bluuebunny/crossref_metadata_2025 huggingface dataset:
Artifical neural networks in RF MEMS switch modelling
Authors: Marinkovic Zlatica , Markovic Vera , Ciric Tomislav , Vietzorreck Larissa , Pronic-Rancic Olivera
Published: May 2016

The increased growth of the applications of RF MEMS switches in modern
communication systems has created an increased need for their accurate and
efficient models. Artificial neural networks have appeared as a fast and
efficient modelling tool providing similar accuracy as standard commercial
simulation packages. This paper gives an overview of the applications of
artificial neural networks in modelling of RF MEMS switches, in particular of
the capacitive shunt switches, proposed by the authors of the paper. Models
for the most important switch characteristics in electrical and mechanical
domains are considered, as well as the inverse models aimed to determine the
switch bridge dimensions for specified requirements for the switch
characteristics.
An intelligent power MOSFET driver ASIC circuit with additional integrated safety operation functionality
Authors: Podrzaj Jurij , Trontelj Janez
Published: May 2016

This paper presents an extension to the previously presented conference paper
[1] a power MOSFET driver ASIC with intelligent driving algorithm approach of
the power modern MOSFET devices. The intelligent driving algorithm concept
proposes a realization of power MOSFET gate driving with controlled
source/sink current of the power MOSFET driver circuit. Such approach enables
higher control of the power MOSFET operation behavior, especially during
switching events. Additionally to the previously published work this paper
presents implementation of the intelligent driving algorithm and driver
safety operation functions on a single integrated ASIC circuit. The paper
concludes with presentation of some functions of the manufactured ASIC
circuit in CMOS technology.
Results of the speleological exploration on Pester plateau
Authors: Nesic Dragan
Published: May 2016

During the period 2006-2008, basic speleological research was done on Pester
Plateau in Southwestern Serbia. On that occasion, 40 caves were surveyed, 11
of which were measured in detail. Registered caves were grouped on the basis
of landscape characteristics and morphogenetic relations. Based on the
location and general characteristics of the Pester karst, it is considered
that the objects near Boljare and in the ponor (sinking) area of Borostica
are connected to the drainage system of the Pecina nad Vrazjim firovima
(Vraziji firovi Cave). In morphological terms, the cave Bezdan Kacunova ravan
(Kacunova Cave) near Boljare with its imposing hall is the most important
object on Pester Plateau for the time being. Realized research on Pester
Plateau has the character of basic or initial speleological research, which
should be continued in order to solve different problems of karst in this
area.
Current state of studying precipitation acidification in Serbia
Authors: Talijan Radomir , Andjelkovic Goran
Published: May 2016

Basic relations between the state of air pollution and their effects on
chemistry of precipitation were introduced in this paper. Changes in the
composition of atmosphere were defined by numerous chemical elements and
compounds different in character which also affect the phenomenon of
acidification and alkaline processes. The interconnected sources of emission,
relations between urban and rural, the regime of rainmeasuring system and
climate elements combined as whole give us more complete image of the global
phenomenon and its effects on cities as a contemporary social development
first of all caused by industrialization, its dependance upon fosil sources
of energy and demographic pressure. Characteristics of main pollutants were
considered as well as their ability to modify atmospheric conditions, but
also the influence of climate elements on those conditions, ph rainfall
average value movement, seasonal and daily variations, the influence of
industrial zones and agglomeration on the conditions in the area much wider
than emitters.
Concept of spatial coordinate systems, their defining and implementation as a precondition in geospatial applications
Authors: Nedeljkovic Zoran , Sekulic Aleksandar
Published: May 2016

There are many users of spatial information, and quite large interest about
the nature and genesis of such information. Different users found spatial
information in the form of maps, plans or alphanumerical tables. Recently,
there are more often in the form of spatial databases, and in the form of
geographic information systems. What is behind these spatial data? On what
foundation are they designed? In this article we look at the basic aspects of
space, dimensionality and global coordinate systems in applications of global
geospatial research. Here is explained the definition of the coordinate
system as an abstract entity and, consequently, its implementation or
establishment in the form of a geodetic reference frame, as real geodetic
reference network. The applicative aspect of coordinate systems in this
article is emphasized through recommendations and considerations during usage
of their different implementations.
The evolutive aspect of the short jat substituents following the sonant r - a comparison between the Serbian literary language and the dialect of Vuk’s ancestors
Authors: Ostojic Vladimir
Published: May 2016

