bluuebunny/crossref_metadata_2025 huggingface dataset:
New Fracture-Stimulation Designs and Completion Techniques Result in Better Performance of Shallow Chittim Ranch Wells
Authors: Pandey Vibhas J. , Agreda Aquiles J.
Published: March 2015

The Sacatosa field in west Texas was discovered in 1956. Since then, more than 1,500 wells have been drilled and completed in the main reservoir section known as the San Miguel 1. The San Miguel 1 is primarily low-permeability sandstone, with several shale layers dispersed throughout. Economic development of the field requires effective well stimulation and an active waterflood program to provide pressure maintenance. Unfortunately, the available injection water is of poor quality and can rapidly plug up pore throats with solids, resulting in significant near-wellbore formation damage. When these factors are considered, hydraulic fracturing of both injector and producer wells is a viable option for improved long-term well performance. However, because of relatively shallow depths, traditional hydraulic-fracturing practices can lead to a multiplane fracture system with a mix of horizontal and vertical components. A significant presence of horizontal fractures can be detrimental to fractured-well performance because of the low conductivities of the fractures. In producer wells, this could impair production if the reservoir is laminated and has low vertical permeability. In injectors, water-front movement and sweep efficiency would be diminished greatly.

This paper discusses the steps taken to plan and develop a strategy to place vertical fractures in shallow San Miguel 1 sands. These findings can easily be extended to similar shallow-depth reservoirs worldwide. Some major modifications in completion design included changes in perforation strategy, redesign of the pump schedule, and implementation of a staged stimulation. Fracturing treatments were pumped on a total of 26 injectors and eight producers through a variety of methods, including coiled-tubing fracturing. Post-fracture analysis suggests a strong vertical-fracture component, and analysis of injectivity tests shows fracture parameters in line with design objectives. All the producers that were fracture stimulated with this technique reported higher initial production when compared with wells stimulated through the use of legacy treatment schedules.
Simulation of Gel Filter-Cake Formation, Gel Cleanup, and Post-Fracture Well Performance in Hydraulically Fractured Gas Wells
Authors: Charoenwongsa Sarinya , Kazemi Hossein , Fakcharoenphol Perapon , Miskimins Jennifer L.
Published: March 2015

Polymer and gel damage is a major issue in the cleanup of hydraulically fractured gas wells. This paper addresses the issue by using a gas/water flow model that simulates fracture propagation with gel filter cake-formation as mechanical trapping of polymer molecules on the fracture face and filtrate transport into the adjacent matrix. The model accounts for polymer as a chemical component. This approach is different than treating polymer as a highly viscous gel phase, which is the common method in most literature. In this model, the gel filter-cake thickness is calculated on the basis of experimental data. For leakoff, the model allows only the sheared polymer molecules, which are the major cause of formation permeability reduction, to cross the fracture face into the formation and adsorb on the matrix. Other features of the model include water blockage, non-Newtonian flow, non-Darcy flow, and proppant and reservoir compaction.
Laboratory Measurement of Hydraulic-Fracture Conductivities in the Barnett Shale
Authors: Zhang J.. , Kamenov A.. , Zhu D.. , Hill A.D.. D.
Published: March 2015

Horizontal wells that intersect multistage transverse fractures created by low-viscosity fracturing fluid with low proppant loadings are the key to revitalizing production from the Mississippian Barnett shale in the Fort Worth basin in Texas. However, direct laboratory measurements of both natural- and induced-fracture conductivities under realistic experimental-design conditions are needed for reliable well-performance analysis and fracture-design optimization.

In this work, a series of experiments was conducted to measure the conductivity of unpropped natural fractures, propped natural fractures, unpropped induced fractures, and propped induced fractures with a modified American Petroleum Institute (API) conductivity cell at room temperature. Fractures were induced along the natural bedding planes, preserving fracture-surface asperities. Natural-fracture infill was taken into consideration during conductivity measurements. Proppants of various sizes were placed manually between rough fracture surfaces at realistic concentrations. The two sides of the rough fractures either were aligned or were displaced with a 0.1-in. offset. After pressure testing on the system integrity, nitrogen was flowed through the proppant pack or unpropped fracture to measure the conductivity.

Results from 88 experiments show that the conductivity of hydraulic fractures in shale can be measured accurately in a laboratory with appropriate experimental procedures and good control over experimental errors. It is proved that unpropped, aligned fractures can provide a conductive path after removal of free particles and debris because of the brittleness and lamination of shale. Moreover, poorly cemented natural fractures and unpropped displaced fractures can create conductivities of up to 0.5 md-ft at formation-closure stress, which is one to two orders of magnitude greater than the conductivity provided by cemented natural fractures and unpropped aligned fractures. This study shows that propped-fracture conductivity increases with larger proppant size and higher proppant concentration. Longer-term fracture-conductivity measurements indicate that, within 20 hours, the fracture conductivity could be reduced by as much as 20%.
Use of Tracers To Evaluate and Optimize Scale-Squeeze-Treatment Design in the Norne Field
Authors: Vazquez O.. , Mackay E.. , Tjomsland T.. , Nygård O.. , Storås E..
Published: March 2015

