bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of sedimentation rates in the distributary basin of the Mississippi River, the Atchafalaya River Basin, USA
Authors: Rosen Timothy , Xu Y. Jun
Published: March 2015

The Atchafalaya River Basin (ARB) is the largest distributary basin of the Mississippi River composing anastomosing channels, backwater swamps, freshwater marshes, and wetland forests. Sedimentation in the ARB has presented management issues concerning habitat changes from open water areas to bottomland hardwood forests. A thorough understanding of sediment transport and deposition in the basin is not only required for proper management of the ARB, but is crucial for regional sediment budgets that affect the Mississippi River Delta Plain. In this study, we calculated 31 years (1980–2010) of total suspended sediment (TSS) inflow and outflow of the Atchafalaya River to quantify the long-term sediment retention in the basin. We then estimated sedimentation rates in the basin by spatially relating the retention with changes of turbid water area derived from Landsat imagery. The study found an annual average TSS inflow of 54.0 megatonnes (MT) and an annual average TSS outflow of 48.7 MT, resulting in an average annual retention of 5.3 MT. Spatially derived mean sedimentation rates were estimated between 0.06 and 0.153 mm d−1. The spatial estimates for sedimentation proved promising and with more sediment data available could become an invaluable tool for managing the ARB in the future.
Corporate social responsibility of regional institutions: save water and money with an ecological economics perspective in a climate change context
Authors: Sepúlveda Joel
Published: March 2015

As ecological economic fundamentalists argue, we need a new paradigm for changing current global economic system basics. The real problem is that the limits of ecological economics are based on unrealistic or utopian objectives in the proposed research frameworks. Taking this problem into account, present research demonstrates that the combination of mixed methods creates valid results. In this case, the hydrologic footprint reduction method was created to achieve the main objective: to prove the usefulness of combining environmental science techniques along with economics tools. The most important result of the work is the relationships between export/import product balances in the Basque Country, Spain (among the three most important economic regions along with Cataluña and Madrid) and their implications in maximizing effectiveness in saving water and money thanks to external hydrologic footprint analysis. A comparison was made between global and local consumption patterns using the water footprint method. It demonstrated the importance of making small changes, which imply direct and indirect benefits for the economy and hydrologic resources.
Adapting flood management to climate change: comparing policy frames and governance practices in the Low Countries
Authors: Crabbé Ann , Wiering Mark , Liefferink Duncan
Published: March 2015

Belgium and the Netherlands together form the Low Countries. Empirical research in Flanders (the Dutch-speaking part of Belgium) and the Netherlands proves that there are substantive differences in the organization of governance processes regarding flood management in response to climate change. This article answers the question of how Flanders and the Netherlands, confronted with universal challenges and dilemmas in the governance of adaptation to climate change – integration versus differentiation (multi-sector versus sector-based governance), the problem of scaling (multi-level governance) and the division of public and private responsibilities (multi-actor governance) – are designing and structuring their approaches. More specifically, we look at how differences in the framing of climate adaptation can explain why organizational practices differ. For this purpose, a distinction is made between diagnostic framing (what is the problem?), prognostic framing (what could be possible solutions?) and action framing (how to act?). By referring to existing policy frames, the article explains recent policy choices on climate change adaptation in flood management.
Detection of regional climate change effects on alpine hydrology by daily resolution trend analysis in Tyrol, Austria
Authors: Kormann Christoph , Francke Till , Bronstert Axel
Published: March 2015

Owing to average temperature increases of at least twice the global mean, climate change is expected to have strong impacts on local hydrology and climatology in the Alps. Nevertheless, trend analyses of hydro-climatic station data rarely reveal clear patterns concerning climate change signals except in temperature observations. However, trend research has thus far mostly been based on analysing trends of averaged data such as yearly, seasonal or monthly averages and has therefore often not been able to detect the finer temporal dynamics. For this reason, we derived 30-day moving average trends, providing a daily resolution of the timing and magnitude of trends within the seasons. Results are validated by including different time periods. We studied daily observations of mean temperature, liquid and solid precipitation, snow height and runoff in the relatively dry central Alpine region in Tyrol, Austria. Our results indicate that the vast majority of changes are observed throughout spring to early summer, most likely triggered by the strong temperature increase during this season. Temperature, streamflow and snow trends have clearly amplified during recent decades. The overall results are consistent over the entire investigation area and different time periods.
Co-Simulation Study for Fuzzy ESP Control Strategy on Vehicle
Authors: Li Shengqin , Zhao Li , Yang Chunbo
Published: March 2015

