bluuebunny/crossref_metadata_2025_split huggingface dataset:
Condensate Production – The Nigerian Perspective
Authors: Nwabueze Dili O. 
Published: December 2007

Abstract
High Pressure/High Temperature wells are essentially gas-condensate wells and gas injection is a fundamental exploitation strategy for gas-condensate reservoirs.
Concerted effort towards appropriate exploitation of this type of wells will lead to enhanced and rational production of condensate.
There are four basic sources of condensate; (1) oil well gas plants, (2) gas – condensate field plants, (3) gas well field plants and (4) cycling plants.
Regardless of the source, hydrocarbon condensate is of immense value and relevance to global energy demand.
With regard to Nigeria, condensate production will uplift the economy as condensate production is out of OPEC regulation. Also condensate is more profitable than crude oil on equal volume basis as its price is comparable to the price of naphtha.
Normally the greatest harvest of condensate is from gas – condensate reservoirs operated with cycling plants.
This paper highlights the tremendous benefit of rational production of condensate to our economy and strategic energy reserves conservation.
The Applicability of Concrete Polymer Materials for Use in Geothermal Environments
Authors: Kukachka L.E. 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

Abstract
The feasibility of using concrete polymer composites as materials of construction for handling hot brine was demonstrated in 1972. The results from these tests indicated that the composites had long-term stability in seawater at 177 deg. C and in acid solutions. Since then the work has been extended to develop materials for use in geothermal systems. To date, high temperature polymer concrete systems have been formulated, polymer concrete systems have been formulated, and laboratory and field tests performed in brine, flashing brine, and steam at temperatures up to 240 deg. C. Results are available from field exposures of up to 12 months in four geothermal environments. Testing at two other sites is in progress. Good durability is indicated. Based upon progress. Good durability is indicated. Based upon these results, potential applications in geothermal processes have been identified.

Introduction
The availability of durable and economic materials of construction for handling hot brine and steam is a serious problem in the development of geothermal energy. To date, corrosion and scale incrustations have been encountered in all geothermal plants, and to various degrees, adversely affected plant life times and Dower output.
General guides to materials selection for oxygen-free geothermal systems have been published by Shannon. At a temperature of 120 deg. C and pH less than 6, the use of expensive materials such as pH less than 6, the use of expensive materials such as titanium, zirconium, and Hastalloy C is suggested.
Severe corrosion of carbon steel occurs in aerated geothermal fluids at a temperature of 60 deg. C. The corrosion rate in aerated systems is reported to be 100 times greater than in oxygen free geothermal fluids. As a result, all condensate and cooling water piping at The Geysers is constructed of stainless steel or plastic-lined material. It is also necessary to coat plastic-lined material. It is also necessary to coat all concrete surfaces that come in contact with water with coal-tar epoxy compounds or synthetic rubber.
The corrosion rate of carbon steel is highly dependent upon the pH of the brine. At the predicted pH of 4.9 for oxygen-free Salton Sea brines predicted pH of 4.9 for oxygen-free Salton Sea brines and a temperature of 50 deg. C, a service life of less than 15 yr is estimated. At a pH of 4, the estimated service life is 2 yr.
Electrochemical attack due to high sulfate containing soils present in many parts of the western states may restrict the use of carbon steel pipe in the development of medium temperature geothermal reservoirs.
Down-Hole Corrosion in a Salton Sea Geothermal Well
Authors: Treseder Richard S. , Wieland Rita 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

