bluuebunny/crossref_metadata_2025 huggingface dataset:
Implementation of a CO2 Foam Pilot Study in the SACROC Field: Performance Evaluation
Authors: Sanders Aaron W. , Jones Raymond M. , Linroth Mark , Nguyen Quoc P.
Published: October 2012

A new conformance solution has been developed to help producers reach and recover more oil from existing wells while simultaneously reducing operating expenditures. This new technology successfully addresses shortcomings associated with existing miscible gas EOR (enhanced oil recovery) processes by generating foams of supercritical CO2 fluid and water in the formation which alter mobility and improve vertical conformance. Ultimately, the process can improve the profitability of existing wells by enhancing reservoir sweep efficiency, thereby allowing access to previously bypassed oil. This report describes the technology development process and documents successful field trial results from Kinder Morgan's SACROC field.
Engineering Hydraulic Treatment of Existing Fracture Networks
Authors: Pettitt Will , Damjanac Branko , Hazzard Jim , Han Yanhui , Sanchez-Nagel Marisela , Nagel Neal , Reyes-Montes Juan , Young R. Paul
Published: October 2012

Observations from field monitoring indicate the presence of existing fracture networks significantly affect, and may control, the history of hydraulic treatments. Existing fractures allow pathways for treatment fluids to migrate efficiently through the formation, stimulating connectivity to larger reservoir volumes. This paper examines the relationship between hydraulic treatments and fracture networks, and investigates the ability to engineer the hydraulic conductivity of the stimulated volume. Fracture network engineering (FNE) involves the engineering design of rock mass disturbance through the use of advanced techniques to model fractured rock masses numerically, and then correlate field observations with simulated fractures generated within the models. Modeling algorithms accurately address the hydromechanical physics of hydraulic treatments developed across a range of applications in rock engineering.

A Synthetic Rock Mass (SRM) model is constructed by explicitly defining a discrete fracture network within a modeled rock matrix. Hydraulic treatment into the SRM allows fracture dilatancy, propagation and shearing to be realized in the emergent behavior of the bonded particle model in three dimensions and at the scale of the treated volume. Simulated microseismicity is generated when the fractures are disturbed or propagated providing a method for correlation with field observations. Illustrative models show how hydraulic treatments stimulate fracture networks and generate new hydraulic fractures in volumes not expected in conventional design analysis connecting existing fractures with preferential alignment. By combining SRM models with field observations it is possible to investigate the relation and sensitivity of hydraulic treatments to existing fracture networks, and therefore, engineer the most optimal use of these fractures in the performance of a given project. Developmental challenges are discussed, including the sensitivity of the techniques to fracture network uncertainties and the accurate representation of microseismic source data within the models.
Study on the Volumetric Behavior of Base Oils, Brines, and Drilling Fluids Under Extreme Temperatures and Pressures
Authors: Zamora Mario , Roy Sanjit , Slater Kenneth , Troncoso John
Published: October 2012

Drilling fluid densities vary significantly over wide ranges of temperature and pressure, a concern that is particularly critical in deepwater, Arctic, and high-temperature/high-pressure wells. The variations can impact well integrity, well design, regulatory compliance, and drilling efficiency.

Drilling fluid densities depend on the compressibility and thermal expansion of the fluids (liquids) and solids used in their formulation. Suitable pressure-volume-temperature correlations for these fluids previously have been fairly inaccessible, due primarily to continually changing base fluids and blends, and the lack of readily available test equipment.

This study was conducted to measure the volumetric behavior under extreme temperatures and pressures of a broad range of the oils, synthetics, and brines currently used in industry to prepare oil, synthetic, and water-based drilling fluids. It follows a recent study that successfully qualified the commercially available test equipment.

For the most part, tests were run at temperatures from 36 to 600°F and pressures from atmospheric to 30,000 psi, ranges that generally exceed those used in published studies. Correlation coefficients are provided for reference and to demonstrate their use in a compositional, material-balance model to accurately predict drilling fluid density as a function of temperature and pressure. Tests run on field drilling fluids are included to demonstrate how these data can be used in procedures and software to predict equivalent static densities and hydrostatic pressure during drilling operations.
A New Family of Nanoparticle Based Drilling Fluids
Authors: Sharma Mukul M. , Zhang R. , Chenevert M. E. , Ji L. , Guo Q. , Friedheim J.
Published: October 2012

A new family of water-based drilling fluids that contain nano-particles has been tested to evaluate its interaction with shales. It was shown in an earlier paper that nano-particles dramatically reduce the flow of water into a shale formation. In this study we have developed and tested a new family of commercially available drilling fluids that can be used to drill shales.

Drilling shale formations with water-based fluids offers some tremendous environmental and economic advantages. To date the use of such fluids have been limited to hard shales such as the Barnett. In this paper we have developed and lab tested water-based drilling fluids that contain nano-particles that can be applied to a much broader range of shales.

