bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Investigation of Counter-Current Imbibition Processes in Diatomite
Authors: Zhou D. , Jia L. , Kamath J. , Kovscek A. R. 
Published: December 2007

Abstract
Oil recovery from low permeability reservoirs is strategically important because of the large resources locked in such formations. Imbibition is fundamental to oil recovery from such reservoirs under most secondary and improved recovery processes of practical interest. It is also characteristic of porous medium wettability. The rate and the extent of imbibition depend critically on the viscosity of the wetting and nonwetting phases. In this study, we present our recent work on imaging imbibition in low permeability porous media (diatomite) with X-ray computed tomography. The viscosity ratio between nonwetting and wetting fluids is varied over several orders of magnitude yielding different levels of imbibition performance. We also perform a mathematical analysis of counter-current imbibition processes and develop a modified scaling group incorporating the mobility ratio. This modified group is physically based and appears to improve scaling accuracy of countercurrent imbibition significantly.
Relief for worn-out API Ring Wellheads
Authors: Jones Jeff 
Published: December 2007

Abstract
Texaco has been concerned for years with the problems of wellhead emissions and has spent much time and money on prevention and control. One weak point in the typical wellhead system is the API ring wellhead flange seal. Improper installation procedure is the main cause of seal failure. For those few instances of defective flanges, Texaco developed an elastomer backup seal that prevents expensive flange replacement.
Dynamic Flow Performance Modeling of a Gas-Lift Valve
Authors: Faustinelli J. G. , Doty D. R. 
Published: December 2007

Abstract
A new unified model that predicts the flow performance of nitrogen charged injection pressure operated gas-lift valves has been developed and is able to predict the volumetric flow rate more accurately than previous models. The new model exhibits orifice, throttling and transition flows which encompass all of the flow regimes encountered in a gas-lift valve. The model is based upon fundamental physical principles and has the advantage of describing the internal flow mechanics occurring at the ball-seat and port locations.
The model predicts an isentropic process from the upstream condition to the minimum flow area. The model also predicts a pressure recovery associated with the sudden gas expansion occurring beyond the minimum area of flow. This recovery was verified by experimental data, and it has been included in the new model. Previous models did not incorporate the pressure recovery effect, and in order to match the experimental data, it was necessary to empirically modify the compressible flow theory used to develop these models.
The new model is simpler (i.e. requiring fewer empirical coefficients), more reliable, more accurate and more theoretically consistent than previous models. The new model allows a feasible explanation of the fundamental physical behavior of the different flow regimes within a gas lift valve. Experimental data, obtained from a dynamic test facility, show an excellent agreement between the data and the predictions generated using the new model.
Use of Coiled-Tubing on Production Wells Located in the San Jorge Basin
Authors: Zurita D. N. , Abella F. J. , Luongo S. , Maino J. C. , Montenegro E. M. , Panza L. A. , Lopez R. E. , Sequra H. R. , Romero V. M. , Cavieres G. E. Gomez , Homes A. H. , Romero E. O. 
Published: December 2007

Abstract
In the continuous search of the optimization of investmensts and the reduction of operative costs, Repsol-YPF decided to research the possibility of the use of Coiled Tubing to produce traditional diameter wells at the Golfo San Jorge Basin. This represents a further step after an experience undertaken in reduced diameters started in 19971.
Through this new experience it was proven that it is posible to produce wells with diameters higher than 3.5 in. Using coiled tubing in mechanical pumping, generating at the same time new possiblilities for coiled tubing with other artificial lift systems.
Problems in Gas Hydrates: Practical Guidelines for Field Remediation
Authors: PAEZ J.E. , Blok R. 
Published: December 2007

Abstract
Natural gas hydrate formation is a costly and challenging problem for the oil and gas industry. In recent years, two new families of chemical additives have been commercially developed to prevent hydrate plugging problems in production lines. This approach is commonly known as low-dose inhibition, and the two families are kinetic inhibitors and anti-agglomerants. Evolution of these new products is proceeding at a rapid pace, in order to meet goals of covering a greater range of operating conditions and finding an economically and environmentally attractive alternative to thermodynamic inhibition.
Successful deployment of low-dose inhibitors depends on an appropriate selection of inhibitors and a complete understanding of the system. Based on a synthesis of available literature on application of low-dose inhibitors to hydrocarbon processing equipment and handling facilities, this paper describes a methodology for designing a deployment strategy. This guide provides a systematic approach to aid production engineers in deploying low-dose inhibitors in existing facilities and new developments. An easy-to-follow flow chart is given.
The information provided in this article was compiled from published data, and experience provided by several companies in the oil and gas industry.

