bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevention of Dissolution and Re-Precipitation of Calcium Sulfate While Acidizing
Authors: Quintero Harvey , Maley Darren Michael , Zafar Farah
Published: March 2015

Calcium sulfate in the form of gypsum (CaSO4.2H2O) and anhydrite (CaSO4) is one of the most prevalent evaporite minerals typically found in the prolific middle Devonian carbonate rocks of the Western Canadian Sedimentary Basin (WCSB). Strong mineral acids, in particular hydrochloric acid (HCl), are employed to enhance permeability in the near wellbore area of the oil wells in these carbonate-bearing formations during matrix stimulation and hydraulic fracturing treatments. When calcium sulfate (CaSO4) comes in contact with the live acid, partial dissolution can occur. As the acid solution is progressively spent inside the carbonate rock, the concentration of unassociated calcium ions will increase. These ions will become readily available to react with the sulfate ions in the neutralized solution and cause, the unavoidable re-precipitation of CaSO4 crystals in the pore throat, therefore severely plugging the newly created flow channels.

Based on Le Chatelier's principle and the common ion effect, the addition of a soluble calcium salt to the treating acid package has been an economical oil field practice established to suppress the initial dissolution of CaSO4. However, a secondary protection mechanism is still required because sulfate-rich connate water could commingle with the spent acid solution during swabbing and/or flowback operations, reaching the ideal conditions for CaSO4 precipitation.

To date, most of the CaSO4 scale inhibitors that have been applied for acid treatments relied on either the retardation of CaSO4 crystal growth, or the creation of soluble complex salts with the calcium ions. This paper intends to detail the development and laboratory testing of a broad spectrum scale inhibitor specially formulated for high salinity and acid solutions that not only prevents the precipitation of CaSO4, but also helps to inhibit the initial dissolution of CaSO4.

Introduction

Covering a vast extension of 1.4 million square kilometers (Bowers 1997), The WCSB defines its coordinates between the southwestern border of the Canadian shield in Manitoba and the eastern flank of the Canadian Rocky Mountain system in British Columbia. Within the WCSB, approximately half is composed of carbonate reservoirs of the Devonian age. These Carbonate formations combine for a project reserve of 15 billion barrels of oil and 35 trillion cubic feet of natural gas (Li 2002). These important reserves of hydrocarbons have been successfully exploited since the late 1940's (Milligan 1998).
Investigation of Asphaltene-Asphaltene Association and Aggregation for Compositional Reservoir Simulators By Quantitative Molecular Representations
Authors: Hibi Ryutaro , Tagami Kanako , Kobayashi Kazuya , Liang Yunfeng , Honda Hiromi , Murata Sumihiko , Matsuoka Toshifumi , Morimoto Masato , Uetani Takaaki , Boek Edo Sicco
Published: March 2015

The objective of this research is to properly calculate the association energy with molecular models of asphaltenes using Molecular Dynamics (MD) simulations. Asphaltene precipitation clogs pore throats of reservoir rocks, and significantly reduces the production rate. To better understand the asphaltene precipitation, a process-modeling methodology has been developed. The cubic-plus association equation of state (CPA) (Li & Firoozabadi, 2010) is effective in the modeling, and contains only one adjustable parameter, that is, association energy of asphaltene, however, we were not able to correctly evaluate the association energy by the currently available methods. Quantitative Molecular Representations (QMR) method provides systematic structural representations of asphaltenes based on analytical data of a crude oil, from which molecular models of asphaltene can be obtained. These models will be employed in this study for calculation of the association energy.

Two different asphaltene models were generated for two different crude oils (Oil 'A' and Oil 'M'). The potential of mean force (PMF) is calculated with two models of asphaltene molecules in liquid benzene for two kinds of asphaltenes using umbrella sampling method. The association energy is calculated by the difference between values at the lowest bottom of a trough and at infinity of the PMF curve. As the calculation conditions, temperature and pressure are 300 K and 100 bar, respectively.

The PMF profiles for asphaltenes from Oil 'A' and Oil 'M' were obtained, and the values of association energy were estimated as -8.39 kJ/mol and -8.91 kJ/mol, respectively. Two aromatic planes of asphaltene molecules are stacked with each other at the minimum energy point. This π-π stacking is one of the main interactions to form asphaltene nano-aggregation. The results of asphaltenes from Oil 'A' and Oil 'M' have a similar tendency; for example, the distance between the centers of mass of two asphaltenes at the minimum energy points factually equal.

The data obtained in this work should be used in the thermodynamic model of phase behavior of asphaltene dealing with asphaltene association and precipitation. It will improve the prediction ability of reservoir simulators with cubic-plus association equation of state.
Developing Strategies and Guidelines of Reservoir Data Acquisition Campaigns in One of the Major Operators in the North Field - Qatar
Authors: Al-Sharawy Mahmoud , Haidar Faesal Abdulla , Al-Medaihki Ali A , Al Meer Haytham Abdulaziz , Kandil Ahmed
Published: March 2015

Developing efficient strategies for reservoir data acquisition is a key aspect of reservoir surveillance that is highly valued by oil and gas operating companies. The purpose of reservoir data acquisition is to monitor well and reservoir properties such as flow capacity, skin damage around the wells as well as average reservoir pressure and production profiles in order to optimize and maintain well production.

