coal seams. At present, flue gases exhausted from coal-fired plant must be separated to extract pure CO2 before injecting it into coal seams.

In order to enhance the efficiency of carbon capture and storage (CCS) from a coal-fired power plant, oxy-fuel combustion technology has been employed. This technology uses pure oxygen to burn the coal, and consequently CO2 concentration in the flue gas is theoretically increased up to 95%.

This study aims to simulate the CH4 replacement mechanism in coal by using pure CO2 and a synthesized flue gas (99% CO2 and 1% SO2) that is similar to the emission gas from the coal-fired power plants. A measurement procedure for gas adsorption is employed which, after establishing methane adsorption equilibrium of the coal samples, injects pure CO2 or the synthesized flue gas into an adsorption cell in order to investigate CH4 replacement properties. Coal samples used for the present experiments were taken from the coal seams of Vietnam, Japan, Australia, China and Indonesia. The samples were crushed to particle sizes ranging from 250 µm to 5 mm. The concentration of gases was taken from the adsorption cell and analyzed by using a gas chromatograph. Adsorption isotherms of CH4, CO2 and SO2 were measured by using the volumetric method apparatus.

This paper discusses the characteristics of methane replacement by using pure CO2, the synthesized flue gas and the effect of SO2 on adsorption properties of coal.

Introduction

Global warming and climate change due to the greenhouse effect continue to be a serious problem. In particular, CO2 emission into the atmosphere from coal-fired power plants needs to be reduced. One of the most promising methods of reducing CO2 emissions is CO2 sequestration in deep, unminable coal seams. The CO2 adsorption capacities of coals were investigated by Huy et al.(1). The results showed that CO2 adsorption was double that of CH4.
Practical Considerations in Estimating Test Duration for Perforation Inflow Tests
Authors: Theys S. , Brunner F. , Mattar L. , Rahman N.M.A.
Published: June 2010

Perforation inflow tests are short, cost-effective and environmentally- friendly solutions to estimate the initial reservoir pressure, permeability and skin, immediately after perforating the well. The reservoir-dominated (radial) flow regime must be reached before terminating the test in order to obtain reasonable estimates of these parameters. These reservoir parameters and chamber (or wellbore) volume directly influence the rate of build-up of pressure and the test duration. In the field, it is not easy to ascertain whether or not sufficient data has been obtained so that the test can be terminated, especially when the data is not analyzed in real time. If the rate of build-up is closely monitored, it is possible to predict whether (i) the minimum required data will be obtained within the stipulated test time, (ii) the test has to be run longer, or (iii) a downhole shut-in is required.

In this paper, analytical simulation is used to run a sensitivity study on reservoir and well parameters and see how these affect the onset of the reservoir-dominated flow regime. The impulse derivative is used to identify the presence of reservoir-dominated flow. The rate of pressure build-up at I hour is used to determine if sufficient data will be collected within the test duration.

The outcome is a practical field guide to help the operator decide whether the test should be continued, modified or stopped.

Introduction

Perforation inflow tests are short and therefore increasingly popular in the industry. They can deliver valuable reservoir information, such as the initial reservoir pressure, the reservoir permeability and the skin effect. The data obtained from perforation inflow tests can be divided into two parts:the early-time data is wellbore storage dominated, andthe late-time data is reservoir- dominated.

Perforation inflow tests are not likely to exceed approximately 24 hours, and should be designed so that reservoir-dominated flow occurs during that period. For cases where wellbore storage does not excessively affect the early time data and when reservoir permeability is high enough, the duration of the perforation inflow test is likely sufficient to reach radial flow. However, for large wellbore storage and low reservoir permeability, the time to reach reservoir- dominated flow will be prohibitively long. In such cases, one option is to reduce wellbore storage by running a bridge plug, thus reducing the effects that initially masked the true reservoir performance.
Prediction of Carbon Dioxide Production in SAGD Operations
Authors: Thimm H.F.
Published: June 2010

In 2007, work was published on the predictability of hydrogen sulphide production in Athabasca SAGD projects. It was possible to predict the hydrogen sulphide production per unit volume of bitumen produced against steam zone temperature, by assuming pseudo-zero order kinetics, using the Arrhenius energy published by Strausz and his co-workers at the University of Alberta.