The paper discusses the evolutive aspects of short ?jat? following the sonant
r usage during the formation of the modern Serbian literary language and its
treatment in the Serbo-Croatistic and the Serbistic descriptive and normative
literature. In addition to the basic issue of the distribution of the short
?jat?s? substituent following the sonant r in dialects of Montenegro,
particularly in the native dialect of Vuk Karadzic?s ancestors, the author
also addresses the question related to the mechanisms that cause short ?jat?
following the sonant r in ijekavian dialects to be reduced sometimes to e,
and sometimes to je. Substitution of short ?jat? following the sonant r in
Jezera-Sarani dialect had important evolution from the times of ?classical
Vukovian ijekavism?. In this dialect, forms with rje do not occur, except in
the word starjesina. Here, r and j remained in the same syllable, which set
the stage for iotization and depalatalization. The analysis of the paper
describes the situation in Jezera-Sarani dialect as well as the situation in
other Montenegrian dialects of the older and newer Eastern-Herzegovian type.
The author as well takes into consideration that our Pravopis has already
disregarded the Vukovian tradition with omitting j that follows sonant r in
the examples pogreska and greska. In order to eliminate the disunity, the
author concludes that the status of the group re should not be questioned
from the aspect of literary language standards.
Ethnic identity and patriotism as predictors of collective guilt acceptance
Authors: Niskanovic Jelena , Petrovic Nebojsa
Published: May 2016

Collective guilt is a group emotion, developed and shared between group
members as a result of dealing with past misdeeds committed by members of own
group. Collective guilt is associated with restitution, reparation and
forgiveness seeking toward victimised group. This paper will examine
relationship between ethnic identity and collective guilt acceptance, so we
can determine relationship between different levels of ethnic identification
and collective guilt acceptance. Also, it will be examined indirect effect of
blind and constructive patriotism on relationship of ethnic identification
and collective guilt acceptance. Survey was conducted in the context of
existing interpretations of past war in Bosnia and Herzegovina, among persons
of Serb ethnic group. There is negative relationship between ethnic identity
and collective guilt acceptance, indicating that collective guilt is higher
for middle identifiers in comparison with low and high identifiers. Blind
patriotism has moderate effect between ethnic identity and collective guilt
acceptance, with higher level of blind patriotism negative influence of
ethnic identity on collective guilt acceptance is stronger. There is indirect
effect of constructive patriotism between ethnic identity and collective
guilt acceptance with relatively small effect. Given results indicating
importance of ethnic identification on developing collective guilt acceptance
but only to the certain level which allows dealing with responsibility
regarding actions committed by members of own group.
Properties of Zig-zag nickel nanostructures obtained by glad technique
Authors: Potocnik Jelena , Nenadovic Milos , Jokic Bojan , Popovic Maja , Rakocevic Zlatko
Published: May 2016

Zig-zag structure of the nickel thin film has been obtained using Glancing
Angle Deposition (GLAD) technique. Glass substrate was positioned 75 degrees
with respect to the substrate normal. The obtained nickel thin film was
characterized by X-ray Photoelectron Spectroscopy, Scanning Electron
Microscopy and Atomic Force Microscopy. Surface energy of the deposited thin
film was determined by measuring the contact angle using the static sessile
drop method.
Prognostic importance of metabolic tumor parameters on initial FDG-PET/CT in patients with isolated infradiaphragmatic Hodgkin’s lymphoma
Authors: Alagoz Engin , Okuyucu Kursat , Ince Semra , Ozgur Gokhan , Ozmen Ozlem , Karacalioglu Alper , Ozturk Mustafa , Arslan Nuri
Published: May 2016

Background/Aim. Isolated infradiaphragmatic lymph node involvement is not common and makes up 5?13% of stage I-II Hodgkin?s lymphoma. Important subjects about prognostic factors and optimal treatment of isolated infradiaphragmatic Hodgkin?s lymphoma (II HL) have not been clearly defined. We aimed to evaluate the prognostic value of metabolic tumor indices on initial 18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) through quantitative PET/CT parameters together with the classical predefined risk factors for patients with II HL. Methods. This retrospective cohort study conducted between 2004 and 2015 included 21 patients for whom FDG-PET/CT were requested for primary staging. Quantitative PET/CT parameters (maximum standardized uptake value ? SUV max) average standardized uptake value ? SUV mean, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were used to estimate disease-free survival and overall survival. Results. Univariate Cox regression analysis was performed for all potential risk factors impacting metastasis/recurrence of the disease. Factors which had values of p < 0.2 after univariate analysis (sex, age, stage, bulky disease, SUV max, SUV mean, MTV, TLG) were processed with the multivariate model. Sex, TLG and bulky disease were found to be statistically significant risk factors for prognosis of outcome in patients with IIHL after multivariate analysis. Conclusion. The existence of bulky disease at the diagnosis and high TLG values on primary staging by FDG-PET/CT are potential risk factors for both disease-free survival and overall survival in Hodgkin?s lymphoma with isolated infradiaphragmatic lymph node involvement.
Production Integrated Sand Control Benchmark for Mature Field Development
Authors: Chan Keng Seng , Chong Danny , Masoudi Rahim , Othman Mohamad B. , Bt M Nordin Norbashinatun Salmi
Published: May 2016