ESP can help the road vehicle to improve driving dynamics and prevent accidents which result from loss of
control. Based on the theory and account method of Multi-body System Dynamics, the Multi-body System Dynamics
model of an A-class car is built by the ADAMS/Car software, which includes steering system, front and rear suspension,
braking system, body, and so on. In order to study the handling stability of vehicle with ESP control system, the vehicle
yaw rate is set as the controlling aim, to build the fuzzy controller of ESP. The performance evaluation methods of vehicle
with ESP are proposed to evaluate the handling stability of vehicle with ESP. The results show that the vehicle with ESP
can keep the right path, the yaw rate and the vehicle slip angle is all controlled better. The handling stability of vehicle can
be improved.
Optimal Staging of Lymphoma during Pregnancy is Crucial
Authors: van Dam Laura , N Han Sileny , Dierickx Daan , Amant Frédéric
Published: March 2015

A letter in response to: Noa Lavi, Horowitz NA, Brenner B. An update on the management of hematologic malignancies in pregnancy. Womens Health 10(3), 255–266 (2014).
Asymptomatic Cervical Polyps: Can We Just Let them Be?
Authors: Nelson Anita L , Papa Rhett R , Ritchie Julia J
Published: March 2015

Aim: Routine polypectomy is still practiced in many settings. The objective of this study was to establish the frequency of dysplasia or malignancy found in cervical polyps from a multiyear sample after abnormal specimens performed for indication were excluded. Materials & Methods: This is a retrospective study of the pathology results from 2006–2013, inclusive. Results: The study included 898 polyps from 854 nonpregnant women, after the 17 abnormal specimens from women who presented with complaints of abnormal bleeding or for evaluation of abnormal cytological tests were excluded; none of the 898 specimens showed any significant abnormalities. The results did not vary by patient age or polyp size. Conclusion: Routine removal of cervical polyps in asymptomatic women with current, normal cervical cytology testing is unwarranted because it adds little to their management and it has the potential to cause harm.
Diversity of Cyanobacteria in the Zasavica river, Serbia
Authors: Predojevic Dragana , Popovic Sladjana , Kljajic Zeljko , Subakov-Simic Gordana , Blagojevic Ana , Jovanovic Jelena , Lazic Milojko
Published: March 2015

Cyanobacteria are ancient organisms that are capable of colonizing different
habitats in various climatic zones due to their plasticity and rapid
accommodation. They are a widely studied group of microorganisms due to the
presence of many potentially toxic and invasive species. The aim of this
research was a diversity exploration of the freshwater Cyanobacteria in the
Zasavica River, which is part of the Special Nature Reserve ?Zasavica? in
Serbia. Organisms were sampled once a month at two study sites during one
year. Phytoplankton and metaphyton analysis showed the presence of 50
freshwater cyanobacterial taxa, of which 12 are new taxa for Serbia. Three
invasive and potentially toxic species (Cylindrospermopsis raciborskii,
Sphaerospermopsis aphanizomenoides and Raphidiopsis mediterranea) were
recorded only in metaphyton in April at one site. It can be expected that, if
conditions change, this species can migrate and form phytoplankton blooms.
Retraction: Radenovic L, Selakovic V, Janac B, Todorovic D. Effect of glutamate antagonists effect on nitric oxide production in rat brain following intrahippocampal injection, Arch Biol Sci. 2007;59(1):29-36, DOI: 10.2298/ABS0701029R
Authors: Editorial E
Published: March 2015

This is a notice of retraction of the article: Effect of
glutamate antagonists effect on nitric oxide production in rat brain
following intrahippocampal injection, published in the Archives of Biological
Sciences in 2007, Vol. 59, Issue 1. The Editor-in-Chief has been informed
that this paper plagiarizes an earlier paper: Radenovic L, Selakovic V.
Differential effects of NMDA and AMPA/kainate receptor antagonists on nitric
oxide production in rat brain following intrahippocampal injection. Brain Res
Bull. 2005;67(1-2):133-41. The results presented in the article that is being
retracted overlap with the results presented in the original article without
appropriate justification, permission or crossreferencing. After confirmation
of this fact, the Editor-in-Chief of the Archives of Biological Sciences has
decided to retract the paper immediately. We apologize to the readers of the
journal that it took so many years to notice this error and to retract the
paper. We request readers of the journal to directly get in touch with the
editorial office and the editors of the journal for similar cases in the
future, so that they can be handled promptly.

 Link to the retracted article 10.2298/ABS0701029R
The relations between personality traits and psychopathy as measured by ratings and self-report
Authors: Kujacic Daliborka , Medjedovic Janko , Knezevic Goran
Published: March 2015

