bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Seismic Attribute Filtering with Factorial Kriging to Estimate Porous Volume: A Case Study on a Brazilian East Coast Offshore Turbidite Reservoir
Authors: Mundim Evaldo Cesário , Remacre Armando Z. 
Published: December 2007

Abstract
The estimation of reservoir properties is a risky issue. Uncertainties come around; the number of wells (hard data) is often low and poorly distributed. Densely sampled, 3D seismic information (soft information) has been seen as a key to reducing interwell uncertainties. As it is well known, however, even after seismic processing, noises and sign distortions remain if not introduced by the processing itself. Moreover, inconsistency in horizons picking, during interpretation, worsens the quality of the obtained attributes with corresponding impact for its use as a predictive variable for reservoir mean properties estimation.
In this paper, we discuss incorporation of seismic attributes filtered by Factorial Kriging via conditional simulation on reservoir porous volume estimation. The seismic attribute mean acoustic impedance obtained from a 3D seismic program with seismic stratigraphic inversion is considered. It shows itself to be well correlated to the porous thickness of the reservoir interval under consideration. A nested corregionalized model, which presented two structures, was fitted to the attribute. The small range associated to data noises was filtered by Factorial Kriging, which improved the correlation between the acoustic impedance and the porous thickness. The dispersion of the conditional simulation constrained by the filtered seismic attribute is lower than the dispersion of the conditional simulation constrained by the pre-filtering attribute, reducing the uncertainty of the reservoir porous volume estimation.
Lateral Discrimination of Sand Packets with 3D-Seismic-Derived Acoustic Impedances, La Itala, Golfo San Jorge, Argentina
Authors: Merletti Germán , Marcos Victoria , Courtade Sergio F. , Pringgadani Meilando 
Published: December 2007

Abstract
The depositional environment in the west section of the Golfo San Jorge Basin is characterized by fluvial sand-shale sequences in which the reservoirs rarely have thickness that exceeds 10m, while average thickness is 4m. The acquired seismic has a tuning thickness of 17m, so that the wavelet effect and thin bed interferences make the seismic derived attribute analysis not ideal for lateral and vertical delineation of sandstone complexes. The seismic limitations of only describing interfaces without discriminating lithologies, is overcome inverting 3D seismic traces into pseudo logs of Acoustic Impedances by applying a constraint sparse spike algorithm. Both well data (lithology and compaction) and horizons (structural framework) help to constrain the process, thus the reflectivity series found meets the criteria of minimizing the residual between the synthetic model and the real 3D seismic trace. An Acoustic Impedance volume is derived from the reflectivity series, (the frequency spectrum is limited to the seismic bandwith lacking the low frequencies corresponding to compaction) and is called bandlimited. Impedance logs from key wells were generated, filtered to a range between 0-7 Hz and then interpolated (honoring both the stratigraphy and the structural framework) to generate a low frequency model of impedances. By merging the low frequency model with the bandlimited volume a total Acoustic impedance volume is obtained.
Well data analysis describes that Acoustic impedances not only at well frequency but also at seismic frequency are visualized as maximum for sandstone packets. The acoustic impedances derived from the inversion process are sensitive to the presence of a stack of several sand units and hence can be used to map lateral variations of petrophysical reservoir properties. We have attempted to quantify the petrophysical properties of such sand sequences using extensive well control. To do so we first low-pass filtered the well logs to exhibit vertical variations consistent with those of the 3-D seismic data. The low-pass filtered logs were further analyzed via lithology-based cross-plots to ascertain their effective petrophysical properties. This procedure successfully provided us a quantitative model to predict vertical and lateral variations of petrophysical properties from seismic-derived acoustic impedances. We have also developed a similar procedure based on attributes extracted from the reflectivity data generated as by-product of the inversion process. This effectively allowed us to delineate the lateral and vertical petrophysical behavior of useful sand units for subsequent in-fill and step-out development operations. We have successfully tested this methodology on a number of new wells in the area.
Optimizing Development Costs by Applying a Monobore Well Design
Authors: García Rodolfo , Alfaro Edgardo , Bernardis Alfredo , Casalis Daniel , Gallardo José , Del Zotto Daniel , Alonso Adrián 
Published: December 2007