When squeezing scale inhibitors (SIs) into oil-production wells, the inhibitor should usually be uniformly placed in the open intervals to optimize squeeze lifetime. In wells with varying reservoir quality and/or significant crossflow, however, uniform placement is difficult to obtain. Flow diverters are frequently used to improve the chemical placement. In many cases, it is of great interest to evaluate the squeeze performance and assess the actual placement and back production of inhibitor to gather well information and thereby optimize future squeeze designs. This can be particularly interesting in subsea wells in which other types of data collection, such as production logging, are not feasible because of high intervention costs and high operational risk. This study suggests the use of tracers during squeeze treatments to evaluate the placement as an alternative to running production-logging tools (PLTs).

The main purpose of this paper is to demonstrate the applicability of tracers [in this particular study, the injection of a potassium chloride (KCl) slug in a producer well in the Norne field] to evaluate the layer flow-rate profile along the completion interval, which depends on the pressure and geological properties of each layer. The study consists of verifying the layer flow-rate profile predicted by a history-matched reservoir model. On the basis of this layer flow-rate profile, a tracer-injection program is designed, which includes two production stages at different rates. Finally, on the basis of the reservoir-model predictions, it is identified that each layer is at different pressures, which leads to a distinctive return profile.

To evaluate the match between the observed data and the simulation data, the layer flow-rate profile from the reservoir model was used to populate a specialized near-wellbore model for scale-squeeze treatments. The match between the observed data and the simulated data was good. However, the near-wellbore model, in particular the layer flow-rate profile, was fine-tuned further. Finally, the fine-tuned near-wellbore model was used to optimize future treatments more accurately with the fine-tuned layer flow-rate profile.
Activator Development for Controlling Degradation Rates of Polymeric Diverting Agents
Authors: Reddy B.R.. R. , Cortez-Montalvo Janette
Published: March 2015

Hydrolytically degradable polymers (generally aliphatic polyesters) have been used in a variety of applications in the oil field, such as fluid diversion, fluid-loss control, and filter-cake-removal applications. In general, diverting agents and fluid-loss-control materials are only necessary to perform the intended function for a finite amount of time. Once the well is completed or placed on production, it is desirable that the degradable materials be removed so that they no longer have any influence on subsequent fluid flow. With time and temperature, the degradable polymers will break down by forming water-soluble byproducts, leaving behind limited, if any, residual formation damage. The effective formation sealing by these materials while in place, and eventual cleanup, has made them sought after materials for a growing number of applications. However, for cooler temperatures and applications for which the well must be placed on production rather quickly, there have not been many options to controllably increase the rates of polymer degradation.

Strong acids and bases are known to accelerate the degradation of polyesters. Use of these materials can present several disadvantages, such as corrosion and/or undesirable reactions with the formation. This paper discusses amine- and aminoalcohol-based compounds as potential degradation accelerators (DAs) of polymers containing ester-functional groups in the polymer backbone. Oligomeric polyamines, such as ethylenediamine (EDA) and its homologues, and aminoalcohols, such as ethanolamine (EA), were tested as accelerators for polymer breakdown. Commercial polyesters tested in this study had variable crystalline and amorphous content. With one exception, polyglycolic acid (PGA), all polyesters contained polylactic acid (PLA)/polylactide either exclusively or as one of the components. The tests were performed under static conditions by aging known quantities of particulate polymers with identical particle-size distributions in excess aqueous fluids, and loss in recovered dried mass was measured periodically at test temperature. The results indicated that oligomeric polyamines accelerated polymer degradation significantly compared with water. The degradation rates were the highest for totally amorphous polymer and decreased with the increase in crystallinity. Some semicrystalline polymers appeared to increase in weight initially before manifesting weight loss because of degradation, especially in the presence of a polymeric amine, and to a lesser extent in the presence of water. Among aminoalcohols, EA containing a primary amine group was significantly more effective than that containing a tertiary amine in degrading semicrystalline polymers. Trialkanolamines appeared to cause swelling of the particulate semicrystalline polymers before significant weight loss from degradation manifested. Mechanistic implications of the results relating the degrading chemicals and the polymer properties and compositions are proposed.
Evaluation and Performance of Packer-Type Downhole Gas Separators
Authors: McCoy J.N.. N. , Podio A.L.. L. , Rowlan O.L.. L. , Becker D..
Published: March 2015

Advances in horizontal drilling and large fracturing technology have resulted in wells that produce larger volumes of oil and gas than have been common domestically. Artificially lifting large volumes of oil and associated gas to the surface has always been a problem because of the difficulty of separating liquid from large volumes of gas downhole, especially in rod-pumped wells.

This paper describes a separation technique that uses a packing element to divert the formation fluids through the separator and into the casing annulus at the top of the separator, above the pump inlet at the bottom of the separator, so that the liquids and gas can separate by gravity. The pump seating nipple is located at the bottom of the separator so that the pressure drop is less in the liquids moving from the casing annulus to the pump intake. Better pump fillage is obtained with the technique of setting the pump intake at the bottom of the separator rather than above the long separator, as show by the field data.

