bluuebunny/crossref_metadata_2025 huggingface dataset:
The Formation and Chemical Nature of Amorphous Dithiazine Produced From Use Of Hexahydrotriazine Based Hydrogen Sulfide Scavengers and the Use of an Alternative Scavenger to Minimize Solid Formation in Sour Gas Applications
Authors: Taylor Grahame N. , Prince Philippe , Matherly Ron , Ponnapati Ramakrishna , Tompkins Rose , Panchalingam Vaithilingam , Jovancicevic Vladimir , Ramachandran Sunder
Published: June 2014

The most commonly used hydrogen sulfide (H2S) scavengers, hexahydrotriazines, are cost effective, efficient solutions to sour gas treatment. As the product consumes H2S and the by-product concentration increases, very often solid deposits occur, the most problematic of which is "amorphous dithiazine". It is produced from a solution of, for example, tris-(2-hyroxyethyl)-hexahydro-s-triazine. Recent findings have confirmed that this material is not a different physical form of the monomeric dithiazine but rather a polymeric structure which results from opening of the dithiazine ring. Evidence is presented here for the first step in this polymerization reaction. Thereafter, a ring opening of the dithiazine occurs to yield a polymeric, highly insoluble material. It has been observed that the critical chemical species in the initiation of this chain reaction is the bisulfide anion that is produced from the reaction of H2S with ethanolamine liberated in the sulfur insertion reaction undergone by tris-(2-hyroxyethyl)-hexahydro-s-triazine. This process has been artificially induced by the reaction of monomeric or crystalline 5-hydroxyethyl dithiazine and ethanolammonium hydrosulfide. It is hoped that a better understanding of the chemical process giving rise to this intractable solid will enable more efficient, environmentally favorable disposal of the waste fluids and, at best, total avoidance of this undesirable condition.

A novel approach to address this issue of troublesome solids, the use of an alternative scavenger type, is presented in this paper. The disposal of the waste fluids was a key issue in our consideration since the disposal of spent triazine based scavenger fluids is becoming ever more challenging and costly. Scaling tendencies at high pH is another issue for any new scavenger and plays a key role in the method of waste fluid disposal. Recent field trial data are also presented to demonstrate the efficacy of the new scavenger.
Integrated Rock-Typing with Capillary Pressure Curve Clustering
Authors: Fournier Frédérique , Fabre Gilles , Aug Christophe
Published: June 2014

This paper proposes a new methodology for an automatic classification of capillary pressure curves in order to build petrophysical rock-types which, in a second step, are compared to lithofacies for ensuring consistent and significant connection between lithological and petrophysical characteristics. The methodology is based on a pattern recognition strategy, where the curves to be classified are described by a certain number of features. In our approach, the features are derived using a principal component analysis applied to the series of capillary pressure curves under analysis. They correspond to the correlation coefficients of the principal components with the curves that should be classified. Other types of curves could be classified with this approach, for example curves of pore size distribution. This methodology is discussed through an application to the rock-typing of a clastic reservoir, and it is shown that relevant rock-types were obtained based on this classification approach. It is also shown that the classification helps in better quantifying the correspondences between the rock-types and the lithofacies.
A Novel Infinite-Acting-Radial-Flow Analysis Procedure for Estimating Permeability Anisotropy From an Observation-Probe Pressure Response at a Vertical, Horizontal, or Inclined Wellbore
Authors: Onur M.. , Hegeman P.S.. S. , Gök I.M.. M.
Published: June 2014

This paper presents a new infinite-acting-radial-flow (IARF) analysis procedure for estimating horizontal and vertical permeability solely from pressure-transient data acquired at an observation probe during an interval pressure-transient test (IPTT) conducted with a single-probe, dual-probe, or dual-packer module. The procedure is based on new infinite-acting-radial-flow equations that apply for all inclination angles of the wellbore in a single-layer, 3D anisotropic, homogeneous porous medium. The equations for 2D anisotropic cases are also presented and are derived from the general equations given for the 3D anisotropic case. It is shown that the radial-flow equation presented reduces to Prats' (1970) equation assuming infinite-acting radial flow at an observation point along a vertical wellbore in isotropic or 2D anisotropic formations of finite bed thickness.