Abstract
The An Aike-Barda Las Vegas field, located in the Austral basin 80 km west of Rio Gallegos, Argentina, represents an important discovery in basin development in recent years. The field is an important Springhill formation gas reservoir at an approximate depth of 3100 m and with static pressure of 4400 psi. Gas rates are up to 1 MM m3/d/well.
Drilling appraisal and development wells requires the optimization of every operation involved. In this context, improvements in well construction and completion methodology are important contributions. Original well design included 13 ⅜-in. surface and 9 ⅝-in. and 7-in. casings, with a permanent packer and 4 ½-in. tubing. The new monobore well design reduces the diameter of each drilled section, narrowing to a 4 ½-in. monobore installation through the pay zone. The rigless completion includes coiled tubing.
Before adopting the design change, potential risk analyses were made to account for the possibility of future reentries and for simultaneous development of a second target (Magallanes formation) at 1700 m. The final well design model showed a cost savings of 30 percent, a sizeable impact on the economics of this project.
Modeling Aspects of Wellbore Stability in Shales
Authors: Frydman M. , da Fontoura S. A. B. 
Published: December 2007

Abstract
Drilling problems associated with wellbore instability are normally aggravated when crossing shale layers. Instabilities in shales may be caused by a complex mechanism of shale-drilling fluid interaction and by the overstress of the rock formation. Wellbore stability models that include some aspects of this coupled phenomenon have already been developed. However, the use of these models without the knowledge of the associated simplifications may lead to wrong conclusions.
The present paper discusses the modeling aspects of the coupled process. Three formulations are compared: an analytical elastic solution without the diffusion process, an analytical poroelastic solution and a numerical chemical-hydro-mechanical model. The objective is to analyze the applicability of each model.
Design of an Acid Stimulation System With Chlorine Dioxide for the Treatment of Water-Injection Wells
Authors: Cavallaro A. , Curci E. , Galliano G. , Vicente M. , Crosta D. , Leanza H. 
Published: December 2007

Abstract
Water treatment and injection well stimulation are two important contributions to oil lifting cost at Barrancas oil field. As most of mature fields, waterfloding represents a hugh amount of oil production. Although average water quality is quite good some injection wells require regular hydrochloric acid stimulation in order to restore injectivity, impaired by different solids, mainly calcium carbonate and sulfides. A new stimulation system was designed. The system combines the conventional acid system with an aqueous chlorine dioxide solution.In this approach chlorine dioxide activates at the bottom of the injection well. The oxidating power of chlorine dioxide removes completely all solids that are not sensitive to acid treatments. The synergistic effect of the proposed treatment was determined in two different flow core tests on reservoir samples.Due to successful results at the lab, a decision was made to perform field tests in four injection wells. A dramatic and continuous decrease in wellhead pressure were the results obtained after several weeks of treatment. In order to analyze and prevent corrosion effects a parallel study was designed and conducted on tubing samples at reservoir conditions.
Water Control Experiences in the Motatan Field Using Specially Designed Gels
Authors: Alvarez Inés , Espinoza Mária G. , Amaury Marín T. , Hernández María I. , Rossana Caira , Der Sarkissian Juan , Martínez José L. 
Published: December 2007