Abstract
Corrosion data were obtained in a well in the Salton Sea Geothermal Field. These data were obtained from inspection of steel tubing removed from the 4200-foot well and from specimens of various alloys exposed at the bottom of the well. Analyses were made of scale on the tubing surface at five locations of varying depth. Corrosion data were obtained also from specimens exposed in surface equipment handling the steam and high salinity brine produced by the well.
Corrosion of the API Grade J-55 tubing was characterized by extensive pitting. The maximum localized corrosion rate varied from 2000 mils/yr at the bottom of the well to about 100 mils/yr at the top. The principal composition difference among the five principal composition difference among the five scale samples was in the silica content, which varied from 3% at the bottom to 27% at the top. Thus, it is possible that silica deposition is a factor in the reduced corrosion observed at the top of the well.
Of the alloys exposed at the bottom of the well, the least corrosion was observed with Type 316L stainless steel and Inconel 600 (2 mils/yr or less). Cracking was observed with stressed specimens of Type 410 stainless steel, Monel 400, Monel K-500, and Inconel X-750, but not with Type 316L stainless steel and Inconel 600.

Introduction
Some years ago Shell Oil Company drilled two wells in the Salton Sea Geothermal Field. This project was subsequently abandoned. As part of the exploratory program, corrosion data were obtained both on program, corrosion data were obtained both on the surface and downhole. In view of the current interest in the possible exploitation of the geothermal energy resources of this field, it was decided to publish the preliminary corrosion test data that were preliminary corrosion test data that were obtained during this early program.
Corrosion data were obtained from stressed and unstressed specimens exposed at the bottom of one well, and from similar tests in surface equipment handling the steam and high salinity brine produced by another well in the same field.
A Parallel Multi-Block Black-Oil Model in Multi-Model Implementation
Authors: Lu Qin , Peszynska Malgorzata , Wheeler Mary F. 
Published: December 2007

Abstract
We discuss the multi-block algorithm for an implicit black-oil model as implemented in a multi-phase simulator framework IPARS. The multi-block algorithm consists of decomposition of the simulation domain into multiple non-overlapping subdomains or blocks according to the geometric, geological and physical/chemical properties, distribution of wells, etc. Each block can have its own grid system, and the grids of the neighboring blocks can be non-matching on the interface, which allows, for example, for local grid refinement, or discrete fault or fracture modeling. Adjacent blocks are coupled across the interface by a set of conditions imposing continuity of the primary variables and component mass fluxes, which is realized with the use of special interface mortar variables. The resulting system is solved by an interface Newton procedure. Regularization techniques and preconditioners are proposed to improve the performance of the solver. The multi-block technique is effective and scalable, as shown by our numerical experiments. In addition, we present how the multi-block black-oil model has been used in the coupling of different physical models.
Modeling Asphaltene Precipitation and Dispersive Mixing in the Vapex Process
Authors: Nghiem Long X. , Sammon Peter H. , Kohse Bruce F. 
Published: December 2007

Abstract
This paper describes the modelling of two important aspects in the simulation of the Vapex process for heavy oil: (1) dispersive mixing and (2) asphaltene precipitation.
The growth of the solvent chamber in the Vapex process is controlled by molecular diffusion and convective dispersion. It is shown that transverse dispersion is the dominant mechanism for fluid mixing at the solvent-oil interface. Simulation results obtained with both longitudinal and transverse dispersion, and with transverse dispersion only are illustrated and discussed.
The asphaltene precipitate is modelled as two solids: solid 1, which is in equilibrium with the asphaltene component in the oil phase, and solid 2, which is formed from solid 1 through a chemical reaction. Solid 2 can be used to represent the association of asphaltene and resins molecules and its precipitation can be made irreversible.
Representation of Crossflow Effects in Advanced Wells in a Multipurpose Reservoir Simulator
Authors: Caillabet Y. , Fabrie P. , Lemonnier P. , Masson R. , Ricois O. 
Published: December 2007