The applicability of the analysis procedure is demonstrated by considering synthetic and field packer/probe IPTT data. The synthetic IPTT examples include horizontal- and slanted-well cases, but the field IPTT is for a vertical well. The results indicate that the procedure provides reliable estimates of horizontal and vertical permeability solely from observation-probe pressure data during radial flow for vertical, horizontal, and inclined wellbores. Most importantly, the analysis does not require that both spherical and radial flow prevail at the observation probe during the test.
Kashagan Field Approaching Production Start-Up: Insight Into Reservoir Characteristics
Authors: Albertini C. , Bado L. , Calabrese M. , Francesconi A. , Leoni G. , Tarantini V.
Published: June 2014

Since field discovery, several studies have been performed in order to estimate the reservoir characteristics. In fact data collection has allowed a better understanding of this complex carbonate reservoir, although uncertainties still remain. The first step of production ramp-up will achieve 180,000 stb/d, actually constrained by the gas handling capacity. The production will be delivered by wells located in the D and A islands, whose potential exceeds this production target. Platform Interior wells performance has been defined through a Reservoir-Rock-Type petro-physical characterization matching well test data while Rim wells, characterized by outstanding performances, have been modeled trying to represent the very complex framework constituted by rock-matrix, karst features and fractures. The second ramp-up at 370,000 stb/d will be achieved by the expansion of the gas handling capacity through the start of gas injection applied to the Platform Interior. This phase will rely on the conversion of four D island producers into injectors: their injectivity will be affected by the maximum gas injection pressure, constrained by the cap-rock integrity and the reservoir pressure draw-down achieved during the initial pre-depletion. The gas injection effectiveness will be affected by Platform Interior heterogeneity and by the possible presence of a fracture network. Next development steps will be influenced by the Rim connectivity, actually not well understood.
Advantages of Up-Dip Water-Miscible Gas Injection
Authors: Namani Mehran , Høier Lars , Kleppe Jon
Published: June 2014

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

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

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

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

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

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

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

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

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

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

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

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.
Sustainability Reporting And The Oil And Gas Industry - Challenges And Emerging Trends
Authors: Janus Bertrand , Murphy Helen
Published: June 2014

Sustainability reporting is both a responsible and expected method for companies to communicate publicly on their environmental and social performance. The oil and gas industry has achieved many notable successes in the field of sustainability but challenges remain and it is becoming increasingly important for individual companies to tell their own stories in a clear, transparent, and straightforward manner.

For oil and gas companies, reporting can provide a robust platform for describing how strategic issues are being addressed through long-term plans and current initiatives. Stakeholders can find details of a company’s high level vision and strategy for dealing with sustainability-related impacts, implementing action plans and assessing outcomes.

Sustainability reporting within the oil and gas industry has evolved significantly over the past ten years with increasing numbers of companies producing reports, and these reports then being presented in ever more dynamic ways. There is an increasing focus on reporting as a critical engagement process with company stakeholders as well as employees, and organisations are now reporting on many more indicators than in the past, particularly regarding social and economic issues.

As a result, the sustainability reporting landscape is continuously evolving as companies find new ways to report on the ways in which they conduct their operations. This paper will examine best practices in the oil and gas industry’s reporting on sustainability and will discuss the following aspects in more detail:

- Industry reporting frameworks - Reporting challenges - Emerging trends in reporting
The Effect of Deluge Spray Systems on Large Scale Fires
Authors: Høiset Stian , Glittum Eli
Published: June 2014

A series of 56 large scale fire epxeriments in the range of 40 to 120 MW has been carried out in a generic offshore module. The effect of deluge fire water application has been measured for different set-ups. Both deluge nozzle type and water application rate have been varied in the experiments.