Introduction
Natural gas hydrate formation is a costly and challenging problem for the oil and gas industry and tends to be most critical for offshore facilities. Since the time when hydrates were first identified1, the oil and gas industry has injected a constant flow of resources into the search for an economic and environment friendly solution to the problem of hydrate prevention.
Thermodynamic inhibition has been the conventional approach to natural gas hydrate inhibition. System composition or operating conditions are altered so that over the range of operating temperatures and pressures, the hydrocarbon system falls outside the pressure-temperature region in which hydrate formation can occur. (See Figure 1)2.
Keeping operating pressures and temperatures out of the hydrate formation region can be achieved by making system adjustments such as applying heat, using insulated pipelines, or adding chemical compounds (thermodynamic inhibitors) that change the behaviour of the new mixture.
A systematic Approach to Sampling During Well Testing
Authors: Dybdahl Bjørn , Hjermstad Hans Petter 
Published: December 2007

Abstract
The industry is focusing on cost reductions by saving on expensive rig time and on reducing the impact on the environment during well testing. Decisions regarding field development are increasingly taken based on the results of samples and data obtained by wireline formation tester/samplers (WFT/S) and not on data obtained by flow to surface during a drill stem test. The use of oil-based mud to increase the drilling rate is also becoming more common. These measures reduce the likelihood of obtaining quality fluid samples and increase the uncertainty in field development projects related to fluid data. A systematic approach to fluid sampling is presented which discusses the different aspects related to the quality of fluid data obtained depending on the sampling method, type of reservoir fluid system and formation properties. Recommendations for the decision making process are presented.
First Horizontal Well Opens New Gas Opportunities in the Sierra Chata Field, Neuquén Basin, Argentina
Authors: Sanz C. A. , Nilson G. J. , Acree J. F. , del Pino M. 
Published: December 2007

Abstract
The first horizontal re-entry gas well was successfully drilled and put on line in the Sierra Chata field in the Neuquén basin in Argentina. This article compares the model forecast with the results obtained. The objectives were: (1) to add gas reserves and (2) to incorporate horizontal technology that will allow access thin or low permeability sands, in remote areas that would be economically marginal with vertical wells.
Recent interpretation of 3-D seismic and geologic data indicated that the "D" Sands were better developed to the northwest of the vertical well SCh-17. In order to access gas reserves postulated to exist there, it was planned to drill a horizontal re-entry well utilizing the existing vertical well, SCh-17 as a re-entry conduit. From the well SCh-17 a re-entry was made at 244 m from the deviation point (KOP) in 1600 m MD, drilling slightly up-dip to 2975 m MD, using with a downhole motor and a MWD logging system.
Shale-silt lithologies within the sand members affect the vertical transmissibility (TZ) between the "D" Sand members. Sensitivity runs were made using a reservoir simulator built to test the effect of such variables on the horizontal well productivity. For the most probable case, an initial flowrate of 17.7 MMscfd (502 Mm3/d) was predicted. A final cumulative production of 7.3 BSCF (206.7 MMm3) of gas was predicted by the numerical simulation model.
Six months of production history confirmed the forecast and assumptions made in the well proposal and also encourage new horizontal prospects. This year, two additional horizontal wells have been proposed to be drilled in the Sierra Chata field applying some of the concepts proven by the subject well. At least one of which will include an additional deviation of the horizontal wellbore to intersect multiple target zones.
Experiences in the Use of ESP's in Orinoco Belt Cerro Negro Area, Venezuela
Authors: Ramos Marcelo A. , Rojas Carlos R. 
Published: December 2007

Abstract
Traditionally, in the Cerro Negro area up until 1995, conventional rod pumping units and progressive cavity pumps were used in vertical and inclined wells with production rates ranging between 200 and 600 b/d.
With the incorporation of the horizontal drilling technologies in unconsolidated sands for the construction of wells with high productivity indexes (4-6 b/d/psi), the evaluation of electrical submersibles pumps (ESP) begun as an alternative to handle high production volumes of 8 degrees API bitumen characterized by its viscosity of 5500 cp at a reservoir temperature of 130°F.
To aid production, a dual well completion design was used, parallel to the production tubing a second tubing with a smaller diameter was installed to allow diluent (32°API) injection at the bottom of the wells, diluting the bitumen from 12.5 to 13.5° API, an decreasing its viscosity to a range of 500–800 cp. Additionally, buy lowering the viscosity gas separation was aided before the intake of the pump.
At the beginning of the project, ESP's with nominal capacities of 4000 b/d of flow were installed in re-entry wells, diluent injection was done using ½" coiled tubing attached to the production tubing parallel the power cable, reaching production rates in the order of 800 to 1000 b/d of bitumen. Subsequently, in new horizontal wells, ESP's with capacities of 8000 and 6000 b/d of flow were installed, and two different diluent injection string designs were used.
The first design used was two 1/2″ coiled tubing strings assembled with the power cable, with this system diluent was injected at the pump level; the second design was regular 1,5-1,9″ cs-hydrill tubing strapped to the production string, allowing diluent injection below the pump, at the top of first slots in the horizontal liner
This second system was selected as standard together with ESP with a nominal capacity of 6000 b/d. Bitumen production rates ranging from 1500 to 2000 b/d of bitumen are obtained by injecting 400 to 600 b/d of diluent, decreasing friction losses and obtaining an average of 30% of pump efficiency. Additionally, the use of the system has increased the run life of the pumps, actually 33 months.
To improve the efficiency of the ESP pumps new devices are being tested, an inducer was installed in substitution to the down hole gas separator. Simulations indicate that this device, placed at the intake of the pump, will permit gas handling through the pump, decreasing the fluid column weight.
Orinoco Belt, Cerro Negro Area: Development of Downhole Diluent Injection Completions
Authors: Alexander Rojas R. 
Published: December 2007