Water-based drilling fluids have been formulated that incorporate nano-particles in them at a very reasonable cost. The rheology and stability of these muds were tested. A family of such fluids has been developed and tested in the lab. It is found that the muds are quite stable at elevated pressures and temperatures and offer a wide range of rheological properties. These muds also offer good lubricity and are, therefore suitable for applications in drilling the lateral section of the hole in shales. Tests were also conducted to measure the extent of invasion of water into shales when they are exposed to nano-particle based drilling fluids. The invasion into the shale was reduced by 10 to 100 times indicating that wellbore instability problems will be minimized when these muds are used.

Drilling long lateral sections in shales and tight gas reservoirs is often the largest capital cost associated with the development of these resources. Nano-particle based drilling fluids have the potential to significantly cut these drilling and disposal costs and offer significant environmental benefits.
Integrating Improved Environmental Performance into Rig Design
Authors: Delisio Sam , Grosvenor Courtney , Meissner Niels , Ogg Jeremy , Wagner Natalie
Published: October 2012

As sustainability and environmental stewardship become an elevated priority in energy policy around the world, the oil and gas industry faces ever-more-stringent regulations, while investors and stakeholders increasingly expect quantification of environmental performance and health and safety factors. With these evolving concerns and pressure from customers, the public, and government to reduce environmental impact, the financial costs and public backlash from making mistakes are growing. As the liaison between the public and many natural resources, the oil and gas industry is in a very important position to protect and sustain these resources for future generations. Thus, technological advances and a re-evaluation of standard drilling practices are required in the field in order to continue meeting the nation's growing energy demand while simultaneously working to eliminate environmental and human safety hazards via equipment automation; reduced air emissions, water consumptions, fuel use, land use, and waste streams; improved well control technology; and use of more energy-efficient materials. These advances are also a prerequisite to improve market access to environmentally-sensitive areas and heavily regulated regions of the world. A shared goal between supply companies and operators to develop and deploy environmentally-friendly drilling solutions based on operator and customer needs, public concerns, and government regulations will help move the industry toward a safer, more efficient, zero-spill, low-carbon future. This paper discusses some of the technologies and examples of how effectively managing environmental performance are also good business practice.
Production Analysis in the Eagle Ford Shale — Best Practices for Diagnostic Interpretations, Analysis, and Modeling
Authors: Ilk D. , Broussard N. J. , Blasingame T. A.
Published: October 2012

The Eagle Ford Shale (South Texas, USA) is emerging as the foremost "liquids-rich" shale play in North America. As such, the use of production data analysis in the Eagle Ford Shale has tremendous importance in:

Determining well/reservoir properties; Establishing completion effectiveness; and Estimating future production.

The Eagle Ford Shale presents additional difficulty in the form of fluid behavior characterization. Near-critical PVT behavior (as in the case of the Eagle Ford Shale) is an important component of well performance, which cannot be overlooked during analysis and modeling. The results of this work address the common challenges encountered during production analysis and modeling of the Eagle Ford shale wells. In particular, it is shown that significant differences are observed in production forecast due to characterization of the fluid. This work provides a systematic workflow to analyze and forecast production data in near-critical reservoirs with examples from the Eagle Ford Shale and delivers more insight into analysis of production data in unconventional "liquids-rich" reservoirs, and offers to decrease the uncertainty related with production forecast that is mainly caused by lack of understanding of "near-critical" fluid behavior.
Shear-Enhanced Two-Phase Flow Properties in Athabasca Sands
Authors: Hamza Syed M. , Olson Jon E. , Holder Jon
Published: October 2012

Field results in Steam Assisted Gravity Drainage (SAGD) heavy oil operations suggest formation permeability changes during production operations. We investigate this process using samples constructed from loose Athabasca sand. Our results indicate that permeability changes (absolute and relative) and endpoint oil and water saturation variation are a function of loading boundary conditions. Triaxial loading paths (increasing mean stress) show increased permeability with sample dilatancy upon failure at low confining stress (100 to 400 psi) that diminishes when run at higher confining stress (800 psi). Residual oil saturation increases during compaction and decreases during dilation while initial water saturation decreases during compaction and increases during dilation. Radial extension tests (decreasing mean stress) result in larger increases in permeability upon failure and dilatancy, and lower residual oil and higher initial water saturations. Finally, failure induced by unloading through pore pressure increase, run under fixed displacement, fixed stress, or mixed axial versus confining boundary conditions, show minimal permeability changes until the effective stresses approach zero. However, the increase in initial water saturation and decrease in residual oil saturation are as significant as or greater than what was seen in the triaxial compression and radial extension tests. Overall, results show that lab experiments support increased permeability due to steam injection operations in heavy oil, and more importantly, the observed reduction in residual oil saturation implies SAGD induced deformation should improve recovery factors.
Technology and Equipment Design for Global Shale Markets
Authors: Brantley Lydia , Major Thomas
Published: October 2012

Shale gas is widely considered to be revolutionizing the industry in the U.S. Various countries have begun shale exploration, but none have begun pursuing it with the aggressive growth characteristic of the North American experience. While the price of natural gas in some regions can be three to five times higher than in the U.S., the nature of lease agreements, geological characteristics, and political and societal factors all shape different emerging shale development models.