The objective of this study was to examine the relations between psychopathy
- as assessed by ratings (PCL-R) and by self-report (SRP3) - on one side, and
The Five-Factor personality Model - expanded to include the traits Amorality
and Disintegration - on the other. Both methods examined four traits of
psychopathy: interpersonal, affective, lifestyle and antisocial
characteristics. Data were collected on a sample of 112 male convicts. The
results show the absence of congruence between the two methods - self-report
and rating - in case of interpersonal and affective psychopathic
dispositions. This incongruence is also reflected in their relations with
personality traits. The self-report measures and the ratings of Lifestyle and
Antisocial tendencies are related to amorality, aggressiveness, schizotypy,
Neuroticism and impulsivity. However, the ratings of affective and
interpersonal style are related to the integrated, organized, and emotionally
stable aspects of personality. The results are interpreted in the light of
differences between the methods of assessment and in the light of the
essential characteristics of the psychopathic phenomena.
Bimodal Spectroscopy of Formalin Fixed Samples to Discriminate Dysplastic and Tumor Brain Tissues
Authors: Anand S. , Cicchi R. , Giordano F. , Buccoliero A. M. , Guerrini R. , Pavone F. S
Published: March 2015

Biomedical spectroscopy has gained attention in the past few years for disease diagnosis. Fluorescence and Raman spectroscopies provide finger-print information related to biochemical and morphological alterations when tissues progress from the normal to a malignant stage. Usually, freshly excised tissue specimens are preferred for bio-spectroscopic studies. However, ethical issues, sample availability and distance between the surgery room and the laboratory provide an impelling restriction for in-vitro spectroscopic studies using freshly excised samples. After surgical resection tissues are fixed in 4% formalin for histological studies under a light microscope. The process of fixation prevents degradation of tissues. In this study, we probe the use of formalin fixed sample for differentiating normal and dysplastic brain tissues using fluorescence and Raman spectroscopies. It was found that fluorescence spectral profile changes in the wavelength range from 550-750 nm between dysplastic and tumor samples. Also, significant differences were found in the Raman spectral profiles of such samples. The results indicate a potential diagnostic application of spectroscopy in formalin fixed brain samples for differentiating dysplastic and tumor brain tissues.
Multispectral Video-Microscope Modified for Skin Diagnostics
Authors: Rubins U. , Zaharans J. , Ļihačova I. , Spigulis J.
Published: March 2015

Commercial DinoLite AD413 digital microscope was modified for skin diagnostics purposes. The original LED ring (4 white and 4 ultraviolet light emitters) of microscope was replaced by a custom-designed 16-LED ring module consisting of four LED groups (450, 545, 660 and 940 nm), and an onboard LED controller with USB hub was added. The video acquisition and LED switching are performed using custom-designed Matlab software which provides real-time spectral analysis of multi-spectral images and calculation of skin chromophore optical density. The developed multispectral video-microscope is mainly meant for diagnostics of skin malformations, e.g. skin cancerous lesions.
Changing The Game In The Stimulation of Thick Carbonate Gas Reservoirs
Authors: Thabet ElSayed Ahmed , Brady Mark Edward , Parsons Christopher A. , Byrne Sean , Voropaev Sergei V. , Lesko Timothy Michael , Tardy Philippe Michel , Cohen Charles Edouard , Mchaweh Abdulsalam
Published: March 2015

In this paper we present details of the approach utilized to optimize the completion and stimulation campaign in the continued development of a large gas carbonate field in the Middle East. A new acid diverter was deployed along with a revised placement model, field calibrated to more accurately predict treatment pressure responses, to optimize treatment design and to maximize diversion in this layered reservoir. Results presented include typical stimulation treatment plots alongside model post treatment pressure history matches, pre and post stimulation production logs, clean up data and well test interpretations. We also present details on how this new approach facilitated the execution of simultaneous drilling and well intervention operations.

We describe high permeability, multi zone treatments with a bullheaded matrix acid technique. We observed through large bore tubing treatment pressures in excess of 3000 psi, far above what is typically observed in this field. A degradable fibrous material was incorporated into an in-situ self viscosifying surfactant based acid formulation to effect the diversion responses and we observed negligible returns of fibres during clean up operations. We observed uniform inflow profiles, validating the technique and provide evidence that the use of such a fluid system is capable, in certain circumstances, of reconnecting to natural fracture and loss zones. We have also observed significant benefits in reduced flaring requirements for well clean up.

We conclude that this technique has facilitated enhanced diversion and promoted uniform zonal depletion. We have also found operational benefits in deploying the system in that commingled zones, normally perforated and stimulated in several stages can now be easily and effectively stimulated using a one-stage technique.

The stimulation of thick carbonate intervals presents several challenges if the long term well and field productivity is considered. Overcoming these challenges without additional well interventions such as setting retrievable bridge plugs or the introduction of ball sealers, requiring slick line re-entry to ensure no interference with surveillance activities, significantly reduces operational risk and well site exposure.
Assessing Fluid Migration and Quantifying Remaining Oil Saturation in a Mature Carbonate Reservoir: Dukhan Arab D
Authors: Barrios Vera Levin Jose , Muhamad Rais Tajjul , Trabelsi Ali , Al-Qarshubi Ibrahim , Al-Ansi Hussain Abdulla
Published: March 2015

The large, mature Dukhan field is located onshore Qatar. The Arab D is the main oil reservoir in terms of size and production potential. The development of the reservoir commenced from North to South, which created initial differential pressure depletion between two of the southern sectors of the reservoir.

