bluuebunny/crossref_metadata_2025_split huggingface dataset:
Advantages of Up-Dip Water-Miscible Gas Injection
Authors: Namani Mehran , Høier Lars , Kleppe Jon 
Published: June 2014

Abstract
In this study a numerical reservoir model has been built using synthetic reservoir and fluid characteristics which can reflect realistic conditions in a field scale process. The miscibility conditions are considered to be fulfilled. The model has been implemented to investigate the behavior of up-dip water-miscible gas injection in terms of volumetric sweep efficiency.
The phenomenon of up-dip water-miscible gas injection has been analyzed using analytical methods to check the accuracy of computed segregation distance. To be able to use an analytical method for estimating complete segregation distance, the relative mobility of gas and water in the mixed zone versus water-gas ratio has been calculated using Buckley-Leverett theory. The resulting volumetric sweep in a dipping model is also compared to a horizontal model with the same properties to verify the analytical results which show the up-dip water-miscible gas injection can have a good volumetric sweep, even better than a horizontal model. Afterwards, a sensitivity analysis has been carried out to check if the nature of the phenomenon is similar to that for horizontal models. The extent of the gas-water mixed zone, the permeability pattern, layering and anisotropy in permeability, WAG ratio, total injection rate and prior gas injection are the parameters that have been studied for this part.
Even though stable up-dip miscible gas injection gives an inspiring volumetric sweep, common heterogeneities in the reservoirs which can result in viscous tonguing and fingering frequently prohibit this to happen. However, up-dip water-miscible gas injection may be an alternative method that is quite efficient and economical as compared with miscible-gas injection.
Pore Scale Modeling of Brine Dependent Pore Space Evolution in Carbonates
Authors: Pedersen Janne , Vinningland Jan Ludvig , Jettestuen Espen , Madland Merete Vadla , Hiorth Aksel 
Published: June 2014

Abstract
Rock fluid interactions play a crucial role in chemical EOR methods. Possible EOR methods are usually screened at core scale before being considered for implementation on field scale. It is therefore essential to have reliable methods for interpreting core scale experiments and to extract relevant parameters to be used in field scale investigations. In general, core scale experiments targeting rock-fluid interactions are not easy to interpret by standard Darcy scale models. In this paper we present a pore scale lattice Boltzmann model that is capable of simulating fluid flow in the pore space while interacting with individual rock minerals to induce mineral precipitation and/or dissolution causing dynamical changes in the pore space geometry. We discuss different mineral growth models, and compare chemical flooding lattice Boltzmann simulations with core scale experiments. The pore scale model we present in this paper can only be qualitatively compared with experiments, but we demonstrate that by incorporating mineral growth we are able to capture important trends in the experimental data which is not possible by using standard rate equations in combination with Darcy scale models.
Enhance of Oil Production from an Old Well in Thin Carbonate Reservoir through Acid Tunneling - A Case Study
Authors: Siddiqui M. A. , Sharma S. S. , Al-Ajmi M. F. , Hassan M. O , Ashkanani F. H. , Al-Bahar Z. A. , Zaki H. , Lounas L. 
Published: June 2014

Abstract
The effectiveness of stimulation using hydrochloric acid in high permeability, fractured carbonate reservoir is a challenge due to several reasons like fast acid spending rates, high leak off and non-effective diversion. All these limit the success rate of matrix stimulation using hydrochloric acid. Ultimately the communication between reservoir and wellbore will be less optimum leading to less than expected well performance. The industry is in continuous search of an effective stimulation technique through which good communication between reservoir and wellbore can be established.
In the pursuit of maximizing oil production, Kuwait Oil Company is implementing various new technologies. Recently, acid tunneling technology was piloted in an old producer well in one of its prolific yet challenging Mauddud carbonate reservoir. Acid tunneling is a new approach of stimulation that supersedes normal matrix stimulation in carbonate reservoirs to enhance reservoir contact by creating tunnels through dissolution of rock in acid.
Mauddud is a super-giant depletion-drive oil reservoir in NK field undergoing massive development efforts with enhancement in oil production through phased pattern-water flood. The reservoir has 10 layers and the average permeability of the reservoir ranges between 15 md to 1D predominantly due to fractures and vugs, which are distributed and extended variedly from layer to the other.
The acid tunneling pilot was performed in an old well in Mauddud limestone located in south-eastern part of Raudhatain field where the rock quality is poor compared to the crestal area. The well was selected for pilot due to poor production. The well does not enjoy injection support due to a sealing fault between it and an injector, lying a kilometer away. The well penetrated three layers A, B and C in Mauddud.
Two tunnels of 25 ft each were created using 15% HCl acid. The well showed good production after acid tunneling job and the productivity index of the well increased three times. The well is still showing good performance even after one year. These pilot results lead to full scale field implementation of this technology. The paper presents a case study describing advantages of acid tunneling, well selection criteria for this technology application, selection of effective acid concentration for the job and also limitations of the technology. All these informations work as a guideline to implement this technology in mass scale.
Global Sensitivity Analysis for Natural Fracture Geological Modeling Parameters from Pressure Transient Tests
Authors: Morton K. L. , Booth R. J. , Chugunov N. , Biryukov D. , Fitzpatrick A. , Kuchuk F. J. 
Published: June 2014