This paper also describes a quantitative technique for evaluating the effectiveness of downhole gas separators. Often, the evaluation of separator performance is based only on pump fillage and the total gas production from the well, instead of a comparison of the liquid fillage in the pump in relation to the percentage of liquid that exists in the casing annulus surrounding the pump.
Time-Dependent Fracture-Interference Effects in Pad Wells
Authors: Manchanda R.. , Sharma M.M.. M. , Holzhauser S..
Published: March 2015

Hydraulic fracturing in shale formations induces microseismic events in a region we refer to as the microseismic volume. Many of these microseismic events are signatures of failure in the formation that are believed to be a result of induced unpropped (IU) fractures beyond the primary propped fracture. Areally extensive microseismicity may be evidence that these IU fractures occur and extend spatially beyond the propped fracture during pumping in many unconventional reservoirs. We present evidence that these fractures close over time after pumping is stopped and that this closure of IU fractures can have a significant impact on stress interference between fractures.

To illustrate these effects, microseismic and radioactive-tracer data are presented for four laterals drilled and fractured from a single pad. Two wells on this pad were fractured with the consecutive-fracturing sequence, and the other two wells were fractured with the zipper-fracturing sequence. Geomechanical simulations were performed to model the pad scenario and explain the microseismic and tracer observations, with emphasis on the two different fracturing sequences.

Our simulations show that the opening of the IU fractures results in significant temporary changes to the stress field in the rock. One consequence of this is that later fracture stages tend to propagate into the open-fracture networks of IU fractures created earlier because of stress reorientation. This can lead to inefficient usage of fluid, proppant, and capital because the region that is being stimulated has already been stimulated by the previous stage. By analyzing the net pressure, radioactive-tracer data, and microseismic data from the four-well pad, we show that these IU fractures close over time because the fracture fluid leaks off. This reduces the stress shadow, and subsequent induced fractures are no longer subjected to the significantly altered stresses, allowing for more-efficient fracture-network coverage by subsequent fractures in a horizontal well. On the basis of the data presented and computer simulations, we propose the idea of maximizing the time between fracturing in the microseismic volume of a recently fractured region (within operational constraints). The time required for the IU fractures to close can be estimated from our models and varies on the basis of the reservoir and fluid properties from several hours to days. One example of how this is accomplished in practice is zipper fractures. However, our work suggests that there also may be other fracture-sequencing strategies for accomplishing this.
Geology and Geohistory Contribute to Flow Assurance, Part II: Asphaltene-Risk Evaluation Incorporating Geological Heterogeneity and Covering All Operating Temperatures
Authors: Yonebayashi Hideharu , Tosic Slavko
Published: March 2015

This paper will present more-detailed discussion of asphaltene risk by updating new asphaltene-onset-pressure (AOP) results, and it will capture range-of-temperature conditions (i.e., from reservoir temperature to surface-operating temperature). For integrating these updates into the risk-matrix chart proposed in the previous work by Yonebayashi et al. (2013), geological heterogeneity of fluid-sampling location will be taken into account. A study of numerical modeling (applying the cubic-plus-association equation of state) treated the geological heterogeneity as a variation of asphaltene content, and reproduced asphaltene-precipitation envelopes, which were well-matched to the overall trend of experimental AOP detection. To conclude, this work reduced the uncertainty of the asphaltene-precipitation boundary at reservoir temperature, and showed a consistent shifting of the asphaltene-precipitation boundary by temperature range.
Fines Migration in Fractured Wells: Integrating Modeling With Field and Laboratory Data
Authors: Marquez M.. , Williams W.. , Knobles M.. , Bedrikovetsky P.. , You Z..
Published: March 2015

Production and drawdown data from 10 subsea deepwater fractured wells have been modeled with an analytical model for unsteady-state flow with fines migration. The simulation results and the field data indicated a good match, within 5%. A sensitivity study conducted on initial concentration of fines, flow rate, maximum fines-mobilization velocity, fines distribution, formation damage, and filtration coefficients confirmed that the model-matching parameters are within values reported commonly in the literature. This paper describes the methodology used to integrate the modeling predictions with field and laboratory data to identify probable causes for increasing skins and declining productivity-index values observed in some of the wells under investigation. It discusses the results of an experiment designed to simultaneously assess the effects of pressure depletion and compaction on fines production and permeability with a triaxial-stress apparatus. This is, to the best of our knowledge, the first time an experiment of this nature is reported in the literature. The good match between the modeling and the field data, further validated with laboratory experiments, allows for discussion of long-term predictions on well productivity impacting current reservoir-management strategies and field-development plans.
Use of Model-Predictive Control for Automating SAGD Well-Pair Operations: A Simulation Study
Authors: Patel K.. , Aske E.M.. M. , Fredriksen M..
Published: March 2015

For more than a decade, the steam-assisted-gravity-drainage (SAGD) process has been in use commercially to extract heavy oil from Athabasca oil-sand deposits located a few hundred meters below the surface. Operating challenges in the SAGD phase of operations arise not only because the process is hidden below the surface, but also because of the number of well pairs needed to drain the reserves and the number of variables that need to be considered for each well pair.

