bluuebunny/crossref_metadata_2025_split huggingface dataset:
Producing Extra-Heavy Oil From the Orinoco Belt, Cerro Negro Area, Venezuela, Using Bottomdrive Progressive Cavity Pumps
Authors: Ramos M. A. , Brown J. C. , Rojas M. , Kuyucu O. , Flores J. G. 
Published: December 2007

Abstract
Until 1995, in the Cerro Negro area within the Orinoco belt of Venezuela, rod pumping units and top-drive progressive cavity pumps (PCPs) had been the traditional means of artificial lift for vertical and deviated wells, with production rates ranging from 200 to 600 BOPD of extra-heavy oil (8°API gravity and viscosities of 2,000 cp at a reservoir temperature of 133°F). More recently, with the implementation of horizontal drilling technologies for the construction of wells in unconsolidated sandstones, electrical submersibles pumps (ESPs) became an alternative to handle higher production volumes1. Even more recently, top-drive PCPs have been installed in the Cerro Negro area to produce extra-heavy oil at high rates.
Hybrid artificial lift technologies, such as bottom-drive progressive cavity pumping, which combine features of the ESP and the PCP systems, have recently been successfully evaluated in the Orinoco belt to exploit extra-heavy oil reserves economically. A typical completion assembly includes a multisensor gauge to obtain downhole pressures, temperatures, vibration of the system, and power-cable current leaks; a 4-pole motor; protector; 4:1-ratio gear box; and the PCP. The functional design of the bottom-drive PCP facilitates the handling of viscous and abrasive fluids, increases the flow rate, and diminishes the operational costs. Advantages of this application also include the complete elimination of tubing wear by eliminating the rod string, greater torque capacity, lower surface maintenance, lower load and horsepower requirements, and less frictional losses.
The application of bottom-drive PCPs in the Cerro Negro area have resulted in production rates of up to 1,000 BOPD of extra-heavy oil with 50% less horsepower requirements in comparison to those of conventional top-drive PCP systems.
Pore-Level Investigation of Heavy-Oil Depressurisation
Authors: Shahabi-Nejad K. , Danesh A. , Cordelier P. , Hamon G. 
Published: December 2007

Abstract
Bubble nucleation, growth and mobilisation of gas are important phenomena encounter in oil production by the depressurisation process. The drive energy for oil production during pressure depletion is supplied initially by oil expansion but mainly by gas evolution from solution and expansion of reservoir fluids. Some heavy oil reservoirs in Venezuela and Canada show a high recovery factor during primary production under the solution gas drive process. Factors responsible for high oil recovery in heavy oil reservoirs are not well understood to allow reliable predictions to be made for economic evaluation of the process. A series of flow visualisation tests at the pore level was conducted using a high-pressure glass micromodel to identify the key features of the process.
A heavy crude oil, with a viscosity of 2500 cp at the bubble point pressure and API of around 10, was used to perform the tests at reservoir conditions. Micromodels with realistic pore pattern and different wettability characteristics, including oil-wet, water-wet and mixed-wet were used in the tests. A series of experiments was performed to study the effect of depletion rate, saturation history and water presence on the nucleation process, gas evolution and hydrocarbon movements.
Our observations highlighted the significance of test conditions, particularly saturation history and operational conditions on the nucleation process and bubble formation. Laboratory tests can produce a large number of bubbles formed by pre-existing micro bubbles activation, or a limited number of bubbles due to bulk nucleation, resulting in widely different depressurisation results. Hence, interpretation of laboratory data and its application to field performance would require particular considerations as identified in this study.
Critical gas saturation and subsequent gas/oil production are strongly affected by the critical value of supersaturation and the number of bubbles formed during depressurisation. Two generalised correlations have been developed to predict the above parameters at realistic reservoir conditions.
The experimental data generated in this study and interpretation of the results provide information on gas nucleation, critical supersaturation, bubble density and critical gas saturation, which are essential in field development planning and estimation of oil and gas recovery by depressurisation. The study also clears a number of ambiguities in the literature on prevailing mechanisms in depletion of heavy oil and contradictions between laboratory and field results.
Geomechanical Effects on the SAGD Process
Authors: Collins P. M. 
Published: December 2007