The main findings from the experiments are:

Deluge water application has better effect on liquid spray fires than on gas jet fires. A deluge water application rate of 10 (l/min)/m2 will have negligible or little effect on the highest gas temperature in the fire. A deluge water application rate of 20 (l/min)/m2 has a documented more favourable effect than an application rate of 10 (l/min)/m2. For gas jet fires, the flame hotspot temperature will persist, independent of deluge configuration. The choice of MV vs HV deluge nozzles is dependent on fire scenario. MV nozzles have their strength in reducing heat fluxes and iso-fluxes volumes, thereby reducing the amount of equipment and structure exposed to high radiation load. HV nozzles have their strength in ability to equipment cooling and lower vulnerability to wind.
25 Years of Operating Germany's Largest Oilfield Mittelplate: Applying the Experience to Exploratory Drilling in a National Park which is an UNESCO World Natural Heritage Site
Authors: Oppermann H.. , Zettlitzer M..
Published: June 2014

Germany’s largest oilfield Mittelplate is located in the tidal flats of the Wadden Sea off the North Sea coast. In 1985 this unique area was designated as a National Park and was awarded the status of an UNESCO World Heritage Site in 2009.

To meet the conditions of this ecologically sensitive tidal region an artificial drilling and production island - Mittelplate A was designed and installed about 7 km off the coast. Since the start of production in 1987 innovative and unusual technological solutions were a prerequisite for achieving safe, environmentally compatible development of the Mittelplate oil reservoir. 25 years of incident-free operations show that the sensitive ecosystem is not impacted by any work being carried out. Sophisticated monitoring and control systems and the deployment of experienced, responsible specialists ensure safe and environmentally friendly drilling and production operations with highest quality.

Of key importance are open discussions with the competent authorities, the National Parks Board, nature conservation and environmental associations, the municipalities and other stakeholders, e.g. NGOs.

Additional oil reserve potential has been identified in the vicinity and south of Mittelplate oilfield which needs to be explored by drilling four wells in the National Park environment. A Wadden Sea Exploration Project has been set up and the experience of the Mittelplate operation will be utilized during all phases of this campaign, i.e. engineering, approval, construction and operations.

The exploratory drilling will be performed with a special designed barge based drilling rig setup. As conventional production tests are not allowed an extended logging and sampling program will be executed in case of discoveries. Afterwards the wells will be plugged and abandoned and the four drilling sites will be completely restored. In case of commercial discovery the reserves will be developed either from the existing Mittelplate A facilities or from onshore with Extended Reach Drilling up to 15 km TD.
Norwegian Oil and Gas Industry Project to Reduce Hydrocarbon Leaks
Authors: Vinnem Jan Erik , Røed Willy
Published: June 2014

The prevention of hydrocarbon (HC) leaks is of great importance because they are the most critical precursor events that may lead to major accidents, such as in the case of Piper Alpha. The number of HC leaks on offshore production installations on the Norwegian continental shelf (NCS) peaked just after the year 2000, with more than 40 leaks per year of an initial rate greater than 0.1 kg/s. The Norwegian Oil and Gas Association (Norwegian Oil and Gas) conducted a reduction project from 2003 to 2008, which resulted in only 10 HC leaks greater than 0.1 kg/s in 2007. The number of leaks increased in the years after 2007, and there were 15, on average, in the period 2008–2010, without any significant increase in the number of installations. Norwegian Oil and Gas started a new project early in 2011 to reduce the number of HC leaks yet further. The initiative will be completed at the end of 2013, but has already started to show promising results. A study undertaken as part of the project concluded that more than 50% of the leaks are associated with the failure of operational barriers during human intervention into the process systems. Human and organizational factors predominate with respect to circumstances and root causes. This paper presents the HC-leak-reduction project, the rationale behind it, and its main activities, which aim to reflect the operational challenges. The activities tie in closely with the results of the analysis of the leaks during the period 2008 through 2011. The single operational barrier that has failed most commonly is the verification of critical activities. The paper also discusses the risk-reduction principles in a barrier context, with an emphasis on operational barriers, as well as some of the challenges faced in the project.
Leading from Within: Awakening Personal Commitment to Safety
Authors: Blair Seb
Published: June 2014

Leaders lead with everything they do and say, whether they intend to or not. In our work we’ve seen that reality put many leaders far outside their comfort zones. Safety leadership isn’t just initiatives and numbers. It’s personal. As many leaders have learned, people remember most what you do in situations involving people and principles—for example, whether (and how) you approached employees working at-risk or challenged decisions that increased exposure.