It is believed that differential depletion resulted in considerable fluid migration across sector boundaries. Therefore, it has introduced uncertainty in quantifying the remaining oil in place, recovery efficiency and reserves.

This paper describes the use of conventional material balance and volumetric techniques to investigate the reservoir behavior in order to shed light on fluid migration, the current oil in place and recovery efficiency, as well as identifying limitations and uncertainties. Material balance and fluid migration results indicated new scenarios for oil and water migration between the two southern sectors. The technique has proven to be valuable in understanding a complex reservoir engineering problem.

In order to better understand the migration process and to complement and validate the results of the material balance, and support the numerical simulation study, a data collection programme was carried out by drilling wells and low invasion cores in partially swept zones of the reservoir. The cores are used to determine remaining oil saturation (ROS), residual oil saturation (Sorw), wettability and relative permeability (SCAL) data. The preliminary results of this programme are presented in this paper.

Integration of the available and additional ROS and SCAL data will be instrumental during the subsequent stages of the reservoir study in defining the remaining reserves of the field and future upside potential of the reservoir. Therefore the work programme, assumptions and results presented in this paper may be of general interest and used as a reference for this kind of application.

Introduction

The development of the remaining oil in some areas of the Arab D reservoir will largely depend on the understanding of the fluid migration. As part of the ongoing reservoir studies, conventional material balance and volumetric analyses were carried out on the Arab D reservoir with the aim of characterizing the current drive mechanism and quantifying fluid migration between reservoir sectors.

The first part of this paper describes this analysis which was performed in stages as follows:Collection and validation of input data.Analysis of production, injection and pressure histories.Single tank material balance analysis.Multi tank material balance and sensitivity analysis of fluid migration.Estimation of unswept remaining oil above the current oil-water contact by volumetric analysis.Determination of waterflood sweep efficiency.
Measurement of Gas Viscosity at High Pressures and High Temperatures
Authors: Ling Kegang , McCain William D. , Davani Ehsan , Falcone Gioia
Published: March 2015

Gas viscosity is an important fluid property in petroleum engineering due to its impact in oil and gas production and transportation where it contributes to the resistance to the flow of a fluid both in porous media and pipes. Although the property has been studied thoroughly at low to intermediate pressures and temperatures, there is lack of detailed knowledge of gas viscosity behavior at high pressures and high temperatures (HPHT) in the oil and gas industry.

The need to understand and be able to predict gas viscosity at HPHT has become increasingly important as exploration and production has moved to ever deeper formations where HPHT conditions are more likely to be encountered. Knowledge of gas viscosity is required for fundamental petroleum engineering calculations that allow one to optimize the overall management of a HPHT gas field and to better estimate reserves. Existing gas viscosity correlations are derived using measured data at low to moderate pressures and temperatures, i.e. less than 10,000 psia and 300 oF, and then extrapolated to HPHT conditions. No measured gas viscosities at HPHT are currently available, and so the validity of this extrapolation approach is doubtful due to the lack of experimental calibration.

The falling body viscometer is selected to measure gas viscosity for a pressure range of 3,000 to 24,500 psia and temperature range of 100 to 415 oF. Nitrogen was used to calibrate the instrument and to account for the fact that the concentrations of non-hydrocarbons are observed to increase dramatically in HPHT reservoirs. Then methane viscosity is measured to reflect the fact that, at HPHT conditions, the reservoir fluids will be very lean gases, typically methane with some degree of impurity. The experiments showed that while the correlation of Lee et al. accurately estimates gas viscosity at low to moderate pressure and temperature, it does not provide a good match to gas viscosity at HPHT conditions.

Introduction

HPHT gas reservoirs are defined as having pressures greater than 10,000 psia and temperatures over 300ºF. Modeling the performance of these unconventional reservoirs requires the understanding of gas behavior at elevated pressure and temperature. An important fluid property is gas viscosity, as it is used to model the gas mobility in the reservoir that can have a significant impact on reserves estimation during field development planning.

Accurate measurements of gas viscosity at HPHT conditions are both extremely difficult and expensive. Thus, this fluid property is typically estimated from published correlations that are based on laboratory data.

Unfortunately, the correlations available today do not have a sufficiently broad range of applicability in terms of pressure and temperature, and so their accuracy may be doubtful for the prediction of gas viscosity at HPHT conditions.
Advancing Self-Mitigating Sand Control Screen
Authors: Yeh Charles S. , Moffett Tracy , Petrie Dennis H. , Entchev Pavlin B. , Long Ted , Troshko Andrey , Grubert Marcel Andre , Dale Bruce A. , Barry Michael D. , Hecker Michael Thomas , Howell David A.
Published: March 2015

MazeFlo™ technology enables a sand control screen to self-mitigate mechanical damage and improve reliability in sand-prone well production. A self-mitigating screen uses redundant sand control screens and compartment baffles to restrict the effects of any mechanical screen failure to a local compartment. The hydrocarbon flow continues intact through the remaining undamaged screen compartments. This innovative, patented technology is being commercialized in collaboration with a selected service company.