Abstract
We have observed that pressure transient data gathered in most naturally fractured reservoirs tend not to exhibit the well-known characteristic behavior, including pressure derivative, of the Warren and Root (1963) dual-porosity reservoir model. In reality, there are a rich variety of flow regimes dependent on the fracture distribution, spatial intensity and fracture conductivity. A semi-analytical solution for pressure transient behavior of fractured reservoirs has recently been presented that can be used to model the pressure response of formations with an arbitrary fracture distribution, density, and conductivity. The fractured system can be distributed discretely or continuously (network) with conductivities ranging from very low to infinite. Using the semi-analytical solution for fractured reservoirs, we perform a sensitivity analysis to identify which reservoir and geological parameters can be estimated from pressure transient test data collected from single or multiple well locations.
We employ principal component analysis to explore the model parameterization as a pre-screening step. The global sensitivity analysis (GSA) methodology is then employed to determine how the uncertainty of each parameter influences the uncertainty in the output from the reservoir model. This methodology avoids the need to apply a linearized model. Our results indicate that near-wellbore region fracture conductivities have the largest contribution to the total variance of the ensemble of output pressure responses whether the well intersects fractures or not. While this is an intuitive result, GSA indicates that this parameter may be estimated independently from other geomodeling parameters unlike interpretations based on the dual-porosity pressure transient solutions. This study describes how GSA is used to design a pressure transient well test for uncertain reservoir parameters.
A Model for Brine-Dependent Spontaneous Imbibition Experiments with Porous Plate
Authors: Andersen Pål ØstebØ , Ahsan Rajib , Evje Steinar , Bratteli Fred , Madland Merete , Hiorth Aksel 
Published: June 2014

Abstract
Spontaneous imbibition can be an important oil recovery mechanism, especially in water wet fractured reservoirs. Lab tests have shown that oil recovery from chalk core plugs by spontaneous imbibition can be highly dependent on the composition of the in situ brine and the imbibing brine. This is interpreted such that species in the brine are able to influence the oil-water-rock chemistry and alter the wettability of the rock from mixed-wet towards more water-wet. Especially this is reflected in a shift in capillary pressure curves, relative permeability curves and residual saturations. In recent works experiments have been performed on chalk cores to measure brine-dependent capillary pressure curves using the porous plate method. Solutions of NaCl and Na2SO4 at same ionic strength were used as initial and imbibing brine in different configurations. It seems sulfate has the potential to alter the wettability by adsorbing on the chalk rock surface. Especially, the oil recovery systematically increased with the amount of sulfate in the system.
In this paper we present a model for these porous plate imbibition experiments to relate oil-recovery to the brine composition. As input we use measured properties of materials and fluids and the determined capillary pressure curves representing the more water-wet and more oil-wet states. Wettability alteration is incorporated by shifting the brine-dependent parameters according to the amount of adsorbed sulfate. At first we match the recovery profiles at fixed wetting states as given by systems with and without fixed concentrations of sulfate corresponding to more or less water-wet, respectively. Then we use the model to match an experiment where wettability shifts towards more water-wet as given by introducing sulfate to a system (where NaCl is the initial brine) by imbibing with Na2SO4 brine. The history-matching is done by comparing oil recovery profiles at different pressures. Ultimately, we make some predictions of how brines with varying sulfate concentration can affect the wettability and more importantly, the oil recovery.
Secondary and Tertiary Low Salinity Water Floods: Experiments and Modeling
Authors: Fjelde Ingebret , Asen Siv Marie , Omekeh Aruoture , Polanska Anna 
Published: June 2014