In North America, variations in shale gas plays have resulted in differences in technology and equipment design. The Horn River, for example, is located in a flat environment with very cold winters, while the Marcellus is located in a population-dense area with small local roads. These examples result in differences to field, well, and equipment design. This will be exaggerated as we move to international locations. In Europe, for example, road regulations restrict weight and dimensions, requiring rigs to break into smaller modules, and limiting the horsepower on a single fracture pumping unit. Novel fracture methods, such as pin-point fracturing, may be given different considerations internationally, potentially reducing horsepower requirements. Additionally, as international markets move into commercial development of resources, the truck traffic, emissions reduction, and need for smaller overall surface footprint will likely drive the market toward more wells per pad. This will cause rig design to follow closely the development seen in Canada's multi-well pad design with load limits and equipment designed more like the Marcellus.

This paper investigates the impact of varying emerging global markets on the future of technology and innovation in shale and tight gas reservoirs. The influences such as geological, political, and infrastructure on equipment design for varying gas reservoirs will be discussed.
Phase Behavior of Gas Condensates in Shales Due to Pore Proximity Effects: Implications for Transport, Reserves and Well Productivity
Authors: Devegowda Deepak , Sapmanee Kanin , Civan Faruk , Sigal Richard
Published: October 2012

The present study investigates the alteration of the properties, transport, and production of gas-condensates in shale gas reservoirs and develops and demonstrates an effective and practical methodology to apply these modifications in existing numerical simulation software. Simple models that investigate the phenomena can be investigated without the need for any modifications to an existing simulation code, but realistic models will require significant modifications. Our modeling results indicate that when pore sizes are in the sub-10 nm range, typical of many gas shales, the influence of pore walls on the phase behavior and viscosity of typical gas-condensate fluids is dramatic, in both organic and inorganic pores, and creates favorable fluid and transport conditions leading to enhanced production. This is because the fluid mixture in such porous formations tends to exhibit behavior similar to that of a dry gas or a leaner gas-condensate system, thereby reducing the condensate banking effect considerably in the near-wellbore region and consequently, not impairing the productivity of the producing well. The results also underscore possible reasons for the significant production of condensate liquid from these nanoporous media in contrast to what is expected based on the industry's collective experience with conventional reservoirs. Consequently, the analysis and exercises carried out in this article provide valuable insights into the nature of fluid behavior and advances our understanding of the mechanisms of gas-condensate transport in extremely low permeability nanoporous media.
Inaccuracy in Pipeline Compressor Station Construction Cost Estimation
Authors: Rui Zhenhua , Metz Paul , Wang Xiaoqing , Chen Gang , Zhou Xiyu , Reynolds Douglas
Published: October 2012

The aim of this paper is to investigate pipeline compressor station project cost overruns. A total of 220 pipeline compressor station projects constructed between 1992 and 2008 have been collected, including material, labor, miscellaneous, land, and total costs, compressor station capacity, location, and year of completion. Statistical methods are applied to identify the distribution of cost overruns and overrun causes. Overall average overrun rates of pipeline compressor station material, labor, miscellaneous, land and total costs are 0.03, 0.60, 0.02, −0.14, and 0.11, respectively. Cost estimations of compressor station construction components are biased except for the material cost. In addition, the cost estimation errors of underestimated compressor station construction components are generally larger than those of overestimated components. Results of the analysis show that compressor station project size, capacity, location, and year of completion have different impacts on individual construction cost component cost overruns.
Autonomous ICD Single Phase Testing
Authors: Least Brandon , Greci Stephen , Burkey Russell , Ufford Adam , Wileman Angel
Published: October 2012

Reservoir flow control is important for maximizing hydrocarbon production. Traditional in-flow control devices (ICDs) attempt to balance the completion pressure differential with the reservoir pressure differential so that even flow across production zones is maintained. This maximizes oil production by delaying unwanted fluids from breaking through. Unfortunately, when lower viscosity fluids do break through, they take over the well, significantly reducing production of the desired hydrocarbon. This paper describes the design and function of a new self-adjusting in-flow control device (AICD). When hydrocarbons are producing from all zones, the AICD will behave as a traditional ICD, balancing flow. However, when low-viscosity fluids break through, the AICD chokes them, significantly slowing flow from the zone producing the undesirable fluids. This autonomous function enables the well to continue producing the desired hydrocarbons for a longer time, maximizing total production.

The paper describes the laboratory testing performed to evaluate the performance of the new AICD in field-like conditions. Results from single phase experimental flow testing with model fluids are presented and discussed.