Before 2009, Qatargas' reservoir data acquisition strategy was mainly based on applying Modified Isochronal Test (MIT), Production Logging Tool (PLT) and Bottom Hole Static Pressure (BHSP) surveys separately.

In this paper, we developed new data acquisition strategies and guidelines and compared with the old strategy. The major difference between the two is that the PLT, PBU (Pressure Build Up), multirate Flow-After-Flow (FAF) and static pressure gradient surveys are conducted in one well intervention operation in the new strategy compared with three interventions operations including PLT/PBU/static gradient, MIT and BHSP surveys in the old one. In addition, Reservoir Saturation Tool (RST), Electromagnetic Inspection Tool (EMIT) and Platform Multifinger Imaging Tool (PMIT) surveys are included in the new strategy to collect more information about the reservoir and well integrity. This is highly advantageous in terms of reducing the time and cost required for test performance. Unlike the old strategy, which requires extended shut in periods, the new strategy requires short shut in periods which result in reduced production loss. Furthermore, combining the various well tests in one operation give more practical workflow with minimized risks of repeated well intervention and maximized quantity of data gathering.

Based on our data acquisition experience at Qatargas, we belive that applying the new data acquisition strategy would add more value to the oil & gas industry in terms of reducing the operation risks, saving costs and collecting more data at the same time.

Introduction

The function of reservoir surveillance is to provide facts, information, knowledge and intelligence necessary1 to:Chronicle reservoir performance.Provide information on performance parameters to improve ability for prediction.Identify or anticipate barriers to meet or exceed forecast performance and provide methodologies to mitigate the impact.

Qatar's North field (NF) is one of the largest known non-associated gas fields in the world. It covers an area of approximately 6,000 square kilometers. The field was discovered in 1971. The first development drilling project was initiated in 1987 with the first production occurring in 1991.
Integration of the PLT and PBU Data in Permeability Modeling Workflow
Authors: Benlacheheb Mohamed , Al Meer Haytham Abdulaziz , Kandil Ahmed , Ross Fraser , Rimach Millagritos
Published: March 2015

Permeability prediction always constitutes a challenging step in the modeling process. Reservoir heterogeneity such as diagenesis, fracturing and effective connected geobodies are the main factors complicating the prediction. Hence, limiting permeability model to core data only could lead to unsatisfactory results while history matching. As consequence, poor reservoir performance prediction will be obtained. In such circumstance, further permeability enhancement using PBU and PLT data are usually needed.

The Core or log derived Permeability captures the heterogeneity around the wellbore whereas well test data describes the reservoir in accordance with the radius of investigation. In addition to that, the measured core permeability is absolute while the fluid flow in the reservoir is governed by the effective permeability which is captured by well test data.

Having the advantage of continuous monitoring program including PLT and PBU constitute a precious and considerable piece of data. These amounts of PLTs allow capturing the vertical heterogeneity in the reservoir while the PBU tests give better areal distribution of the KH test.

A ratio of KH test over KH core can be calculated and usually assumed as a good indicator of presence of fractures. In this case, an appropriate Discrete Fracture Network (DFN) model is required to build the permeability model. However, if the ratio is indicating matrix contribution a more simplistic approach can be applied and gives reasonable results.

By identifying the contributing intervals from PLT results coupled with the KH test over KH core ratio, the core permeability is then elevated to the test permeability.

The objective of this work is to present the application of this approach in different blocks in one giant gas field which shows improvement in the permeability prediction; results are supported by dynamic analytical model performance.

Introduction

Estimating effective permeability at reservoir scale is a challenging task especialy in carbonates due to the fact that their depositional process and the diagenetic history can be very complex, resulting in heterogeneity of the pore system. In addition to that, fractutres can occure in the reservoir leading to additional difficulties to characterize the permeability. As consequence of that, high permeability intervals can be developed at different scale, those streaks might not be captured by core and log data.
Extending the life of Brown Field Developments by Acoustic Impedance-Conditioned 3D Reservoir Modelling: An Example from a Mature Gulf of Suez Carbonate Producing Asset (Ras Fanar Field), Egypt
Authors: Vaughan Richard David
Published: March 2015

Discovered in April 1978, Ras Fanar Field in the Gulf of Suez of Egypt has delivered a total cumulative production of 114 MMSTB oil (Jan 2013) from Middle Miocene coralline algal buildups and laterally intercalated dolomitic layers within sabkhas deposits. OOIP was estimated to be 90 MMSTB in 1984.