Abstract
SAGD (steam-assisted gravity drainage) is a robust thermal process that has revolutionized the economic recovery of heavy oil and bitumen from the immense oil sands deposits in western Canada, which have 1.6 to 2.5 trillion barrels of oil in place. With steam injection, reservoir pressures and temperatures are raised. These elevated pressure and temperatures alter the rock stresses sufficiently to cause shear failure within and beyond the growing steam chamber. The associated increases in porosity, permeability, and water transmissibility accelerate the process. Pressures ahead of the steam chamber are substantially increased, which promote future growth of the steam chamber. A methodology for determining the optimum injection pressure for geomechanical enhancement is presented, which allows operators to custom-tailor steam pressures to their reservoirs.
In response, these geomechanical enhancements of porosity, permeability, and mobility alter the growth pattern of the steam chamber. The stresses in the rock will determine the directionality of the steam chamber growth, and these are largely a function of the reservoir depth and tectonic loading. By anticipating the SAGD growth pattern, operators can optimize on the orientation and spacing of their wells.
Monitoring of the SAGD process is central to understanding where the process has been successful. Methods of monitoring the steam chamber are presented, including the use of satellite radar interferometry. Monitoring is particularly important to ensure caprock integrity, as it is paramount that SAGD operations be contained within the reservoir.
There are several quarter-billion dollar SAGD projects in western Canada that are currently in the design stage. It is essential that these designs use a fuller understanding of the SAGD process in order to optimize on well placement and facilities design. Only by including the interaction of SAGD and geomechanics can we achieve a more complete understanding of the process.
Recovery of Heavy Oil and Bitumen Using Disc-Stack Centrifuge Technology
Authors: Agrell J. , Faucher M. 
Published: December 2007

Abstract
Recent technological advances are making the exploitation of heavy crude oil reserves increasingly profitable. This paper describes the use of nozzle-type disc-stack centrifuges for dehydration of heavy oil.
The nature and composition of heavy oil leads to a number of undesirable properties, such as its tendency to form stable emulsions in the presence of asphaltenes, particles and other emulsifiers occurring naturally in the oil. This, combined with a high viscosity and a relatively high content of solids, makes dehydration a challenging task that introduces new concerns when compared to light crude oil.
As the density of the heavy oil increases and approaches that of water, conventional static and gravity-based separation systems become unacceptably large and require excessive heating and chemical addition to produce pipeline specification oil. Hence, the disc-stack centrifuge is proposed as an efficient solution in a compact size, enabling breakdown of stable emulsions and removal of dispersed water droplets and solid contaminants from heavy and viscous crudes, in both onshore and offshore installations.
Insights Into In-Situ Combustion by Analytical and Pore-Network Modeling
Authors: Akkutlu I. Y. , Lu C. , Yortsos Y. C. 
Published: December 2007

Abstract
In-situ combustion is a subject of continuing interest due to its rich interplay of flow, mass/heat transfer and reactions. The process complexity, however, has precluded its thorough understanding. In this paper, we provide some analytical results and pore-network simulations that explore fundamental aspects of this process.
The analytical approach relies on high-activation energy asymptotics. It consists of the assumption that the combustion front is a thin layer, within which reactions occur. We review our recent findings and derive exact results for the front temperature, the front propagation velocity and oxygen consumption. The results are then compared to pore-network simulations, where the effects of pore structure are included in a detailed simulation at the pore-network level. The simulations demonstrate the validity of the thin layer assumption and provide approaches for upscaling.
Then, the effect of porous medium heterogeneity, a ubiquitous feature of oil reservoirs, on the front is considered, in particular, in the form of a layered reservoir system. The fronts in two layers can be coupled under certain conditions, depending on the permeability-thickness contrast R between the layers, the extent h of external heat losses and the inlet conditions. We derive the parameter space, where this coupling occurs, and compare the results with the porenetwork simulations. Stability of the derived stationary nonequilibrium states is also analyzed. It is shown that the adiabatic states are always stable; whereas the non-adiabatic states being conditionally stable. This suggests that coherence of the fronts in the layered system is possible under certain conditions and that the effect of heterogeneity is not as detrimental to the process and its sweep efficiency, provided that heterogeneity does not exceed a certain limit, Rc.
Geomechanical Model of Oil Sands
Authors: Li P. , Chalaturnyk R. J. 
Published: December 2007

Abstract
Oil sands geomechanics plays an important role in the oil sands recovery processes, such as surface mining, cyclic steam stimulation and SAGD, which are widely applied in the development of oil sands resources in Alberta, Canada. Coupled reservoir geomechanical simulation techniques have been developed and used for the design of in situ recovery processes, particularly for SAGD. Thus, a realistic geomechanical model of oil sands material is a critical component in these reservoir geomechanical simulations. This paper presents the development of an oil sands model based on the analysis of laboratory testing results provided by different researchers, including Oldakowski, Samieh and Wong, and Touhidi-Baghni. On the basis of this analysis, 25 numerical experiments were conducted to match these laboratory tests, including the stress paths, as those applied in the laboratory experiments. Consequently, a comprehensive geomechanical model of oil sands material was established based on these numerical experiments. The proposed strain softening model parameters, such as the modulus of elasticity, peak and post-peak friction angle, and dilation angle, can be applied in the coupled reservoir geomechanical simulations of thermal recovery processes, including the SAGD process.
Recent Advances in Granular-Based Sand Control Design Operations and Their Performance Evaluation
Authors: Tovar J. J. , Webster C. M. 
Published: December 2007