Current offshore marginal field development and mature field re-development in Malaysia consistently encountered high development cost and low recovery or incremental recovery. Wells are being drilled and completed at a high cost of15 to 30 M$ per well while the estimated ultimate recovery (EUR) per well is as low as < 0.4 M Bbl. The associated well development cost (WDC) can be higher than 75 $/Bbl. This high WDC cost can be further aggravated by a significant increase in completion cost if an expensive sand control method is required to mitigate risk of sand production. Rock mechanical properties, stress and pressure distribution can vary widely, from layer to layer, rockfacies to facies in the reservoir. Reservoir pore pressure and its distribution could also change drastically during the entire production life cycle. With results of field case studies as examples, this paper is to share our engineering approach in first determining where and when we need sand control based on the geo-mechanical sand-free critical drawdown pressure (CDP)evaluation for the selected well type, configuration and completion. The generated CDP will be later coupled with the current pressure and fluid distribution predicted from the reservoir simulation model and confirmed with the historical pressure and production data for well type, completion and sand control strategy in mature fields. Decision to implement a proper sand control can be made by comparing the CDP with the minimum drawdown pressure (MDP)required to meet the expected production rate target. Sand control method selection shall then be based not only on the sand particle size distribution, well life and the mode of well production (single selective or commingle) but also on maximizing reservoir contact and oil and gas recovery per well. The presented workflows and methodologies is to constitute a new sand control benchmark for well design and production optimization and serve as an engineering guide for optimizing the sand control cost in Malaysia.
Surmounting the Challenges Leads to Discovery of New Field in Deep Jurassic Formation. : A Case Study.
Authors: Al-Ibrahim Abdullah Reda , Duggirala Vidya Sagar , Manimaran A. , Al-Salali Yousef Zaid , Packirisamy S. , Ibrahim Anwar
Published: May 2016

This paper shares and discusses the challenges faced and activities that led to a significant discovery in a deep carbonate reservoir. It covers the successful well-testing design as well as the methods and procedures adopted to complete short term test of this well safely.

A new structure in the state of Kuwait was identified for drilling the first exploratory well targeted at deeper Jurassic formations. Adjacent fields to this structure are HPHT naturally fractured reservoirs and fluids are sour in nature. The target well was sidetracked twice with two different kick-off points while drilling the deep formations due to well control problems. Deep formations in combination with HPHT and sour environment created unusual challenges while testing several zones in this well.

Based on past experience, a simple test string assembly suitable for HPHT and sour environment was selected for this well. Perforating using deep penetration TCP guns, stimulation with Breakdown acid followed by emulsified acid and testing with Drill Stem Testing (DST) techniques were applied for evaluating the deep formations. During short term testing of second zone, gun hanger has moved upward by about 900 feet and plugged 5" production liner top preventing any flow/access from the zone below. Though this zone produced hydrocarbon, full potential could not be established due to plugging. The last zone was successfully tested and produced significant amount of gas and 44.5o API oil with 1% H2S. Meticulous planning and testing strategies could overcome many challenges to discover commercial quantities of hydrocarbon from new field.

This new discovery adds significant hydrocarbon reserves and put a new field on the map of the state of Kuwait. Based on the commercial success in this well, further exploration and development activities are being planned to focus on the same structure.
Applications of Downhole In-Situ Reservoir Fluid Properties in Interval Pressure Transient Test
Authors: Hademi N.R. , Daungkaew S. , Chokthanyawat S. , Kiatpadungkul W. , Platt C. , Limniyakul T. , Last N.
Published: May 2016

Pressure transient analysis has been known as an important tool to properly characterize a reservoir. The scales of measurement for different testing methods depend mainly on their radius of investigation, i.e. how far pressure changes/disturbance can be seen into reservoirs. In a large reservoir, a fullscale testing method such as a Drill Stem Test (DST) is required to test enough reservoir volume for flow assurance purposes. To test for the reservoir extent, a production test is required to reach reservoir boundaries.

In recent years, there have been tremendous developments for short period testing methods. The Formation Tester (FT) is one of the tools that are used to evaluate reservoir fluid properties and acquire pressure transient data from both dual packer and single probe configurations. With the current Downhole Fluid Analyzer (DFA) technology, reservoir fluid properties such as composition, Gas-Oil-Ratio (GOR), in-situ density, and viscosity can be obtained in real time. These insitu fluid properties can be used to analyze pressure transient data for reservoir permeability, skin factor, and reservoir heterogeneity; and as a result, the DFA serve to push IPTT applications to another step forward.

This paper will specifically focus on the application of DFA for IPTT purposes and also a continuation of several published papers which discussed the use of different scales of pressure transient data. The results from this paper will mainly focus on the use of single probe and dual packer IPTT to obtain reservoir properties in thinly bedded reservoirs with waxy crudes from the South East Asia region. The viscosity variation from oil based mud filtrate to reservoir fluid during the pump-out and its effect on the pressure derivative will be discussed using actual examples to demonstrate this point.