This paper presents a simple but apparently effective 3D reservoir modelling workflow which used acoustic impedance (AI) data and its relationship to effective porosity as a deterministic 3D modelling parameter ("porosity-facies"). In 2002 an AI-conditioned model for the Ras Fanar Field was completed and a number of infill wells were successfully drilled within the main field which mediated the production decline of the field. Based on the model a number of higher risked drilling targets were subsequently identified to the west of the main field. The westward extension of the Ras Fanar field was confirmed by well RF-B10 in 2004. This well encountered the original field oil-water contact at 2450' TVDss despite 20 years production in the main field. The oil-water contact is thought to be in part influenced by secondary gas cap expansion which has "pushed" the oil column back to the original spill point.

Ras Fanar West development drilling has subsequently targeted lagoonal patch reef bodies landward of the main Ras Fanar Field "reef "trend. Each development well has been carefully positioned within the highest quality "porosity facies". The target locations have been optimised so that the reservoir is penetrated with the standoff from the gas-oil and oil-water contacts. Two phases of development have been successfully implemented, primarily based on the AI-conditioned reservoir model. Incremental production of 10 MMSTB has been achieved from the Ras Fanar West development area since 2004 and significant upside is still recognised.

Introduction

The Ras Fanar Field lies some 2 Km offshore east of from the town of Ras Gharib (Figure 1). The field comprises NW-SE trending structural trap bounded by a major fault system to the SW and tilted to the NE. The depositional setting of the reservoir comprises a 10–12 Km wide carbonate ramp which extends eastwards from Ras Gharib Field to Ras Fanar Field. The proposed sequence stratigraphic geological model allows for both lateral and vertical facies transitions between the Nullipore carbonates and South Gharib evaporitic-carbonate units. Several phases of upward-shoaling deposition are noted and main reef trend and patch reefs were periodically exposed as islands or raised beaches. Periods of subaerial exposure created high porosity layers (Super Permeability layers) within the reservoir resulting from karstification, solution collapse brecciation and possible mixing-zone dolomitisation. Diagenetic overprinting of the original facies was intense therefore a petrophysical-based modelling procedure was adopted (Figure 2).
Stable Fracturing Fluids From Waste Water
Authors: Kakadjian Sarkis , Thompson Joseph Earl , Torres Jose Roberto , Quintero H.
Published: March 2015

Environmental concerns and public opinion have elevated the visibility of hydraulic fracturing. Currently oil companies and operators acquire fresh water for fracturing treatments on the front end and pay to dispose or transport the flowback or produced water on the back end, increasing dramatically the cost of the hydraulic fracturing job. We report a newly developed fracturing fluid system utilizing 100% untreated produced water which eliminates the upfront costs of purchasing fresh water. In addition, the back end costs are significantly reduced by transporting produced and/or flowback water to locations for re-use rather than to disposal well(s) located miles away or even in other states.

This new system uses conventional gelling agents and crosslinkers used in active US shale plays, addressing the fracturing focus initiative.

This new fluid system was developed for temperature ranges between 120–300+ °F. Field tests prove shear stability and good proppant transport at 20 BPM through a 1.25 in sliding sleeve baffle. The fracturing fluid system can be designed for instant or delayed crosslinking in recycle water with total dissolved solids exceeding 300,000 mg/L with hardness exceeding 30,000 mg/L. Another concern in the past was the presence of boron in produced water. This system can be used in water containing boron levels exceeding 500 mg/L.

The code for recycle water has been broken utilizing this unique fracturing fluid system designed to conserve fresh water aquifers and recycle produced and flowback waters, reducing significantly disposal costs.

This paper reports laboratory testing of the fluid characteristics in untreated produced water from the Bakkenas well as the outcome of hybrid fluids in field applications, recommendations for field applications and economic impacts on fracturing fluid systems.
Challenge and Successful Application for Scale Removal in Oil Field, Egypt: Field Study
Authors: Hamdy Emad , Abu Bakr Mohamed , Abd El-Hay Ahmed , Sisostris Samir , Anwar Mohamed , El Farouk Omar
Published: March 2015

Water flooding is the hinge pin for Petrobel Oil Field. Water injection is supplied from shallow water supply wells. Compatibility tests, Petrographic Techniques and quantitative calculations of scale tendency using specific software had indicated probable deposition of calcium sulphate scale in the near-wellbore (Critical Matrix). Calcium sulphate scale, paraffin & was have been recognized to be a major operational problem. The bad consequences of scale formation& organic deposits comprised the contribution to flow restriction thus resulting in oil and gas production decrease. The nature of calcium sulphate scale is very hard and can't be dissolved with known dissolver. Sister companies that has similar problem were always going to the mechanical remover options which usually lead to further formation damage when invasion of formation rock by small particle sizes of the scale components.

Extensive lab and field work was conducted to determine the suitable chemicals to dissolve calcium sulphate scale.

The Production of Sidri formation which is currently contained 23 % of belayim land field OOIP (original oil in place) and currently contributes 27 % to the total oil production has been stopped dramatically in some wells.

Sidri formation exhibits a high degree of permeability, heterogeneity and increase water injection was done in some areas that lead to increase the possibility of forming scale, most of scale in Belayim onshore is calcium sulphate.