Developing the strength to do the right thing in these moments (and in all the other ones) comes from having a clear and unshakable emotional commitment to safety. In other words, to lead safety well, you first need to care about it. The good news is the value for safety is something we all inherently have. It may be dormant or poorly defined, but it is something we as leaders can awaken and use to drive our decisions, actions, and communications. When we cultivate a deep emotional commitment to safety, we provide ourselves the tools to navigate the hard moments effectively. Most important, we engage the hearts and minds of others to awaken their own commitment to safety.
Beyond PSM: Integrating Culture and Leadership into Process Incident Prevention
Authors: Blair Seb
Published: June 2014

Prominent incidents such as Oxy’s Piper Alpha explosion, the Esso Longford gas explosion, and the BP Deepwater Horizon spill have given rise to new rules and practices in the implementation of process safety management. Despite this attention, major incidents continue to occur. Research has shown that alongside the proximate causes of each incident, there also existed an underlying fabric of systems, mechanisms, and culture that allowed risk to persist and processes to be ignored. The conclusion is that traditional approaches to process safety management are not sufficient for addressing the precursors that lead up to catastrophic events.

Leaders in process safety management have recognized that the systems designed to control and mitigate major events are only as effective as the culture in which they operate. Leaders create culture through what they do and what they do not do, culture shapes behavior, and behavior is how systems are implemented.

To advance beyond the level of safety achieved through process safety management systems alone, organizations should adopt a Comprehensive Process Incident Prevention approach that builds on the foundation of process safety management to create a safety process that integrates culture with leadership characteristics critical to catastrophic event prevention. This approach includes four major components: Anticipation, Inquiry, Execution, and Resilience. Both individually and collectively, these four components build a strong safety culture that supports effective technical and management safety systems that are designed to prevent catastrophic events.
Examination of Static and Dynamic Filtration on Core Plug Samples on High Temperature
Authors: Federer-Kovács Gabriella , Mátrai Andrea
Published: June 2014

Developing drilling mud technology follows the industrial needs but in the interest of reducing formation damage the object is choosing the most suitable mud. It is even more important question when the pressure and temperature in a well is high. This paper tries to make this choice easier by measuring static and dynamic filtration of drilling mud on changing temperature.

Before designing a HPHT well there are two important cases which must be considered, the margin between the fracture gradient and the pore pressure is small what is critical in the design of the well and HPHT wells usually have high ECD (Equivalent Circulating Density) that leads to lost circulation problems that becomes difficult to control. The choice of accurate mud density is critical due to the narrow margin between the pore pressure and the fracture gradient. The applied mud has to stay stable under extreme temperatures and pressures and has to have optimized rheology to minimize ECD.

In our presentation we will show the results and comparison of the experiments that were conducted using a dynamic HPHT filter press with core sample plugs as filters both static and dynamic conditions to determine the filtrate and thickness and composition of the filter cake. The quantity and quality of spurt loss and fluid loss was compared on different temperatures and core samples. Filtration rate is one of the most complex mud properties because it may be influenced by almost any change in other properties-rheology, composition and particle size distribution-and in this way its effect on formation damage. At elevated temperatures these effects are more significant.
Fracturing a Non-Conventional Oil Reservoir Offshore Congo - Case History
Authors: Garcia Euro , Orski K , Marpaung F , Gonzalez-Dunia J , Bertin J
Published: June 2014

The oilfield Tchendo, located 18 miles off the coast of the Republic of Congo, has been operated since 1991 by Total E&P Congo in depths of approximately 100 meters of water.

The shallowest of the three reservoirs, the Sénonien reservoir (400 m TVD SS), involves an intercalation of carbonate layers with thicker (5 to 15 meters) but poorer quality siltstones.