The end results may contradict traditional testing methods on the use of virgin reservoir fluid properties for pressure transient analysis. Hopefully, this paper might open another option when FT is deployed together with the current DFA tool for quick and effective reservoir evaluation in thinly bedded reservoirs which are often encountered in many parts of the world.
Petrophysical Reservoir Characterisation of a Complex Heavy Oil Carbonate Reservoir in North Oman
Authors: Al-Bulushi Nabil , Al-Mjeni Rifaat , Said Dhiya , Al-Yaarubi Azzan
Published: May 2016

There have been a number of major heavy oil discoveries in Oman in recent years. In order to devise efficient and cost effective recovery mechanism careful and detailed subsurface understanding of these fields is critical. To this end, petrophysical understanding plays a critical role, as it represents a basic building block of the static and dynamic models. The field under study is a fractured carbonate reservoir with high viscous oil. It is believed that this reservoir has gone through various cycles of drainage and imbibition. Thus, in addition to the complex geology, understanding of fluid distribution and fluid mobility are among major challenges that detailed petrophysical evaluation needs to address. Understanding these parameters will help determine the feasibility of the recovery methodology to be adopted.

This paper details a novel petrophysical workflow that integrates 3D NMR, multiarray/multi frequency dielectric measurements, borehole images, and core analysis. The core analysis focused on capillary pressures, Dean-Stark, and rock typing. Fracture studies included detailed image analysis and extensive fall off test for understanding the nature and distribution of the fracture network in the reservoir. The wealth of well data coupled with geological and dynamic data reduced the overall reservoir properties and fluid distribution uncertainties.

Dielectric data provided resistivity independent saturations validated by Dean-Stark data. Combining dielectric and 3D NMR data allowed better formation characterization and fluid type evaluation and their present day distribution. Additionally, this combination indicated that water is not at an irreducible state in the reservoir. This was supported by the core saturation height function which indicated that present day saturation should be much higher if the reservoir was in drainage mode. These results were crucial to evaluate development options, underlying uncertainty/risks of this reservoir, and design optimum future data acquisition requirements.
Well Integrity During Operating the First Offshore Gas Wells in Saudi Arabia; Experiences and Lessons Learned
Authors: Alsyed Samih M. , Uzcategui Elio A. , Adesegha Rotimi , Al-Ahmari Abdulrahman S.
Published: May 2016

Annulus pressure is an important key to maintaining Well Integrity. During the start-up of Saudi Arabia's first offshore non-associated gas field containing high pressure high rate sour gas wells, a continuous increase of some annuli pressures was experienced despite the fact that these annuli were cemented to surface. During any well production, the heat transfer from the produced fluid to the trapped annuli fluids causes annuli pressures to increase to levels that could exceed collapse and/or burst pressure limits of the casings. This is especially true during early startup of the well when all annuli fluids are cold (offshore wells) or at ambient temperature (Onshore wells).

To ensure that the pressures does not exceed the maximum allowable limit of well tubular various calculations were performed, taking into account not only the tubular limitations but also the formation pressures these casings encountered, to set the maximum limit. Periodic bleeding of pressures and continuous monitoring was necessary to avoid reaching this maximum set limit for the first four months of production.

In this paper performance of the different annuli is analyzed and discussed. Calculation methods are also discussed in details which were employed to determine the maximum allowable pressure limit for each annulus. Elimination of frequent bleeding of 1st casing-casing annulus in one of the wells by revisiting the maximum limit, taking into consideration the formation pressure the casing was set in are some of the lessons learned documented during this first offshore gas field startup and will be put forth in the paper.
Improving Safety & Reliability Through Process Safety Management in Gas Handling Facilities
Authors: Al-Adwani Adnan Eid , Kapavarapu Venkata Madhusudana Rao
Published: May 2016

During the whole Facility Life Cycle of a Gas handling plant, Risk Management for protection of environment and communities and prevention of major hazards along with Asset Management are the key drivers for making the facility compliant with Health & Safety Regulations and Environmental issues and at the same time profitable economic and able to preserve asset value by improving the level of operational and process safety has become a crucial and challenging issue in a HSE perspective in Gas handling facilities.

Process safety can be placed at the intersection of these independent but interrelated aspects and can be regarded as the key element for performing an integrated and comprehensive analysis capable to maximize plant effectiveness ensuring the best safety level, minimizing risks to safety and security and limiting at the same time downtime due to operational disruption or interruption, thus achieving consistency throughout the whole project life cycle.

Therefore an effective process safety management demands a holistic and systematic approach for improving operational and process safety throughout the whole project life cycle from design and construction, through operation and maintenance, to decommissioning.