Precipitation of mixed organic/inorganic deposits (Calcium Sulfate Scale) resulted in decreasing the permeability in the critical matrix and perforation tunnels. Scale formed in the near-wellbore reduces oil production by blocking the narrow pore throats of the matrix itself

This paper highlights Petrobel first application by using the new innovation product SCSR in Belayim land field (Sidri formation), its success and results based on extensive lab studies, SCSR was tested and applied through an effective treatment strategy proposed to remove the scale efficiently; the program was designed taking into consideration the nature of the scale. Furthermore the proposed treatments were conducted and placed using coiled tubing (CT).
The Importance of Critical Flow Considerations in Understanding Jet Pump Performance: The Mangala Field
Authors: Verma Sumil Kumar , Ojha Shiv Prakash , Jha Mihir , Singh Aditya Kumar , Kefford Paul , Kumar Piyush , Tandon Rohit , Kumar Sunil , Prasad Dhruva , Singh Manjit Kumar
Published: March 2015

The Mangala field, located in Rajasthan, India, is characterized by multi-Darcy sandstones, containing waxy and viscous crude oil from which most of the production is being lifted using jet pumps. This is one of the largest applications of hot water jet pumping in the world. The earlier works presented on jet pumping by the operator highlight pump screening, design, monitoring, and operational challenges (Chavan et al-2012 and Singh et al-2013).During the jet pump design work over the years, it was observed that the field results were not matching with the design particularly for wells with relatively high free gas at the pump intake. It was realized that the physics of multiphase flow in critical flow conditions was not captured fully. This paper highlights the new approach taken to model jet pumps based on the theory presented by R.G. Cunningham (ASME, JFE 1995) which explicitly captures the effect of free gas entering the pump and the onset of critical flow. The approach taken to analyze the well and jet pump performance firstly involved evaluating each part of the well independently (sand face to pump suction, flow through the jet pump, and flow from the jet pump to surface).The availability of downhole gauges in a number of the Mangala wells allowed each component of the well performance to be analyzed and validated in isolation. A final complete mathematical model of the entire well was then developed to allow predictions of the hydraulic performance of the jet pumps to be made. This paper presents the above methodology and validation of results through field trials in the Mangala wells.

Introduction:

Jet pumps are widely used as a form of artificial lift due to numerous advantages like the absence of reciprocating parts which allows tolerance of power and a viscous production fluid can be produced. Another advantage is the compactness of working section and ability to attain variation in liquid rates with minimal variation in jet pump design. Disadvantages include the cost of infrastructure associated with requirement of high pressure power fluid which needs to be pumped downhole and increase in the liquid handling capacity required at plant level.

In the Mangala field where even the downhole flow assurance of the produced crude is a challenge due to the high wax content, jet pumps provide down-hole flow assurance by utilizing hot water as power fluid. They are also very convenient to install and retrieve with no workover cost required. These features and others as mentioned by Chavan et al. (2012) led to the field-wise use of jet pumps in Mangala.
RFEC PIG Designed for Long Distance Inspection
Authors: Mazraeh Ali Ahmadian , Alnaimi Firas B Ismail , Mohamed Sahari Khairul Salleh Bin
Published: March 2015

This paper presents an innovative approach for the design and development of Pipeline Inspection Gauge (PIG) which can inspect pipes from 15" up to 30" with a simple change of shirts using the latest technologies such as Electromagnetic Acoustic Transducer (EMAT) sensors as well as Remote Field Eddy Current (RFEC) sensors for oil pipes inspection, through the creation of a simulation tool capable of generating simulated images from pipeline using Inertial Navigation System (INS) for highest accuracy and precision inspection to protect the environment and equipment from any unexpected accident. There are several dynamo motors utilized to regenerate green efficient power from the flow of the medium inside the pipeline to elongate the distance of investigation by the mean of reduction of the number of individual pigging processes to save time and cost for companies. The INS uses accelerometers and gyroscopes of the type "Integrated Micro Electro-Mechanical Systems" (iMEMS), to carry out the mapping corresponding to the inspected pipes. Fluid hammer effect is another factor which has been considered during designing this pig. To avoid such case to occur the design has been revised and several arms have been devised around the robot to maintain the speed and position of pig all the way through the pipeline.

Introduction

Pipelines are considered to be the safest way for transportation of large amounts of liquid and gas over large distances. Pipelines are one of the cornerstones of modern civilization constituting an essential part of the infrastructure. More than 3 million kilometers of pipelines connect the reservoirs of oil and gas, the ports of shipment, the refineries and the storage facilities today. Non-destructive testing of the pipeline system by means of in-line inspection using intelligent pigs has become an important part of this system in ensuring its safe and economic operation. In order to prevent pipeline failure, any defect that may become critical has to be detected early enough. As most of the pipelines are buried and also covered by a protective coating, a complete inspection can only be done from the inside. This is achieved with in-line inspection using automated inspection systems called intelligent pigs (or smart pigs). The ultimate goal of this type of inspection is to detect a certain type of defect with a high Probability of Detection (POD) and to provide high resolution data that allow precise sizing of the detected defects. (WILLEMS, 2008)

