bluuebunny/crossref_metadata_2025_split huggingface dataset:
Natural Gas Hydrates: Development and Test of Innovative Methods for Gas Production From Hydrate-Bearing Sediments
Authors: Schicks J. M. , Spangenberg E. , Steinhauer B. , Klump J. , Giese R. , Erzinger J. , Haeckel M. , Bigalke N. , Savy J-P. , Kossel E. , Deusner C. , Wallmann K. 
Published: February 2011

Abstract
Huge amounts of CH4 bound in natural gas hydrates lead to the idea of using hydrate bearing sediments as an energy resource. Natural gas hydrates remain stable as long as they are in mechanical, thermal and chemical equilibrium with their environments. Thus, for the production of gas from hydrate bearing sediments, at least one of these equilibrium states must be disturbed by depressurization, thermal stimulation or addition of chemicals such as CO2. In the framework of the German national gas hydrate research project SUGAR (Submarine Gas Hydrate Reservoirs), all three reaction routes - alone or in combination - are tested. The aim is to find the most flexible and efficient, but also environmentally friendly method for gas production from hydrates. One method in this context is the thermal stimulation using in situ combustion. Therefore, a heat exchange reactor was designed and tested for the catalytic oxidation of methane. Furthermore, a large scale reservoir simulator (Volume 425 l) was realized, to synthesize hydrates in sediments under conditions similar to nature and to test the efficiency of the reactor. Thermocouples placed in the reservoir simulator collect data regarding the expansion of the heat front, respectively. These data are used for numerical simulations for up scaling from laboratory to field conditions. However, thermal stimulation may be used alone or in combination with CO2 sequestration. Therefore, laboratory studies on the methane production from pure hydrate phases as well as hydrate bearing sediments by use of CO2 injection are investigated using several analytic tools such as Nuclear Magnetic Resonance spectroscopy, confocal Raman spectroscopy and X-ray diffraction. In this study we present the experimental set up of the large scale reservoir simulator and the reactor design. Preliminary results show that the catalytic oxidation of CH4 in a countercurrent heat exchange reactor operated as a temperature controlled, autothermal reaction outside of the flammability limits of CH4 is a safe and promising tool for the thermal stimulation of hydrates. In addition, preliminary results from the laboratory studies on the CO2-CH4 swapping process in pure and porefilling gas hydrates are presented focussing on the kinetics of this process.
Ensuring Contractor Alignment With Safety Culture
Authors: van de Riet Ben PGM 
Published: February 2011

Abstract
The contractor ratio within the oil and gas extraction industry has increased significantly over the past two decades. With this rise in the number of contractors, the frequency of injury has also increased. Furthermore, compensation for contractor injuries is less regulated than for direct-hire employees, thus increasing liability and potential cost. As such, it has become imperative for oil and gas companies to better align and engage contactors to existing HSE policies, thereby decreasing the injury and accident frequency and preventing potential associated costs.
Confluent factors such as heightened globalization, the global recession and the integration of new technologies and extraction techniques have led to increased utilization of contractors in the oil and gas sector. While companies and contractors have the same objective as it pertains to safety – to prevent all injuries and accidents – it is ultimately the company that determines the level of safety in the workplace. To deliver improved safety outcomes for contractors, DuPont developed an approach to contractor safety management that has proven efficacious in decreasing the frequency of injuries and accidents among its contractors. The system is composed of six complementary processes: (1) the selection of contractors with satisfactory safety records, (2) the inclusion of safety standards in contractual obligations, (3) clarification of expectations upon award of bid, (4) orientation and training of contractor teams, (5) monitoring of safety activities, and (6) a post-contract evaluation to assess success and lessons learned.
To ensure efficacy, companies must first develop an appropriate context for contractor safety by familiarizing themselves with safety issues that affect contractors specifically, demonstrating a visible management commitment and developing a strong safety culture based on behavior modification and a collective responsibility for safety. While companies must manage contractor safety as they would their own personnel, the development of knowledge transfer methodologies, implementation strategies, and transparent monitoring processes are necessary to optimize safety outcomes for contractors. Furthermore, managers must integrate the six steps into their existing HSE policy and contractor recruitment process.
This paper will describe the benefits of improving the front-end contractor hiring process – selection of contractors with demonstrated satisfactory safety performance, contractual requirement to work safely and clarification of safety expectations upon award – as it not only initiates safety dialogue, but allows for an understanding of the financial and practical implications of incorporating expectations into their bid. Moreover, the paper will discuss the importance of instilling and reinforcing the company’s culture of safety. Companies that have implemented this management system have seen dramatic reductions in injuries and accidents among contractors, and consequently an increase in productivity and an improvement in employee morale.
Evaluation of Specialized Cement System for Long-Term Steam Injection Well Integrity
Authors: Pershikova E. M. , Chougnet-Sirapian A. , Loiseau A. , Khater W. , Garnier A. 
Published: February 2011