An examination of field results for carbon dioxide production in Athabasca projects shows that the predictability of carbon dioxide is less simple. The carbon dioxide production is not erratic but goes through a distinct temperature minimum, an important result in view of the dependence of silica production in SAGD and scaling behaviour in facilities on carbon dioxide. Again, as for hydrogen sulphide production, it is possible to estimate carbon dioxide production by a simple graphical technique, which is shown.

Partial explanations for the observed temperature minimum are offered.

Introduction

The production of acid gases in SAGD projects is a matter of some importance. A number of operational characteristics depend on the presence of carbon dioxide as produced through dissolution in produced water. It has been shown previously(1) that silica production is strongly dependent on dissolved carbon dioxide. There is likewise evidence that aggressive degassing of produced water has caused unwanted scales of silicate minerals, such as talc, chrysotile and tremolite, to be deposited in various parts of the facilities(2).

A simple production diagram for hydrogen sulphide in SAGD was recently reported by Thimm(3). The hydrogen sulphide produced per unit bitumen could be described as a simple Arrheniustype relationship with steam zone temperature, using an activation energy of 56,220 - 65,920 J/mole (13,450 - 15,770 cal/mole). The assumption of pseudo-zero order kinetics yielded a smooth curve which fitted the field data for most SAGD projects in Athabasca satisfactorily.

The behaviour for carbon dioxide was previously expected to be similar, with an Arrhenius activation energy of 17,520 J/mole (4,192 cal/mole)(4).
Application of Temperature Observation Wells During SAGD Operations in a Medium Deep Bitumen Reservoir
Authors: Wang H.Y.
Published: June 2010

The steam assisted gravity drainage (SAGD) pilot test in the LiaoHe oilfield of China is the first SAGD project conducted in China in the deeper bitumen reservoir (650 - 800 m), using a combination of vertical injectors and horizontal producers. Temperature observation wells play an important role in the understanding of the pilot performance and optimization of the operation process. This paper will present the objectives, principles, interpretation and application of the temperature observation wells in the pilot area. A number of production problems were identified and solutions were sought to improve the SAGD performance through the use of temperature and other data obtained from the observation wells.

Introduction

This paper is a continuation of CIPC paper 2006-146. That paper introduced the successful test of the SAGD pilot in a deep biutmen reservoir in China(1). The pilot has been expanded to include 12 horizontal wells since the presentation of the original paper. The earlier two wells have reached a daily oil rate of over 100 m3/day per well. The current recovery factor is approximately 27% and the anticipated ultimate recovery is over 60%.

Compared with most current Canadian SAGD projects, the reservoirs in the LiaoHe oil field operated by PetroChina presented two challenges to the use of SAGD technologies. First, the reservoir depth exceeded 500 m (530 - 810 m) compared to the typical 200 - 500 m present in most Canadian SAGD projects(2), which increased the heat loss from the injection wellbores to the overburden Second, the reservoir had been subjected to primary production by Cyclic Steam Stimulation (CSS) prior to the implementation of the SAGD process while for the majority of the Canadian SAGD projects the technique is applied directly to a virgin reservoir. The current recovery factor by CSS in the LiaoHe reservoir is approximately 20% of the OOIP. This prior depletion by CSS complicated the conversion to SAGD applications and determination of operating parameters caused by the alteration in the distribution of the remaining oil saturation present in the formation (Figure 1).
Protocols for Slotted Liner Design for Optimum SAGD Operation
Authors: Bennion D.B. , Gupta S. , Gittins S. , Hollies D.
Published: June 2010

Slotted liners are used extensively in the majority of steam assisted gravity drainage (SAGD) operations conducted in Western Canada due to their superior mechanical strength and integrity in contrast to other mechanical sand-control devices. These liners are required because of the generally poorly or unconsolidated nature of the majority of formations in which SAGD applications are conducted. These liners can have a variety of configurations with varying slot density, slotting patterns, slot apertures and slot internal geometries. The overall objective of a successful slotted liner design is to ensure that the liner allows the maximum production of bitumen and other fluids with a minimum pressure drop, while retaining the majority of the formation sand and preventing infill of the horizontal section of the well with solids and erosion and failure of downhole pumps and surface equipment. This paper describes a detailed lab test protocol which was successfully developed over a number years for the design and evaluation of slot geometry for SAGD applications, describes test procedures used and quantifies some of the major mechanisms discovered that lead to the plugging of slots. It has been found that in addition to grain size of the sand under consideration and slot geometry, that clay content of the formation, flow velocity, wetting phase type and pH play crucial roles in the plugging mechanism of slotted liners. Clay plugging at the top portion of the slots has been found to be the dominant damage mechanism.