This paper reviews the initial design and development of the self-mitigating screen prototype. The screen design balances flow hydraulics, well performance, mechanical integrity, and manufacturing complexity all while maintaining practical screen dimensions. Successful self-mitigation, after failure of an outer screen, requires that the incoming sand packs a compartment to shut off the flow path before any significant erosion occurs along the flow path to the redundant inner screen. The baffles are configured to both redirect fluid momentum from any "hot spot" inflow at the outer screen and impose a minimal friction loss during production through undamaged compartments. Each component in a compartment is designed to sustain erosion from the incoming sand of a failed outer screen. The offset outer and redundant inner screens are sized to minimize the impact on productivity when compared to conventional screens. The mechanical strength of the self-mitigating sand screen is also targeted to be equivalent to conventional screens.

Development of the self-mitigating screen prototype is proceeding and includes extensive qualification by multiple modeling techniques and physical testing. The innovative, self-mitigating capability expands the current operating limits of screens in sand control completions. In a broader view, the self-mitigating screen enhances overall reliability and longevity and can be integrated with other emerging technologies such as openhole zonal isolation, inflow control, and intelligent wells for enhanced production flexibility. MazeFlo sand screens will expand ExxonMobil's suite of innovative sand control solutions that include Alternate Path® technology, NAFPacSM process, openhole gravel packing with zonal isolation, and customizable sand control for extreme length completions and injection conformance.
Increasing Recovery in the Complex Reservoirs in the Al Shaheen Field, Offshore Qatar, by Mastering Reservoir Pressure for Large Scale Horizontal Infill Drilling
Authors: Lopdrup Thomas P. , Ohrt Henrik Bjerre , Lechner Michael , El-Itawi Ghina , Noman Rashed , Jaafar Mohd Rushdan
Published: March 2015

The giant Al Shaheen field offshore Qatar comprises six stacked carbonate and sandstone reservoirs developed with extended reach horizontal wells. More than 130 horizontal production and injection development wells had been drilled up to end 2005 when implementation of a new large scale field development plan commenced. The new development plan, FDP 2005, comprises 163 additional horizontal development wells from six existing and three new locations.

The initial development phases in Al Shaheen comprised radial and parallel well patterns of long horizontal wells with a well spacing designed to enable effective appraisal and data gathering. A significant part of the FDP 2005 is dependent on successful horizontal infill drilling where close well spacing is required to ensure optimal recovery of the low permeability carbonate formations.

The combination of stacked reservoirs, reservoir heterogeneities, long horizontal wells, close well spacing and past production and injection result in pressure regimes along the wells which are challenging to predict but crucial to manage for successful well planning and execution. Successful implementation of the FDP 2005 requires a detailed and systematic approach for reservoir pressure conditioning to ensure acceptable pressure gradients along the new wells while at the same time minimize the impact on the short term oil production.

This paper describes the challenges related to the reservoir pressure conditioning in the complex Al Shaheen field offshore Qatar. The applied methodology covering systematic use of reservoir simulation models, nodal analyses, pressure transient analyses and timely shut-in of producers and injectors to map and manage pressure regimes is presented.

Introduction

The Al Shaheen field is located in Block 5, offshore Qatar, covering an area of some 2080 km2, Figure 1. The main reservoir targets include the Lower Cretaceous Kharaib B and Shuaiba carbonate formations and the overlaying Nahr Umr sandstone formation, Figure 2. The carbonate reservoirs are characterized by relatively thin oil columns with a large areal extent with typical permeabilities in the 1–10 mD range. The reservoir fluid properties exhibit large lateral variations, with oil gravities ranging from 16–38 °API within the same reservoir. The field contains several gas caps and shows large variations in solution gas-oil ratio and saturation pressures.

Following the discovery of the Cretaceous oil accumulation in 1974, various operators drilled a number of appraisal wells and comprehensive studies were conducted at the time in order to establish the feasibility of development. However, well tests in the vertical appraisal wells yielded discouraging results and it was concluded that development was not economically feasible1.
Novel Perforation Job Design Leads To Successful TCP Shoot In A 3000 Foot Horizontal Carbonate Producer
Authors: Shindy Ahmed M. , Khedr Osama H. , Salsman Alan Dean , Bennett G
Published: March 2015

A recent horizontal producer well was drilled as part of a multilateral openhole completion pair in the Arabian Gulf area. The casing of the main wellbore could not get to bottom which necessitated the bottom lateral be cased and cemented for isolation purposes and then perforated. The decision to perforate the 3000' horizontal section was unexpected so supplies were insufficient to perforate this long section using the traditional perforating method.