In light of the above considerations a tool for process safety management has been elaborated and is hereafter described as a new structured approach of BAD ACTOR Identification in the facilities and its mitigation methods.

Process Improvement approach was adopted in Kuwait Oil Company in Gas Management group and Gas Operations team and the similar culture was inculcated in to the operation employees to report all process incidents and BAD ACTORS. These BAD ACTOR events will be analyzed based on risk prioritization by conducting structure Risk analysis and Root cause analysis of various methods and recommendations will be implemented to avoid similar incidents to improve the reliability of the plant operations.
Collapse Strength Study for the Solid Expandable Tubular
Authors: Chen Qiang , Gao Shan , Li Yiliang , Li Tao , Bi Xiuling , Han Weiye , Sun Qiang
Published: May 2016

The paper summarized an experimental and theoretical study of the collapse resistant ability of solid expandable tubular (SET)after expansion, and the formula used to calculate the collapse strength of casing was modified to make it adaptable to the expandable tubular.

One key limiting factor of the expandable tubular in its application in the open hole well to replace the casing is its post-expanded mechanical properties. The collapse strength of the expandable tubular after expansion was significantly compromised as the result of the comprehensive influence by the change of factors like the ovality, eccentricity and residual stress. In view of these problems, firstly full-scale expansion experiments were performed to examine all the impact of those factors; secondly the formula was modified based on the experimental data; thirdly the collapse experiments were carried out to test the strength of post-expanded tubulars as well as the accuracy of the modified formula.

The results demonstrated that after large-scale plastic deformation, the dimension of the tubular changed dramatically as represented by the increase of eccentricity and ovality, the residual stress also appeared on both inside and outside surface of the tubular, the starting point of the collapse occurred at the position with the least wall thickness. The calculation results which reflected the average collapse strength of the tubular were larger than the actual experimental outcome but the error was kept well within 15%.

We expect the research will contribute to the better understanding of the collapse resistant ability of post-expanded tubular and form the necessary technical basis for it future broad use.
Lithofacies Classification: From Sedimentologic Analysis to 3D Reservoir Modelling
Authors: Chen Jiajie
Published: May 2016

Deepwater depositions are complicated processes reflecting the combined effects of global eustatic sea-level variation, regional sediment input, climate, paleo-topography, and many other factors. The complex depositional processes give rise to various depositional facies, which significantly impacts reservoir connectivity and quality. The description of deepwater depositional facies can be performed in details at sedimentologic level based on corematerials, in which complex sedimentation feature such as grain and matrixcomposition, grain-size distribution, color, sorting, roundness, climbingripple, cross bedding, various amount of mud clasts within massive sandstone, degree of bio-alteration, and so on, are considered to classify the facies. Such a detailed facies analysis is necessary because it provides information regarding the geological processes and associated environment that is responsible for the accumulation of the reservoir rocks. However, when dealing with reservoir modeling, it can be too sturdy to include all detailed facies types from sedimentologic description. Main attention should be paid to identify just the major facies types that bear geological environment signature, yet simple enough for any reservoir simulators to handle. This study integrates outcrop data with subsurface data, compares patterns of facies variations from outcrops to several deepwater fields, and suggests that for reservoir modeling purpose most of the deepwater turbidite fields can be described by four major facies types, channel/lobe axis, off-axis, margin, and background. Each of these facies has its range of reservoir properties, and the overall performance of the reservoirs depends on the relative proportions of various facies types and their spatial arrangement. By applying advanced technology, log data are trained to recognize facies types based on the patterns defined from core studies. The detailed log facies types can also be represented by four major groups. As a result, integration of core, log, and outcrop data leads to a robust solution for handling the complex lithofacies issues in 3D geological model, enabling better development of strategy forfield development.
A Dynamic Hybrid Model to Simulate Fractured Reservoirs
Authors: Shuhong Wu , Xiaobo Li , Qiaoyun Li , Hua Li , Baohua Wang , Wen Yuan
Published: May 2016

Fractured reservoirs simulation has long been challenge to reservoir engineers to handle the complex geometry structure of fractured reservoir and fluid flow processes in it which includes viscous, capillary, gravitational and diffusive effect. In traditional reservoirs simulation, the fractured reservoir is usually divided into matrix and fracture interacting continua such as Dual Porosity model or Dual Permeability model. It is assumed in these models that the fracture system is in a steady state which the width, length, density of the fractures in reservoir does not change during the whole production history, therefore, it is not possible to simulate fractures variation effect with these models.

In order to simulate the unsteady state of fracture system, a dynamic hybrid model has been developed in the paper which a dynamic transitivity tensor model is overlapped to Dual Porosity model. It is assumed that the fracture network is the primary continuum for fluid flow, the matrix of low permeability, high storability is considered to be a sink or source to the fracture. The matrix and the fracture communicate through an exchange term which describes the fluidflow between matrix and fracture. The fracture network is considered to be in unsteady state in which fracture has possibility to widen, lengthen, and close during oil production. A transitivity tensor is introduced to describe these processes, which is a function of pressure, stress, density of fractures.