Introduction

SAGD is being used extensively in Western Canada and other areas in the world as an effective and economic means for the recovery of heavy oil and bitumen reserves and represents the current primary technology for the exploitation of this large hydrocarbon resource(1-5).
Experimental and Economic Analysis of the Thermal Solvent and Hybrid Solvent Processes
Authors: Frauenfeld T.W. , Jossy C. , Bleile J. , Krispin D. , Ivory J.
Published: June 2010

Several partially scaled laboratory model experiments were conducted to evaluate a hybrid solvent-steam process for recovery of heavy oil or bitumen. All experiments used Athabasca UTF bitumen, and modelled a 30-metre-thick formation. The experiments were compared using a common set of economic assumptions. The experiments showed that a hybrid solvent-steam process could recover bitumen at steam-oil ratios much lower than those observed for steam assisted gravity drainage (SAGD), and achieve reasonable ultimate oil recovery (60% IOIP). The economic analysis based on experiments indicated that a hybrid solvent-steam process could be more cost-effective than SAGD for a 30-m Athabasca formation.

Introduction

Some heavy oil reservoirs are difficult to produce by cold production. The oil may be immobile at reservoir temperature, or there may be some initial oil mobility and some reservoir drive energy, but the sand strength precludes the production of wormholes. These reservoirs may contain dead oil, as in the case of Athabasca bitumen, or they may have some dissolved gas, as in the case of Cold Lake or Burnt Lake reservoirs.

SAGD is the main commercial technology used for in-situ recovery of these oils. Because of the increasing costs for energy (natural gas) and the increasing restrictions on fresh water usage, solvent-based processes (VAPEX, Thermal Solvent, Hybrid Solvent, N-Solv, Savex) have been proposed as alternative technologies for heavy oil and bitumen production. Most of these technologies utilize a pair of horizontal wells, similar to those used in SAGD, but use a gaseous solvent, typically propane, alone or in conjunction with steam, to recover the oil.

The VAPEX process may be augmented by adding heat. Heating of a horizontal wellbore will reduce bitumen viscosity sufficiently to produce a large increase in oil production rate. The heat also serves to initiate communication between the injector and the producer. The heat also serves to speed the diffusion of solvent into the oil. The combination of heated wellbores and VAPEX is known as the thermal solvent process.
Simultaneous Estimation of Relative Permeability and Porosity/Permeability Fields by History Matching Production Data
Authors: Eydinov D. , Gao G. , Li G. , Reynolds A.C.
Published: June 2010

This paper presents a procedure to estimate relative permeability curves together with gridblock porosities and permeabilities by automatic history matching three-phase flow production data using the LBFGS algorithm for optimization and the adjoint method for generating sensitivity coefficients. Both power law and B-splines are considered for the representation of relative permeability curves. Power law functions provide a simple representation; however, B-splines have the advantage of being able to accurately represent any set of relative permeability curves. In the B-spline representation, we provide a simple procedure based on a transformation of parameters (control points) defining the B-splines to ensure that monotonic curves are obtained. Without this transformation, the automatic history-matching process fails. If endpoint saturations are included as parameters, we show how to modify the adjoint procedure to account for the fact that initial conditions are sensitive to endpoint saturations. While the history-matching process is inherently non-unique, we show that reasonable estimates of relative permeability curves and porosity/ permeability fields can be obtained for a synthetic reservoir example. We also provide a quantification of the uncertainty in model parameters and reservoir performance prediction using the randomized maximum likelihood (RML) method.

Introduction

Usually, the relative permeability curves are obtained from labs through coreflood tests. However, they can also be incorporated into the history matching procedure as model parameters. Archer and Wong(1) and Yang and Watson(2) were among the early researchers to consider the estimation of relative permeability curves by history matching laboratory coreflood data. A detailed literature review is given in Reynolds et al.(3). Reynolds et al.(3) also discussed the estimation of three-phase relative permeabilities by history matching production data.

