bluuebunny/crossref_metadata_2025 huggingface dataset:
Tribological Characteristics of Copper Based Composites with Al2O3 Particles at Various Temperatures
Authors: Hvizdoš P. , Besterci M. , Kulu P. , Kvačkaj T.
Published: April 2013

Two copper based composites: an experimental Cu-Al2O3 and commercial GlidCop AL-60 grade (with 1.1 wt.% Al2O3) with grains size approximately 1–2 µm were treated by Equal Channel Angular Pressure (ECAP) technique in order to induce severe plastic deformation and to reduce the grain size by about an order of magnitude. Microstructure of the as-received and ECAPed states of both systems were observed. Hardness of the experimental materials was measured by instrumented indentation. Tribological properties were studied by pin-on-disk technique in dry sliding against a steel ball at a various temperatures from room temperature up to 873 K. For all systems the coefficient of friction and specific wear rates were evaluated. Worn surfaces were studied by scanning electron microscopy and level of oxidation was measured using EDX spectrometry. It was found that between 473 K and 673 K the coefficient of friction decreased significantly. At lower temperatures the finer grained systems were more wear resistant than the as-received ones. The wear rate of all systems decreased down to zero at 673 K due to formation of hard oxide rich layers. Damage mechanisms were identified and their relationship with structural characteristics was inferred.
Response of the Cr-alloyed PM Steels on Vacuum Sintering and Heat Treatment
Authors: Bidulský Róbert , Bidulská Jana , Actis Grande Marco
Published: April 2013

The present paper deals with the evaluation of different vacuum heat treatments on the fracture surfaces of a low alloyed sintered steel in correlation with the mechanical and plastic properties achieved. The heat treatment conditions consist of the sintering process in vacuum furnace at 1393 K for 1800 s with an integrated final tempering at 473 K for 3600 s. The average cooling rates were calculated in the range of 1393 K to 673 K and were 0.1 K/s, 0.235 K/s, 3 K/s and 6 K/s, respectively. Vacuum heat treatment performed is supporting bainite/martensitic microstructure with increasing cooling rates; it provides a marked increase in strength coupled to a decrease in ductility. The typical microstructure appearances on the fracture surfaces show that microstructure-fracture developments are closely associated with strength/plastic properties. The fracture surface mode at higher magnification revealing two main micromechanisms of fracture: brittle (transgranular cleavage fracture) and ductile (dimples and plastic deformation by slip). Finally, the cooling rate of the vacuum furnace in order of 3 K/s is sufficient to obtain suitable properties of strength and plasticity which can however be accepted for several applications.
Application of PMU-Based Information in the Indian Power System
Authors: Agarwal P.K. , Agarwal V.K. , Rathour Harish
Published: April 2013

SCADA/EMS system has been the most commonly used tool for real-time power system operation and control throughout the world.

This system has been found to be very useful in steady-state analysis of the power system. The ever-increasing dependence of human society and every country’s economy on electrical energy calls for reliable power delivery. In order to meet these expectations, engineers across the globe have been exploring such new technologies that can improve upon the limitations of SCADA and provide dynamic visibility of the power system. A breakthrough has now been achieved in the form of synchrophasor technology. Synchrophasor measurements using phasor measurement units (PMUs) deployed over a wide area, facilitate dynamic state measurement and visualization of a power system, which are useful in monitoring safety and security of the grid. The Power System Operation Corporation (POSOCO) has taken initiative and implemented a pilot project wherein nine phasor measurement units (PMUs) along with one phasor data concentrator (PDC) were commissioned in the Northern Region (NR) of India. The primary objective of this pilot project was to comprehend the synchrophasor technology and its applications in power system operation. The data received and information derived from the pilot project have been found to be very useful and helped in improving the performance of the grid operation in several ways. The pilot project is operational for the last two years; in the meanwhile, many other initiatives have also been taken in other regions by POSOCO. This article details the utilization of the data collected from the pilot projects and the application of the data in the improvement of Indian power grid.
Effective embedding of residually hyperbolic groups into direct products of extensions of centralizers
Authors: Kharlampovich Olga , Macdonald Jeremy
Published: April 2013

For any torsion-free hyperbolic group Γ and any group
On accuracy of solving Symm's equation by
a fully discrete projection method
Authors: Solodky Sergey G. , Semenova Evgeniya V.
Published: April 2013

A problem of an approximate solving of Symm's integral equation for
an infinitely smooth closed boundary is considered. For a fully
discrete projection method, error estimates are found in the metric
of Sobolev spaces. A discretization parameter is chosen by balancing
principle.
Tuning the influence of metal nanoparticles on ZnO photoluminescence by atomic-layer-deposited dielectric spacer
Authors: Liu Monan , Chen Rui , Adamo Giorgio , MacDonald Kevin F. , Sie Edbert J. , Sum Tze Chien , Zheludev Nikolay I. , Sun Handong , Fan Hong Jin
Published: April 2013