Various attempts to enhance productivity on existing wells were unsuccessfully carried out since initial production, including selective or extensive perforation, acid treatments on the carbonate layers, and, in recent years, hydrajetting fracture stimulation on three wells.

Although the field is non-conventional, so far, it has been developed conventionally. A large amount of the original oil in place still remains in the reservoir. To make the redevelopment project viable, a step change in stimulation techniques is to be undertaken.

Two workovers were performed at the end of 2012 as a "proof-of-concept". Innovative fracturing technologies, including hydrajetting, were combined to deliver a non-sleeve scenario for horizontal well multi-stage fracturing. The workovers resulted in the largest fracturing treatment executed by Total on an offshore well.

This paper reports on the lessons learned in the process of fracturing this non-conventional reservoirs that will be capitalized for the future redevelopment of the project.
Flow Units: From Conventional to Tight-Gas to Shale-Gas to Tight-Oil to Shale-Oil Reservoirs
Authors: Aguilera Roberto
Published: June 2014

Core data from various North American basins with the support of limited amounts of data from other basins around the world have shown in the past that process speed or delivery speed (the ratio of permeability to porosity) provides a continuum between conventional, tight-, and shale-gas reservoirs (Aguilera 2010a). This work shows that the previous observation can be extended to tight-oil and shale-oil reservoirs. The link between the various hydrocarbon fluids is provided by the word “petroleum” in the “total petroleum system (TPS),” which encompasses liquid and gas hydrocarbons found in conventional, tight, and shale reservoirs.

Results of the present study lead to distinctive flow units for each type of reservoir that can be linked empirically to gas and oil rates and, under favorable conditions, to production decline. To make the work tractable, the bulk of the data used in this paper has been extracted from published geologic and petroleum-engineering literature.

The paper introduces an unrestricted/transient/interlinear transition flow period in a triple-porosity model for evaluating the rate performance of multistage-hydraulically-fractured (MSHF) tight-oil reservoirs. Under ideal conditions, this flow period is recognized by a straight line with a slope of –1.0 on log-log coordinates. However, the slope can change (e.g., to –0.75), depending on reservoir characteristics, as shown with production data from the Cardium and Shaunavon formations in Canada. This interlinear flow period has not been reported previously in the literature because the standard assumption for MSHF reservoirs has been that of a pseudosteady-state transition between the linear flow periods.

It is concluded that there is a significant practical potential in the use of process speed as part of the flow-unit characterization of unconventional petroleum reservoirs. There is also potential for the evaluation of production-decline rates by the use of the triple-porosity model presented in this study.
Design Parameters and Technique Evaluation of Combustion Processes from Tube Testing
Authors: Oliveros L. R. , Yatte F. C. , Bottia H. , Muñoz S. F.
Published: June 2014

In situ combustion (ISC) is one of the improve recovery methods with a high potential to increase the recovery of heavy crude oil. Although we mentioned this major advantage, this process has not being used in Colombia yet. This fact due mainly to the complexity of the involved phenomenon, therefore a field project must be design after extended laboratory investigation.

Experimental tests in combustion tubes made through the main conditions in the oilfield have being the process' evaluation tool with the highest acceptance. These tests show the speed and stability of the combustion front and the obtained results from the production's analysis of fluids, mainly the ones of the exhaust gases. It is possible to calculate the basic combustion parameters by using: combustible consumption, required air, air- combustible relation, hydrogen- carbon atomic, and oxygen use. The parameters mentioned before let, trough different scaling analytic methods to evaluate the technical and economic viability of the process in the field.

In this work was developed a computational tool that allow calculating the design parameters through different scaling analytic methods Nelson & McNeil, Gates & Ramey y Moore et al). Comparing the results got from the different described methods, when scaling two tests in a combustion tube, they show similar numbers. Taking into account that Nelson and McNeil's method is the most useful one due to the oilfield characteristic, it was made a sensitivity of operational parameters and the result permitted to study the relation between the oilfield operational variables