Abstract
Wellbore crossflow can have an important effect on the well production in highly stratified reservoirs. This phenomenon may also appear using EOR techniques or in advanced wells. In those cases, crossflow must be accurately represented and shutting the crossflowing layers may create significant errors on the forecast production and severe numerical problems. This paper describes the method which has been implemented in an all-purpose reservoir simulator. Our method handles both Black Oil and compositional models in a fully implicit scheme. The wells are discretized in different segments where pressure and compositions are determined. These segments generally correspond to the perforated reservoir cells. The wellbore equations are decoupled from the main Newton resolution for CPU time reduction reasons. The characteristic time-scales in the reservoir and the wells are very different, i.e. the well variables vary more rapidly than the reservoir ones. To ensure good simulation times, cheap computations are made on the wells to reach a pseudo steady state prior to the Newton resolution.
The crossflow model is used on both vertical and horizontal wells and also multilateral wells. Well control can be managed using the build-in algorithms that have been extended to crossflowing wells.
Simulation runs showing the accuracy and reliability of the crossflow modelling are presented. The numerical solution is compared with the results from other studies and with a semi analytical method.
The Calculation of Pseudo Functions Using Potential Averaging Methods
Authors: Darman N. H. , Pickup G. E. , Sorbie K. S. 
Published: December 2007

Abstract
A number of methods for calculating dynamic pseudo-functions have been developed over the years although there is still a lack of understanding as to why a certain method will succeed in some cases but fail in others. In this paper, we describe the results of an assessment of several methods, namely the Kyte and Berry (KB) method, the Stone method, the Hewett and Archer (HA) method and the Transmissibility-Weighted (TW) method. We have analyzed the equations for deriving the methods and investigated the results of numerical simulations in a variety of cases to enable us to gain new insights into these, and related, upscaling methods.
We start with immiscible gas/oil displacements in horizontal cross-sectional models with 2D → 1D scale-up. For such cases, the potential drop along the system is equal in both phases, i.e. ΔΦo = ΔΦg. Therefore, any method which maintains this equality will be successful. This is the case for the Stone, the HA and the TW methods, but not for the KB method, which uses relative permeability weighting. Despite the fact that the HA and TW pseudos are calculated differently and the shapes of the relative permeability curves are different, the resulting fractional flow curves are identical and hence identical results are obtained in terms of recovery and breakthrough. When the model is dipping, the pressure drops are different in each phase, and the Stone method (which always assumes that ΔΦo = ΔΦg) fails while the HA and TW methods still succeed.
In more complicated models, with 2D → 2D or 3D → 3D scale-up, the fluid mobilities are more important, because they govern the global pressure field and hence the flow paths of the fluids through the system. We show that the HA and TW methods both produce accurate results, provided directional pseudos are used.
Numerical Simulation of Oil Displacement by Water in a Vuggy Fractured Porous Medium
Authors: Rivas-Gómez S. , González-Guevara J. A. , Cruz-Hernández J. , Galindo-Nava A. P. , Camacho–Velázquez R. , Islas-Juárez R. , Pineda-Muñoz A. 
Published: December 2007

Abstract
This paper presents a numerical simulation study of the flow behavior within a vuggy fractured medium when oil is displaced by water. The experiments were conducted with an acrylic cell, where fractures were represented by channels of 2 mm wide, 1.7 mm depth and 16 cm long, whereas the vugs were represented by cylinders of 1 cm diameter and 1.7 mm depth. The experimental runs were carried out at different water injection rates between 2 and 200 ml/h and variable pressure between 0.006 and 0.910 psi.
The simulation runs, carried out using Eclipse 300 reservoir simulator, required to discretize the domain by using a rectangular grid with 2 mm square cells. Each cell in the vugs was divided into 3, 4 and 5 parts to approximate the vugs shape.
To simulate correctly the phenomena that occur in the experimental cell, it was necessary to try 3 different two-dimensional grids (up to12000 cells were used). It was also necessary to generate relative permeability curves and its corresponding capillary pressure curve.
Furthemore a method to calculate the capillary pressure is presented, both when the wetting or nonwetting relative permeability is available.
A good representation of the lab results was obtained through the simulation. This is relevant as an application of a reservoir simulator to study the dynamical behavior of fluids at this scale.
Environmental Risk Assessment of a Leakage based Injection Water Discharge from Draugen on the Norwegian Continental Shelf
Authors: Vik Eilen Arctander , Oen Amy , Edvardsson Trym , Isaksen Tor Finn , Flatval Kirsti , Ystanes Lars 
Published: December 2007