There is increasing interest in tuning the optical and optoelectronic properties of semiconductor nanostructures using metal nanoparticles in their applications in light-emitting and detection devices. In this work we study the effect of a dielectric Al2O3 gap layer (i.e., spacer) on the interaction of ZnO nanowires with metal nanoparticles. The Al2O3 spacer thickness is varied in the range of 1–25 nm using atomic layer deposition (ALD) in order to tune the interaction. It is found that ~5 nm is an optimum spacer thickness common for most metals, although the enhancement ratio of the near-bandedge emission differs among the metals. Consistent results are obtained from both photoluminescence (PL) and cathodoluminescence (CL) spectroscopies, with the latter being applied to the optical properties of individual semiconductor/metal nanoheterostructures. The interaction is primarily proposed to be related to coupling of ZnO excitons with local surface plasmons of metals, although other mechanisms should not be ruled out.
Early- and late-arriving photons in diffuse optical tomography/Früh und spät ankommende Photonen in der diffusen optischen Tomographie
Authors: Proskurin Sergey G. , Potlov Anton Y.
Published: April 2013

A method of diffuse optical tomography (DOT) is described for the direct detection of absorbing and scattering inhomogeneities such as cysts, hematoma, or tumors. DOT can also be used to detect small changes in the oxygenation and deoxygenation of blood in designated regions of the heads of neonates, and in breast cancer. In contrast to the early part of time-resolved transmittance of a femtosecond pulse, late-arriving photons are used for this purpose. A 2D numerical simulation is used for quantitative matching of diffuse model curves to experimental data. The finite difference method is used for computer simulation of movements of a cloud of photons from the surface of an object to its center. The 3D representations of the time point spread functions (TPSF) represent a flat surface in a homogeneous case. Lower parts of the surface indicate the presence of inhomogeneities at the corresponding angles.
Finely tuned response of native prey to an invasive predator in a freshwater system
Authors: Bourdeau Paul E. , Pangle Kevin L. , Reed Emily M. , Peacor Scott D.
Published: April 2013

Lack of shared evolutionary history reduces the expectation that native prey will detect and respond to invasive predators. Four mechanisms may explain the adaptive response that is nevertheless seen in various systems: prey may perceive the invasive predator through cue similarity with preexisting predators, cues of conspecifics eaten by the invasive predator, a learned response based on experience with the invasive predator (e.g., cue association), and cues from the invasive predator that are specific to it. We performed laboratory experiments in which zooplankton (Daphnia mendotae) responded adaptively to the zooplanktivore Bythotrephes longimanus (migrating downward), showed no response to taxonomically similar predatory cladocerans, and responded adaptively to more taxonomically distant native fish (migrating downward) and native shrimp (migrating upward). Conspecific cues associated with Bythotrephes predation actually reduced the response of D. mendotae to Bythotrephes. Combined with previous experiments that rule out learning, our experiments rule out the first three mechanisms above, demonstrating that D. mendotae respond to cues specific to and produced directly by Bythotrephes. This finely tuned response may be retained from an ancestral species that coevolved with Bythotrephes in its native range, or may have rapidly evolved due to strong selection by the invasive predator.
Optimization of the "Fractured Triangle" to Determine Matrix/Fracture Permeability Ratio, Fracture Partitioning Coefficient and Intensity Index Derived from the Fractured Triangle of Pressure Transient Analyses
Authors: Elkewidy Tarek Ibrahim
Published: April 2013

In a previous research (IPTC 14187) a new technique was introduced to characterize all kinds of naturally fractured reservoirs on the Megascopic scale of pressure transient analyses. The technique is optimized through application of pressure derivative methods to yield a very characteristic graphical representation (triangle) of each hydraulic "flow" unit in the fractured reservoir.

The graphical technique along with newly derived formulas yield the most important petrophysical and engineering parameters about the heterogeneous naturally fractured reservoir including effective fractures, matrix and skin systems volumes, partitioning coefficient, fracture intensity index, formation resistivity factor, formation tortuosity, effective drainage radius, damage radius, effective cementation exponent, fracture porosity, matrix porosity, storativity ratio, in addition to fracture permeability, matrix permeability, damaged permeability, average permeability, pressure drop across the damage area, skin factor, damage permeability, average/dimensionless diffusivity factor, flow efficiency, damage ratio/factor, economic implication of formation damage, average hydraulic "flow" unit quality index.