Different control philosophies have been suggested and used to control SAGD well pairs, which focus on a single variable or a few out of the many variables to be considered. None of these philosophies have been found to consider the well pair as a whole, with interactions between the downhole variables, and none of the philosophies have been found to include predictive capability. In this paper, we demonstrate, for the first time, how model-predictive control (MPC) can be used to control, stabilize, and assist optimization of an SAGD well pair.

This paper shows how we used proprietary MPC software to control and stabilize a typical configuration of a numerically simulated virtual SAGD well pair. Our simulation results demonstrate that MPC is suitable for use in the SAGD industry and provides insights into the use of MPC to manage actual SAGD operation.
Interpreting Distributed-Temperature Measurements in Deepwater Gas-Well Testing: Estimation of Static and Dynamic Thermal Gradients and Flow Rates
Authors: Kabir C.S.. S. , Yi X.. , Jakymec M.. , Hasan A.R.. R.
Published: March 2015

In typical drillstem testing (DST), transient pressures are gathered downhole while rate measurements occur at the surface. Effects of heat transfer on pressure, particularly during a buildup test in a gas well, necessitate the close proximity of pressure measurements to the point of fluid entry. While pressure measurements are reliable with sufficient resolution in most settings, rate measurements often lack synergy with pressure because of the sensor resolution and the frequency of monitoring. The reduced-rate sensor resolution and rate-monitoring frequency may precipitate significant uncertainty in transient-test interpretations.

This paper presents a case study for a deepwater asset in Western Australia, where, in addition to the traditional downhole-pressure and surface-rate measurements, temperatures were recorded at various depth stations in four wells, each in a different reservoir, before, during, and after transient testing. These temperature data allowed estimation of gas-flow rates. The computational accuracy of flow rates increased at shallower depths because increased heat transfer, leading to larger temperature difference, enhanced the fidelity of measurements. Overall, the distributed-temperature data allowed the estimation of temperature gradients, including their nonlinear trends, for both the static geothermal and dynamic flows.
A Probabilistic Methodology To Evaluate the Cost Efficiency of Rigless Technology for Subsea Multiwell Abandonment
Authors: Moeinikia F.. , Fjelde K.K.. K. , Saasen A.. , Vrålstad T.. , Arild Ø..
Published: March 2015

In a few years, there will be a need for performing a considerable number of subsea plug-and-abandonment (P&A) operations on the Norwegian continental shelf. There are certain challenges associated with this. These include more-difficult access to subsea wells compared with ordinary platform wells, high daily rates of semisubmersible rigs, and the fact that these rigs will be allocated for drilling new exploration-and-production wells to sustain the hydrocarbon production. At the moment, there is large focus on finding rigless technologies to reduce P&A cost and use of rig time. A probabilistic approach should be used to assess the cost- and duration-saving potential of such technologies relative to semisubmersible rigs.

In this paper, we will consider rigless technologies for performing parts of the P&A operation. For the first time, a probabilistic approach, including learning curves, correlations, and possible risk events, is used to evaluate subsea batch-operated P&A.

A realistic example that includes the use of a semisubmersible rig for batch-operated P&A of subsea production wells is used to show how a probabilistic methodology can be implemented for obtaining probabilistic estimates of P&A cost and duration. Inclusion of learning curves and correlations makes the application of a probabilistic approach for multiwell campaigns challenging. It is demonstrated how to incorporate learning curves, correlations, and possible risk events to capture a realistic range of cost and duration for multiwell P&A operations. In a second operational example, a light-well-intervention vessel is used to accomplish preparatory work and wellhead cutting and removal for P&A of the subsea production wells in batch campaigns. These two scenarios will be compared from a cost and duration point of view. Moreover, the advantages associated with riserless technologies for multiwell abandonment are discussed.
Reservoir Simulation, Ion Reactions, and Near-Wellbore Modeling To Aid Scale Management in a Subsea Gulf of Mexico Field
Authors: Mackay E.J. , Jordan M.M. , Ishkov O. , Vazquez O.
Published: March 2015

This paper presents the findings of a study into the impact of reservoir flow behavior on the scaling risk at production wells and the options for managing this scaling risk for a deepwater sandstone reservoir in the Gulf of Mexico. One significant feature in this field is that flow takes place through isolated formation layers, and choices made regarding the seawater-injection wells have a great impact, not only on the barium sulfate (BaSO4) scaling tendency, but also on the placement of scale-inhibitor squeeze treatments in the producers. In addition to seawater injection, oil production is supported by the aquifer. The first stage of this study involved identifying the split between connate water, aquifer water, and seawater in the produced brine. This provided data that could be used to calculate the evolution of the scaling risk over the life cycle of each well. The formation brines contained barium, the injection water was full-sulfate seawater, and the relative proportion of brine (the water-production rate, pressure, and temperature conditions) determined the scaling risk. The evaluation of the extent of reactions between the injection water (sulfate) and formation water (barium) from injection to production well can result in a significant reduction in the available barium within the produced water, and hence, the scaling risk and scale-inhibitor concentration required for prevention of scale deposition. In this study, because the injection wells were completed with inflow-control valves (ICVs), the opportunity was given to manage the injection split by means of these ICVs, not only to improve sweep efficiency, but also to balance reservoir pressures and make squeeze treatments more efficient. This study will present the squeeze-treatment volumes and estimated treatment lifetimes possible for two scenarios for the water-injection application to this deepwater field. The implications of this type of study will be highlighted in terms of the options that these data will allow an operator to consider before commissioning water injection in these challenging environments.
Diagnostic Fracture Injection Tests: Common Mistakes, Misfires, and Misdiagnoses
Authors: Barree R.D.. D. , Miskimins J.L.. L. , Gilbert J.V.. V.
Published: March 2015