The current work is a natural extension of Reynolds et al.(3). In this paper, we provide an alternative method for relative permeability estimation based on B-spline approximation. Compared to power law representation, B-splines have the advantage of being able to accurately represent any set of relative permeability curves.
Nine-Lumped Kinetic Models ofLiquefied Petroleum Gas Under Aromatization Reaction Conditions
Authors: You H.
Published: June 2010

The aromatization reaction of liquefied petroleum gas has been studied by using three liquefied petroleum gases as the raw material and LBO-A as the catalyst. Nine-lump kinetics model networks have been put forward on the basis of lumped theory and the aromatization reaction mechanism. In the network, the aromatization reaction species are firstly lumped into C4=, C40, n-paraffin, i-paraffin, olefins, aromatics, C2-3=, H2 + C1-30, and coke. A mathematical method is first introduced to study the product distribution of the liquefied petroleum gas aromatization reaction. The results from experimental data are in accordance with the quantitative analytical conclusions drawn from the calculated data.

Introduction

In 1994, 1.27 hundred million tons of petroleum were processed, more than 2.2 million tons of ethylene were produced, and the resources of liquefied petroleum gas (C4 fraction and C5 fraction) reached approximately 3.7 million tons in China(1,2). The resources of liquefied petroleum gas have become more and more abundant in China; the output of liquefied petroleum gas is more than 300 thousand tons per year(3,4). The resources of liquefied petroleum gas are mainly from three resources in China: oil and gas fields, refineries and from gas cracking(5).

The resources of liquefied petroleum gas are not completely used to create higher value products, whereas most resources are burned as fuel(6). Recently, research work has focused mainly on how to use liquefied petroleum gas effectively(7,8). The various quantitatively analytical methods have been studied, but the lumped-kinetics models are seldom done.

In this paper, nine-lumped kinetics models, which can predict aromatization reaction product distribution under various operating conditions and calculate the maximum deviations of the product yield between calculated results and practical values, are established for a confined fluidized bed reactor.
Drill-String Torsional Vibration Suppression Using GA Optimized Controllers
Authors: Karkoub M. , Abdel-Magid Y.L. , Balachandran B.
Published: June 2010

Failure of drill-strings is very costly in terms of money and time and occurs more frequently than oil companies would like to see. There are many reasons for drill-string failure, such as vibration, fatigue, and buckling. This paper addresses the problem of suppression of stick-slip oscillations in oil well drill-strings using proportional integral derivative (PID) and lead-lag controllers in conjunction with genetic algorithms. Simulation results are presented to validate the proposed control schemes.

Introduction

The drilling process is affected by the dynamically induced vibrations caused by design imperfections as well as material elasticity. Because of these vibrations, premature wear and damage of drilling equipment may occur. Vibrations can decrease the rate of penetration (ROP), and thereby increase the cost of the well(1,2,3). Moreover, vibrations can interfere with measurement-while-drilling (MWD) tools or even cause their damage. Another major problem caused by vibrations is the induced wellbore instabilities which can worsen the condition of the well(4,5).

The literature on drill-strings can be classified in three groups: drill-string modelling, drill-string control, and drill-string technology. In this paper, we will focus on drill-string dynamics and control. There have been a significant number of research publications on drill-string dynamics and a representative few are considered here. Many different models for drill-strings are available in the literature, which may include one or more of the following phenomena: bit-bounce, stick-slip, forward and backward whirl, axial, lateral, and torsional vibrations; see, for example, Christoforou et al.(6), Jansen and van den Steen(7,8), and Leine et al.(9). Stick-slip is a major cause of torsional vibrations and many researchers have tried to minimize its effect on the behaviour of the drill-strings using active damping techniques(10,11,12). These techniques reduce the torque fluctuations and torsional drill-string vibrations affecting in this manner the stick-slip conditions. The underlying concept is to reduce the amplitude of the downhole rotational vibrations using torque feedback. The feedback is used by the rotational drive, which slows down the rotary rate when the torque increases and speeds it up when the torque decreases(8,13,14).
Development of Marginal/Mature Oil Fields: A Case Study of the Sinclair Field
Authors: Resnyanskiy P. , Babadagli T.
Published: June 2010

Development of marginal/mature fields has become popular because of a significant decline in new field discoveries and high oil prices. In particular, small size fields of this kind are more challenging because of limited options for development. This paper presents a study on the Sinclair field located in Alberta, Canada. The field has 19 wells, six of which are horizontal, and have been in production for more than 20 years. Despite the quality of oil (40°API, 1.5 cp) and rock properties (20% average porosity, water-wet sandstone), the current production is less than 100 bbl/D for the whole field. The field is now undergoing waterflooding. The main challenges are the thin pay zone (~4 m), severe water production and a puzzling recovery factor of approximately 10%.