Rather than delaying the well completion and deferring production from this well, an effort was put into looking for alternatives. With the help of a perforation modeling tool it was shown that the horizontal section could be shot using a dynamic underbalance job design at greatly reduced shot densities and still achieve an injectivity, required for acid matrix stimulation, and subsequent productivity greater than if the well were to be shot conventionally at 6 spf. This technique of dynamic underbalance had been successfully used locally on wireline perforating jobs in short intervals but never on such a long well section nor at such low shot densities.

Another potential complication with the conventional perforating technique is the presence of a 2nd open hole lateral which was in communication with the well to be perforated. This meant that the zone would be shot in an overbalanced condition which can lead to post perforation damage and poor injectivity.

This paper will describe the process used to establish the dynamic underbalance perforation job design suitable for this well, the final job design, the execution of the job and the obtained results of this successful application. The results indicated better than expected injectivity prior to acid matrix stimulation and better than expected well productivity post stimulation. The improved well productivity is based on modeled and also nearby well production results.

A successful job design methodology and execution has been tried for the first time in this region and has potential applications to many other wells.

Background

The horizontal well that forms the basis for this case study was drilled offshore in the Arabian Gulf in 2007. The well was intended to be completed as an openhole producing well and the case under consideration here was one of 2 lateral drains (Figure 1). During the well construction process the 7" casing was set at higher than planned depth leaving a part of upper reservoir in communication with lower reservoir below the 7" casing shoe. This reservoir section would interfere with the production from the lower 6" hole so it was decided to run a 4 ½" liner and extent it up into the 7" casing to provide isolation between the two laterals. With a cemented liner in place this necessitated the requirement to perforate the liner section in order to produce the well.
Carbonate Rock Physics Issues
Authors: Liu Enru , Payne Michael A. , Xu Shiyu , Baechle Gregor , Harris Christopher E.
Published: March 2015

Limestone and dolomite reservoirs account for approximately 50% of oil and gas production worldwide, yet seismic responses in carbonate rocks are poorly understood. Development of a carbonate rock physics model is extremely difficult because pore systems are more complex in carbonates than they are in clastics. Carbonates can have a variety of pore types, such as moldic, vuggy, interparticle, and intraparticle. The complex pore system creates significant scatter in the porosity-velocity relationship, as indicated in experimental results (e.g., Anselmetti and Eberli, 2001). Pore shape appears to be the dominant factor in carbonate rock physics. Moldic, intraframe, and vuggy pores tend to be rounded and make the rock stronger (faster) than when the pores are interparticle. Micro pores (e.g., microcracks) tend to be flat and make the rock weaker. To effectively characterize carbonate reservoir rocks, it is critical to develop a rock physics model capable of handling different pore types.

In addition to pore types and pore shapes, other factors need to be included in a physics-based rock model. Some specific additional factors are lithology and grain shapes, multiphase fluids and wetting effects, rock-fluid interactions (poro-elasticity), stress effects, anisotropy, heterogeneity and scale effects, chemical changes to the framework, and corrections for environmental effects due to logging conditions. Any rock physics model should be calibrated and validated with controlled laboratory experiments, field measurements, and computational rock physics. In this paper, we demonstrate the impact and validation of several of these factors.

Carbonate Rock Physics Model

We prefer an analytical rock physics model rather than empirical ones due to both the predictive power that it provides without having to acquire so much analog data and its physics-based nature. Empirical rock physics models are widely used due to their simplicity in fitting a relationship between parameters. The advantage of an analytical model is that once the parameters describing the physical controlling factors are determined, the model can be applied anywhere that the controlling parameters can be estimated. This achieves better predictions and deeper understanding of the subsurface than empirical models with less data. Nonlinear physics-based inclusion models (e.g., Kuster and Toksoz, 1974) are attractive because they handle various factors that impact seismic response in an internally consistent manner.
Integrated Field Development - Improved Field Planning and Operation Optimization
Authors: Serbini Feroney , Kok Wee Low , Wong Lee Hin , Bustamante Nicolas Gomez
Published: March 2015

Field development, operation optimization, production system de-bottlenecking, reservoir management and field re-development involve studies and analyses from multidiscipline engineers and experts that require effective communication of the impact of the results from one discipline to another. Through an integrated subsurfaceto-

surface-to-economic modeling technology, the team members are able to model all components of the production system simultaneously and evaluate potential development scenarios, thus resulting in optimal decisions. The Integrated Asset Modelling technology integrates reservoirs, wells, surface infrastructure, and process facilities as well as the asset's operating parameters, financial metrics, and economic conditions into a single production management environment.