The technique is extended to derive the fracture partitioning coefficient and intensity index in terms of storativity ratio generated from the fractured triangle of pressure transient analyses along with new fracture/matrix permeability ratio and fracture/matrix porosity ratio are introduced to aid describing the degree of reservoir heteroginity. Again the graphical technique of the fractured triangle has proven to be successful for all kinds of fractured reservoirs including clastics, carbonates and basement rocks. This study will present the theory along with successful field application with the results.
On the Accuracy of Dimensionless Inflow Performance Relationships for Gas wells
Authors: Kalantariasl A.. , Farhadi I.. , Nasriani H. R.
Published: April 2013

Usually four-point backpressure test, an isochronal test or a modified isochronal test is conducted to predict gas well deliverability. During past decades several simple dimensionless inflow performance relationships (IPRs) have been developed to eliminate the need for conducting multi-point test by using only data from a single drawdown or build-up test. The capability and accuracy of these models should be evaluated with measured field data using wide range of fluid and rock properties. This paper addresses the limitations, accuracy and optimal use of proposed dimensionless inflow performance correlations (Mishra and Caudle, 1984, Al-Attar and Al-Zuhair, 2009) based on back-pressure field test data of 53 wells that cover a broad range of AOF, reservoir pressure, well stabilized rate and pressure. The results show that both methods lose their accuracy at high rate and low drawdown conditions with unacceptable overprediction of AOFs. None of the studied models are recommended to use when dimensionless pressure (ratio of the well pressure to the reservoir pressure) is above 0.9. Advantages and ranges of optimal use of different models are discussed through error analysis.
Effective Analytical Approaches to Enhance Productivity of Low Producing Gas Wells
Authors: Rahim Zillur , Waspada Dwi , Al-Anazi Hamoud , Al-Kanaan Adnan , Pacheco Eduardo
Published: April 2013

Hydraulic fracturing is a widely used technology in the industry to enhance oil and gas production, particularly in tight formations. Tight gas and shale cannot sustain commercial production rates without fracturing. Although the technique has been used in the industry for many years and vast improvements have been made in upgrading fluid chemistry, proppant types, pump schedule sequence, and overall well completion system, a close evaluation is always required to ascertain that the fracturing has provided the level of productivity expected from the candidate well. Such evaluation and analysis will help improve and optimize the stimulation technique for any given reservoir and field conditions, address specific challenges in that area, and determine remedial plans on any well that did not show expected results in terms of productivity enhancement.

Saudi Arabian gas wells are usually stimulated to enhance and sustain production. Wells drilled in the R-1 reservoir in Field-A, that exhibit low to moderate permeability, are routinely hydraulically fractured. Many of these wells produce a high, sustained rate after a successful stimulation treatment. Some others do not perform up to expectation as seen from the rate decline. This can be caused mainly by inefficient fracture treatments such as achieving short half-length, limited vertical coverage, and poor post-frac cleanup. A critical and intense work on numerous wells has been performed using available data from geology, open hole logs, cores, pressure transient tests, etc., to understand and quantify reservoir characteristics, fracture properties, and flow capacity of these wells to come up with plans to improve productivity. Such plans include remedial treatments such as refracturing, placing additional perforations in previous unperforated intervals, initiating hydraulic fractures in different layers, and sidetracking the well to change its trajectory and geometry to contact new producing intervals. This paper summarizes the well conditions, complete evaluation processes, and suggests remedial procedures for each well to ensure full potential.
High Quality Images while Drilling
Authors: Bazara Magdi , Al Sharafi Mohamed , Maalouf Janine , Kindi Zainab Al
Published: April 2013

Drilling highly deviated wells in heavily fractured and complex heterogeneous carbonate formations is a challenging process that requires a real time monitoring and utilizing an MWD and LWD technology. Currently PDO is developing X field and drilling horizontal wells for gas in A formation in which the reservoir compromises a heterogeneous vuggy limestone and fractures network that is distributed all over the field. The challenge faced during drilling is the total drilling mud losses due to presence of major fractures, consequently those fractures represent a threat for early water break through and shortening the life of the well. PDO has utilized the Ultra high resolution LWD resistivity images in several wells to tackle this problem, which successfully helped to identify the fractures zones that contributed to the drilling mud losses and design completion to isolate those fractures zones. As well as selecting a proper perforation zones away from the fractures.

Having different depths of investigation can help to analyses invasion, provide inputs for petrophysical formation evaluation and to differentiate between features that appears near wellbore or deep in the formation. After drilling, memory data which has better sampling and data density was processed and quick geological interpretation was performed, The interpretation included complete structural borehole features identification such as (Structural dip computation by picking bed boundaries intersected while drilling), Detailed fractures characterization.