Intelligent pigs are automated inspection systems which are usually designed such that one inspection tool is looking for a specific type of defect utilizing one technology. Table 1 shows an overview. The main inspection methods that are used are Magnetic Flux Leakage (MFL) and Ultrasonics (UT).
Gas Zone Shut-off by Wireline in Offshore Open- Hole Gravel Pack Completions
Authors: Lee Kean-Seng , Lima Jairo Da Costa
Published: March 2015

ExxonMobil has successfully executed two wireline through tubing Gas Shut-Off (GSO) workovers in high angle Open Hole Gravel Pack (OHGP) completions to isolate High Gas Oil Ratio (HGOR) zones that resulted in cost effective significant oil production increases. This paper summarizes the opportunity identification and production logging results, Gas Shut-Off concept, wellwork planning and execution, and production results.

The GSO workovers were on a Tension Leg Platform (TLP) in a deep water offshore field. Isolation of HGOR zones was achieved by installing a wireline deployed stackable straddle system across the heel of the OHGP interval. Both wells have OHGP completions for sand control but without External Casing Packers (ECP) to prevent flow through the gravel pack interval.

Modeling of an isolation straddle's effect on in-flow from the reservoir through the completion was performed. Results suggested that internal isolation could provide effective GSO without ECPs. Optimal straddle length was determined to minimize production from the HGOR zone while promoting production from low GOR zones. Surface tests were conducted for installation and retrieval of the completion equipment as well as integration and function of tools and equipment from multiple service companies. First well operation included the first use of coil tubing by ExxonMobil on a TLP for a workover to mill a downhole completion restriction.

Both wells went from being cycled to continuous and lower GOR production after the interventions. The first well produced 5,000 BOPD at 6,000 scf/B GOR during the cycling period and production increased to 10,000 BOPD at 1000 scf/B GOR after GSO. The second well produced 6,000 BOPD at 6,000 scf/B GOR during cycling and 10,000 BOPD at 500 scf/B GOR after GSO.
pH Measurement for Low Soluble Salts Monitoring in Monoethylene Glycol(MEG) Regeneration System
Authors: Jeon Yooil , Park Suyoul , Seo Yutaek , Ko Minsu
Published: March 2015

MEG (Monoethylene Glycol) is usually used as a gas hydrate inhibitor, and it is essential to regenerate and re-inject this into well because great amount of MEG is consumed to control the gas hydrate problems. MEG is recovered as rich MEG from the topside. Rich MEG is a water solution, which is about 50 wt% of MEG with rich water. This is regenerated as lean MEG through MEG regeneration process. Lean MEG is high concentration of MEG.

In the production of subsea oil and gas, formation water is also produced. Formation water contains salts1. This causes problem in MEG regeneration process. If problem arises, the whole process is stopped2. And it can result in tremendous loss. It is important to know the salts equilibrium under MEG regeneration conditions in order to prevent problems related to deposition and scale precipitation.

That is, MEG regeneration process is to separate water and salts from the mixed solution, which is composed of MEG, water, and salts. Using the difference in vapor pressure to separate water is called re-concentration and to separate salts is called reclamation process.

As it shows from figure 1 and figure 2, density of MEG solution increases along with increase of NaCl and MEG concentration. NaCl concentration was calculated from the conductivity. If MEG effect and salts effect are separated, assumption of MEG concentration is possible inversely. Sandengen introduced this method in his paper3.

But there is a limit to monitor the MEG system with only these results. Ions which are included within the formation water are Sodium (Na+), Potassium (K+), Calcium (Ca2+), Magnesium (Mg2+), Barium (Ba2+), Strontium (Sr2+), Iron (Fe2+), Chloride (Cl-), Sulfate (SO42-), Alkalinity as HCO3-, and Bromide (Br-) etc.1. Salts can be separated into low soluble salts and high soluble salts. High soluble salts are dissolved in water well like NaCl and KCl. Low soluble salts cannot be dissolved in water well like CaCO3 and MgSO44.

There are two methods in MEG regeneration. One is the full stream concept, and the other is slip stream concept5. Many studies were conducted to explain this process. In the full stream concept, high soluble salts and low soluble salts are not sorted. The reclamation process flashes the feed solution. In the slip stream concept, water is separated in the re-concentration process first, and then from part of it, high soluble salts are removed using flash. Core of this concept is to tolerate some of high soluble salts. On the other hand, since low soluble salts are at high risk of scale problems, it is removed in the pre-treatment process beforehand. Enough studies on low soluble salts need to be conducted. Only measurements of density and conductivity are not enough, and they have limits.
Pressure Buildup or Falloff Test Analysis for a Well in Commingled Reservoirs with Flow Rate Profile Logging
Authors: Lin Jia En
Published: March 2015

Description of layered reservoirs is important from a reservoir evaluation and management standpoint because layering affects primary and secondary oil recovery and large variations in permeability-thickness product or skin in different layers have great influence on well performance and production. Commingled reservoirs, where each layer has the same initial pressure without crossflow and layers may have distinct values for thickness, permeability, porosity, fracture half length and skin factor, have been investigated by many authors. Most of research work in multilayered well test analysis focus on estimating individual layer permeabilities, skin factors, fracture half length and formation pressures from well test data. But previous research work indicated that conventional buildup and drawdown(or falloff and injection) testing for wells in commingled reservoirs is only used for determining average reservoir parameters and could not be used for determining individual layer parameters in the absence of the use of the entire history of wellbore pressure and layer production.