The current study consists of three phases: numerical reservoir modelling and history match to understand the reasons for low oil production and to analyze the hydrodynamic characteristics of the field, characterization of reservoir and interwell connectivity using static and production data and proposing an enhanced oil recovery technique supported by field scale numerical simulation. After modelling and history matching stages, potential reserves locations are estimated for possible dilute surfactant injection. Based on interwell connectivity, different injection schemes that use some producers as injectors are tested. The obtained results are subject to further evaluation and analysis to derive the economic viability of the field.
CO2 Temperature Prediction in Injection Tubing Considering Supercritical Condition at Yubari ECBM Pilot-Test
Authors: Yasunami Tetsu , Sasaki Kyuro , Sugai Yuichi
Published: June 2010

The Japanese consortium to enhance CO2-ECBM carried out a pilot project on CO2 injection from 2002 to 2007 in the city of Yubari, Hokkaido, Japan. However, supercritical CO2 could not be obtained because of low CO2 injectivity and heat loss along the deep injection tubing. The absolute pressure and CO2 temperature at the bottomhole was approximately 15.5 MPa and 28°C, respectively. Therefore, it can be assumed that CO2 was injected into the coal seam in its liquid phase. Liquid CO2 is less permeable in the coal seam because of its high viscosity and the resultant swelling of the coal matrix to decrease permeability.

This study provides a numerical system to predict CO2 flow characteristics of pressure, temperature, supercritical or liquid by considering heat transfer from the injector into surrounding casings and strata. This study focused on keeping supercritical CO2 in the tubing because the viscosity of supercritical CO2 is 40% less than that of liquid CO2. The CO2 temperature required to keep CO2 in its supercritical condition from the surface to the bottom was successfully predicted for various CO2 injection rates and electric heating powers.

Finally, injected CO2 is expected to be supercritical at an injection rate of over 12 ton/d without any heating.
A 3D Finite Element Model for History Matching Hydraulic Fracturing in Unconsolidated Sands Formation
Authors: Xu Bin , Wong Ron C.K.
Published: June 2010

Field hydraulic fracturing tests data provide valuable information regarding the mechanical and hydraulic behaviours of the reservoir formation. By history matching the field bottomhole pressure vs. time curve from hydraulic fracturing tests, a set of field-calibrated geomechanical models can be obtained, which is an important asset for any further works on utilizing geomechanics to enhance the injection and production performance. This paper presents a 3D finite element model for history matching the complete bottomhole pressure vs. time curve generated during hydraulic fracturing tests, considering the injection rate as input. To simulate the hydraulic fracturing process in unconsolidated sands formation, a poro-elasto-plastic constitutive model, together with a strain-induced anisotropic full permeability model, are formulated and implemented into a 3D finite element geomechanical simulator. Unlike the conventional simulation of hydraulic fracturing in hard rock, hydraulic fracturing in an unconsolidated sands reservoir is simulated as a large area of shear dilated plastic zone, inside of which the effective stresses are low and hydraulic conductivities are high. It is shown that the proposed numerical model can capture the hydraulic fracture initiation and propagation in unconsolidated sands formation and matches the field pressure vs. time curve.
Simulation of Bacterial Souring Control in an Alberta Heavy-Oil Reservoir
Authors: Coombe Dennis A. , Jack Tom , Voordouw Gerrit , Zhang Frank , Clay Bill , Miner Kirk
Published: June 2010

This paper presents the development of a simulation model describing the bacterial-induced souring of an Alberta heavy-oil producing field and its remediation via injection of nitrate. An area of the field with extensive bacterial activity was selected for the simulation study. The primary production and water-flood injection phases were history matched with basic reservoir maps and injection/production operating conditions adjusted via an automatic history match algorithm. Extensive chemical and microbiological compositional data for injected and produced waters were collected and analyzed at the University of Calgary and a mathematical model of the souring process and its remediation treatment was developed based on the information collected. Simulation indicated the volumetric distribution of the hydrogen sulfide over time and how the injected nitrate was distributed and acted to achieve souring control. Predicted individual production well responses were shown to be consistent with field observations, and issues regarding improved monitoring and design of laboratory experiments for future field operations are highlighted. Hence, simulation can be a useful tool in understanding and designing remedial treatments to bacterial souring in the Western Canada Sedimentary Basin.
Coupling Immiscible CO2 Technology and Polymer Injection to Maximize EOR Performance for Heavy Oils
Authors: Zhang Yiping , Huang Sam S. , Luo Peng
Published: June 2010