To identify type of fractures(conductive, resistive), morphology and geometry of each fractures (continuous, discontinuous) and fractures density and distribution along the logged interval. Minor sub-seismic faults were also identified from the images. The geological interpretation of the high resolution resistivity images revealed the presence of a few major conductive fractures that were possibly enhanced by drilling and a large number of partial discontinuous conductive and resistive fractures.
Importance of Checking Quality Control of Data in Describing Oil and Gas Reservoirs and Its Effect in Calculating Important Reservoir Parameters and Thus, Oil and Gas Reserves
Authors: Zaafran Zaher M.
Published: April 2013

This paper discusses more than 30 years of experience in auditing and evaluating oil and gas fields and its value in managing risks/uncertainties around the globe. These activities are highly dependent on the quality of the data utilized, especially those of well log data, together with the techniques used in measuring the physical and the fluid properties of both the core data, the interpretation of the well logs, the pressure transient analysis, and the Pressure Volume Temperature (PVT) data of the associated reservoirs.

The importance of using correct data by checking its quality has become one of the most challenging and important tools in reducing risks and uncertainties in recent years. This conclusion has been based on the fact that while auditing and evaluating oil and gas fields around the globe in the past 30 years, a vast majority of the data that I have observed has been found to be compromised. Moreover, it was also observed that while analysis was highly dependent on the quality of the data utilized, the interpretation procedures accordingly requires accurate input data (like in the case of log interpretation, pressure transient analysis or even core and PVT analysis), and these analysis were found to have serious errors on parameters involved in calculating important reservoir parameters and constructing geological models required for future reservoir development and reservoir management.

Field examples to show the size of the damages created by using unchecked data quality will be exhibited in this study especially in heterogeneous reservoirs. How to accurately calculate important reservoir parameters with field examples will also be illustrated, and the effects of such techniques in reducing uncertainties by calculating oil and gas reserves will also be addressed.

Summary and suggestions of ideal methods will be included in our assessment of data to better describe reservoirs, constructing better geological models, calculating oil and gas reserves and reducing risk and uncertainties; and thus, calculating accurate overall recovery factors.

It may be concluded from this publication that since these techniques has been a significant factor in either enhancing or reconstructing a better and accurate geological model used in most of the studies which were carried out by the author in each field evaluation around the globe, I am highly confident that Egypt might benefit by using the same principals to better describe their reservoirs and accurately construct their geological models.
Uncertainty Analysis by Model Selection Technique and Its Application in Economic Valuation of a Large Field
Authors: Singh Harpreet , Srinivasan Sanjay
Published: April 2013

Uncertainty assessment for economic valuation of a field generally involves developing multiple subsurface realizations combined with different development scenarios, thereby rendering the task computationally expensive and time consuming. In addition, the task of updating the models with new information is equally daunting leading to enormous and unreasonable simplifications to the economic valuation procedure.

This paper presents a novel approach that renders the uncertainty assessment less cumbersome and more efficient/accurate with the help of a new uncertainty assessment approach. The proposed approach makes use of a model selection algorithm to reduce the number of subsurface realization necessary for uncertainty assessment. A model selection framework does the work of refining an initial suite of reservoir models to a final set of reservoir models that depict production characteristics close to the observed field history. Model selection algorithm attempts to group reservoir models based on the common connectivity characteristics exhibited by them and then retrieve the group exhibiting characteristics that are closest to the observed response for a reservoir. The model selection technique is thus an efficient way to reduce number of realizations and save computational time for doing uncertainty analysis, and yet be optimally constrained to the available data.

An illustrative example with a dataset for a large field is used to show the proposed methodology for economic valuation of a large field. Well testing data from two wells is used as two sets of history data for the model selection procedure. Real option valuation (ROV), a probabilistic approach, is used to infer the economics of the reservoir. The case described will demonstrate that the proposed approach is systematic, reduces the time of computation, and allows the rigorous application of economic analysis without making any undue simplifications and assumptions.
Modeling of the Change of Rock Petrophysical Properties Due to Sulfur Deposition in Sour Gas Reservoirs
Authors: Mahmoud M. A. , Gadallah M. A.
Published: April 2013

Deposition of sulfur as a solid phase will result in plugging the pore space available for gas flow and reduce the reservoir productivity. For the isothermal conditions in the reservoir, the reduction in reservoir pressure below a critical value will cause the elemental sulfur to deposit in the formation. Sulfur deposition can cause severe loss in the pore space available for gas, and in will affect the gas well productivity.

In this paper a new analytical was developed to predict the effect of sulfur deposition on the damage of the near- wellbore. The damage will be quantified through the investigation of the effect of sulfur deposition on the reservoir porosity, permeability, relative permeability, and the change in rock wettability due to sulfur deposition especially in the near-wellbore region. The developed model considered the change in reservoir gas properties with the change in reservoir pressure which has been neglected by previous investigators. The main objective of these models is to investigate the effect of radial distance on formation damage. Different rock and fluid properties accurate correlation were used in this model for better results prediction. Coreflood experiment was performed to determine the effect of sulfur deposition on the carbonate rock permeability, porosity, and wettability. The experiment was used to determine the effect of sulfur adsorption on the rock petrophysical properties.