Over the last 20 years, diagnostic fracture injection tests (DFITs) have evolved into commonly used techniques that can provide valuable information about the reservoir, as well as hydraulic-fracture-treatment parameters. Thousands of tests are pumped every year in both conventional and unconventional reservoirs. Unfortunately, many tests that are pumped provide poor or no results because of either problematic data acquisition or incorrect analysis of the acquired data.

This paper discusses common issues and mistakes made while acquiring DFIT data. Guidelines on how to avoid these errors and secure the best possible data are provided, including data resolution, pump rates, test duration, and fluid selection. Strategies are provided to estimate the time required to reach fracture closure and establish stable reservoir transients for analysis.

The last part of the paper addresses potential (and commonly observed) problems in the analysis of the DFIT. These issues can be magnified in tight-gas and shale reservoirs because of the long data-acquisition times and the subtle pressure transients that can occur. Specific issues that are discussed include poor instantaneous-shut-in-pressure data from perforation restriction, loss of hydrostatic head, gas entry and the resulting phase segregation, the use of gelled fluids, and errors in after-closure analysis.
A New Comprehensive Model for Predicting Liquid Loading in Gas Wells
Authors: Luo Shu , Kelkar Mohan , Pereyra Eduardo , Sarica Cem
Published: March 2015

Liquid loading, which can lead to rapid gas-rate decline and can even cease gas production, is a common phenomenon found in most mature gas wells. An accurate prediction of the inception of liquid loading is of great interest to operators, for the reason that remedial measures can be applied in a timely manner to prevent such conditions from being realized, thereby extending the production life of the gas well. However, the mechanism that is responsible for liquid loading still remains controversial. In the literature, at least three different definitions of liquid loading exist. The first definition is based on the intersection of inflow and outflow curves, the second definition is based on the reversal of entrained liquid droplets, and the third definition is based on the reversal of liquid film. These definitions yield different results when predicting the inception of liquid loading. In this paper, a new definition of liquid loading is introduced. This new definition is based on the relative contributions of gravity and residual pressure drop, and it is validated by its agreement with air/water experimental data.

A new comprehensive model is developed that is based on the Barnea (1986, 1987) model. For vertical wells, the new model can better predict the inception of liquid loading than the widely used Turner et al. (1969) equation. For deviated wells, it is observed in the field and in laboratories that liquid loading starts much earlier than in vertical wells, and most liquid-loading equations are not appropriate for deviated wells. The new model takes into account the nonuniform film thickness around the circumferential position of the pipe, and, thus, it improves the prediction of liquid loading in deviated wells. The new model is validated through the use of field data in the literature and experimental data obtained at the University of Tulsa. In addition to the literature data, a new set of field data is reported and used to validate the new model, which shows a significant improvement over the droplet model as well as other film models.
Application of Conventional Well Logs To Characterize Spatial Heterogeneity in Carbonate Formations Required for Prediction of Acid-Fracture Conductivity
Authors: Saneifar Mehrnoosh , Heidari Zoya , Hill A.D.. D.
Published: March 2015

Acid etching, as the consequence of heterogeneous distribution of petrophysical and compositional properties, results in the conductivity of acid fractures in carbonate reservoirs. Reliable characterization of small-scale formation spatial heterogeneity by use of geostatistical analysis (i.e., variogram analysis) can improve prediction of acid-fracture conductivity significantly. Previous publications suggest that permeability correlation length can be used to assimilate spatial heterogeneity in prediction of acid-fracture conductivity. Well logs are good candidates to provide information about petrophysical and compositional properties of the formation with the required resolution for prediction of acid-fracture conductivity. However, the assessment of permeability and mineralogy from conventional well logs is challenging because of high spatial heterogeneity and complex pore structure. Rock typing has been suggested in the literature to improve permeability assessment in carbonates. Most of the previously introduced rock-typing methods are dependent on core measurements. However, core data are generally sparse and not available with the sampling rate required for prediction of acid-fracture conductivity.

The main objective of this paper is to quantify formation spatial heterogeneity with variogram analysis of well logs and well-log-based estimates of petrophysical and compositional properties in carbonate reservoirs. We introduce an iterative permeability-assessment technique that is based on well logs, which takes into account characteristics of different rock classes in the reservoir. Furthermore, we propose three rock-classification techniques that are based on conventional well logs and that take into account static and dynamic petrophysical properties of the formation as well as mineral composition.