The paper will detail the dynamic hybrid model such as its assumptions, equations, mechanisms and also its applications in the fractured reservoirs simulation. The simulation results show that the dynamic hybrid model has high potential to accurately simulate the dynamic fracture network as well as the fluid flow with the capillary, gravitational and diffusive effects between matrix and fracture.
First Installations of the 9-5/8-in. Enhanced Single-Trip Multi-Zone Sand-Control Technology in Offshore Brunei
Authors: Fourie Bernard , Marpaung Billman , Jansen Rene , Wong Andrew , Mok David
Published: May 2016

Brunei Shell Petroleum (BSP) operates the mature South West Ampa (SWA) and Bugan Fields in Brunei Darussalam. The fields, located 10 to 21 kilometers offshore Brunei in water depths ranging from 10 to 40m, are major sources of oil and gas production. Controlling sand production is a key completion challenge as the reservoirs are composed of multilayer unconsolidated sands, requiring sand control for safe production. Cased-hole, stack-pack systems were considered as the default solution for shallow reservoir zones and wells. Dueto the reduced production rates in some reservoirs in the fields and increasingrig costs there is a demand to improve the cased-hole gravel pack efficiency.

The wells require zonal isolation and sand-control treatment. Cased-hole stack packs have been a reliable completion method, due to their capabilities for better zonal isolation and multi-zone functionality. Due to the reduced production rates in the mature fields, however, wells were no longer considered economically feasible. Therefore, BSP decided to try a new 9-5/8-in. enhanced single trip multi zone gravel pack system. This system appeared capable of providing significantly greater cost efficiency than conventional cased-hole stack-pack systems, which would make the marginal wells profitable.

This paper describes the 3 wells completed by BSP in 2010 and 2011 using the enhanced single trip multi zone gravel pack system. For the 3 wells, a total of10 zones required a sand control treatment. The paper also will describe why the enhanced single trip multi zone gravel pack system was chosen and will discuss the wellbore configuration, the implementation, and other field possibilities for the system. Finally, the paper will discuss the "bestpractices" learned from the first enhanced single trip multi zone gravel pack system installations; the challenges encountered during the job execution, and also, will compare the enhanced single trip multi zone gravel pack system with the conventional cased-hole stack-pack system to highlight the advantages of the new system.
Hawiyah Gas Plant New Thermal Oxidiser Combustion Control Philosophy
Authors: Almubarak Yousef , Al-Tawil Haider M.
Published: May 2016

Hawiyah Gas Plant at Saudi Aramco recently commissioned a thermal oxidizer. The thermal oxidizer unit has two main functions that shall be achieved. The first function is to oxidize and destroy the Acid gas which has minute quantities of BTX. The BTX shall be fully destroyed at a temperature above 1800 deg F. The second main function of the unit is to provide heating media for the hot water which is used in the re-boiler of the DGA stripper in sweet gas treating unit. The hot water temperature controller has a set point of 350 Deg F thus providing constant water temperatures to the gas treat process. Hawiyah gas plant will share through this paper the internal effort to rectify the original control philosophy design problems submitted by the equipment vendor of the thermal oxidizer that fail to accommodate both functions at the same time. The paper will shed the light on all of the new innovative major advance control loops configured to achieve the appropriate hot water temperature, combustion chamber temperature in addition to the Oxygen trimming advance control. The new control scheme helps the plant to achieve more reliable system to any process changes, it helps to maintain the targeted process parameters set points and optimize the fuel consumption. Hawiyah Gas Plant will present the actual reduced figures in the fuel consumption after the modification and shows the improved in the equipment reliability.

In the first part of the paper, brief description of HGP process will be shown. And In this introduction, the role and function of the Gas Treating unit 6 and its thermal oxidizer units will be discussed.

Then there will brief disciption of the basic start up and firing scheme for the thermal oxidizer. After that, the paper will discuss the refractory dry out and the heat up requirements and how this is achieved by the logic.
D50 Shift Factor Shifting the Concept of SBMs Performance Evaluation
Authors: Amanullah Md. , Allen Tim , Kilani Mohammed
Published: May 2016

Different grades of sized bridging materials such as ultra-fine, fine, medium and coarse grades are frequently used in drill-in fluid formulations to enhance fluid characteristics, improve mud cake quality and eliminate or reduce formation damage while drilling. Selection of high quality and long lasting SBMs is an essential part of superior drill-in fluid design to achieve these goals. Historically, color, provenience or origin of the SBM samples were evaluated visually or by applying some geological analysis tools such as the petrographic tools to identify and select highly durable and mechanically strong SBM products. These subjective and inappropriate methods of assessment frequently lead to disastrous SBMs performance in down hole conditions.