Abstract
Traditionally, in Orinoco Belt Cerro Negro area, Venezuela, beam, progressive cavity and electrical submersible pumps have been used for bitumen extraction.
In order to facilitate bitumen transportation down hole to surface, diluent is injected to decrease formation viscosities which are in the order of 5000 Cps at reservoir conditions (135 F, 3500 ft depht and 1200 psia).
Diluent is injected through the annular space, by gravity in beam and progressitive cavity pumps. This method, in some cases, does not guarantee proper dilution at the entrance of the pump because of the gas accumulation at the annular section, causing, in some cases, lifting problems, such as high torque, high loads in the rod strings, damages in the rods, operational problems in surface lifting units and pumps working at maximum discharge pressures limits.
In order to guarantee proper operation in the electrical submersible pumps bitumen should be diluted before entering to the pump.
In 1995, some tests began with new completion designs, in order to guarantee an homogeneous mixture at the bottom. The result has been a different completion for each method, using additional accessories at the entrance and at the discharge of the pumps, to improve transport, pumping efficiency, higher production and an improvement of the system running life.
The design consists on a injection port located, either at the pump entrance or at the pump discharge a continuous 3000 ft 0.5" or 1.9" diameter tubing, and a perforated injection 1.9" diameter tubing attached to injection port allowing the diluent get to the producing zone in order to improve dilution..
Emerging Technologies in Subsurface Monitoring of Petroleum Reservoirs
Authors: Islam M. R. 
Published: December 2007

AbstractMost oil fields do not produce more than 45% of the oil-in-place, even after enhanced oil recovery schemes have been applied. Most of this unproduced oil is missing because most displacement techniques by-pass significant portion of the original reserve. Finding this missing oil can lead to significant economic windfalls because the infrastructure for additional oil recovery is already in place and the cost of production is likely to be minimal. In this paper, all existing monitoring techniques, including 4D seismic and downhole seismic sensors, are reviewed. This is followed by a comprehensive review of emerging technologies in subsurface monitoring. These techniques include multi-well seismic, electrical resistivity tomography, electromagnetic and ultrasonic imaging, acoustic and fibre-optic imaging, as well as laser/infrared or MRI/NMR visualization near the wellbore region.A detailed analysis indicates that for an accurate reservoir engineering analysis, geostatistical models should have information of 1m scale. This is the only scale that would satisfy the representative elemental volume (REV) requirement of an enhanced oil recovery (EOR) system. This scale length is orders of magnitude higher than that of core samples and at least an order of magnitude lower than the conventional seismic data. This data gap constitutes the weakest link between geophysical information and reservoir engineering. Any attempt to reconstitute the reservoir without information regarding petrophysical properties and fluid saturations in the 1m level, one risks falling into the trap of multiple solutions – a typical problem of history matching through reservoir simulation. To obtain a resolution of 1m scale, one must investigate the possibility of using 50-2000 Hz seismic frequency range. While this seismic range cannot be used with vertical seismic profiles (VSP) because of the travelling distance constraints, multiwell imaging can be used with multi-component receivers. This system, in combination with borehole seismic sources, can provide one with the desired resolution. The same system can be used in combination with resistivity tomography, a method that has recently given satisfactory results for tracking ground-water contamination. The images can be further refined with acoustic and fibre-optic imaging techniques. These techniques can provide satisfactory details to track viscous fingering, wormholes, and other time-dependent properties of an active reservoir. Finally, infrared/laser or MRI/NMR imaging of a wellbore is still in its nascent state of development, but holds great promises for the future applications of real-time monitoring and eventual dynamic reservoir management.
Early Environmental Warning System for Underground River Crossings
Authors: Pisano Guillermo , Bouzas Carlos , Villa Horacio 
Published: December 2007