We applied the proposed techniques successfully in two carbonate formations—Happy Spraberry oil field and Hugoton gas field. The petrophysical rock classification is in good agreement with identified core-derived rock classes. The results show approximately 54% improvement in permeability assessment compared with conventional permeability-assessment techniques, which can improve prediction of acid-stimulation jobs significantly. Finally, we investigated the direct application of well logs and well-log-based estimates of petrophysical and compositional properties for variogram analysis required to characterize formation spatial heterogeneity. We conducted variogram analysis in both field examples. The results show that the direct application of well logs and well-log-based estimates of petrophysical/compositional properties is reliable to characterize formation spatial heterogeneity. We also showed that application of well logs can enhance assessment of spatial heterogeneity compared with core measurements.
Reverse Cleanout in a Geothermal Well: Analysis of a Failed Coiled-Tubing Operation
Authors: Reinsch T. , Regenspurg S. , Feldbusch E. , Saadat A. , Huenges E. , Erbas K. , Zimmermann G. , Henninges J.
Published: March 2015

During the production of geothermal brine from a production well in Groβ Schönebeck, Germany, an obstruction was observed when logging the reservoir interval of the well. Several bailer runs were performed to identify the cause, and it was discovered that mainly loose precipitates and fragments of coating from the production tubing were obstructing the well. To remove the fill from of the well, a reverse-cleanout operation with coiled tubing was performed. Because of wellbore restrictions, particle size, and the rheology of the fill, only a small portion of the obstruction could be removed. This paper describes the coiled-tubing operation and the application of a simple hydraulic model to explain possible reasons for failing to effectively clean out the well.
Allergic Reactions to Local Anesthetics in Dental Patients: Analysis of Intracutaneous and Challenge Tests
Authors: Tomoyasu Yumiko , Mukae Kazuo , Suda Michiyo , Hayashi Tomoko , Ishii Minako , Sakaguchi Mai , Watanabe Yoshihisa , Jinzenji Ayako , Arai Yukiko , Higuchi Hitoshi , Maeda Shigeru , Miyawaki Takuya
Published: March 2015

Some dental patients have histories of adverse reactions to local anesthesia. The aim of the present study was to investigate the frequency of allergy to local anesthetics of dental patients who had histories of adverse reactions to local anesthesia based on the results of allergy tests in our institute over a period of 5 years. We investigated the past medical records of dental patients retrospectively, and twenty patients were studied. Three of the 20 showed a positive or false-positive reaction in the intracutaneous test, and one patient showed a false-positive reaction in the challenge test. Our results suggest that the frequency of allergy to local anesthetics is low even if patients have histories of adverse reactions to local anesthesia. However, allergy tests of local anesthetics should be performed in patients in whom it is uncertain whether they are allergic.
Review of the Research on Energy Consumption Evaluation Index System of Campus
Authors: Ying Han , Jianqiang Han , Guoqiang Xu , Shikuan Liu , Jing Cui
Published: March 2015

In recent years, with the fast development of economy and technology, people's living standards have gradually
improved, which lead people to consume the energy excessively. Especially As the large flow of people and system
complexity, the university campus occupied a large proportion in the energy consumption. Currently, the school
admissions showed a rising trend and the population is highly concentrated. Therefore, the construction of the campus
enter into a peak period.Tthe scale of the campus is expanding, and more and more energy is consumed. To solve these
issues, it starts from the campus energy-saving and energy-consuming to establish an effective evaluation system of
energy consumption. On one hand, it could be understood that d the overall situation of building energy consumption
easily, on the other hand, it can detect the movements of the different aspects of building energy consumption, in order to
facilitate the further development of campus building energy in the future work. It is reviewed the research status of the
campus energy consumption evaluation index system at home and abroad, and proposes some future prospects on
constructing green campus in the article.
The effect of various vegetable oils on pollutant emissions of biodiesel blends with gasoil in a furnace
Authors: Heravi Hamid , Hosseini Saeed , Bamoharram Fatemeh , Baharara Javad
Published: March 2015

In this paper the effect of various vegetable oils on pollutant emissions of
biodiesel blends with gasoil in a furnace is studied experimentally. The
exhaust gas temperature and emissions of CO, NOx and SO2 are measured by an
R-type thermocouple and TESTO 350-XL gas analyzer respectively. The oil of
soybean, sunflower, canola and corn are used in transesterification process
of biodiesel. The results show that maximum of temperature, NOx emission and
SO2 emission are achieved for the combustion of sunflower methyl ester and
corn methyl ester blends with gasoil in contrast with combustion of soybean
methyl ester and canola methyl ester blends with gasoil. Also the minimum of
CO emission is reached for combustion of these fuels.
GLP-1R Agonists Modulate Enteric Immune Responses Through the Intestinal Intraepithelial Lymphocyte GLP-1R
Authors: Yusta Bernardo , Baggio Laurie L. , Koehler Jacqueline , Holland Dianne , Cao Xiemin , Pinnell Lee J. , Johnson-Henry Kathene C. , Yeung William , Surette Michael G. , Bang K.W. Annie , Sherman Philip M. , Drucker Daniel J.
Published: March 2015