Model predictions showed that sulfur deposition depends on the radial distance from the well bore. The analytical model can be used to predict the sulfur deposition in the near-wellbore region. Sulfur deposition was found to have a great effect on the rock wettability, and in turn the gas production will be affected. It was confirmed experimentally that the sulfur deposition reduced the carbonate core porosity, permeability, and changed the contact angle. The contact angle increased which means sulfur adsorption on the rock surfaces changed the rock towards more gas wet rock.
Experimental Investigations of CO2 Solubility and Variations in Petrophysical Properties due to CO2 Storage in Carbonate Reservoir Rocks
Authors: Shedid Shedid A. , Salem Adel M.
Published: April 2013

The carbon dioxide (CO2) sequestration and storage in aquifers and depleted oil and gas reservoirs is eminently a feasible solution to provide substantial cut in overall emission into the atmosphere. The current need is to understand the factors affecting the CO2 sequestration potential and capacity of particular formation/reservoir.

The purpose of this study is to investigate the CO2 storage in carbonate reservoir rocks under different conditions of pressure and temperature. Two groups of experiments were undertaken including; (1) investigating the CO2 solubility under different brine salinities, and different pressure and temperature conditions, and (2) studying the effect of CO2 storage time interval on porosity and permeability of carbonate reservoir rocks. Core storage experiments were undertaken using actual and similar core samples saturated with 25, 000 ppm NaCl brine. The potential of the CO2 storage capacity and variations in porosity and permeability are evaluated and quantified.

The results showed that solubility of carbon dioxide decreases with increase in brine salinity and/or temperature. The increase of pressure causes a decrease in carbon dioxide solubility. In addition, the effect of temperature on carbon dioxide solubility diminishes above 120 °F and 4,000 psi pressure. The results also indicated that storage of carbon dioxide increases the petrophysical properties of porosity and permeability of carbonate rocks when the storage period is more than 150 days. On the other side, the CO2 storage for short time < 7 days causes reduction in porosity and permeability of carbonate reservoir rock.

The application of the attained results of this study is expected to have good impact on design storage process of carbon dioxide, validation of developed mathematical models, and improving our understanding of the process.
New Insights into Evaluating the Damage due to Calcium Sulfate Scale Precipitation during Low and High Salinity Water Injection
Authors: Mahmoud M. A. , Gadallah M. A.
Published: April 2013

Scale deposition is one of the most serious oilfield problems when two incompatible waters interact chemically and precipitate minerals. Typical examples are sea water, with high concentration of sulfate ions and formation waters with high concentrations of calcium, barium, and strontium ions. Mixing of these waters could cause precipitation of calcium sulfate, barium sulfate and/or strontium sulfate. Sea water treatment does not remove the entire sulfate ions from the injected water, at least 100 ppm sulfate will remain and even this low concentration may cause damage.

This study was conducted to investigate the damage caused by deposition of calcium sulfate precipitation, describing the damage using material balance method, and then a new technique will be proposed to prevent the damage due to calcium sulfate. The result of the experimental data showed the reduction of permeability at least by 20% from its initial value due to sea water injection. The results from field data showed a reduction of the water injection rate from 25,000 to 5000 bbl/day in one month due to calcium sulfate precipitation. The results of the new analytical model showed that in about one month the injection rate will stop or the injection pressure will exceeds the fracture pressure of the formation.

High salinity water injection caused severe formation damage and the injectivity declined faster compared to the low salinity water injection. The material balance calculations showed a good match between the experimental, field, and predicted data. The new method was very effective in preventing and removing sulfate precipitation. The cost of the new method was lower compared to the sulfate removal process and this method can be used with the injected water and no sulfate will precipitate.
Low-Productivity Sand Characterization and Identification of Bypassed Oil and Water Source with Advanced Production and Pulsed Neutron Logging, A Unique Key for Improving Field Productivity
Authors: Van Steene Marie , Abugren Yosra , Joshi Sameer , Thabet Enas , Ahmed Mohamed Mostafa
Published: April 2013

An oil well with two perforated zones had an initial production rate of ~2,400 BOPD with water traces. Within 3 months, production decreased to ~1,000 BOPD and water cut increased to >25%. It was critical to identify the cause of decreasing productivity and increasing water cut to plan for remedial action.

The reservoir was evaluated by integrating several answers obtained from reservoir saturation characterization through use of pulsed neutron capture and water-flow log data, as well as from conventional and advanced production logging.

Production logging showed that water was sourced from the lower perforated interval, while only a small proportion of the flow came from the upper reservoir layer. Pulsed neutron logging confirmed a high amount of depletion in the zone below the lower perforation, with oil remaining in the upper part of the lower perforated zone and in the upper perforated zone. Bypassed oil was also found below the water-producing zone, confined between the oil/water contact and a thin shale break. This shale break is a major permeability barrier and allows lateral water movement through the high-permeability lower zone.