Abstract
Sand control operations and particularly those using granular filter media such as gravel packs and frac & pack are being carried out in increasing numbers and in more demanding environments. Improvements continue to be made in terms of equipment, fluids and operations. However, with the increasing emphasis on well productivity and minimizing impairment, it is clear that a better understanding of some of the current causes of impairment is required.
The design of sand control filter media continues to be based on a limited number of discrete formation samples that are taken to be fully representative of the actual grain sizes throughout the interval of interest. It is often difficult to clearly identify the causes and location of the impairment unless expensive evaluation tools such as PLTs are utilized.
This paper presents the results of research work that have successfully resulted in an analytical tool and a new granular system that allows improved design and evaluation of sand control operations. A system for the determination of grain size and pore blocking mechanisms on a foot-by-foot basis has been developed. Furthermore a granular filter media has been devised such that permeability damage from solids migration can be reversed. The results presented are based on "flow of solid particles through porous media" principles. The work included laboratory testing for various gravels and these results are also included. Field validation was carried out with data from LDAs and an offshore deviated well.
New Applications of Well Log Parameters in Coalbed Methane (CBM) Reservoir Evaluation at the Drunkards Wash Unit, Uinta Basin, Utah
Authors: Yang Y. , Cloud T. A. , Van Kirk C. W. 
Published: December 2007

Abstract
The application of well logs in the CBM industry is usually limited to the identification of coal seams, coal thickness calculation, and estimation of gas in place1. In order to take full advantage of the abundant well log data collected at the Drunkards Wash Unit (DWU) and better understand log responses in CBM reservoirs, a study was performed with three major objectives. First, a new method was devised to calculate a permeability indicator using the shallow resistivity measured by the focused electrode tool. Second, the resistivity log was observed as a critical parameter to distinguish coal from non-coal formations in significantly enlarged well bores. And finally, based on the observed correlations between coal and log parameters, a comprehensive log cutoff system was established and a computer analysis model was developed to identify a diverse coal lithology system present at DWU.
Real-Time Optical Monitoring of Bottomhole Pressure During Extreme Overbalanced Perforating and Production Testing of a Remote Alaskan Exploration Well
Authors: Bond A. J. , Kragas T. K. , Mathias S. W. 
Published: December 2007

Abstract
Permanent downhole pressure gauges are becoming a standard completion component in many production wells. However, their use in exploration wells to date has been limited. Wireline-deployed memory gauges are more likely to be used to obtain downhole pressure data during testing of exploration wells. Unfortunately, pressure data from memory gauges does little to help the operator manage and optimize the completion and testing of a well where uncertainties in rock strength, pore pressures, and production rates can be high. Installation of a permanent downhole gauge in an exploration well can provide valuable data for real-time management of the production testing process. In addition, it can continue to monitor reservoir pressure after the well is shut-in.
This paper discusses the installation, application, and value of a permanent optical sensing pressure and temperature gauge system installed in an exploration well (Carbon #1) in the National Petroleum Reserve, Alaska (NPRA) during April 2004. The well was a delineation/confirmation well in a large hydrocarbon accumulation discovered during previous winter drilling seasons. All exploration work in the NPRA is done from ice roads and pads and therefore the season is limited by weather. Challenges and unique aspects of the installation included arctic winter operations, flawless integration of the data into surface well testing data acquisition systems and the ability to monitor real time bottom hole treating pressures during an EOB (extreme overbalanced) perforating treatment.
The real time data proved to be invaluable for determining the effectiveness of the stimulation treatment as well as optimizing the duration of the production test and final pressure build-up test. The ability to monitor pressure data real time rather than having to run and retrieve multiple memory pressure gauges provided nearly "textbook" data quality during multi-rate testing. The well is now temporarily abandoned and is available for use as a pressure monitoring well during future development. The results of the stimulation and well testing operation were very successful and will lead to a future commercial development in the NPRA.
Safety Is No Accident
Authors: Al Araimi N. , Mahajan M. 
Published: December 2007