The testing results proved that the AICD could restrict flow from zones producing undesirable fluids. The discussion further shows that if technology such as the new AICD is applied to new well completion designs, total hydrocarbon recovery will be enhanced, providing a significant benefit for production companies and those involved in design and modeling of new well completions.
Development of a Correlation for the Estimation of Condensate to Gas Ratio CGR and Other Key Gas Properties From Density/Molecular Weight
Authors: Dindoruk Birol
Published: October 2012

Condensate to Gas Ratio (CGR) is a measure of liquid content of a naturally occurring hydrocarbon mixture that is classified as gas condensate at reservoir conditions. It is also one of the most important parameters that impacts the economics of gas projects. In many cases, especially in the case of stranded gas, significant project value will be drawn from the liquid content of the gas. There are number of difficulties in measuring the CGR of a gas stream in the laboratory, or sometimes simply the value may not be known. Some of the difficulties in lab processes (but not limited to) originate from:

Non-equilibrium flash and carry-over Amount of the fluid used (volume constraints and errors)

In this paper, we have developed a simple easy to use semi-empirical correlation that accurately estimates the CGR of a gas condensate system using fluid densities (or molecular weights). Fluid densities can be obtained either from gradient measurements or directly from the laboratory measurements. To our knowledge, there is no equivalent correlation published in literature. The proposed correlation can be used for:

Exploration support to estimate the CGR ranges (valid up to CGR = 350 STB/MMSCF). Form a yard-stick to quality-check laboratory experiments. Generate necessary input parameters for other key gas properties: such as Z-factor, gas formation volume factor, Molecular weight, gas viscosity and even compositions. Reconciliation of contaminated samples against the measured or estimated fluid densities.
Uncovering the Potential of Thin, Tight Gas Reservoirs in Sichuan Basin, China - New Development Campaign Using New LWD Imaging Technology and Innovative Interpretation Workflows
Authors: Gang Lv Zong , Run Peng Hai , Qin Xia , Rong Li Qi , Parlindungan H. M. , Zhao Jing Kai , Denichou Jean-Michel , Yuk Ha Stephanie Chow , Ju Song
Published: October 2012

Located in central China, the Sichuan basin holds the biggest gas reserve in the country. Tight gas reservoir (limestone, dolomite, and tight sand) development has been taking place since early 1992.

Since then, relatively thicker gas reservoirs have been commonly developed, and more challenging, very thin reservoirs are now being targeted. Long horizontal drilling combined with multistage hydraulic fracturing is planned. However, the management of the subsurface uncertainties appears as the biggest challenge.

Located in a major compressional tectonic area, the geological province presents reverse/thrust faults and high structural dip uncertainty. Lateral property changes in the dolomite target reservoir and a stratigraphic thickness of the reservoir that varies from 1 m to 2 m add to the difficulty.

To overcome these challenges and to enhance reservoir understanding, advanced logging-while-drilling acquisition and real-time transmission of high-resolution electrical borehole images, azimuthal gamma ray, and multidepth measurement of formation resistivity were deployed in a recently completed gas well.

Based on these data and advanced techniques, structural features including dips, faults, and fractures could be clearly identified in real time while drilling and helped the team to: 1) accurately geosteer the well and significantly reduce the probability of erroneous lateral placement and 2) optimize the completion design and planning of the hydraulic fracturing staging and segmentations.

Completed in 2011, the well represents the first successful completion in the thin, tight gas reservoir; a 1095-m horizontal section was drilled with 91% net-to-gross and the gas production was recorded at 123 700 m3/d, exceeding the set production goal of the well by 33%.

This particular success is proving that a thin, tight gas reservoir can be profitably developed. Several subsequent wells have been planned to be drilled in different target zones in the Sichuan basin.
Wettability in CO2/Brine/Quartz Systems: An Experimental Study at Reservoir Conditions
Authors: Saraji Soheil , Goual Lamia , Piri Mohammad
Published: October 2012

A new experimental setup is developed that is capable of performing accurate IFT and contact angle measurements under extreme conditions, i.e., high pressure (up to 15,000 psi), high temperature (up to 200°C), and with highly corrosive fluids. The apparatus is equipped with an advanced and accurate temperature control system and a pulse-free Quizix pump to provide precise and stable experimental pressures and temperatures. Pre-equilibration of phases is achieved before each test, outside the measurement cell, to avoid non-equilibrium effects. Using an advanced drop shape analysis technique (ADSA-NA) and an automated polynomial fit, advancing and reseeding contact angles were measured with a protruded needle. The results cover a range of temperatures and pressures including subcritical and supercritical CO2 phases allowing characterization of wettability under both conditions. This preliminary study shows that wettability of quartz surface alters towards less water-wet condition when CO2 phase changes from subcritical to supercritical conditions. In addition, changes in wettability of quartz may not be monotonous function of temperature.
Artificial Lift Optimization with Foamer Technology in the Alliance Shale Gas Field
Authors: Farina Lisa , Passucci Claudio , Di Lullo Alberto , Negri Emanuele , Anderson Shawn , Page Stan
Published: October 2012

In the last years, the shale gas business has gained increasing emphasis within the major oil & gas companies. In particular, Quicksilver Resources and eni e&p, through its subsidiary eni US Operating Co., and are jointly involved in the development of the Alliance shale gas field in the prolific Barnett shale play located in Texas. Recently, both companies started a common effort to optimize production and lift costs. Such efforts included a deeper analysis of the artificial lift performance and exploitation of additional deliquification technologies.