With approximately 90% of Saskatchewan's original heavy oil in place remaining in the ground, there is excellent potential for the application of enhanced oil recovery (EOR) methods and new technologies. The goal of the study discussed in this paper was to investigate if a new proposed process--coupling CO2 and polymer injection--can increase EOR performance for heavy oil reservoirs. The oil recovery performance of three EOR modes [water-alternating-gas (CO2 WAG) injection, polymer-alone flood and coupled CO2 and polymer injection] was compared in laboratory-scale linear coreflood tests in waterflooded cores. The immiscible CO2 WAG process recovered 15.3% original oil in place (OOIP) with 6.16 MSCF/stb gas utilization. Under a controlled maximum pressure drop across the core, the polymer-alone (0.4 wt%) flood produced an additional 12.93% OOIP above the initial waterflood recovery. However, the coupled CO2 and polymer injection process (using a polymer concentration of only 0.2 wt%) gave better recovery efficiency (18.7% OOIP) than the polymer-alone flood. Moreover, it had much better gas utilization than the CO2 WAG run, consuming only 2.0 MSCF/stb, or one-third of the amount of CO2 used in that run to recover the same amount of oil. This performance comparison demonstrates two of the biggest advantages of coupled CO2 and polymer injection: it can effectively reduce the pressure drop across the core and can obtain encouraging recovery if the optimal polymer concentration is added to the water.
Numerical History Match of the Burnt Lake SAGD Process
Authors: Ito Yoshiaki , Chen Joyce J.
Published: June 2010

The Burnt Lake Oil Sand Lease is located approximately 300 km northeast of Edmonton. The lease is estimated to contain 330x106 m3 of bitumen in place in the Clearwater oil sands formation. Cold production was tested in the lease to recover 11°API - 12°API crude bitumen between 1990 - 1993.

Three pairs of SAGD operations began in April 1997 after 3 months of circulation. Many interesting characteristics were identified in the injection and production history. During the first year of operation, pressure and oil production rates decreased when steam injection rates were reduced. After the second year of operation, oil production rates responded inversely to steam injection rates. Oil rates were reduced when steam rates were increased, and oil rates increased when steam rates were reduced. Declines in oil rates were relatively slow over the entire operation period. When the steam injection was stopped for approximately 5 months after 5 years of operation, the operation pressure and oil production rates were gradually reduced during this period.

Many other unexpected trends were also observed. All these features were consistently seen in all three pairs. This paper presents these behaviours in detail. A simulation study of 9 years of performance of Pair 1 was conducted to understand these characteristics. The history match demonstrated that oil production was achieved by two different mechanisms: one was expansion of the steam chamber and the other was drainage of oil from the layer above the steam chamber. Many unexpected performances were the result of the combination of these two recovery mechanisms.
Evaluation of Recovery Technologies for the Grosmont Carbonate Reservoirs
Authors: Jiang Qi , Yuan Jian-Yang , Russel-Houston Jen , Thornton Bruce , Squires Andrew
Published: June 2010

The Upper Devonian Grosmont formation is a bitumen-saturated, carbonate unit located in Northern Alberta. It is considered to be among the world?s next largest unconventional oil resource plays. Since early 2006, there has been an increased interest in Grosmont resources exhibited by a range of companies, including super-majors.

Several in-situ pilot tests were conducted in the central portion of this area in the 1970s and 1980s, using steam and in-situ combustion processes. Similar to field tests in the McMurray formation oil sands before invention of the Steam-Assisted Gravity Drainage (SAGD) process, none of the early recovery technologies tested proved to be economic. Because the "gravity" drainage process has proved successful in commercial development of the McMurray formation oil sands since the mid- to late-1990s, the recovery potential for the Grosmont formation should be re-evaluated, based on improved recovery techniques.

Results from cyclic steam stimulation (CSS) field tests are compared and analyzed to understand the similarity and fundamental differences in reservoir properties between the McMurray formation oil sands and the Grosmont formation carbonate rocks. A preliminary interpretation is provided for laboratory test results for solvent processes applied to Grosmont carbonate cores. The scaling considerations from the laboratory results to field expectations are discussed. The paper also provides a direction for future studies and optimization opportunities for reservoir recovery leading to the commercial development of Grosmont carbonate reservoirs.
Externalities in Payment Card Networks: Theory and Evidence
Authors: Chakravorti Sujit
Published: June 2010