This paper presents new testing and analysis techniques without using entire history of wellbore pressure and layer production to obtain individual layer permeabilities, skin factors, racture half length and formation pressures for a well in commingled reservoirs by using stabile flow rate data from flow profile tests acquired with production logging tools at the top of each layer before shutting-in the well and conventional pressure buildup or falloff data from the well. Before making any multilayer analysis, conventional well test analysis or type-curve analysis using log-log and derivative methods should be performed to estimate average permeability, ,fracture half length and skin factors of the total system. It can then be used as initial input values for simultaneous interpretation using an analytical model combined with nonlinear least squares estimation and type curves to estimate individual-layer permeabilities, skin factors, fracture half length and reservoir pressures. But If we use entire history of wellbore pressure and layer production, we can reduce the multiple solutions, to enhance the reliability of interpretation results.
Worshiping in Public: Theological Justice and the Res Publica in City of God 19
Authors: Morgan Brandon
Published: March 2015

Abstract:

In this article I trace an interpretation of City of God, book 19, that acknowledges the intrinsic relationship between Augustine's account of justice and worship within his critique of the Roman commonwealth. This interpretation of book 19 suggests that justice, defined theologically by Augustine, remains a necessary criterion for the existence of a truly public social community, which in turn limits the possibility of constructing an Augustinian politics divorced from the theological forms of critique that his account entails. The arguments of book 19 remain consistent with Augustine's overall attempt in the City of God to claim that the proper worship of the heavenly city (in which Israel and the Church are in direct lineage) mediates the only sufficient curative to the pursuits of glory and domination instantiated by the idolatries of the earthly city. This account more adequately acknowledges Augustine's theological commitments as the animators of his remarks about political entities while also questioning the sufficiency of any “political Augustinianism” that does not include the overall theological critique of City of God as among its primary purposes.
Maximizing Animal Theology: Maximus the Confessor on the Value of Non-Human Animals and the Human Calling
Authors: Hiuser Kris
Published: March 2015

Abstract:

This article adds to the growing body of work regarding the place of animals within Christian doctrine through engaging with the theological writings of Maximus the Confessor. In this article I shall do two things. First I shall argue that the theology of Maximus makes three claims that have significant bearing on how we can understand non-human animals: (1) all creatures made by God have an inherent worth and value based on God's creative and providential acts, as well as Maximus's logoi theology, (2) these same creatures are included in God's redemptive concerns, as shown by their presence within the shared goal of deification for all creation, and (3) humans have a unique calling in helping to achieve such redemption and this sanctifying role constitutes a necessary part of what it means to be human. Second, on the basis of these ideas I shall then demonstrate how such ideas create direct implications for how Christians might respond to intensive industrial farming of non-human animals, an institution that will be shown to be at great odds with the human calling toward sanctifying creation. Given such a state, the presence of factory farming is an institution that the theology of Maximus suggests is highly problematic and stands in need of serious ethical reflection.
Faith Matters: Towards a Public Missiology in the Midst of the Ecological Crisis
Authors: Fensham Charles
Published: March 2015

Abstract:

The article examines public missiology in the light of the ecological crisis by situating public missiology in the larger context of public theology. It responds to the challenge of finding ways for Christian communities to act in the light of climate change. It notes developments in public theology, as well as the rise and dominance of a consumer capitalist economic story that frustrates action for the integrity of God's creation. It identifies public missiology with a locus in public theology. It distinguishes public missiology as the discipline that involves the church in active engagement. Drawing on the seminal thought of David Bosch and the work of Gregory Leffel in public Christian activism, the article argues for five dimensions in public missiology, which are inextricably intertwined. They include a public disposition of ongoing repentance, a humble and prayerful engagement within Christian community, an active engagement with the ecological crisis in the world (evangelism in community), a public telling of the story of the meaning of God's creation (proclamation), and a call to turn toward action for the integrity of creation (conversion). Out of the interplay of these dimensions, through theological reflection and careful consideration of critical social theory, a new public missiological story is to be woven that can capture the imagination of people, both of faith and no faith, to action for a healed creation.
RETRACTED: Differential temporal expression of S100β in developing rat brain
Authors: Patro Nisha , Naik Aijaz , Patro Ishan K.
Published: March 2015