Due to the limitation and ambiguity of the petrographic methods, attempt was made to identify high quality and long lasting SBMs by evaluating acid solubility of SBMs. Though this evaluation criterion is good from acid solubility point of view, it has no relevance to mechanical behavior of SBMs while drilling. Hence, the assessment method also provided misleading information regarding SBMs performance in down hole conditions. Due to the failure of the above approaches, attempt was made to assess SBMs quality using Brinnel Hardness Tester. The outcome of the research was not reliable and inconclusive and thus was not successful in providing a guiding tool for SBMs performance evaluation.

This paper describes a fit-for-purpose index parameter defined as the D50 Shift Factor that readily indicates the relative toughness of SBM products and thus provides a powerful guiding tool for high quality SBM product selection for superior drill-in fluid formulations. The index parameter is based on size degradation principle of SBM particles i.e. weak SBMs will cause higher shift of the D50 size compared to tough SBM products. Experimental results demonstrate the usefulness of the D50 Shift Factor in SBM performance evaluation and superior fluid formulations for trouble-free, economic and non-damaging drilling operation.
Remaining Oil Distribution Pattern of Massive Matured Oilfield with Strong Bottom Water: An Integrated Reservoir View
Authors: Rao Liangyu , Wu Xianghong , Wang Hui
Published: May 2016

The highlight of this study is to establish the distribution pattern of remaining oil in massive matured oilfield developed by bottom water under watercut over 90%. The approach combines reservoir engineering and numerical simulation to demonstrate the controlling factor and distribution pattern of remaining oil and complexity water oil movement. The study involves dynamically describing of water oil movement and studying of remaining oil enrichment mechanism and conducting a detailed typical numerical reservoir simulation of Hoilfield.

The results of the integrated reservoir study show that remaining oil distribution pattern was seven distribution forms (that is flower-like oil, isolated-island oil, ridge oil, attic oil, banded oil, roof oil, sandwich oil)controlled by micro-structure, inter-beds, rhythm, heterogeneity, faults, well pattern and development strategy, and water movement was affected by the transformation of water energy and the formation of water-flooding advantage flow channel, and which was formed for heterogeneity that is production rate heterogeneity, reservoir heterogeneity such as dual porosity and high permeability heterogeneity. Furthermore, the horizontal oil mainly located in flower-like oil which controlled by structure and well pattern, vertical oil mainly located in attic oil controlled by structure, isolated-island oil controlled by local micro-structure, and roof oil controlled by structure and rhythm.

The mechanism study also show that inter-bed can affect the distribution of remaining oil when the dimensionless inter-bed radius larger than 0.6 and has little effect on remaining oil when smaller than 0.2, and remaining oil may located on upper zone, lower part and cross inter-bed, and the high oil viscosity also made oil be remained under the inter-bed. The mechanism study show a great agreement with the simulation study of H oilfield, and can support the following development adjustment and EOR study.
Carbonate reservoir interaction with supercritical carbon dioxide
Authors: El-Hajj H. , Odi U. , Gupta A.
Published: May 2016

It is well known that with continued production from wet gas reservoirs, the reservoir pressure eventually falls below the dew point pressure leading to condensation and loss of gas productivity in the reservoir. The concept of simultaneously injecting CO2 in a gas reservoir for long term storage while at the same time accelerating production of the gas reservoir is intriguing and promising. CO2 may also interact with carbonate matrix by changing porosity and permeability of the host rock; this is true for reservoirs that are found in the Gulf Region.

Core floods experiments with carbon dioxide aging were conducted in a core sample analogue to carbonate at reservoir conditions. CO2 interaction in carbonate formation was evaluated by XRF and SEM analysis; furthermore mineral trapping was also investigated by AFM.

The results of the laboratory study showed that the CO2 would dissolve some of the rock at high pressure aging. Dissolved carbonate was found also to be precipitated along the core after decreasing the pressure of the system.

The results of this study are directly applicable for evaluating CO2 Huff-n-Puff, a process that can potentially raise the reservoir pressure back above the original dew point. Results of this experiment help answer some critical questions related to introducing CO2 in wet gas reservoirs and its interaction with carbonate reservoirs.
Innovative Single-Phase Tank Technology for In-Situ Sample Validation Enhances Fluid Sampling Integrity
Authors: Galvan Sanchez Francisco
Published: May 2016

Millions of dollars are spent each year drilling in deepwater areas to prove the presence of hydrocarbons. Wireline formation testers (WFT) are able to capture and retrieve multiple, discreet hydrocarbon discreet hydrocarbon fluid samples at in-situ conditions. Expeditious sample validation once the sample bottles are retrieved at the surface, expeditious sample validation is critical because it provides certainty on sample type and quality. The typical process for well-site wellsite sample validation can be very expensive and high risk because it requires a full laboratory restoration apparatus, a portable lab, and trained personnel to handle high-pressure samples —often under unfavorable conditions.