Abstract
Change of injection brine composition from high to low salinity has been reported to improve the oil recovery in some field pilots and core flooding studies. In other studies low salinity water flooding (LSWF) has not been successful. It has also been reported that LSWF can be successful in secondary floods but not in tertiary floods.
The main objective for the reported study has been to investigate the oil recovery and cation concentrations in effluent samples during secondary and tertiary LSWF experiments using brines of different compositions. These results have been combined with evaluation of cation exchange during these floods by simulations and history matching to estimate the saturation functions.
When diluted formation water (LSW2) was injected in secondary floods, the oil production was only slightly higher than the total oil production during secondary flooding with formation water (FW) followed by tertiary flooding with LSW2. In the secondary flood with LSW2 the oil was produced during a long period, and wettability alteration appeared to occur during the flood. LSW2 was also found to give less water-wet conditions than FW. When LSW2 was injected to a core aged with LSW2, the oil production was slow and rather low remaining oil saturation was obtained. In a secondary flood with optimized low salinity water composition selected based on evaluation of cation exchange on clay surfaces, the oil recovery was found to be faster than in the secondary LSWF with LSW2 (diluted FW). By modeling of the cation exchange in the flooding experiments, it was found that the change in oil recovery profile can be explained with the change in the concentrations of divalent cations on the clay surfaces.
It is concluded that the potential for secondary and tertiary LSWF, will strongly depend on the compositions of rock, FW and LSW. The potential for tertiary LSWF will also strongly depend on the composition of the high salinity brine injected in the secondary flood.
Modeling of cation exchange during the reservoir history can be used to evaluate the potential for LSWF of the oil reservoirs and to optimize the LSW compositions.
Effects of carbon dioxide leakages on shallow aquifer properties
Authors: Tsakiroglou C. D. , Aggelopoulos C. A. , Terzi K. A. , Bountas I. 
Published: June 2014

Abstract
The mineralogy of well-sorted silica sand is modified by mixing it with an aqueous solution of metal (Fe, Mn, Cu, Co, Ni, Cr, Zn, Cd) salts and increasing very slowly the pH so that insoluble metal oxides/hydroxides co-precipitate on sand grains. The modified sand is packed in two fixed-bed columns saturated with water which is injected at a constant and low influx rate. In the one column, gas CO2 is co-injected at a flow rate that is one order of magnitude higher than that of water, while the flow test in the other column is used as control experiment. The pressures drop across the aqueous and gas phases are recorded continuously to track any potential changes of the (column averaged) relative permeabilities. Water effluent samples are collected to measure physicochemical parameters (e.g. pH, conductivity, etc) and metal cation concentration by atomic absorption spectroscopy. The mineralogy of sand is identified with scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and quantified with atomic absorption spectroscopy. The kinetics of CO2 dissolution and aqueous phase acidification along the porous medium is simulated under conditions of constant and uniform distribution of water saturation. The highest rates of metal cation release, due to geochemical solid/aqueous phase reactions, are observed during the initial and transient phase of the experiment as the CO2 dissolution and water acidification have not yet been completed, whereas the fluid saturation and relative permeability change respectably. The CO2 dissolution rate is enhanced as the water saturation decsreases due to the higher specific interfacial area.
Socio Economic Challenges of Shale Gas Developments in Europe
Authors: Heinz Walter 
Published: June 2014

Abstract
In Europe, the exploration of shale gas resources has just started, but with the exception of Poland most activities have been halted or delayed because of stakeholder concerns about environmental risks of hydraulic fracturing. With examples from Poland and Germany, the paper summarizes these socio-economic challenges, covers the sensitive dialogue of technical experts with non-technical stakeholders, discusses suggestions on how to address perceived versus real environmental risks, and concludes with an outlook on how these constraints may be overcome so that shale gas developments in Europe may proceed.
According to published stakeholder concerns and media coverage in Europe, most of the concerns are linked to a perceived risk of groundwater contamination through the use of chemicals during hydraulic fracturing, or the release of methane or induced seismicity. Based on an analysis of perceived versus real environmental risks, and how they have been addressed in the media, suggestions for a re-focus of stakeholder communication and management are drawn.
Operators might be well advised to develop a collaborative strategy to overcome stakeholder concerns in an industry with a poor reputation and biased media coverage. The paper provides suggestions for such a strategy refocus with the objectives of creating stakeholder acceptance and gaining supporters. Elements of this are full disclosure of project information, stakeholder engagement and education, promotion of shale gas benefits, and avoidance of environmental and health & safety impacts.
The critical public discussions in Europe have not only halted or delayed shale gas developments, they have also impacted industry reputation in the region, including conventional oil and developments, as well as other industries. Stakeholder acceptance has thus become the dominant challenge of shale gas developments. It is therefore crucial for the operators and partners to collaboratively invest in promotion, information, and education. This in return will balance biased media coverage, and gain trust and acceptance, thus allowing for further shale gas developments in Europe.
Environmental Baseline Assessment of a Large Natural Area in Southern Italy
Authors: Remonti Michele , Azzolini Stefano 
Published: June 2014