This paper presents a case study of an Integrated Asset model for a brown field re-development study project. The field has been producing over 25 years and is going through a field re-development plan with the implementation of Immiscible Water Alternate Gas scheme (iWAG). One of the primary aims of the project is to improve recovery factor through the debottlenecking of the surface system and EOR implementation of Immiscible Water Alternate Gas (iWAG) scheme. The Integrated Asset Modelling technology was used to perform a multi-disciplinary modeling and simulation environment to take into account new system mass balance by integrating the different components of the production system with the dynamic behavior of the reservoir.

The study showed the following results:• The impact of the facility bottleneck was identified and a debottleneck scenario was proposed• The suboptimal conceptual design was identified and a revised design was recommended• Production losses were evaluated averting significant impact to project financial metrics

Introduction

The Integrated Asset Model simulation case study described, herewith, was performed on a field that contains seven reservoirs that produce from more than 100 production wells and facilities. The original field layout consists of three production platforms, a separation and liquid handling platform, and a gashandling platform. In the re-development program for EOR Scheme, two tripods and one central processing platform are proposed to be added. The introduction of new infill wells and iWAG Enhance Oil Recovery scheme are expected to increase the liquid production.

An Integrated Asset model was created based on the conceptual design of the re-development program and was used to simulate and analyze the field planning scenarios. The integrated model was also used to identify the constraints within the entire production system that consists of Reservoir Simulation models and Well-Network models.
Multiphase Metering in Siberian Gas and Condensate Fields - Lessons leant in Multiphase Well Testing Operations since 2006.
Authors: Theuveny Bertrand C. , Romashkin Sergey Vyacheslavovich , Shako Valery , Rymarenko Konstantin , Afanasyev Vitaliy , Nukhaev Marat , Sultangareev Rustem
Published: March 2015

A number of multiphase flowmeters were recently deployed in the Yamal peninsula in Northern Siberia to perform multiphase measurements of the rates of gas and condensate wells. The utilization of multiphase flowmeters in wet gas and condensate wells is relatively new, and significant progress have been made in the understanding and the quantification of multiphase flowmeter uncertainties in flow loop. Little field experience is documented to date and this paper presents field data in this very challenging domain.

The operating environment combines an exceptional set of constraints ranging from high Gas Volume Fraction (up to 99.5%), water and hydrates, a large permafrost zone, tough environmental regulations, and a range of logistical constraints including difficulty of access to remoteness and communication challenges.

The paper describes the metrological evaluation of the full operations - not limiting itself to the dual energy gamma Venturi multiphase flowmeter that is being used, but also to the fluid property estimation. A discussion of the specific regulatory reporting in Russia for gas wells also presents some of the particularities of these operations.

The paper presents the results of testing over 50 wells since 2006- comparison to traditional and other multiphase flow metering devices are presented. Some unexpected behavior of these condensate wells are presented - confirmed by other instruments, resulting in a series of recommendations that provide a significant modification to the traditional guidelines used for the measurements of rates of gas, condensate and water in similar wells.

A brief discussion on the applicability of the multiphase measurements to condensate allocation workflows concludes the paper.

Introduction

Recent focus on gas condensate testing in the Yamal peninsula has pushed a number of operators to consider alternative way to perform such measurements. The operating are is quite challenging and located slightly north of the arctic circle in Northern Siberia as shown in Figure 1.
A Recipe to balance 'Black Box' and Deterministic Methods when designing Geological Models
Authors: Kuhn Oliver , Descamps Rien
Published: March 2015

This paper presents and discusses an experience based working approach and philosophy for geological modelling. The aim is to encourage a discussion on how to best balance and synergize powerful modelling technologies available today with bright thinking of scientists working for the petroleum industry. This method consists of (1) proper model framing in order to meet business objectives, (2) analysis of a suitable modelling technique to enable effective delivery of results, (3) in-depth uncertainty analysis through a dissection of the subsurface into its individual components, (4) selection of appropriate range of subsurface scenarios which cover uncertainties and risks (5) a variety of manipulative tools which can help to implement subsurface concepts which cannot easily be addressed with geostatistics and (6) a threefold tactic ("self-criticism" - "supervision" - "peer review") to facilitate quality control.

Introduction

This paper provides some nontechnical and technical methods which may help to achieve static geological modelling results faster and with a stronger link to business objectives.

The challenge today is not to fall prey to the "menace of the black box" by over-using powerful computer programs. Now-adays, with statistical algorithms being quite advanced, different models can be run in a very short time and the temptation is large to mechanically advance pushing buttons beyond the objectives and the aim of the modelling exercise planned. Modelling should not be chasing a "holy grail", but use the computing power efficiently and in a fit for purpose way to improve subsurface understanding, to plan and execute development projects in a safe and successful manner and to keep geological information and interpretation understandable and auditable.