Radial glial cells (RGs) originally considered to provide scaffold to the radially migrating neurons constitute a heterogeneous population of the regionally variable precursor cells that generate both neurons as well as glia depending upon the location and the timing of development. Hence specific immunohistochemical markers are required to specify their spatiotemporal location and fate in the neurogenic and gliogenic zones. We hypothesize S100β as a potential and unified marker for both primary and secondary progenitors. To achieve this, cryocut sections from rat brains of varied embryonic and postnatal ages were immunolabeled with a combination of antibodies, i.e., S100β + Nestin, Nestin + GFAP and S100β + GFAP. A large population of the primary and secondary progenitors, lining the VZ and SVZ, simultaneously co-expressed S100β and nestin establishing their progenitor nature. A downregulation of both S100β and nestin noticed by the end of the 1st postnatal week marks their differentiation towards neuronal or glial lineage. In view of the absence of co-expression of GFAP (glial fibrillary acidic protein) either with S100β or nestin, the suitability of accepting GFAP as an early marker of RG’s was eliminated. Thus the dynamic expression of S100β in both the neural stem cells (NSCs) and RGs during embryonic and early neonatal life is associated with its proliferative potential and migration of undifferentiated neuroblasts and astrocytes. Once they lose their potential for proliferation, the S100β expression is repressed with its reemergence in mature astrocytes. This study provides the first clear evidence of S100β expression throughout the period of neurogenesis and early gliogenesis, suggesting its suitability as a radial progenitor cell marker.
Effects of Alpha Particle and Proton Beam Irradiation as Putative Cross-Talk between A549 Cancer Cells and the Endothelial Cells in a Co-Culture System
Authors: Riquier Hélène , Abel Denis , Wera Anne-Catherine , Heuskin Anne-Catherine , Genard Géraldine , Lucas Stéphane , Michiels Carine
Published: March 2015

Background: High-LET ion irradiation is being more and more often used to control tumors in patients. Given that tumors are now considered as complex organs composed of multiple cell types that can influence radiosensitivity, we investigated the effects of proton and alpha particle irradiation on the possible radioprotective cross-talk between cancer and endothelial cells. Materials and Methods: We designed new irradiation chambers that allow co-culture study of cells irradiated with a particle beam. A549 lung carcinoma cells and endothelial cells (EC) were exposed to 1.5 Gy of proton beam or 1 and 2 Gy of alpha particles. Cell responses were studied by clonogenic assays and cell cycle was analyzed by flow cytometry. Gene expression studies were performed using Taqman low density array and by RT-qPCR. Results: A549 cells and EC displayed similar survival fraction and they had similar cell cycle distribution when irradiated alone or in co-culture. Both types of irradiation induced the overexpression of genes involved in cell growth, inflammation and angiogenesis. Conclusions: We set up new irradiation chamber in which two cell types were irradiated together with a particle beam. We could not show that tumor cells and endothelial cells were able to protect each other from particle irradiation. Gene expression changes were observed after particle irradiation that could suggest a possible radioprotective inter-cellular communication between the two cell types but further investigations are needed to confirm these results.
Load Frequency Control in Isolated Micro-Grids with Electrical Vehicles Based on Multivariable Generalized Predictive Theory
Authors: Yang Jun , Zeng Zhili , Tang Yufei , Yan Jun , He Haibo , Wu Yunliang
Published: March 2015

In power systems, although the inertia energy in power sources can partly cover power unbalances caused by load disturbance or renewable energy fluctuation, it is still hard to maintain the frequency deviation within acceptable ranges. However, with the vehicle-to-grid (V2G) technique, electric vehicles (EVs) can act as mobile energy storage units, which could be a solution for load frequency control (LFC) in an isolated grid. In this paper, a LFC model of an isolated micro-grid with EVs, distributed generations and their constraints is developed. In addition, a controller based on multivariable generalized predictive control (MGPC) theory is proposed for LFC in the isolated micro-grid, where EVs and diesel generator (DG) are coordinated to achieve a satisfied performance on load frequency. A benchmark isolated micro-grid with EVs, DG, and wind farm is modeled in the Matlab/Simulink environment to demonstrate the effectiveness of the proposed method. Simulation results demonstrate that with MGPC, the energy stored in EVs can be managed intelligently according to LFC requirement. This improves the system frequency stability with complex operation situations including the random renewable energy resource and the continuous load disturbances.
Achieving Conservation and Equity amidst Extreme Poverty and Climate Risk: The Makira REDD+ Project in Madagascar
Authors: Brimont Laura , Ezzine-de-Blas Driss , Karsenty Alain , Toulon Angélique
Published: March 2015