Payment cards continue to replace cash and checks in advanced economies. Along with the growth of payment card transactions has come greater scrutiny by public authorities of certain payment network rules along with the level of certain fees. This article reviews the growing payment card literature and discusses the impact of several regulatory interventions on card adoption, usage, and social welfare.
Overcoming Data Limitations in Nonparametric Benchmarking: Applying PCA-DEA to Natural Gas Transmission
Authors: Nieswand Maria , Cullmann Astrid , Neumann Anne
Published: June 2010

We empirically demonstrate a practical approach of efficiency evaluation with limited data availability in some regulated industries. We apply PCA-DEA for radial efficiency measurement to U.S. natural gas transmission companies in 2007. PCA-DEA reduces dimensions of the optimization problem while maintaining most of the variation in the original data. Our results suggest that the methodology reduces the probability of over-estimation of individual firm-specific performance.
Network Neutrality: A Survey of the Economic Literature
Authors: Schuett Florian
Published: June 2010

This paper reviews the small but growing economic literature on network neutrality. It considers a number of possible departures from network neutrality, in particular termination fees, second-degree price discrimination, and vertical foreclosure.
Teaching Difficult History: Eric Williams' Capitalism and Slavery and the Challenge of Critical Pedagogy in the Contemporary Classroom
Authors: McCarthy Cameron , Sealey-Ruiz Yolanda
Published: June 2010

A fear of the past can inhibit the freedoms of the present as pedagogic practices that deny complex, and even contradictory, histories bind learners to normative narratives. The failure to recognize the complexities of difficult historical themes – presenting and representing them as something so much simpler so that they may fit in with dominant ways of being – disempowers both the ‘ordinary’ people who shaped history and those whose lives emerge from those histories: if we do not know where we came from, how can we know who we are? The authors examine this concern here through the teaching of the transatlantic slave trade and, in particular, through Eric Williams' seminal book Capitalism and Slavery (1944). Williams released a petrified history into the present and the authors argue that his engagement with history provides a model of post-colonial pedagogy that is urgently relevant to today's classroom. Moreover, his work is highly pertinent to the teaching of the histories of subjugated and even subversive groups struggling to assert their identities against past and present discourses centering upon race, class and gender.
Using a Qualitative Approach to Research to Build Trust Between a Non‐Aboriginal Researcher and Aboriginal Participants (Australia)
Authors: ‘Yotti’ Kingsley Jonathan , Phillips Rebecca , Townsend Mardie , Henderson‐Wilson Claire
Published: June 2010

This article focuses on the qualitative methodologies employed in a research project developed in collaboration with Aboriginal advisors and gaining an in‐depth understanding of Aboriginal Victorian peoples’1 connection to their ancestral lands. It outlines why qualitative methodologies were used and highlights the ethical dimensions of working with Aboriginal Victorian communities. A research partnership was developed between Aboriginal Victorian communities and the non‐Aboriginal researcher and this process was emphasised because in the past Australian Indigenous people have been grossly exploited in health research. The methods of semi‐structured interviews and focus groups were used to gain a better understanding of this topic. The novel point of this article is that it provides an honest reflection of the benefits and limitations of this qualitative research process from the perspectives of a non‐Aboriginal researcher and an Aboriginal participant, when emphasis is placed on a collaborative approach. The paper outlines what a successful qualitative research project looks like in Victorian Aboriginal communities. This can be used as a blueprint not only for working with Aboriginal Victorian communities, who have been marginalised within Australian society, but may also be relevant to other culturally diverse communities throughout the world.
Corporate Culture Narratives as the Performance of Organisational Meaning
Authors: Fenton Taylor Jill , Carroll John
Published: June 2010

This case study is informed by a call for new ways to analyse the enactment of organisational culture using discourse analysis and researcher reflexivity. The colliding research approaches used in this paper open up cultural symbolic data for analysis in ways that allow participants to reflect on their own organisational experiences. The methodology that is employed examines corporate culture narrative from a multifaceted viewpoint to show ways in which organisations seek to maintain their structure and identity in the marketplace. The study draws on narrative and performance methods to show how perceptions about organisational reality can be reinterpreted and communicated in the context of corporate cultural identity and enterprise risk management.
Quantum Chemical Calculations on the Interaction between Flavonol and Functional Monomers (Methacrylic Acid and 4-Vinylpyridine) in Molecularly Imprinted Polymers
Authors: Gómez-Pineda Luis Enrique , Pina-Luis Georgina Esther , Cortés-Romero Carlos Martín , Palomar-Pardavé Manuel Eduardo , Rosquete-Pina Giselle Alicia , Díaz-García Marta Elena , Hernández María de los Angeles Cuán
Published: June 2010