Abstract
Motatan field is located in the Western part of Venezuela. The area has two main lenticular reservoirs which are constituted by low primary permeability sandstone, in most of the cases with a high density of natural microfractures. The Domo Sur area presents high water cut problems, which have been attributed to natural fractures channeling. Therefore, gel technology evaluation was proposed to mitigate this problem. Four wells were selected. The injected gel system was designed to be used at specific reservoir conditions and with Disproportionate Permeability Reduction (DPR) effect. In all cases, the gelant was injected using the bullheading technique and a penetration ratio of about 15-17 feet was used. Overall results showed the system effectiveness, since it reduced water production in all wells. A reduction of 6,900 BWPD (80.4%) was obtained and oil production was increased in 700 BOPD (31.7%), once the water cut was stabilized.
Improvement of Gas Recovery Factor Through the Application of Dewatering Methodology in the Huamampampa Sands of the Aguaragüe Field
Authors: Girardi F. , Lagrenade E. , Mendoza E. , Marín H. , Conti J. J. 
Published: December 2007

Abstract
The Huamampampa formation is one of the best gas reservoirs of Devonian basin located in the North-West of Argentina. In the Aguaragüe field, this natural highly fractured reservoir has produced a large amount of gas, even after most of the producing wells became watered-out.
An excellent improvement of gas recovery factor has been achieved by the implementation of an unusual dewatering methodology. The method consists of applying a gas-lift production system to extract water from each flooded well. This type of exploitation causes a delay of the wells water encroachment and an increment of matrix gas production through the wells located at the top of the structure.
In this paper we show the benefits of the implementation of this gas exploitation scheme as applied to the field.
There have been numerical simulation studies performed in different stages of the exploitation and by different authors. The last study takes into account a vast gas and water production history. Different exploitation cases have been analyzed. The sensitivity scenarios presented here demonstrate the need and the benefits of dewatering.
Analysis of Salinity Changes Caused by Brief Shut-in of Wells in Secondary Oil Recovery
Authors: Somaruga C. A. , Gazzera C. E. , Wouterlood C. J. 
Published: December 2007

Abstract
This paper presents a methodology to determine the origin and dynamics of bottomwater in a producing well influenced by several injectors in a secondary recovery pattern. This methodology requires a brief shut-in period in order to better identify the effect of flow patterns in the near wellbore region of the producer. During the shut-in period, water coming from the dominant injection wells can move forward, invading areas of a layer that has been previously occupied by other waters. Once the well is reopened, a salinity contrast between the injection and produced waters can be measured.
Then, it is proposed to determine the original flow distribution around the producing well by means of a simple balance of salt mass.
Salinity changes produced by shut-in injectors are analyzed as a complementary tool for identification of dominant injectors.
Representative results of several cases that may arise from a hypotetical reservoir are also presented. Finally, a case study from the Neuquen Basin of Argentina is presented that demonstrates the proposed methodology.
Numerical Simulation Model of Highly Faulted Reservoir based on an Integrated Approach in Lake Maracaibo
Authors: Mijares O. , Ramonez M. , Romero M. , Muñoz P. 
Published: December 2007

Abstract
This paper presents the results of the numerical simulation model of the highly faulted reservoir C40/44 located in the West Flank, Block I, Lake Maracaibo western Venezuela. Based on an Integrated Approach study1, the 3D dynamic model allowed to evaluate the impact of the sealing character of the inverse faults and their potential influences in the migration and fluid distribution across the faults, and consequently, the grade of difficulty in the adjustment of the historical production subjected to the water injection influence from Dic/71.
In spite of the simulation model is highly sensitive to the changes of the reservoir parameters, it is considered that the feasibility grade of the model is enough (85%), to understand the relative movement of the fluids for blocks, to quantify with certainty the recurrent remaining reserves and to identify the field development opportunities and exploitation.
Increasing Reserves by Applying 3d Seismic in Mature Exploitation Areas
Authors: Anzulovich L. , Cerdán J. , Regazzoni C. , Lay R. 
Published: December 2007