The Advanced Optical Cylinder (AOC) is the latest evolution development in single phase single-phase sampling technology by Baker Hughes. The AOC sample chamber eliminates the high risk and costs associated with sample quality validation in the field and provides costs associated with sample quality validation in the field and provide the clients with very valuable and timely data regarding their fluid sample. The AOC is nitrogen charged sample tank that provides pressure compensation to retrieve a single phase sample and incorporates visible-near infrared (Vis-NIR)technology to obtain spectroscopic measurements of the sample within the tank. The AOC design incorporates nitrogen compensation, to retrieve a single single-phase sample, as well as visible-near infrared (Vis-NIR)technology to obtain spectroscopic measurements of the sample within the tank. The ability to capture Capturing a single single-phase sample is very important because the accuracy of reservoir fluid samples can provide critical parameters needed for optimal completion and production design. Vis-NIR spectroscopy is a well-established tool used for downhole fluid analysis that provides critical information such as fluid type, sample purity and PVT properties. With the AOC, it is now possible to verify the consistency visible-near-infrared spectra of the captured sample of the crude oil or gas obtained during sampling, as soon as the tanks are retrieved at surface without the need for sample transfer. The benefits include avoiding lengthy waiting periods for PVT laboratory analysis, ensuring the quality of retrieved samples, and enhancing critical economic decisions about the reservoir development.

The AOC provides the best method for non-invasive sample validation of the captured formation fluid sample, using a high-resolution spectrometer that easily connects to the tank to capture detailed visible and NIR spectra of the pressurized fluid sample. This spectrum can then be compared to the fluid analysis data that was captured while the WFT was sampling, further analysis of the VIS-NIR spectra can determine contamination, GOR, bubble point, and API gravity.

Field examples will be used to demonstrate the application and benefits of in-situ sample validation using the AOC.
Fracture Optimization Applying a Novel Traceable Proppant and a Refined Mechanical Earth Model in the Congo Onshore
Authors: Perfetto R. , Saldungaray P. , Martocchia F. , Ceccarelli R.L. , Lorefice R. , Rinaldi F. , Tealdi L. , Dalmasso P.
Published: May 2016

Fracture stimulation has been adopted as an integral part of the completion in the M'Boundi field given the results achieved in enhancing well productivity, as well as the positive impact realized on field development economics. The fracturing process has been optimized over the years through improved reservoir understanding and ensuing implementation of technologies to address the uncovered challenges. Changes to the fracturing fluid formulation to prevent damaging the water sensitive reservoir rock, as well as modified proppant schedules to mitigate proppant embedment are examples of this improvement process.

This paper describes the successful ongoing process of optimizing hydraulic fracturing designs in M'Boundi field. By applying an integrated approach combining various technologies, it was possible to better understand fracture propagation and coverage of the target reservoir. Implementation of a novel non-radioactive traceable proppant allowed accurate frac height measurement at the wellbore. When combined with rocks mechanics derived from sonic logs it led to redefining the mechanical earth model and ultimately the completion and fracturing strategy in the field. The process will be illustrated with examples from a 3-well campaign recently executed onshore Congo.
Using a Novel Spacer and Ultralow Density Cement System to Control Lost Circulation in Coalbed Methane (CBM) Wells
Authors: Wang Chengwen , Wang Ruihe
Published: May 2016

Coalbed methane (CBM) is one of the major clean-burning gas resources. Development and utilization of CBM can increase the energy supply, improve coalmine safety, and protect the global environment. The southern Qinshui basin of China is rich in coalbed methane; it is the first area that obtained good results in the commercial development of CBM in China. However, lost circulation is a common problem during cementing through the fractured coal-seams known as cleats. These cleats form an interconnected fracture network and this allows cement slurry to loss through the coal-seams during cementing operations. Cleats are often wide enough to accept cement slurry, not just cement slurry filtrate. Hence, simply reducing slurry density does not ensure a good cement job. Preventing cement slurry loss to coal-seams while cementing production casing is a major challenge.

To solve lost circulation problem across coal formations, an innovative hydrophilic-fiber-based spacer fluid and ultralow density cement slurries with density of 0.95–1.20 g/cm3 have been formulated. Laboratory tests have verified the effectiveness of hydrophilic-fiber-based spacer fluid in plugging these cleats of coal-seams. The ultralow density cement slurries exhibite favorable properties. These test results are confirmed by the goodfield application results obtained in southern Qinshui basin. Fourteen CBM wells have been successfully cemented using the novel spacer fluid and the ultra low density cement slurries. The combined application of the hydrophilic-fiber-based spacer fluid and the ultralow density cement slurry system is able to successfully combate the lost circulation problem in CBM wells, and provides better zonal isolation as well. This paper provides details about the slurry design and field application, and also presents the cement bond evaluations that verify the conclusions.