Abstract
An environmental baseline study has been conducted in a large (370 km2) natural and remote area of Southern Italy on behalf of an International Oil Company (IOC) to verify the potential impact of exploration and production activities. The territory is mainly mountainous and covered by forests, with limited human pressures and significant biodiversity.
The study has been undertaken over a period of approximately one year. Four seasonal field campaigns have been conducted, to investigate the chemical quality of soil, waters (springs, rivers and groundwater), air and the ecological and functional quality of the river environments, with the definition of EBI (Extended Biotic Index), WSI (Wild State Index) and BSI (Buffer Strip Index). The study comprised a complex data analysis, with the use of statistical, hydrochemical and geochemical methods.
Chemical analyses showed an unexpected presence of heavy metals in all the environmental matrices. Statistical and geochemical methods have been applied to evaluate this result. Principal Components Analysis (PCA) has been used to simplify and aggregate the original information with a repeatable and defensible method. Geochemical interpretation of soil sample test results was undertaken to investigate correlation of heavy metal concentrations with parameters unlikely to have been affected by human activities, such as Iron and Aluminum concentrations which are widely diffused in natural soils, and with silt and clay abundance. Undisturbed bedrock samples have also been collected and analyzed, to make a comparison with the concentrations found in soil samples. The statistical and geochemical methods applied helped to interpret the natural background abundance of heavy metals.
The aim of the project was to establish an environmental baseline for due diligence purposes in a exploration site and to demonstrate that the unexpected heavy metals concentrations measured in soil and water probably have a natural origin. The application of such methods can be of general interest at exploration and production sites to define the environmental baseline prior to the beginning of the development activities.
Identification and Management of Environmentally Critical Elements (First Technical Guidance on ECE's)
Authors: Stewart Cameron , Hayes Sean 
Published: June 2014

Abstract
Despite stringent environmental legislation and the significant reputational impacts of environmental incidents, there are no industry standards specifically aimed at identifying or managing the equipment that prevents such incidents from occurring, A drive towards defining Environmentally Critical Elements (ECEs) has emerged in response to environmental incidents where, in spite of other management systems being in place, incidents have occurred that could have been prevented by systematic analysis and management of the equipment involved. Managing known environmental risks and identifying latent risks will be a major step to improve future performance.
New Guidance has been developed that addresses this gap directly. The development of this guidance constitutes a significant, positive initiative by the industry in the management of environmental risks and incorporates global learning from recent significant environmental incidents. The guidance provides a tool, primarily for offshore operators, drilling rigs and service companies, as well as onshore oil and gas processing terminals to take a structured approach to identify and manage ECEs. However, this approach can be equally applied to wider non-oil & gas industrial sectors. The guideline supports the existing UK regulatory regime and is aligned with applicable international standards such as ISO 14001.
The paper discusses the Guidance in detail covering key concepts such as the ‘environmental event’ - a major environmental hazard where specific controls are required to manage the associated risks – as well as focusing on further key issues such as defining thresholds for environmental events and identifying performance standards.
The paper summarises the full coverage and application of the Guidance as well as the methodology behind its generation and discusses the processes of Assurance, Verification, Implementation and Change Management and how ECE’s should be treated at key management and operational stages. In this new and unique document good practice is set out for the development of a system to enable industry to perform these tasks through a common approach.
A Universal Cultural Change Program to Connect With People Everywhere
Authors: Scotti Davide 
Published: June 2014

Abstract
This paper will share the story of a successful Leadership program that transformed thousands of leaders in Saipem and contributed to shape a strong health & safety culture in a global and multicultural organization.
It is a leadership in health & safety program that is internationally recognized as world class and has entered its fifth year of implementation into a global and multicultural organization like saipem and now through a no-profit Foundation is being shared and implemented by other organizations who want to achieve the next level of safety performance.
But what challenges an organization must face in order to successfully create cultural change towards safety?
Putting the Person in Process Safety
Authors: Bowen Mathew 
Published: June 2014

Abstract
The current thinking in the field of workplace safety distinguishes between process safety and person safety (i.e., the human factors). In actuality, people and their attitudes and behaviours are critical for process safety. If a process safety initiative is conceptualised similarly to other organisational interventions, people play a significant role in determining the success of a process safety initiative. To illustrate this concept, this presentation demonstrates how applying key concepts from the disciplines of Organisational Psychology (e.g., change management), Social Psychology (e.g., team dynamics), and Neuroscience (e.g., thinking patterns and habits) can make process safety initiatives more effective.
Process safety is an important piece of the workplace safety jigsaw puzzle. By integrating this piece with the people piece, the effectiveness of process safety initiatives can be improved. This presentation will challenge attendees’ current assumptions about the role of people in process safety.