Quantum chemical calculations were performed to characterize the interaction of the flavonol molecule (FL) with methacrylic acid (MAA) and 4-vinylpyridine (4VPy) in the formation of imprinted polymers. The polarizable continuum model (PCM) was used to gain insight on the type of interaction between the reactant molecules under vacuum conditions and in the presence of different solvents. The effect of solvent on the pre-polymerization complex formation was evaluated through the stability energy, in which chloroform behaves as the best solvent for the synthesis of the imprinted polymers since it facilitates the reaction by lowering its degree of stabilization. The reactivity was analyzed in terms of the electrostatic surface potential (ESP) and Mulliken charge. By means of these results, it has been possible to determine two potential recognition sites for the interaction of the MAA monomer and one for the 4VPy in relation to the strength of interaction with FL. In this concern, the interaction of the system FL-MAA is stronger than FL-4VPy.
Role of Leukotrienes and Leukotriene Modifiers in Asthma
Authors: Montuschi Paolo
Published: June 2010

Leukotrienes (LTs), including cysteinyl LTs (CysLTs) and LTB4, are potent lipid mediators that are pivotal in the pathophysiology of asthma phenotypes. At least two receptor subtypes for CysLTs – CysLT1 and CysLT2 – have been identified. Most of the pathophysiological effects of CysLTs in asthma, including increased airway smooth muscle activity, microvascular permeability and airway mucus secretion, are mediated by the activation of the CysLT1 receptor. LTB4 may have a role in the development of airway hyperresponsiveness, severe asthma and asthma exacerbations. Although generally less effective than inhaled glucocorticoids, CysLT1 receptor antagonists can be given orally as monotherapy in patients with persistent mild asthma. In patients with more severe asthma, CysLT1 receptor antagonists can be combined with inhaled glucocorticoids. This therapeutic strategy improves asthma control and enables the dose of inhaled glucocorticoids to be reduced, while maintaining similar efficacy. The identification of subgroups of patients with asthma who respond to CysLT1 receptor antagonists is relevant for asthma management, as the response to these drugs is variable. The potential anti-remodeling effect of CysLT1 receptor antagonists might be important for preventing or reversing airway structural changes in patients with asthma. This review discusses the role of LTs in asthma and the therapeutic implications of the pharmacological modulation of the LT pathway for asthma.
Cerebral and Cerebellar Volume Loss in Children and Adolescents with Systemic Lupus Erythematosus: A Review of Clinically Acquired Brain Magnetic Resonance Imaging
Authors: MUSCAL EYAL , TRAIPE ELFRIDES , de GUZMAN MARIETTA M. , MYONES BARRY L. , BREY ROBIN L. , HUNTER JILL V.
Published: June 2010

Objective.

Cerebral atrophy is a prominent feature in adults with systemic lupus erythematosus (SLE). We assessed cerebral and cerebellar volume loss on clinically acquired brain magnetic resonance imaging (MRI) scans of children and adolescents with SLE.

Methods.

We abstracted information on disease course for patients who underwent clinical brain MRI during the period 2002–2008. We completed qualitative assessments of volume loss and measured corpus callosum thickness and ventricular enlargement for patients with lupus and controls.

Results.

Forty-nine children underwent brain MRI during the review period due to clinical indications. The lupus cohort was predominantly female and ethnically diverse. Mean age at imaging was 15.3 ± 2.6 years and mean disease duration was 30.6 ± 33.3 months. Findings suggestive of cerebral and cerebellar volume loss were seen respectively in 89.8% and 91.8% of lupus patients. Cerebral volume loss was moderate or severe in 26.5% of children. Cerebellar volume loss was moderate in 20.4% of these patients. Linear measurement means reflected corpus callosum thinning and ventricular enlargement in lupus patients. Volume loss was observed in newly diagnosed patients prior to corticosteroid use. Disease duration and corticosteroid use did not predict the severity of volume loss. There were statistically significant differences in linear imaging measurements comparing lupus patients to 14 similar-age controls.

Conclusion.

Regional volume loss was observed in most adolescents with lupus undergoing clinical brain MRI scans. As in other pediatric conditions with inflammatory or vascular etiologies, these findings may be reflecting disease-associated neuronal loss and not solely the effects of corticosteroid.