Abstract
The Draugen platform is operated by A/S Norske Shell and is located at Haltenbanken on the Norwegian Continental Shelf. In 1998 a significant leakage was verified from two mini-flow valves in the injection water system on Draugen. An environmental concern was associated with the chemicals that were periodically discharged to sea via the seawater return flow. In addition to implementing the necessary measures in dialog with the Norwegian environmental authorities, A/S Norske Shell conducted an environmental risk assessment of the discharge.
The risk assessment was conducted using ecotoxicological data and relevant information provided by the chemical supplier, and relevant site specific information from the Draugen field. The assessment was performed utilizing the principles in the CHARM (Chemical Hazard Assessment and Risk Management) model, which is applied in several OSPAR countries.
Three discharge scenarios were addressed. The paper outlines the steps carried out in the environmental risk assessment and describe the potential environmental risk to the marine environment, caused by the discharge. The paper will also address the measures implemented and discharge reductions achieved, resulting in a close to zero discharge of injection chemicals in 1999.
Fracturing Fluid System Concentrate Provides Flexibility and Eliminates Waste
Authors: Terracina John , Parker Mark , Slabaugh Billy 
Published: December 2007

Abstract
A fracturing fluid system concentrate has been developed for hydraulic fracturing operations. The concentrate contains a hydrated polymer, a clay-control additive, a surfactant, and buffers. It can be combined readily with water to provide the proper base gel viscosity for the desired application. The stored mixing water that is added to the concentrate can be fresh water or seawater. Hydration is instant; therefore, no work tanks are required. Cleanup is simplified because all of the additives are in the concentrate, and the mixing water that is added to the concentrate remains unchanged. Therefore, the unused water can be disposed of without environmental concern.
The concentrate reduces the amount of materials required on location and offers greater flexibility in increasing or decreasing the polymer load during a treatment. The concentrate can be prepared in advance and transported to a location to be used for a treatment. This eliminates the need to mix fluids from dry materials on location and the potential waste of those fluids if the treatment is delayed. The concentrate is stable for long periods of time, and it can be returned or used at another location if necessary.
The ability to change the fluid system viscosity and to stop fluid mixing provides new flexibility in designing hydraulic fracturing treatments and eliminating waste on location if extensive delays occur.
New Low Viscosity Ester is Suitable for Drilling Fluids in Deepwater Applications
Authors: Burrows Kim , Evans Joannah , Hall John , Kirsner Jeff 
Published: December 2007

Abstract
High biodegradability and relatively low toxicity have long made esters universally recognized as the best base fluids for synthetic-based muds in regards to environmental performance. A major limiting factor in the use of ester-based fluids, particularly in deep water, is the inherently high kinematic viscosity, a condition that is magnified in the cold temperatures encountered in deepwater risers. These higher viscosities are believed to be especially critical in deepwater wells where lack of overburden causes a severely narrowed window between pore pressures and fracture gradients. Other implications of these higher viscosities include limitations on oil/water ratios, mud weights, and drill solids tolerance.
A new low viscosity (LV) ester has been developed which overcomes these limitations while maintaining the significant environmental advantages of the original esters. The new LV ester has a kinematic viscosity nearly equal to that of currently used internal olefins. It allows formulations of drilling fluids that can be used effectively in virtually all drilling applications in the Gulf of Mexico (GOM), including deep water.
The GOM test protocol was developed to prove the viability of the LV ester as a base fluid. This protocol was designed to consider all conditions drilling fluids are expected to encounter during the course of a well. It evaluates the temperature stability, low temperature rheological properties, and the contamination tolerance of drilling fluids formulated with an LV ester base fluid. Three LV ester fluids were subjected to this protocol: an 11.0 ppg mud; a 14.0 ppg mud; and a 16.0 ppg mud. Results from this extensive laboratory testing indicate new LV ester-based fluids have overcome previous limitations, exhibiting exceptional cold temperature rheological properties, the ability to use a wide range of mud weights and oil/water ratios, and a high tolerance to contamination. In July 2000, an LV ester-based drilling fluid was used to drill a 3651 ft. interval of a GOM well in 3,669 ft. of water. The LV ester fluid performed well in comparison to the same interval drilled on an offset well with an internal olefin fluid. The initial results from that field trial are included in this paper.
Gaia Driving the Greenhouse Effect
Authors: Owen Kevin C. , Blythe Brad J. 
Published: December 2007