Achieving forest conservation together with poverty alleviation and equity is an unending challenge in the tropics. The Makira REDD+ pilot project located in northeastern Madagascar is a well-suited case to explore this challenge in conditions of extreme poverty and climatic vulnerability. We assessed the potential effect of project siting on the livelihoods of the local population and which households would be the most strongly impacted by conservation measures. Farmers living in hilly areas must resort to slash-and-burn agriculture (tavy) since a combination of topographic and climatic constraints, such as cyclones, makes permanent rice cultivation very difficult. These are the people who suffer most from conservation-related restriction measures. For practical reasons the project, unfortunately, did not target these farmers. The main focus was on communities with a lower cyclonic risk that are able to practice permanent rice agriculture in the lowlands. To reduce deforestation without violating the principles of equity, REDD+ projects in Madagascar need to better target populations facing high climatic risks and invest in efforts to improve the farmers’ agricultural systems.
On the Road to HIV/AIDS Competence in the Household: Building a Health-Enabling Environment for People Living with HIV/AIDS
Authors: Masquillier Caroline , Wouters Edwin , Mortelmans Dimitri , Van Wyk Brian
Published: March 2015

When aiming to provide chronic disease care within the context of human resource shortages, we should not only consider the responsibility of the individual person living with HIV/AIDS (PLWHA) but also the capacity of the social environment to actively encourage a lifestyle that fosters health. In this social environment, extensive efforts are thus required to increase HIV/AIDS knowledge, reduce stigma, stimulate HIV testing, improve health care-seeking behavior, and encourage safe sexual practices—described in the literature as the need for AIDS competence. In accordance with socio-ecological theory, one cannot restrict the research focus to communities, as AIDS competence studies should also incorporate the intermediate household level. In responding to this research need, the aim of this article is to conceptualize an “HIV/AIDS competent household” based on qualitative interviews and focus group discussions conducted in a township on the outskirts of Cape Town, South Africa. Our results show that a household’s supportive response to disclosure allows a patient to live openly as HIV positive in the household concerned. This may mark the start of the road to HIV/AIDS competence in the household, meaning the PLWHA receives sustainable support throughout the care continuum and positive living becomes the norm for the PLWHA and his or her household. A feedback loop might also be created in which other household members are encouraged to be tested and to disclose their status, which is an important step towards a sustainable response to HIV/AIDS-related challenges. Despite the fact that this road to HIV/AIDS competence at the household level is fragile and prone to various barriers, this article shows that the household has the potential to be a health-enabling environment for PLWHA.
A Sensor Web-Enabled Infrastructure for Precision Farming
Authors: Geipel Jakob , Jackenkroll Markus , Weis Martin , Claupein Wilhelm
Published: March 2015

The use of sensor technologies is standard practice in the domain of precision farming. The variety of vendor-specific sensor systems, control units and processing software has led to increasing efforts in establishing interoperable sensor networks and standardized sensor data infrastructures. This study utilizes open source software and adapts the standards of the Open Geospatial Consortium to introduce a method for the realization of a sensor data infrastructure for precision farming applications. The infrastructure covers the control of sensor systems, the access to sensor data, the transmission of sensor data to web services and the standardized storage of sensor data in a sensor web-enabled server. It permits end users and computer systems to access the sensor data in a well-defined way and to build applications on top of the sensor web services. The infrastructure is scalable to large scenarios, where a multitude of sensor systems and sensor web services are involved. A real-world field trial was set-up to prove the applicability of the infrastructure.
Prediction of Long-Term Treatment Response to Selective Serotonin Reuptake Inhibitors (SSRIs) Using Scalp and Source Loudness Dependence of Auditory Evoked Potentials (LDAEP) Analysis in Patients with Major Depressive Disorder
Authors: Lee Bun-Hee , Park Young-Min , Lee Seung-Hwan , Shim Miseon
Published: March 2015

Background: Animal and clinical studies have demonstrated that the loudness dependence of auditory evoked potentials (LDAEP) is inversely related to central serotonergic activity, with a high LDAEP reflecting weak serotonergic neurotransmission and vice versa, though the findings in humans have been less consistent. In addition, a high pretreatment LDAEP appears to predict a favorable response to antidepressant treatments that augment the actions of serotonin. The aim of this study was to test whether the baseline LDAEP is correlated with response to long-term maintenance treatment in patients with major depressive disorder (MDD). Methods: Scalp N1, P2 and N1/P2 LDAEP and standardized low resolution brain electromagnetic tomography-localized N1, P2, and N1/P2 LDAEP were evaluated in 41 MDD patients before and after they received antidepressant treatment (escitalopram (n = 32, 10.0 ± 4.0 mg/day), sertraline (n = 7, 78.6 ± 26.7 mg/day), and paroxetine controlled-release formulation (n = 2, 18.8 ± 8.8 mg/day)) for more than 12 weeks. A treatment response was defined as a reduction in the Beck Depression Inventory (BDI) score of >50% between baseline and follow-up. Results: The responders had higher baseline scalp P2 and N1/P2 LDAEP than nonresponders (p = 0.017; p = 0.036). In addition, changes in total BDI score between baseline and follow-up were larger in subjects with a high baseline N1/P2 LDAEP than those with a low baseline N1/P2 LDAEP (p = 0.009). There were significantly more responders in the high-LDAEP group than in the low-LDAEP group (p = 0.041). Conclusions: The findings of this study reveal that a high baseline LDAEP is associated with a clinical response to long-term antidepressant treatment.