Abstract
This is an example of the application of a combination of the latest technologies to assure the early detection of leaks in underground river crossings and environmentally sensitive zones of gas and oil fields operated by Perez Companc.
One of the most important environmental impact risks within our oil and gas production operations is the potential possibility of spilling hydrocarbons to our rivers. Tens of cities, that take drinking water for the human consumption or that use the resource as a means of recreation and thousands of hectares irrigated for the maintenance of the agricultural and cattle-raising activity, gives significance to these risks.
To reduce these risks in the 260 mts. long underground crossing of the Neuquén River, located in the Neuquén province, Argentina, an annular casing system was devised. This space is pressurized with nitrogen to a level over that of the pipeline. Any abnormal condition is detected through the supervision of both the casing and pipeline pressures with a very simple control logic implemented in a remote transmission unit (RTU)
In case of a leak, or defect in any system, the RTU is responsible for closing pipeline valves and sending remote and local alarms to the field's SCADA system. The RTU is connected to the Supervision, Control and Data Adquisition (SCADA) System through a digital Spread Spectrum radio link.
The simplicity of the control logic and the pressure transmitters and communication system reliability assures an interesting cost-benefit relationship.
Extensive Evaluation of Aerated Accumulation Technique for Soil Treatment
Authors: Ercoli E. , Gálvez J. , Calleja C. , Calvo V. , Cantero J. , Videla S. , Medaura M. C. , DiPaola M. 
Published: December 2007

Abstract
A pilot study of hydrocarbon biodegradation in soil using the aerated accumulation technique (AA), performed in the oil field Loma La Lata of Repsol-YPF SA in the province of Neuquén (Ercoli and others, IAPG, 2000) yielded satisfactory results. We considered the possibility of applying this biological technique on the treatment of big amounts of contaminated soil. The experimentation showed the possibility of reaching cleaning goals in comparative shorter periods of time, of about three months, starting from soils moderately contaminated with light hydrocarbons. Some important advantages in comparison with other biological techniques such as land-farming or biorestoration were additionally observed. The moisture of the soil was maintained during the treatment with no need of extra addition of water - cost to be considered in superficial treatments- and produced an important spontaneous increment of the temperature of the soil. These two characteristics of the process are particularly attractive for arid soils and cold regions, since these two factors, scarce humidity and low temperature, delay the global kinetic of biodegradation.
On the base of the pilot experiment results, the application of the technique in larger scale on diverse kind of contaminated soils in oil field of Neuquén province was decided. Volumes of 20000 m3 of lightly contaminated soil, 8000 m3 of moderated contaminated soil and 22000 m3 of highly contaminated soil, were treated. In all of the cases, an efficient reduction of the contaminants up to predetermined values was observed. The evaluation of these parameters let us conclude that an important number of cases of contaminated soils with hydrocarbons can be resolved in an efficient and economic form using this technique.
Lateral and Vertical Discrimination of Thin-Bed Fluvial Reservoirs:Geostatistical Inversion of a 3D Seismic Data Set
Authors: Marcos Victoria , Merletti German , Cuenca Alvaro Grijalba , Verdin Carlos Torres 
Published: December 2007

Abstract
The San Jorge Basin is one of the most prolific hydrocarbon bearing zones in Argentina.The Cañadon Seco Formation is characterized by sandstones with thickness usually bellow the tuning lenght, under these conditions high uncertainty exists in sandstone prediction when seismic amplitudes are analyzed, due to interference and tuning effects. This paper presents an estimation procedure that overcomes these limitations based on the extrapolation of the well data further away from its location by Geostatistical Inversion of 3D seismic data. Although vertical sampling of the seismic data is much less dense than the one from logging, its higher lateral resolution is used to complement the high vertical resolution of the well data. Unlike conventional trace based inversion in which the source is the seismic data in Geostatistical Inversion the data source is the well, and the estimated acoustic impedance values satisfy the seismic data, in this way driving resolution to an intermediate range between the well and seismic data. With this procedure stochastic simulations of the petrophysical variables are generated, (density and lithology) that not only honour the hard data of the wells but also the seismic data, and minimize the residual error between the Synthetic model and the real 3D-Seismic trace. Each simulation (SGS-Simulated Annealing and SIS) is itself a possible solution to the problem and it is called a realization, wich is then integrated into an average to optimize the certainty of the predictions. The Acoustic Impedance, density and lithology models derived from GI have a resolution of 1ms. This allowed discriminations of lateral variations in the petrophysics of the reservoir (density porosity) and the delineation of sand packets of up to 6 meters thick. The Geostatistical Inversion turned out to be a very powerful tool for the static reservoir modelling wich can function itself as an input to the dynamic model (reservoir simulation), guide the development of the block and assists to the EOR.