A multilayer test carried out with production logging tools showed that the productivity index of the upper zone was only one-tenth that in the lower zone, due to either intrinsically low permeability or high skin factor. The multilayer testing also showed that of the two comingled layers, the upper layer had approximately one hundredth the permeability of the lower layer. Reperforation of the upper zone resulted in only minor improvement in well production, thus confirming that the low productivity was not caused by high skin factor, but was due to low permeability.

From the testing, it is clear that to produce the oil from the upper zone, it will be necessary to produce the two zones separately, with different drawdown. Since similar conclusions were obtained in other wells in the field, these results provide a fieldwide strategy for improving field productivity.
A Case Study of Evaluating Reservoirs in the Malay Basin
Authors: Zulkipli Siti Najmi , Kyi Ko Ko , Haddad Sammy , Johan Zailily , Wa Wee Wei , Sinnappu Suresh , Lim Lee Chin
Published: April 2013

Formation fluid type and composition are important and integral parameters in reservoir characterization and evaluation. Fluid type and composition can be obtained by capturing samples from limited depth across the producing zone. However, recent advances in downhole fluid analysis (DFA) enable the downhole fluid identification and composition measurement from depth where the fluid samples are either not collected or when PVT results are not readily available. A new wireline technology in insitu fluid analysis (IFA) was used to achieve this objective.

This work is based on field data from a newly drilled well in Malay Basin where the targeted reservoirs are comprised of clastic formation on the upper section of tested interval and of Central Luconia carbonate in the bottom section. The insitu fluid analysis technology has successfully guided the identification of oil and water in the clastic formation and gas in the carbonate. The detailed information on oil and gas composition, CO2 content, and fluid density was obtained in real time.

The presence of water in clastic formation identified by wireline formation tester triggered interest in more investigation. The water producing interval is located at about 100 m down dip from a nearby development well that is producing gas. Instead of initially planned full DST, decision was made to run the wireline formation testing dual packer module to perform interval pressure transient testing (IPTT) after the well had been cased. The IPTT and DFA confirmed the water section and saved significant cost on running unnecessary testing. The methodology, applications and suggested best practices are presented in this work.
Revitalizing Mature Gas Field Using Energized Fracturing Technology In South Italy
Authors: Granado Luis E. , Garritano Roberta , Perfetto Raffaele , Lorefice Roberto , Ceccarelli Roberto L.
Published: April 2013

This paper reviews the fracture stimulation improvement achieved over the well stimulation experience to attempt a field redevelopment through a well revitalization after workover and recompletion with a multistage hydraulic fracturing string using energized fluids, notwithstanding the limited background of fracture technology applications in Italy. The objectives were concentrated on the reserves final recovery of the principal layers and assessment of potential thin layers that has never produce before, which entail the use of technologies state-of-the-art for drilling, completions, stimulation and development plans.

The hydraulic fracturing stimulation technique pumping energized fluids introduced in the Roseto-Montestillo field has proved to be very successful recovering well productivity, however some associated problems have required a process optimization during the intervention. The problems ranged from in situ stress variation, that lead to very high pumping pressure (even in presence of very depleted reservoir), plastic or soft formation with potential proppant embedment issues, effective vertical coverage of the target pays intervals and gel residue with the consequent damage to fracture conductivity.

Here significant gains in production have been observed following the successful fracture treatment optimization moving from conventional borate crosslinked guar polymer to an optimized zirconate fracturing fluid energized with CO2. The use of energized fracturing fluids, expedite the fracture clean up process and dramatically reduce the amount of fluids to be recovered, while aid the lifting process on the other layers where conventional treatments were pumped. All this lead to a higher well productivity sustained along the time while minimize post fracturing problems compare to the jobs with conventional fracture treatment.

This paper summarize the fracture stimulation treatment best practices and review the design along with the operational considerations for the area, including treatment volumes, pump rates, surface equipment, completion selection and fluid chemistry.
Enhancing Oil Recovery in Gulf of Suez by Deep Conformance Control using a Thermally Activated Particle System
Authors: Towns Martin , Lara Angarita Monica , Thrasher David , Denyer Paul , Nabil Mohamed M. , Bayoumi Radi S. , Kinawy Mahmoud M.
Published: April 2013

This paper describes the use of Bright Water™1, a thermally activated particle (TAP), to enhance oil recovery from the giant Morgan field in the Gulf of Suez. The main reservoir of the Morgan field, the Kareem sandstone, has a high well density and has produced under water flood for over 35 years. Despite this, lower permeability zones remain poorly swept while average production water cut exceeds 85%. Deep conformance control is required to improve sweep efficiency.

The authors describe the area selection criteria, the treatment design method and deployment operations. Although Bright Water particles have been deployed in many fields globally, this treatment, completed in September 2012, is particularly noteworthy in that it is the first application of this chemical system via an onshore injection system to simultaneously treat multiple offshore wells. At the time of writing, this is also the largest treatment of its kind performed in a single operation.