Obesity and diabetes are characterized by increased inflammation reflecting disordered control of innate immunity. We reveal a local intestinal intraepithelial lymphocyte (IEL)-GLP-1 receptor (GLP-1R) signaling network that controls mucosal immune responses. Glp1r expression was enriched in intestinal IEL preparations and copurified with markers of Tαβ and Tγδ IELs, the two main subsets of intestinal IELs. Exendin-4 increased cAMP accumulation in purified IELs and reduced the production of cytokines from activated IELs but not from splenocytes ex vivo. These actions were mimicked by forskolin, absent in IELs from Glp1r−/− mice, and attenuated by the GLP-1R agonist exendin (9-39) consistent with a GLP-1R–dependent mechanism of action. Furthermore, Glp1r−/− mice exhibited dysregulated intestinal gene expression, an abnormal representation of microbial species in feces, and enhanced sensitivity to intestinal injury following administration of dextran sodium sulfate. Bone marrow transplantation using wild-type C57BL/6 donors normalized expression of multiple genes regulating immune function and epithelial integrity in Glp1r−/− recipient mice, whereas acute exendin-4 administration robustly induced the expression of genes encoding cytokines and chemokines in normal and injured intestine. Taken together, these findings define a local enteroendocrine-IEL axis linking energy availability, host microbial responses, and mucosal integrity to the control of innate immunity.
Characterization of growth and biochemical composition of sterlet, Acipenser ruthenus L., juveniles from the Dniester population reared in RAS
Authors: Khudyi Oleksy , Kolman Ryszard , Khuda Lidia , Marchenko Mykhailo , Terteryan Larisa
Published: March 2015

A broodstock was created with individuals from the diminishing natural sterlet, Acipenser ruthenus L., population in the upper area of the Dniester basin. Selects and spawners were reared in flow-through tanks with natural thermal regimes. This is the first time artificial reproduction has been performed with this species, followed by incubation and larval rearing. The experimental rearing was conducted in tanks in a recirculating aquaculture system, in which the basic environmental quality parameters were controlled, including water temperature, oxygen saturation, and levels of ammonia and nitrite. During rearing, growth rates and proximate composition of larvae and then juvenile were examined. It was confirmed that during the period of endogenous feeding there was a two-fold decrease in the contents of protein and lipids in the bodies of the larvae. The effects of feeding the sterlet juvenile two different types of commercial feed were compared, and it was confirmed that the feed had a significant impact on sterlet growth rates. The mean daily increase in the body weight of sterlet juvenile fed Skretting feed was 1.91%, while that in the group fed Aller feed was 0.97%. Additionally, the juvenile from the former group was characterized by higher contents of protein and lipids in both the liver and muscle and the fatty acid profile was more varied.
Determining the spring biomass peak of the smallest plankters in selected vendace lakes in Western Pomerania
Authors: Domagała Józef , Ługocki Słukasz , Czerniawski Robert , Pilecka-Rapacz Małgorzata
Published: March 2015

The aim of this study was to determine the prevalence peak of the smallest plankters that are an adequate food resource for vendace (Coregonus albula L.) larvae. This goal was accomplished by determining weekly changes in zooplankton biomass, especially rotifers and nauplii, against changes in basic physicochemical parameters of lake waters. As the results of this paper show, the highest abundance of the smallest plankters, rotifers and nauplii, occurs at a particular temperature for a period of two weeks. The most important variable that determined the peak of small plankter biomass is temperature. Thus, the period of stocking lakes with vendace larvae should be synchronized with this temperature and the coinciding biomass peak of rotifers and nauplii, which are the basic food of vendace larvae.
Improving Learning in a Traditional, Large-Scale Science Module with a Simple And Efficient Learning Design
Authors: Godsk Mikkel
Published: March 2015

This article presents the experiences and results of using a simple learning design for transforming a traditional, large-scale, face-to-face science module in calculus into blended learning where all face-to-face lectures were replaced by webcasts and online activities. The article presents the impact on teaching and learning in terms of how the teacher and the students used the materials and the impact on the students’ performance and satisfaction. The article concludes that replacing face-to-face lectures with webcasts and online activities has the potential to improve learning in terms of a better student performance, higher student satisfaction, and a higher degree of flexibility for the students. In addition, the article discusses implications of using learning design for educational development, how learning design may help breaking with the perception that facilitating blended learning is a daunting process, and, ultimately, its potential for addressing some of the grand challenges in science education and the political agenda of today
Positive Interaction Of Ethanol With Malic Acid In Postharvest Physiology Of Cut Spray Carnation ‘White Natila’
Authors: Begri Fatemeh , Hadavi Ebrahim , Nabigol Amrollah
Published: March 2015