Abstract
There is concern that the build-up of greenhouse gasses (GHG) in the atmosphere may have significant environmental impacts. Despite voluntary reductions and various international initiatives, such as the Kyoto Protocol, the worldwide emissions of GHG continue to rise. For example, the 1997 emissions of GHG in the United States were more than 11% greater than the 1990 levels. By 2010, the GHG emissions of the United States may be more than 20% higher.
The authors of this paper suggest there may be forces beyond human control compelling human society to contribute to the greenhouse effect. The authors suggest the release of the GHG, particularly carbon dioxide, to the atmosphere may be caused by the operation of the Gaia hypothesis. The Gaia hypothesis, developed by Lovelock and Margulis in the 1970s, theorized that the Earth functions as a self-regulating system to maintain conditions on the surface of the planet within certain environmental limits.
The Recent atmospheric levels of carbon dioxide are believed to be significantly lower than the levels that existed over geologic time. The carbon dioxide levels predicted by the year 2100 by some modelers will approach the atmospheric concentrations of this gas that have been estimated for the Carboniferous Period. The year 2100 levels would still be between nine and 18 times lower than carbon dioxide concentrations that have been estimated for the Paleozoic Era. Conversely, if the carbon dioxide concentrations were to continue to drop, as has been the trend since the Paleozoic, the levels may be insufficient to support photosynthesis.
Previous researchers have suggested that, operating under the Gaia hypothesis, the biosphere and the terrestrial environment may act to moderate the impacts arising from the greenhouse effect. The authors of this paper suggest that the functioning of the Gaian forces may actually be driving the human species to contribute to the greenhouse effect.
Human activities may be fulfilling a need of the biosphere by releasing buried carbon reserves to the environment. This reclamation of the buried carbon reserves may ensure that biological productivity is maintained, and increased, over time. If so, greenhouse control measures should focus on measures that accelerate the removal of carbon dioxide by the biosphere, sequestering carbon dioxide from the atmosphere.
E&P Waste Management in the Orinoco Delta
Authors: Melchor A. E. , Da Costa A. , Rodriguez C. , Peña J. R. 
Published: December 2007

Abstract
Tropical wetlands and the presence of indigenous people with an ancient culture and strong economic dependence on natural resources, made the Pedernales field an environmental and social sensitive location. The challenge for BPA was to operate in this area without disrupting the lifestyle of the nearby settlements while preserving the environment.
Pedernales field was designed as a zero discharge operation, where the main was streams were to be re-injected. However, due to operational constraints, the initial waste management strategy had to be changed to one that also allowed the disposal of wastes in an environmentally sound way. Waste recycling, bio-treatment and temporary off site treatment and disposal were the key processes of the new waste management strategy.
During 5 years of operations, a total of approximately 2.6 MM bbl of E&P waste were handled and disposed successfully. Poor area drainage, combined with high annual rainfall and low natural soil supporting capacity, required the use of non-conventional tools and equipment; this was more evident for the disposal of drilling cuttings.
Drilling cuttings were handled by turning them into slurry using a specially designed mixer, and then pumping the slurry to a distance of up to 2 Km from the storage barge. Oil degradation from 6%, oil and grease, down to 1% was accomplished in approximately 180 days. This is considered to be a short time taking into account the high level of soil/waste moisture saturation. Continuous monitoring of water and soil with a simple on-site laboratory proved to be adequate and cost effective for process control and prevent environmental pollution.