In fact, typical shale gas wells are adversely affected by the continuous flow-back of the huge volumes of water used for the frac jobs. In the Alliance field, the most common way to support deliquification was by injecting lift-gas through the casing. Foaming agents were only occasionally deployed and a comprehensive activity to assess their technical and economic performance has been conducted.

In the last six months, extensive foamer injection tests have been performed on several wells, considering the effect of a factors such as production/injection mode (tubing or casing), foamer type and rate, lift-gas rate, gas and water rates and wellhead pressures. The uncommon synergy of continuous foamer and lift-gas injection has also been extensively exploited in horizontal wells.

At the end of the test phase, more than one third of the producing wells had been treated with a foamer and relevant technoeconomic improvements had been achieved. The paper describes in detail the methodology, the field experience and the results obtained.
Development of a Vogel type Inflow Performance Relationship (IPR) for Horizontal wells
Authors: Ogunleye Ayowole Onoopemipo
Published: October 2012

Vogel1's Inflow performance relationship (IPR) is the most frequently used method for evaluating productivity of vertical wells and it has also been proven to be reliable and accurate. Due to this and the increase in the use of horizontal wells, a Vogel type inflow performance relationship for horizontal wells is developed in this paper and skin is included into the equation generated in terms of flow efficiency.

The model is developed by inputting Vogel1, base case parameters into a Reservoir Simulator (Eclipse) and configuring the model as a vertical well. The results of the simulation are then validated with the Vogel1 Reference curve and after validation the configuration of the model is changed from that of a vertical well to a horizontal well. From this horizontal well model, a Vogel type IPR for horizontal wells is developed and skin which is a major factor affecting the productivity of wells is included into the equation generated.

This developed Vogel type IPR for horizontal wells accounts for the flaws of previously used correlations for predicting the performance of horizontal wells. This is achieved by accounting for the heterogeneity of the reservoir as other correlations for predicting the productivity of horizontal wells have assumed a homogenous reservoir which is not the case in real reservoir situations. Skin is also included in thus Developed Vogel type IPR as other correlations have assumed a Zero skin, which is also not the case in real situations.

Finally, the developed Vogel type IPR is tested for accuracy and consistency by comparing it frequently used correlations and the results obtained shows this Developed IPR is consistent and accurate and can therefore be used for evaluating the productivity of horizontal wells.
Modeling and Investigation of the Influence of Capillary Heterogeneity on Relative Permeability
Authors: Krause M. H.
Published: October 2012

A recently developed technique to accurately characterize sub-core scale heterogeneity by Krause et al. (2011, 2012) is applied to investigate the flow rate dependency of relative permeability on heterogeneity. Leverett (1939) first reported the dependency of laboratory measured relative permeability on flow rate, these results have since been both supported (Rapoport and Leas 1953) and challenged (Richardson 1957) by a number of investigators. Studies have shown that this apparent flow rate dependency is a result of both sub-core scale heterogeneity (Corey and Rathjens 1956) and outlet boundary effects (Richardson et al. 1952), however this has only been demonstrated numerically for highly simplified models of porous media. In this paper, flow rate dependency of effective relative permeability is demonstrated using two sandstone rock cores, one a Berea Sandstone having a low degree of heterogeneity, the other a heterogeneous sandstone from the Otway Basin Pilot Project in Australia. Steady-state coreflooding simulations are conducted at a number of injection rates using a single set of input characteristic relative permeability curves, and flow rate dependent effective relative permeability is calculated from the simulation data using Darcy's law. An optimization procedure is then used to derive the input characteristic relative permeability from the flow rate affected effective relative permeability. Results show that even in a Berea Sandstone, which has a relatively low degree of heterogeneity, the impact of fine-scale heterogeneities on measured relative permeability can be significant. Results also show that the apparent flow rate dependency of effective relative permeability is a stronger function of fine-scale heterogeneities than of capillary pressure gradients caused by the end effect. In addition to these observations, this work supports two important conclusions: the first is that using a one-dimensional homogeneous grid to simulate what is really a three-dimensional heterogeneous core can lead to significant errors in the derived relative permeability, even for cores of low heterogeneity. Second, the characteristic relative permeability curves can be accurately determined using flow rate affected effective relative permeability data using numerical simulation, provided the sub-core scale permeability distribution is accurately characterized.
The Study of Mass Transfer between Phases in Gas and Organic Drilling Fluid Mixtures
Authors: Policarpo N. A.
Published: October 2012

The study of mass transfer between phases is a very important issue during drilling operations with organic based drilling fluids. The research in the area is necessary to understand the interaction between the formation fluid (oil and/or gas) and the synthetic drilling fluid filtrate inside the invaded zone and also during a kick situation. A comprehensive literature search was conducted in order to identify the state of the art in the subject and to choose the appropriate experimental procedure and physical/mathematical modeling technique.