In this study, succinic acid (0, 1 and 2 mM), malic acid (0, 1 and 2 mM), ethanol (0, 2 and 4% v/v), and their mixtures were applied as preservative solutions for cut flowers of spread carnation cv. ‘White Natila’ and their effect on the longevity, the amount of absorbed solution, malondialdehyde and chlorophyll content, cell membrane stability, fresh, and dry weight and on a visual quality was determined. A similarity in the effect of malic acid and succinic acid on dry weight and fresh weight loss were found. Ethanol positively affected most of the studied traits, including the vase life and fresh weight loss. The preservative solution containing 1 mM of malic acid and 4% ethanol resulted in the longest average vase life - 11.1 days compared to 8.9 days in the control. Malic acid showed a significant positive synergism with ethanol that makes it reasonable to combine them in preservative solutions intended to extend the vase life of cut spray carnation.
Leaves Of Cut Rose Flower Convert Exogenously Applied Glucose To Sucrose And Translocate It To Petals
Authors: Horibe Takanori , Yamaki Shohei , Yamada Kunio
Published: March 2015

To understand the role that the leaves play in the translocation of soluble carbohydrates in cut rose flowers, we first evaluated the effect of leaf removal on flower quality and the sugar content in petals. Cut rose flowers with leaves had higher soluble sugar content in petals compared with cut flower without leaves. Next, we treated cut flowers with radioactive glucose to clarify translocation routes of exogenously applied sugar. There was no significant difference between the specific radioactivity of sucrose and glucose in leaves, but specific radioactivity of sucrose in petals was much higher than that of glucose. These results suggested that most of the exogenously applied glucose first moved to the leaves, where it was converted into sucrose and then the synthesised sucrose was translocated to the petals. Our results showed that the leaves of cut rose flowers play an important role in the metabolism and transportation of exogenously applied soluble carbohydrates toward the petals, thus contributing to sustaining the post-harvest quality.
Effect Of Priming Of Seeds Of Medicago Sativa ‘Bami’ With Gibberellic Acid On Germination, Seedlings Growth And Antioxidant Enzymes Activity Under Salinity Stress
Authors: Younesi Omid , Moradi Ali
Published: March 2015

The experiment was conducted in order to study effects of seeds priming with gibberellic acid (GA3) at 0, 3, 5 and 8 mM on germination, growth and antioxidant enzymes activity in alfalfa seedlings under salinity stress (200 mM NaCl). All control seeds germinated. The rate of germinated seeds was reduced to 48% in the presence of NaCl, and increased to 76% after seeds priming with 5 mM GA3. Priming with 5 mM GA3 was also correlated with an increase of dry weight of seedlings derived from both stressed and non-stressed seeds as well as with the reduction of electrolyte leakage (EL) and malondialdehyde (MDA) level in salt stressed seedlings. The activity of superoxide dismutase, catalase, guaiacol peroxidase and ascorbate peroxidase in primed and non-primed seeds increased in the presence of NaCl and after priming of seeds with 5 mM GA3, whereas only small effect on glutathione reductase activity in both primed and non-primed seeds was observed. The total ascorbate level was higher in both stressed and non-stressed seedlings from primed seeds. These results suggest that GA3 priming might increase the salt tolerance of alfalfa seedlings through enhancing the activities of antioxidant enzymes and reducing the membrane damage as estimated using biomarkers, EL index and MDA content.
Homologous Recombination Repair Polymorphisms and the Risk for Osteosarcoma / Polimorfizam Gena Odgovornih Za Reparaciju Dnk Homolognom Rekombinacijom I Rizikza Pojavu Osteosarkoma
Authors: Goričar Katja , Kovač Viljem , Jazbec Janez , Lamovec Janez , Dolžan Vita
Published: March 2015

Background: DNA repair mechanisms are essential for maintaining genome stability, and genetic variability in DNA repair genes may contribute to cancer susceptibility. Our aim was to evaluate the influence of polymorphisms in the homologous recombination repair genes XRCC3, RAD51, and NBN on the risk for osteosarcoma.

Methods: In total, 79 osteosarcoma cases and 373 controls were genotyped for eight single nucleotide polymorphisms (SNPs) in XRCC3, RAD51, and NBN. Logistic regression was used to determine the association of these SNPs with risk for osteosarcoma.

Results: None of the investigated SNPs was associated with risk for osteosarcoma in the whole cohort of patients, however, in patients diagnosed before the age of thirty years XRCC3 rs861539 C>T and NBN rs1805794 G>C were associated with significantly decreased risk for osteosarcoma (P=0.047, OR=0.54, 95% CI=0.30-0.99 and P=0.036, OR=0.42, 95% CI=0.19-0.94, respectively). Moreover, in the carriers of a combination of polymorphic alleles in both SNPs risk for osteosarcoma was decreased even more significantly (Ptrend=0.007). The risk for developing osteosarcoma was the lowest in patients with no wild-type alleles for both SNPs (P=0.039, OR=0.31, 95% CI=0.10-0.94).

Conclusions: Our results suggest that polymorphisms in homologous recombination repair genes might contribute to risk for osteosarcoma in patients diagnosed below the age of thirty years.