This application sets a precedent for future treatments in terms of technique and scale. Treating multiple wells simultaneously from an onshore facility greatly reduced the cost of execution operations and minimised operational risk. The treatment's impact on production will be determined from a rigorous programme of well testing and wellhead sampling.
Advances on Partial Coupling in Reservoir Simulation: A New Scheme of Hydromechanical Coupling
Authors: Lautenschläger Carlos Emmanuel , Righetto Guilherme Lima , Inoue Nelson , da Fontoura Sergio Augusto
Published: April 2013

This paper deals with the implementation and validation of a new hydromechanical partial coupling methodology conducted between two commercial simulators of flow and stress. Such configuration is based on a coupling methodology developed by the Computational Geomechanics Group – ATHENA/GTEP - PUC-Rio, based on the consistent inclusion of terms in flow equation in order to approach the results of fully-coupled simulations. The IMEX® flow simulator was included in the workflow of the coupling code in order to widen the application scope of the methodology developed. To include the new option of flow simulator was required some implementation effort together with validation through simplified models. The algorithms developed to guide the programming were defined after detailed study of numerical and computational functioning of the flow software. The results obtained with the new simulator were compared with the pre-existing configuration (ECLIPSE flow simulator), considering one and two way partial coupling and fully coupled models. In the comparison scenarios set out to validate the implementation, it was evaluated changes of average pore pressure in the reservoir, compaction and subsidence, as well pore pressure variations. Comparisons with the results of pre-existing configuration and the full-coupling scheme demonstrated the success of the developed algorithm. The exchange of coupling parameters between simulators, in the new configuration, has been implemented effectively. Parametric studies of the variables also demonstrated the quality of the new configuration coupling. The rigorous choice of exchange parameters between flow and stress simulators is crucial for obtaining reliable results.
Green Gas field Development with Zero Flaring in Egypt
Authors: Abou El Azm Adel
Published: April 2013

In the frame work of global gas flaring reduction, RWE Dea Egypt (RWE Dea) as the development operator for the green gas fields in Disouq Concession, Nile Delta has recognized that the International Finance Corporation (IFC) Social, Environmental, Health and Safety Guidelines and Egyptian environmental Laws emphasize reuction of gas flaring as much as is practicable.

Over the last few years, most international operating companies have worked hard to progress towards "Zero Flaring". In today's technology there are complete flare systems available that provide zero flaring solutions. These systems cannot remove the basic need for flaring in emergency situations as a final safety device, but can and do offer real cost and environmental benefits by extinguishing or managing the flare in daily operations.

This paper provides an overview for the gas development of seven gas fields discovered in the Disouq concession onshore in the Nile Delta region of Egypt and it features a set of measures and techniques that were considered in the design concept to achieve zero flaring. RWE Dea project team decision was made after several technical and commercial discussions in order to find the best feasible scenario and incorporated also the previous experience of zero flaring made in other operating fields in Norway and UK.

RWE Dea adopting zero flaring facilities as an improvement over continuous flaring systems to avoid any flaring during normal operation and minimize the off gases from the process equipment. Off gases which are produced will be collected by a recovery gas compressor and used as fuel.

There are several measures reflected in the design to achieve the zero flaring in Disouq project, which are as follows: Minimizing off gases.Recovery of flash gas by installing a recovery gas compressor.Considering noncontinuous pilot gas system.Considering a highly reliable flare gas ignition system.Selecting a proper flare tip to suit the operating conditions of the Flare Package.Conducting a proper design for storage tanks and using N2 inert gas blanketing instead of fuel gas.Considering a flow meter to measure the gas being sent to flare.Transfer of technology know-how and system design.

There are many significant benefits for operators using zero flaring systems rather than continuous flaring system, such as: Reducing Co2 emission in wasted gas.Saving of gas otherwise wasted in combustionSaving expenses for shut down and flar tip replacement.Reduction in maintenance requirements of the flare system.Significant reduction in the OPEX costs.
Time Lapse PTA to Determine the Impact of Skin, Reservoir Compaction, and Water Movement on Well Productivity Loss: a Field Example from WDDM, Egypt
Authors: Ugoala O.. , Gad K. H. , Whittle T. M. , Stone M.. , Butter M.. , Galal S. K. , Mahmoud H. S.
Published: April 2013

Three productivity loss mechanisms - skin damage, water invasion, and reservoir compaction - are identified in one of the concessions co-owned by BG Group in the Nile Delta of Egypt. To inform the decision if and how to intervene to reverse the loss in productivity, it was important to understand the relative level of impact of each of these mechanisms on the observed drop in productivity.

Pressure Transient Analyses (PTA) of permanent downhole gauge (PDHG) build-up data, obtained during well shut-ins, allows identification of the contribution of skin and effective permeability thickness (kh) to a given well productivity loss. By monitoring build-ups over time, any loss in observed productivity can be attributed either to increased skin or reduced effective kh.