The present experimental work comprises the measurement and modeling of the diffusivity and interface mass transfer coefficients for those gas-liquid systems. The experimental data were obtained with accurate PVT measurements, under high pressure and high temperature conditions. The tests were carried out in the 70°C through 120°C temperature range for n- paraffin liquids with the following mole fraction of gas: i) 15% to 91% mol of CH4 and ii) 27% to 75% mol of CO2. The pressure decay method, which is based on the gas phase pressure decline with time as a consequence of the diffusion process, was applied to data modeling. A transient state diffusion model, with short and long term analytical solution, was applied to determine the mass transfer parameters for the two mixtures: CH4/n-paraffin and CO2/n-paraffin. The results of this ongoing research have two important contributions: i) to increase the safety during well control operations, mitigating the risk of blowouts, and ii) to understand the interaction of formation gas and organic based drilling fluids, especially in reservoir with high CO2 content, as those encountered in the recently found Brazilian sub-salt reservoirs.
Development of a Coupled Wellbore/Reservoir Simulator for Damage Prediction and Remediation
Authors: Shirdel Mahdy
Published: October 2012

Particle deposition is a complex problem in oil fields which affects all aspects of petroleum production, processing, and transportation. Asphaltene deposition has been repeatedly reported in various oil fields with interest on how it impacts the development of a reservoir. In many of the reported cases, it has been indicated that asphaltene deposition damages the wellbore and production facilities more severely than the formation.

A great deal of research has been conducted to study the phase behavior and dynamic aspect of asphaltene deposition. However, there is a lack of comprehensive integrated modeling of asphaltene deposition in the wellbore during the multiphase fluid flow. In this paper, we present an implementation of asphaltene precipitation and deposition models into a thermal, multiphase, multi-component wellbore simulator that can be coupled with a compositional reservoir simulator.

A key contribution of this work is the development of a simulator for predicting the detrimental effects of asphaltene in a well. Simulation results can show where and when the presence of asphaltene particles severely damages the efficiency and the productivity of the wells. This prediction is highly crucial if it is aimed to control the well performance and to optimize productivity.
Analysis and Potential of CO2 Huff-n-Puff for Near Wellbore Condensate Removal and Enhanced Gas Recovery
Authors: Odi Uchenna
Published: October 2012

Wet gas fields often experience reduction in productivity due to condensate banking in the near wellbore region. This occurs when the pressure in the near wellbore region falls below the dew point pressure and also when gas flow in tighter matrixes results in production of lighter components and the liquid dropout of heavier components. Carbon dioxide (CO2) in a process termed CO2 Huff-n-Puff can be used to lower the dew point of the condensate blocking the wellbore, thus removing the condensate blockage. To use CO2 Huff-n-Puff requires analysis of the potential of the interaction between CO2 and condensate. This analysis includes investigation of the impact that CO2 has on dew point pressure, effusion, diffusion coefficients into condensate, and productivity index. The overall objective of this work is to illustrate the potential of using CO2 to remove near wellbore condensate and for CO2 EGR.

To maintain field gas production targets, operators routinely set the bottom hole pressure below the dew point pressure which results in condensate blockage. Injecting CO2 can delay the onset of condensate blockage by reducing the dew point pressure of the condensate blockage zone. The approach illustrated, utilizes CO2 to delay the onset of condensate blockage. Factors such as improved effusion, diffusion, condensate skin factor, and productivity were analyzed to justify the use of CO2 for wellbore condensate removal and EGR.

Results show increases in productivity index after CO2 injection. Increases in productivity index were caused by CO2 evaporating the condensate blockage. Condensate vaporization was caused by CO2 reducing the dew point pressure of the condensate while repressurizing the reservoir above the reduced dew point pressure. Improvements in relative permeability profiles were used to quantify the success of the Huff-n-Puff process while improvements in NPV were used to illustrate the economic impact of using CO2.