Abstract
This paper describes the positive results yielded by a 3 D seismic survey conducted across mature exploitation areas of the La Ventana and Vizcacheras oil fields.
It shows how to carry out integrated field scale studies and discusses the La Ventana Norte and Cañada Dura discoveries made by applying a new structural model derived from said 3 D seismic survey. The discoveries pertain to structurally low areas that had been disregarded before recording the 3-D survey.
The original exploitation area has been substantially extended with the discovery of new separate areas.
Multidisciplinary studies based on 3 D surveys allowed to carry out deep studies on mature oil fields. They also contributed to define fundamental criteria for understanding lithologic and stratigraphic changes, which helped distinguish this type of fields.
Transport Properties of Porous Media from Thin-Sections
Authors: Hidajat I. , Rastogi A. , Singh M. , Mohanty K. K. 
Published: December 2007

Abstract
The objective of this work is to predict transport properties within any complex porous medium from its 2D micro-image. Three-dimensional porous media are generated that have the same porosity, autocorrelation, chord length distribution and lineal path function as a given 2D micro-image of a medium. The properties of the regenerated media are compared with those of the original media. A pore skeleton and Euclidean distance map are determined for the 3D pore-space from which body radius, throat radius and connectivity distributions are extracted. This network structure is used in calculation of transport properties. Specific surface area is estimated accurately. Permeability and formation factor are estimated approximately. The correlations between adjacent pore bodies and throats are identified.
Stratigraphy, Sedimentology, and Reservoir Characteristics of the Lower Member of the Yacimiento El Trébol Formation
Authors: Courtade S. F. , Arijon E. , Salomone G. , Chebli P. 
Published: December 2007

Abstract
Exploration in the offshore Golfo San Jorge Basin requires an understanding of the regional trends of the Lower Yacimiento El Trébol Fm. Sandstones. These reservoir rocks yield the best oil shows in the offshore and they are among the most prospective and prolific onshore reservoir on the Golfo San Jorge Basin's north flank.
Detailed correlation enabled identification of three lower order sequences in this stratigraphic interval. These sequences are recognizable on seismic sections and well logs.
The Lower Yacimiento El Trébol interval was regionally correlated from the offshore wells to the producing intervals at Escalante and El Trébol fields. No major truncations or stratigraphic wedges were identified on seismic lines or well logs, although the individual sequences that comprise this package can thin against some persistent structural highs.
In addition, these sequences were correlated in 144 wells all around the north flank of the basin; sand thickness was measured from the SP curve in these wells. Net sand and sand percent maps were created.
These maps demonstrate that lower Yacimiento El Trébol sandstones are concentrated in sand fairways in the Comodoro Rivadavia area and in the area south of the Marta wells. Conversely, there are many parts of the basin where Lower Yacimiento El Trébol Formation is represented by silts and shales (west and south of Comodoro Rivadavia and between Comodoro Rivadavia and Marta wells).
Sand rich fairways, represented by gross thickness isopachs, map as trends that are perpendicular to the basin edges. Lower Yacimiento El Trébol production is found in these thick sand areas, while in thin sand areas, production comes from the underlying Comodoro Rivadavia Fm.
GIS of Surface Facilities
Authors: Pochettino H. F. , Kovacs G. 
Published: December 2007

Abstract
In all commercial activity, in order to increase the business objective, that is the rentability, the corresponding Administrations work for the maximization of the investments efficiencies.
Each increase in the celerity and precision of the information feed-back process will become in an increase of the benefits because the deviations from the budget and the corresponding actions will be the smallest.
In the Oil Industry an index commonly used, that include the costs started in the different stages of the production process, is the Operative Cost.
Because Surface Facilities are part of the Production System, theirs costs will increase the Operative Cost.
One form to optimize the Surface Facilities cost is by the automation of the Surface Facility's Information Systems so as to reduce answer times. Computing is one tool to find this automation.
GIS is a computing tool developed for integrate information and bases its work in the administration of the information related to points placed over the Earth surface.
The present job shows the GIS Project developed for the Vizcacheras Field Surface Facilities, Province of Mendoza, Argentine Republic.
Steam-Propane Injection for Production Enhancement of Heavy Morichal Oil
Authors: Ferguson M. A. , Mamora D. D. , Goite J. G. 
Published: December 2007