Knowing that effective kh reduction can be as a result of reservoir compaction, a reduction in net reservoir thickness due to water movement, or a reduction in relative permeability due to saturation changes, a number of control wells were selected and categorised, based on their levels of water production - negligible to low water, and moderate to high water producers. The moderate to high water producers already give indication of water breakthrough and possible gas-water-contact (GWC) movements.

Time lapse PTA from these control wells enabled the tracking of changes in skin and effective kh over their producing life.

The results of the investigation showed that although reservoir compaction may be occurring, the effective kh reduction for the low liquid producers is minimal. Hence increasing skin is believed to be the primary cause of the observed productivity losses. For the wells with high water cut, the productivity loss is attributed to both an increase in skin and a reduction in effective kh due to reduced net reservoir thickness and two phase flow in the reservoir.
Enhancing The Overall Productivity of GASCO Integrated Plants Using Available Process Flexibility and Reliability
Authors: Riad Tamer Hamdy
Published: April 2013

GASCO operates two NGL plants located in Alexandria; Amerya LPG plant and Western Desert Gas Complex (WDGC). The Amerya LPG plant receives & treats 300 MMSCFD of western desert gases from Badr 2,3 (Bapetco), Abu-Sanan, south dabah, petro-alm, (neag & sheba), west setra and septco fields, to produce 250 MT/Y LPG for local market and 25 MT/Y condensate to use for the refineries and the other is WDGC plant receives & treats 600 MMSCFD of western desert gases from Al-Obayed (Bapetco), Salam, Tarek and El-Qaser (Khalda) fields, to produce 465 MT/Y of Ethane/Propane mixture used as a feed stock for petrochemical industry (SIDPEC Company) to produce Ethylene and 280 MT/Y & 59 MT/Y of LPG and condensate for the local market consumption adding value for national economy by reducing the imported quantities of the same products and 210 MT/Y of Commercial Propane for export to the international market increasing income from the hard currency to support the national economy. Recently, GASCO has started up a new project to receive & treat extra 300 MMSCFD and also to integrate the two plants to maximize Ethane and Propane productivity. The project design is based on adding new process facilities in Amerya plant to start producing C2+ that directed to WDGC, while a new train is added in WDGC to increase the feed gas capacity and maximize C2+ recovery by applying the Gas Subcooled Process (GSP) as Ethan mode of operation scheme. This paper presents a study to increase the productivity of the two plants by using simulation software applied on field to help the decision making for what the optimum conditions should be applied in different modes of operation to increase the production.
Integrating New Technology Utilizing Risk Management
Authors: Wael Abouamin P. E.
Published: April 2013

Building an ultra-deepwater (UDW) drilling rig that incorporates the latest technology while meeting internal requirements, client specifications, and budget constraints, can be a daunting challenge. Doing so in a post-Macondo environment with a shortage of qualified personnel to man the rig adds even more obstacles to overcome. Ensuring that a variety of rig systems supplied by different vendors will be integrated into a workable rig that is properly maintained is another task for the drilling contractor.

Rowan Companies, Inc. is building 3 UDW drillships in Hyundai's shipyard in Ulsan, Korea. The rigs will incorporate the latest in offshore drilling technology including dual, fully redundant BOPs and BOP control systems, heave compensating drawworks, knuckle boom cranes, and other innovations. They will be capable of drilling at 12, 000 feet with a maximum hookload capacity of 1250 tons and a variable deck load of 20,000 tons.

This paper attempts to demonstrate how implementing a risk management plan during the design and construction of such rigs can help reduce risks associated with major accidents and downtime. This can be accomplished by applying the results of the risk assessments into training of personnel, updating of operational procedures, updating of maintenance procedures, modifying designs, changing control systems and re-programming software.

This paper presents the results of a risk management plan as it was applied to 17 different rig systems: Active Heave DrawworksAnticollision SystemBilge & Ballast SystemsBOP Handling SystemCooling Water SystemsCyberbase and Drilling Control Network SystemFirefighting SystemsFire and Gas Detection SystemIron RoughneckKnuckle Boom CranesPipe Handling SystemRiser Handling SystemTDX 1250 Top DriveThruster SystemWater Tight IntegrityWell Control System - Subsea SystemsWell Control System – Topsides Systems

The risk management plan was implemented in the form of individual risk assessments focused on each of the above mentioned systems utilizing primarily the failure modes, effects, and criticality analysis(FMECA) methodology. It can be quite surprising to evaluate the results of these sessions and realize how powerful these tools can be and how effective they can be in identifying potential faults and weaknesses in the systems. The end result of the risk management plan was a rig that is better integrated, operated by crews that are more familiar with the systems they will man, and functioning in an environment that will reduce accidents and downtime.