Abstract
Most heavy oil resources are found in shallow reservoirs. The challenging conditions of steam injection process to recover heavy oil from these wells impose additional requirements on zonal isolation material properties. At minimum, the ideal cement system must be designed with mechanical strength and flexibility sufficient to withstand the stresses induced by significant thermal loads. However, this ideal system has to acquire these properties at low placement temperatures and keep them at the minimum required level until abandonment and above. Conventional systems traditionally used for steam injection application don't satisfy these minimum properties requirements, which lead to various forms of leaks or even to complete steam breakthrough to the surface.
New specialized cement was developed to reliably maintain zonal isolation in shallow wells under steam injection conditions. This system, designed at the density range of 1,400-1,700 kg/cm3 (11.7–14.2 lbm/gal) is able to develop an excellent combination of mechanical strength and flexibility at the placement temperatures of 15-30 °C. Cement obtained after the initial low temperature curing was then aged at 350°C for 6 months. Every month, a temperature cycle (350°C to ambient temperature to 350°C) was simulated. Mechanical properties (compressive and tensile strengths and Young's modulus) were measured after 1, 3, and 9 months. Numerical simulations of sealant integrity performed with these properties in an annular geometry under shallow well conditions confirm long-term durability of the new system.
The cement's ability to withstand stresses encountered during steam injection was validated in a specific large-scale laboratory setup. A piece of cement sheath was subjected to two consequent temperature cycles from ~ 20 to 180°C with the a ramp-up of 0.6°C/min, equivalent to the worst case scenario for the proposed injector wells in the validation location. New cement system was capable of passing these conditions whereas conventional systems failed to maintain integrity of the well.
Thus, this study confirmed the capability of the new specialized cement system to ensure zonal isolation in shallow wells.
Assessment of CO2 Flooding Potential for Bakken Formation, Saskatchewan
Authors: Wang X. , Luo P. , Er V. , Huang S. 
Published: February 2011

Abstract
The Bakken is an extremely tight formation, with the oil contained mostly in siltstone and sandstone reservoirs with low porosity and permeability. In Saskatchewan alone, there could be an estimated 25 to 100 billion barrels of Bakken oil in place. At present, the combination of horizontal well drilling and the new multi-stage fracturing and completion technologies has been the key to economically unlocking the vast reserves of the Bakken formation. The primary recovery factor, however, remains rather low due to high capillary trapping. While waterflooding could result in unfavorable injectivity issues, carbon dioxide (CO2) miscible flooding provides a promising option for increasing the recovery factor. Higher oil recovery factor can be achieved with CO2 injection through multi-contact miscibility that results in vanishing interfacial tension, viscosity reduction, and oil swelling. This paper conducted a numerical simulation work as an effective and economical means of evaluating CO2 flooding potential for enhanced oil recovery. Different strategies were tested to compare the effects on oil recovery of injection well pattern, continuous and cyclic injection, waterflooding and CO2 flooding, injected gas composition, and heterogeneity. The simulation results show that CO2 flooding presents a technically promising method for recovering the vast Bakken oil.
Unconventional Imaging for Unconventional Reservoirs
Authors: Leskiw C. J. , Nowicki E. , Gates I. D. 
Published: February 2011

Abstract
Thermal stimulation of bitumen in oil sands reservoirs is a critical requirement for the success of steam-based recovery processes. If the bitumen is not heated, it remains at its original viscosity, often in the millions of centipoise, and thus is not mobilized so that it can be moved to a production well. All oil sands reservoirs are heterogeneous; both with respect to geology and fluid composition, and thus steam conformance of steam in the reservoir is not uniform. At present, realtime monitoring of the steam conformance zone in the reservoir is not possible and thus the spatial distribution of heat delivery to the reservoir is uncertain. In this research, a new method for detecting heterogeneity and monitoring steam chambers has been developed and tested by detailed thermal-acoustic reservoir simulation. Here, a thermal fluid flow simulator was coupled to a wave propagation simulator to evaluate the potential of identifying rock and fluid discontinuities within a reservoir by using coded white noise reflection processes. Digital communication systems employ coded white noise processes to advantageously make use of unexpected reflections from environmental heterogeneities. The proposed theory and subsequent simulations reveal that it is possible to resolve features of an unconventional recovery process as well as imaging of heterogeneity within the reservoir as it evolves by using white noise reflection methods. The properties of the signals described provide an opportunity for property detection at lower power levels and higher frequencies than traditional sceismic methods. Furthermore the signals are such that the noise from recovery processes and the native reservoir environment do not interfere with the detection methods allowing for the monitoring method to be used concurrently with the recovery process. A SAGD model is tested and the results show that white noise reflections can be used to detect the edge of steam chambers.
Quantitative Frac Pack Analysis Using Dual Tracer Logs and Down Hole Gauges
Authors: Sanford Jack , Bruton Jeff , Woomer Jim , Singh Amit , Flecker Mike 
Published: February 2011