Abstract
Laboratory experiments have been conducted to investigate the use of propane as a steam additive to enhance production of 13.5°API oil from Morichal field, Venezuela. The main component of the apparatus is an injection cell into which is tamped a sand mix consisting of sand, water, and oil. Thermocouples placed in the cell enable tracking of the steam front. The cell pressure is set at 50 psig, while superheated steam at 160°C is injected at 5 ml/min cold-water equivalent at the top of the cell. Produced liquid is collected from the bottom of the cell, and after emulsion-breaking treatment, oil and water volumes are measured.
Experimental runs have been conducted in which the propane:steam mass ratio is varied from 0:100 (steam only) to 5:100. A run using 5:100 nitrogen:steam mass ratio has also been made to evaluate the contribution of convective heat to oil production. The main findings of this research (derived from four runs with consistent operating conditions) are as follows. First, the propane:steam mass ratio of 5:100 accelerates the start and peak of oil production by 20 % and 13 % pore volume steam injected (cold-water equivalent), compared to steam injection alone. In the field, this could translate into significant gain in discounted revenue and reduction in steam injection costs. Second, oil recoveries appear to be similar in all cases, 63 % - 70 % OOIP. Third, the start of production is practically the same for 0:100 and 1:100 propane:steam ratio and for 5:100 nitrogen:steam ratio, indicating probably a minimum propane:steam ratio requirement. Fourth, oil production acceleration in the 5:100 propane:steam case is probably caused by 'dry distillation'. Last, convective heat transfer at any of these low (5:100) ratios appears to be of secondary importance. Research continues to better understand the mechanism and thereafter model the production of oil under steam-propane injection.
Reservoir Characterization and Exploitation Scheme in the Orinoco Oil Belt
Authors: Uzcategui E. 
Published: December 2007

Abstract
Production development in the Orinoco Oil Belt started with data gathering programs that included high resolution 3D. Although the acquired seismic information was considered of good to very good quality, it was not enough to provide the details needed to maximize the amount of sand contacted through horizontal drilling.
The complexity of the reservoir architecture required additional control data to allow the operator to position the well in targets suitable to support the economic of the project. Additional drilling, in the form of stratigraphical (vertical and/or slanted) and observation wells, plus coring programs, well seismic and rock sampling provided the input for an appropriate reservoir description.
Once model integrating such data were produced, geostatistical manipulation allowed the estimate of ranges of oil in place, sand body typing, aquifer distribution and so forth. This effort clearly impacted the development programs by suggesting changes to multilateral geometry, pad configuration, draining point location and well spacing.
This paper will focus on how should the above mentioned topics to optimize the field performance be linked and still achieve the economic goals for everyone defined in the projects.
Controllability and Observability Issues for SAGD Intelligent Control in Venezuela
Authors: Herrera Lourdes , Mendoza Humberto 
Published: December 2007

Abstract
PDVSA has being operating a Steam Assisted Gravity Drainage (SAGD) process[I1] since 1997, as part of a pilot test carried out in the T a Juana Field, Western Venezuela.
This paper focuses on issues concerning the first step to obtain controllability and observability of the SAGD process taking into account heat distribution, heat management and evolution of steam chamber, at each time, for an efficient reservoir drainage.
Main issues concerning observability are pursued with the installation of subsurface sensors such as discrete pressure and temperature, as well as a fiber optic distributed temperature system. Experiences in PDVSA show that a little portion of the steam chamber can be observed and extrapolated to emerging analytical or numerical related models. In the other hand, issues concerning controllability can be inferred from observing patterns derived from process behavior, coming from direct measurements at bottomhole or from well testing analysis at surface.
General discussion on controllability and observability will be addressed giving particular ideas over experiences in PDVSA, exploring other ways to attack these two issues as for example using microseismic downhole sensors for steam chamber development and incorporating artificial intelligence in control algorithms to manage the process.