Abstract
Well drilling and service operations generally involves heavy machinery, bulky equipment, heavy lifts, hazardous chemicals, challenging well conditions & worksites and tougher logistical elements. All these elements pose a challenge to the achievement of QHSE performance levels the oil and service companies aspire to achieve today. Over recent years, there has been a lot of learning, understanding and research work into these areas. These, coupled with a tremendous shift in awareness and attitudes towards the QHSE aspects of business, both in the operator and service sectors of industry, have brought in noticeable changes in the business environment. The role of QHSE performance now a days is not only limited to social dimension but it has become very decisive factor in the ultimate financial success of any business entity.
In Feb 2005 a major international operator in the Asia Pacific achieved a milestone of 6+ years LTI-free coiled tubing/well servicing operations. Considering that each and every job conducted throughout this six year period involved some combination of the several high potential hazards as stipulated above, this is indeed an achievement to be proud of.
A critical review of the whole process has been attempted in this paper to identify and highlight the critical components, which have played vital roles in the achievement of this great milestone. It is demonstrated that Safety is no accident; it is something we achieve by hard work, deep dedication, tremendous efforts and relentless follow-ups. We believe that the learning from this study would greatly contribute to improvements in safety performance of similar operations worldwide.
Application of Viscoelastic Fracturing Fluids in Appalachian Basin Reservoirs
Authors: Boyer C. M. , Glenn S. , Claypool B. , Weida S. D. , Crain C. D. 
Published: December 2007

Abstract
The Upper Devonian-age black shale of the Central Appalachian basin has been a major natural gas production reservoir since the initial discovery in 1921. In the ensuing 80 years, an assortment of drilling and completion techniques have been applied to the black shale with varying degrees of success. Recent efforts at improving well productivity have focused on improving the hydraulic fracturing operations, especially the minimization of fluid damage to the targeted shale reservoirs. The development of fluid systems with lower polymer loadings has been an important achievement in this effort. Recently, polymer-free viscoelastic surfactant-based (VES) fluid systems have been used in the hydraulic fracturing industry as a final step in the elimination of polymer-based damage. A statistical study of the application of a VES foam fracturing fluid in the Central Appalachian basin was performed. The study compared recent results of polymer-free treatments to traditional completions throughout the field. Results from the polymer-free completions were compared to immediate offsets drilled in the same time frame and completed in correlated intervals. In general, the use of polymer-free fluids improved well productivity, when compared to wells that were completed with a conventional polymer-based fluid. The study also compared the economic impact of the use of VES completion fluids from both an operations and production perspective.
Challenging the Traditional Coalbed Methane Exploration and Evaluation Model
Authors: Weida S. D. , Lambert S. W. , Boyer C. M. 
Published: December 2007

Abstract
Conventional wisdom states that a coalbed methane (CBM) evaluation program should consist, initially, of core hole and permeability testing, followed by flow testing wells, leading to one or more multiple well pilot programs. Such an evaluation program progresses sequentially from lower initial cost for basic data acquisition to higher cost production testing that normally focuses on the construction of a reservoir simulation-based field development model. However, Applications of this approach minimize any consequence of reservoir heterogeneities, which ultimately dominate later large-scale project performance. Due to these heterogeneities, potentially commercial coalbed methane production areas may be bypassed or prematurely condemned. To reduce the likelihood of missing or overlooking otherwise attractive CBM plays, an alternative evaluation model was developed to focus specifically on reservoir heterogeneity. This alternative evaluation program utilizes production distributions derived from proven productive basin area reservoir/operational analogs. The resulting production variability is then weighed against prospective new play areas in order to define more effective exploration program requirements. This results in a more realistic approach to the exploration process and increases the probability of large-scale technical and financial success.
Development of New 15Cr Stainless Steel OCTG with Superior Corrosion Resistance
Authors: Kimura M. , Tamari T. , Yamazaki Y. , Sakata K. , Mochizuki R. , Sato H. 
Published: December 2007

Abstract
New stainless steel OCTG (New 15Cr steel pipe: 0.03C-15Cr-6Ni-2Mo-1Cu) with high strength and superior corrosion resistance has been developed and its capability in oil and gas production environment is shown. The yield strength of the new 15Cr steel pipe was higher than 861 MPa (125 ksi), and good Charpy toughness was obtained in extremely low temperature condition. This material showed remarkably high strength even at high temperature of 200 degree C. The CO2 corrosion resistance was significantly improved so that the critical temperature for the developed pipe was more than 200 degree C at 15 MPa CO2 partial pressure. The superior corrosion resistance for revised the new 15Cr steel pipe was obtained by the higher amount of effective Cr in solution. In addition to this, the new 15Cr steel pipe showed good SSC resistance even in its high yield strength in the mildly sour environment. The good SSC resistance for this developed pipe was obtained by the good pitting resistance, induced from high Cr and Mo addition.