AbstractA combination of multiple down hole gauges and dual density / tracer logs were utilized to quantitatively evaluate distribution of fluid and proppant across a long perforated interval separated in two lobes and to quantify the annular pack percentage across the entire completion interval during a deepwater frac pack treatment in GoM. It was important to evaluate the achievement of an effective fracture in both lobes and define the annular pack percentage across the entire completion interval to be able to produce the well to its potential.This technique quantitatively evaluated the entire frac pack process and determined screen out events in separate lobes and annular pack efficiency. The analysis also defined the dynamics of the treatment fluid and proppant slurry movement during the frac pack pumping operation and their final placement.Several expected as well as unexpected conclusions and observations were identified. In summary, the diagnosis indicated that higher percentage of treatment fluid and proppant was received by the upper sandstone lobe. The exact proppant concentration at lower lobe screen out was identified. A baseline pre-pack value was established, which allowed the annular pack percentage to be calculated across the entire interval. It also provided detailed information on the sequence of events during washout at the crossover tool. All of these allowed the operator to confidently maximize deliverability from the subject well, which is currently producing 110 MMcfd.The results from this case history and the technique described should result in a step change in frac pack evaluation. Quantitative evaluation eliminates any doubts about the effectiveness of the annular pack and allows operators to produce their assets at maximum deliverability. Additionally, it assists future completion designs and type selection.
Geochemical and Geological Characterisation of the Duvernay and Muskwa Formations in Alberta
Authors: Rokosh C. D. , Anderson S. D. , Beaton A. P. , Berhane M. , Pawlowicz J. 
Published: February 2011

Abstract
The ERCB/AGS has collected over 270 core samples from the Duvernay and Muskwa formations in Alberta and run a series of tests to characterize the formation for resource assessment. The geochemical and geological tests include adsorption isotherm, Rock-Eval/TOC, XRD whole rock and clay mineralogy, permeameter, porosimetry, thin section analysis and SEM imaging. The purpose of this talk is to discuss the regional geological and geochemical attributes of the Duvernay and to a lesser extent the Muskwa leading to a shale gas resource assessment. An important aspect of our study is that the samples wer taken to represent a variety of lithofacies and colour variations, for example, and do not necessarily represent the best reservoi rocks. Our purpose is to reveal the attributes of rocks that have resource potential, or lack thereof, as opposed to identifying rocks with reservoir potential. The data will be presented using a series of maps and sections to show the spatial and temporal variations.
Experimental Investigation of Vapor Extraction Process for the Recovery of Bitumen From Vuggy Porous Media
Authors: Rezaei N. , Mohammadzadeh O. , Chatzis I. 
Published: February 2011

Abstract
The application of VAPEX process was carried out in sintered homogeneous and vuggy porosity media with different matrix permeability and porosity, to investigate the behavior of vapor extraction process in vuggy media as a potential recovery process. The VAPEX experiments were conducted using Cold Lake bitumen, and n-pentane as the hydrocarbon solvent. Seven different models were made, four of which were vugular media with different vuggy-to-total pore volume ratios. The vugs were arranged in aligned and staggered configurations. Three homogeneous sintered glass beads models of different permeability and porosity were also made. The vugs in sintered models were created by embedding wood particles of uniform volume (20 mm3 each) in the glass beads continuum between two parallel glass plates and by heating them in the muffle furnace. During the VAPEX experiments, analysis of the live and dead oil production rates, solvent content, and residual oil were conducted. It was observed that the vugs could appreciably facilitate the production of bitumen from the vuggy models compared to the homogeneous model with the same matrix glass bead size. The increase in the vug porosity of the porous space significantly increased the live and dead oil production rates of bitumen and slightly decreased the extent of residual oil saturation left in the model. Unlike the sintered homogeneous models in which the production rate of bitumen remains more or less constant during the VAPEX process, the vuggy porosity models display a boost in the rate of oil production when several vugs are being invaded by the solvent vapor. This behavior was more pronounced in the case of aligned vugs were the vugs were closer to each other and more vugs were invaded simultaneously compared to the staggered vug configuration. The enhanced pore-level mixing of solvent with bitumen, improved petrophysical properties of the porous medium, and the flow communication of matrix with the vugs were found to be important in draining the live oil towards the production well at higher rates.
Correlation Of Outcrop, Seismic, Core Plugs And Thin Sections In Cretaceous Carbonate Rocks From Wasia Group In The U.A.E
Authors: El Husseiny A. H. , Vega S. , Al Mesaabi S. , Ali M. , Weger R. , Eberli G. 
Published: February 2011