Condensate blockage in wet gas reservoirs can be very detrimental in obtaining economic gas recoveries. This work is applicable to quantifying the potential CO2 Huff-n-Puff for near wellbore condensate removal and designing optimal EGR schedules. Results of this work provide a basis for justifying the use of CO2 as a treatment fluid and EGR solvent.
Hopes and Concerns in Couple Relationships across Adulthood and Their Association with Relationship Satisfaction
Authors: Villar Feliciano , Villamizar Diana Janeth
Published: October 2012

The study explored goals in couple relationships, and determined their association with age and the level of satisfaction expressed with the relationship. The participants were made up of 355 volunteers, aged between 20 and 78, who had been in a relationship for more than 6 months. The sample was gathered to ensure an age and gender balance. Participants' goals were ascertained by means of three sentence stems that they completed by expressing a general expectation, a hope, and a concern as regards their relationship. Satisfaction with the relationship was measured by means of Hendrick's Relationship Assessment Scale. Responses to the open-ended sentences were content analyzed and categorized. The frequency of these categories was associated with age, which indicated that an orientation toward growth was less frequent and an orientation toward maintenance was more common in older groups. Except in the youngest group, satisfaction with the relationship was negatively correlated to gains, and positively to maintenance. The study emphasizes the changes experienced in couple-related goals across adulthood and their relevance to satisfaction with the relationship, issues which have received little research attention to date.
Grandparents of Grandchildren with Autism Spectrum Disorders (ASD): Strengthening Relationships through Technology Activities
Authors: Wright Scott D. , D'Astous Valerie , Wright Cheryl A. , Diener Marissa L.
Published: October 2012

This study of grandparent-grandchild relationships was embedded in the context of technology workshops offered for young children on the autism spectrum. The purpose of this research was to examine the perspectives of six involved grandparents regarding their social interactions with their grandchildren in the context of this shared technology experience. Content analysis of transcribed focus group sessions with the grandparents indicated two key themes: expectations were reframed and communication bridges were built through shared interests. Grandparents perceived that their grandchildren learned technological skills, and increased their social interactions with peers, family members (parents, siblings), and grandparents themselves. The positive experience the grandparents perceived their grandchildren to have in the program gave them hope for future educational and employment opportunities for their grandchildren. The grandparents also indicated that the shared interests in the computer program facilitated communication opportunities with their grandchildren, with other grandparents of grandchildren with ASD, and with their adult sons and daughters.
Separation of avermectin components from Streptomyces avemitilis extraction using high-speed counter-current chromatography
Authors: Su Weike , Hou Zhuoni , Liang Xianrui
Published: October 2012

Three compounds of antibiotics-avermectins from fertilizing product of
Streptomyces avemitilis are achieved by high-speed counter-current
chromatography (HSCCC) with a two-phase solvent system composed of
n-hexane-ethyl acetate-methanol-water (6:4:5:5, v/v) on a preparative scale.
The separation condition was: 1.5 mL/min (0 to 200 min) and 2.0 mL/min (200
to the end), 900 rpm and 20?C based on the peak resolution. About 11.9 mg of
avermectin B1a, 1.0 mg of avermectin B1b and 9.6 mg of avermectin B2a from 50
mg of crude extract were obtained by one-step separation. The purities of the
three compounds determined by HPLC were 99.7%, 96.2% and 97.6%, respectively.
Their chemical structures were identified by electron spray ionization mass
spectroscopy (ESI-MS), 1H, 13C nuclear magnetic resonance (NMR).
Lab-on-a-Chip method uncertanties in determination of high-molecular-weight glutenin subunits
Authors: Zivancev Dragan , Nikolovski Branislava , Torbica Aleksandra , Mastilovic Jasna , Djukic Nevena
Published: October 2012

Polymeric wheat endosperm proteins, especially the high-molecular-weight
glutenin subunits (HMW-GS), are probably the most interesting protein
fraction giving the essential information about bread-making quality of wheat
flour. A relatively new method that shows a great potential for a fast,
reliable and automatable analysis of protein purity, sizing and
quantification is microfluidic or Lab-on-a-Chip (LoaC) capillary
electrophoresis. This work was aimed to explore the possibilities of
implementation of LoaC method to analysis of protein samples isolated from a
Serbian common wheat variety, emphasizing the steps that might bring
uncertainties and affect reproducibility of obtained glutenin subunits
quantitation results. A good resolution of protein bands in a molecular
weight range of 14.0 to 220.0 kDa was achieved. The reproducibility of HMW-GS
sizing and quantitation were good, with the average coefficient of variation
values of 1.2% and 12.2%. The ratio of HMW-GS to low-molecular-weight
glutenin subunits (LMW-GS) was about 20%. The investigation ruled out
influences of the extract solution addition and the buffer addition steps of
the applied method, as well as the individual chip influence on GS
quantitation results. However, there was statistically significant difference
between HMW-GS quantitation results of multi-step and one-step extraction
procedures applied prior to glutenin subunits extraction step.
The Wisdom of Sages: Nuclear Physics Education, Knowledge-Inquiry, and Wisdom-Inquiry
Authors: Cottey Alan
Published: October 2012