Model Framing and Initialization

Call for a Conference

Before the start of every modelling exercise a generic framing exercise should be organized. Framing the planned modelling effort is aimed at (1) ensuring the modelling exercise is set on the right track from the start (2) avoiding misunderstanding between different parties involved and (3) to identify gaps in input data/concepts, manpower/funding, technical infrastructure available.
Evaluation of LNG, CNG, GTL and NGH for Monetization of Stranded Associated Gas with the Incentive of Carbon Credit
Authors: Khalilpour Rajab , Karimi Iftekhar A.
Published: March 2015

Associated gas is estimated to account for 17% of global gas reserves. However, majority of associated gas resources are small or located offshore which have made the utilization uneconomical. Operators have thus preferred either flaring or re-injecting the gas rather than utilization. Currently, none of these two options are favored as it is proven that gas re-injection has reverse effect on well recovery over time. Gas flaring is also not pleasant (even not permitted) because of stringent environmental regulations such as carbon tax. These reasons and the elevating energy prices have increased attentions towards utilization of associated gas resources.

There are a number of gas utilization technologies that have the potential to make the development of stranded gas resources economically viable. Some of these however have not yet been fully developed and proven on a commercial scale, though being conceptually feasible. The most advanced among these alternative technologies include LNG, CNG, GTL and NGH. These processes are highly capital-intensive and require considerable gas reserves to justify their deployment. Accordingly, these technologies are challenged to be economical when the size of the field is small (like most of the associated gas resources) or the markets are located far away from the field.

In this study, we have investigated each of these processes based on different variables such as reservoir capacity, distance to market, process CAPEX & OPEX, safety, etc. This paper discusses the pros and cons of these processes and presents the sweet spot for each of the technologies based on gas reserve and distance to market.

Associated Gas Problem

Associated gas is natural gas found in association with crude oil. According to the latest data from EIA, the total gas reserves in the world are about 6200 tcf. However, some studies have estimated that global associated gas reserves without commercial value exceed 1000 tcf (around 17% of total gas) [1].

National Geographic Data Center (NGDC) through collaboration with World Bank's Global Gas Flaring Reduction (GGFR) partnership is carrying out a project to develop a methodology to estimate global gas flaring volumes based on satellite sensor observations. The center has reported the global volume about 4.9–6.1 tcf per annum within the period of 1994 to 2008 with maximum amount of 6.1 tcf in year 2005 and minimum of 4.9 tcf in 2008 [2]. Such amount of gas accounts for about 5–6 % of total world's natural gas consumption [3].
Relative Sea Level reconstruction and time calibration of the Burgan-Mauddud-Wara of the Greater Burgan Field, Kuwait
Authors: Al-anezi Bashar Khalaif , Burman Kishore , Datta Kalyan , Le Guerroue Erwan , Filak Jean-Michel
Published: March 2015

The Albian Cenomanian sea level curve is fairly understood, at the 3rd order, in the Middle East region. We present here an exhaustive stratigraphic framework for the Burgan, Mauddud and Wara formations of the Greater Burgan field of Kuwait that is constrained in terms of accommodation depth of deposition and then relative base level variation.28 stratigraphic sequences (of 4th order) are recognized and propagated over 45cored wells throughout the entire field. Each of these sequences is characterized in terms of sedimentary facies and fossil / ichnofossils content from detailedcore description. For each sequence, an accommodation depth of deposition is then assigned taking into consideration facies changing along the slope of the basin. This process enables relative base level variation to be reconstructed vertically for 45 wells and average to account for intra-basinal tectonic forcing. The last step consists of addressing the basin subsidence history and the duration of the hiatus encountered in the basin using correlation with the global eustaticre cord (Miller et al., 2005; Haq and Al-Qahtami 2005; Haq et al., 1987) and absolute stratigraphic tie (calibrated palynological content).Direct comparison of the reconstructed relative sea level curve with reference curves allows to correlate the falling and rising cycle by picking main flooding surfaces and sequence boundaries. Results show that the Kuwait relative base level variation is in conformity with international chart allowing to constrain the stratigraphyin time. Burgan Formation was deposited during most of the Albian, whereas Mauddud is of late Albian age. Wara Formation and basal Ahmadi are Cenomanian age, as evident from Palynological data.

Introduction:

In Greater Burgan Field a new Geological model was built to capture the heterogeneity in the reservoirs. This called for a study of the depositional model from a Sequence Stratigraphic standpoint. This study has been done on the Albian-Cenomanian Burgan-Mauddud-Wara Formations of the Greater Burgan Field in Kuwait. An exhaustive stratigraphic frame-work for the Formations was built constrained in terms of accommodation, depth of deposition and then relative base level variation. Reconstruction of the historical variation in relative sea level through geological time is key to the understanding of the stratigraphy in proper perspective and prediction of facies in a basin.28 stratigraphic sequences (of 4th order) are recognized based on sedimentary facies associations studied in 45 cored wells across the field. The fourth order cyclicity is corroborated with bathymetry changes interpreted from palynoflora and ichnofossils. Several known methods were tried to reconstruct the sea level variation history in the Greater Burgan Field of Kuwait, which is the world's largest clastic oil field. (Figure1).