Abstract
Previous study, of a geological and petrophysical investigation from an outcrop in the UAE, found a potential correlation between acoustic velocities and fracture density. However, it was not clear what could be the effect of this correlation in the seismic response. The aim of this paper is to extend this previous study to better understand its results and to investigate their significance in the seismic response. To achieve this purpose, we correlated geological and geophysical parameters at four different scales: outcrop, seismic, core plugs and thin sections. We acquired a seismic line on the top of an outcrop. From the same outcrop we examined 17 core plugs and 30 thin sections along different locations. We found that acoustic velocities, measured in the lab, decrease with increase in fracture density. This result was supported by the outcomes of the outcrop-seismic correlation where changes in fracture density were found to be an important factor that affects the seismic response in carbonate rocks. Such correlation can lead to better understanding of the seismic response which can result in an improvement in seismic interpretation of areas with similar geological conditions.
Unconventional Oil Exploration Potential in Early Mature Source Rock Kitchens
Authors: Taher Ahmed K. 
Published: February 2011

Abstract
Most of the simple anticlinal structural traps have already been discovered in Abu Dhabi and most other places in the world. New exploration activities need to be concentrated on other, less obvious plays and subtler trap styles. Oil exploration directly from early mature source rock kitchen is an example of such an unconventional new play type.
Mature source rock strata are normally characterized by strong oil shows while drilling and high hydrocarbon saturations in the interpreted logs. In the past, several attempts have been made in Abu Dhabi to test these promising zones but the productivity was either nil or very low. The low productivity values are mainly related to the low permeability of source rock sediments. Also, the low productivity could be attributed to the conventional testing used for these tight reservoirs.
Oil exploration from the source rock kitchens need to be focused on the areas that are characterized by rich organic matter content and it’s in the early stages of oil generation. Finding economically attractive oil accumulations in the source rock kitchen is linearly increases with the increase of porosity values.
The development of source rock porosity could be attributed to the organic matter richness and the argillaceous nature of these source rock intervals. Also, the conversion of solid organic particles into liquid components will provide additional space for generated hydrocarbons.
The maturation modeling of the Cenomanian, Shilaif Formation indicated the presence of early mature kitchens in the offshore and southern onshore synclines. In some of these localized kitchens, significant quantities of oil were generated but not expelled into the surrounding structures especially in the southwestern onshore syncline. Similarly, the Oxfordian Diyab (Hanifa) Formation is prospective mainly in the northern offshore area. In this area, the Diyab source rock did not reach the expulsion phase yet and the wells data of this area indicated the presence of potential oil accumulations in this area.
The lateral seals for the localized source rock reservoirs are provided by the solid kerogen of the immature source rock at the basin margins. The top seal is provided by thick and tight sediments of Tuwayil and this will delay the primary migration of hydrocarbon out of these kitchens and make it more attractive for exploration activities.
Downhole and Topside Scale Challenge "Removal, Prevention and Inhibition Strategy"
Authors: Al Salami Aisha R. , Monem Alaa A. 
Published: February 2011

Abstract
Downhole scale deposition in the producing strings and wellbores is becoming a serious problem for many oil operating companies, especially when dealing with horizontal wells. For those companies that are using water flood to maintain the reservoir pressure, the problem will be greater as the scale is often calcium, barium and strontium sulphate besides the topside scaling phenomena and the disadvantages of solids at surface facilities
The options for scale removal vary from chemical treatment or mechanical removals and at the worst conditions full rig work over to replace the production tubing.
Consequently, the oil field scale treatment philosophy is "scale prevention is better than cure", accordingly, implementing successful inhibition program is generally the most efficient scale treatment strategy.
This inhibition strategy is based on many factors to enable an appropriate assessment and reliable conclusions particularly for carbonate reservoirs: How the inhibitor interacts with the formation rock matrix.Thermal stability of the inhibitor.Deployment and return profile
In this paper, a severe downhole scale problem is presented focusing on all the treatment parameters starting from the traditional chemical & mechanical removal techniques and ending by the squeeze inhibition programs utilizing the neutralized phosphonate chemistry selected to extend the inhibitor life time, the paper will cover: Impact of the naturalized phosphonate on carbonate reservoirInhibition programs and their modification to improve and extend the squeeze life time without damaging the reservoir materialInhibitor deployment, fluid returns monitoring and optimization.Impact of the water breakthrough & brines mixing on scale formation at surface facilitiesNegative impact of solids formation on the topside facilitiesScale dissolver chemical selection and optimization