This article addresses the difference between knowledge-inquiry and wisdom-inquiry in nuclear physics education. In the spirit of an earlier study of 57 senior-level textbooks for first-degree physics students, this work focuses here on a remarkable use of literary quotations in one such book. Particles and Nuclei: an introduction to the physical concepts, by B. Povh et al, opens with an epigraph from Wilhelm Busch's Max und Moritz which has been rendered, in the celebrated translation by C.T. Brooks, as ‘Not alone to solve the double/Rule of Three shall man take trouble;/But must hear with pleasure Sages/Teach the wisdom of the ages.’ What the student gets, however, is technical material followed abruptly at the very end by the following biblical advice, from the Book of Jeremiah: ‘And it shall be, when thou hast made an end of reading this book, that thou shalt bind a stone to it, and cast it into the midst of Euphrates.’ From a study of these and other quotations and other features of the book the present author infers a strong desire to express something important about wisdom, which is, however, even more powerfully suppressed by the ideology of knowledge-inquiry. The article ends with a brief discussion of ‘wisdom of the ages' and ‘wisdom for our age’.
Audit Reporting for Going-Concern Uncertainty: A Research Synthesis
Authors: Carson Elizabeth , Fargher Neil L. , Geiger Marshall A. , Lennox Clive S. , Raghunandan K. , Willekens Marleen
Published: October 2012

In this synthesis we review research on going-concern modified audit opinions (GCOs) and develop a framework to categorize this research. We identify three major areas of research: (1) determinants of GCOs that include client factors, auditor factors, auditor-client relationships, and other environmental factors; (2) accuracy of GCOs; and (3) consequences arising from GCOs. We identify method-related considerations for researchers working in the area and identify future research opportunities.
Measuring Top Management's IT Governance Knowledge Absorptive Capacity
Authors: Ali Syaiful , Green Peter , Robb Alastair
Published: October 2012

Top management's involvement in IT governance appears to positively influence the establishment and implementation of effective IT governance within organizations. Considering the lack of advancement in the area in practice, this study offers a deeper understanding of dimensions that help to explain top management's knowledge of IT governance. Using absorptive capacity as its theoretical underpinning, and based on Australian empirical data, this study shows that for top management to achieve higher levels of absorptive capacity of IT governance knowledge (ACAP-ITG), they need to focus on four dimensions: prior relevant knowledge, effective communication network, appropriate communication climate, and effective knowledge scanning. To further support the usefulness of the ACAP-ITG construct, this study empirically tested the relationship between the construct and corporate performance. This study presents top management in organizations with useful measures that can help them assess their organization's strengths and weaknesses related to ACAP-ITG.
The effect of mental rotation on changes in plasma testosterone and cortisol levels
Authors: Durdiaková Jaroslava , Hodosy Július , Kubranská Aneta , Ostatníková Daniela , Celec Peter
Published: October 2012

Testosterone level has an influence on cognitive functions, especially spatial abilities. The relationship is, however, bidirectional and brain activity also affects testosterone levels. The aim of this study was to analyze the effects of an intensive 3D mental rotation task on testosterone levels in young healthy men and women. In the mental rotation task, men reached a higher top score (P=0.027) and total score (P=0.004) compared to women. In 8 out of 9 women (P=0.008) but not in men (P=0.129) testosterone levels decreased after one hour of mental rotation testing. A significant gender difference was shown (P<0.0001). In all women, plasma cortisol levels was significantly lower after testing (P=0.004). In men cortisol levels decreased in 7 out of 9 subjects (P=0.039). A significant gender difference was not found (P=0.19). No association was found in women between baseline testosterone levels and mental rotation total score (P=0.810). In men there was a positive correlation between baseline testosterone and mental rotation total score (P=0.015). A significant difference gender difference was seen in the association between testosterone and mental rotation score (P<0.05). Mental rotation stimuli caused significant changes in hormonal levels of testosterone and cortisol. A gender-specific response was detected in testosterone fluctuation.
Antimicrobial activity of Thymus longicaulis C. Presl essential oil against respiratory pathogens
Authors: Vladimir-Knežević Sanda , Kosalec Ivan , Babac Marija , Petrović Marinko , Ralić Jovica , Matica Biserka , Blažeković Biljana
Published: October 2012

Thymus longicaulis C. Presl is a small aromatic perennial herb used as a traditional remedy for cold, flu and cough. Composition of the essential oil of T. longicaulis from Croatia and its in vitro antimicrobial activity against the most common respiratory pathogens were evaluated. The yield of essential oil obtained by hydrodistillation from aerial plant parts was 1.2%. According to the GC-MS analysis, a total of forty one compounds (99%) were identified. Thymol (46.3%), γ-terpinene (16.2%), thymyl methyl ether (11.4%), and p-cymene (9.4%) were the main components. Antimicrobial activity of the essential oil against six clinically isolated bacterial and yeast strains was determined using standard disc agar diffusion method and microdilution broth assay. The essential oil exhibited antimicrobial activity towards all tested respiratory pathogens. The most sensitive strains were Haemophilus influenzae and Streptococcus pneumoniae(MIC=0.78 mg/mL), while Staphylococcus aureus was the most resistant (MIC>25.00 mg/mL). Our results indicate that T. longicaulis essential oil could be effective against clinically relevant respiratory pathogens which have the ability to develop resistance to antimicrobial drugs.