bluuebunny/crossref_metadata_2025_split huggingface dataset:
Artificial-Lift Systems Pattern Recognition Using Neural Networks
Authors: Ocanto Leonardo , Rojas Alexander 
Published: December 2007

Abstract
Artificial Neural Networks (ANN) are computational algorithms well suited to identify non-evident regularities and correlations in data. ANN are especially useful when there is missing or noisy process data, and when a mathematical model of the process is not readily available, as is the case with some Artificial Lift methods. Some ANN models exhibit excellent dimensionality reduction and visualization capabilities, mapping non-linear statistical relationships between high-dimensional data into simple geometric relationships, preserving the most important topological relationships of the data set. Thus, useful insight on the behavior of the process under study can be gained and used in its analysis and diagnosis. All this makes ANN a very useful tool in the exploratory phase of data mining. Results of several case studies applying ANN in pattern recognition of some Artificial Lift systemas are presented.
ESP's Application in Oritupano-Leona block, East Venezuela
Authors: Novillo Gumersindo , Cedeño Herman 
Published: December 2007

Abstract
This paper describes the successful experience obtained in using electro-submersible pumps (ESP) in the production of abrasive and corrosive fluids. The study covers 60 wells operated by the Consorcio equiped with ESP's in Oritupano–Leona field, States of Anzoategui and Monagas, East Venezuela.
The influence of the reservoir on the pump run life is reviewed. Currently, 46% of the total oil is produced through ESP's, the first instaled in 1996. Most of the failures are related to sand production and corrosion. Since the start of this program, pulling jobs due to ESP's failures have been significantly reduced, due to practices that increase the run life of the pumps, including: -a start-up procedure to reduce fines production-an exhaustive, teamwork based, study of the failures-the use of special abrasion / corrosion resistant materials
All of these factors combined have allowed to optimize the application of ESP's in this field. Details of the various methodologies used to achieve the optimization of the ESP system in Oritupano and Leona fields are presented.
Optimized Reservoir Development Using High Angle Wells, El Furrial Field, Venezuela
Authors: Smith Richard W. , Colmenares Rodolfo , Rosas Eulalio , Echeverria Isaura 
Published: December 2007

Abstract
The El Furrial field is one of the major field assets of Venezuela and is operated by PDVSA (Petroleos de Venezuela, S.A.), the national oil company. Its current production of over 450,000 BOPD makes it a giant oil field. Development of the field, which has an average reservoir depth of approximately 15000 feet, is in its mature stages due to implementation of high-pressure gas injection. PDVSA has consistently followed a forward planning approach related to reservoir management. Using high angle deviation drilling techniques allows development wells to be strategically located by penetrating the reservoir at high angles to optimize production rate, extend well life, increase reserves per well, reduce operating expenses, and reduce total field development costs.
A reservoir model was constructed and simulated using detailed reservoir stratigraphy to determine realistic potential of high angle wells. Five wells have been drilled as of June 2000 and the first four wells have proven the effectiveness of the design. The philosophy, the modeling technique, the well design considerations, the problems encountered, well results, and economic criteria provide a clear understanding of the risk of this technology not previously used at this depth in Venezuela. The result was the first high angle well in the deep, challenging environment of eastern Venezuela, followed by four others.
Results show that optimization objectives can be attained using high angle wells (HAW), mainly increasing per-well production rate, maximizing per-well recovery and extending the break-through time of gas or water from pressure maintenance and enhanced oil recovery projects. Well results indicate the geological and simulation modeling technique is reliable and accurate. A pilot program shows HAW technology provides major advantages to increase production rate and to reduce the overall number of wells needed to reach production objectives. However, the project also has experienced a number of unexpected drilling problems. 1
The costs associated with the total project are significant but more importantly, this program becomes very attractive due to: Long-term benefits of decreased water-cut related to current water injection.Decreased gas breakthrough due to high-pressure gas injection.Fewer wells are required to meet production goals.
The technical contributions include: The modeling technique of applying detailed stratigraphy to a full-scale reservoir model is accurate if performed with the appropriate objectives in mind.The application of state-of-the-art drilling techniques to attain high angles at deep drilling depth is possible. However, drilling problems caused by formation instability require more study and experience.This method can be applied to other fields in the eastern Venezuelan basin currently under, or planned to be under, enhanced recovery programs and development programs.
Underbalanced EMWD-AP At La Concepción Block, Maracaibo Basin, Venezuela
Authors: Romero F. J. , Pi D. , Cinquegrani A. 
Published: December 2007

Abstract
High deviation angle and a highly fractured carbonates reservoir with abnormally low pressures (depleted) were the greatest challenges in the drilling program to develop the deep objectives of La Concepción field. The development of an underbalanced drilling system was required to overcome the massive loss of circulation and associated problems.
An electromagnetic down hole telemetry system was selected to allow the acquisition in real time of measurements of well bore inclination, annular bottom hole pressure and temperature. This system is not dependent of the circulating fluid nature (liquid, gas or a mix of them) to transmit the information up the hole via sonic waves.
Consideration specific to this project ranged from simple ones, like the relationship between the formation pressure and the conditions and rate of injection of mud and nitrogen, to complex ones, like optimizing directional drilling trajectories, determining the minimum allowable equivalent circulating density to maintain stable wellbore, or establishing the minimum antenna height required to transmit the information from the bottom hole measurement tool to surface.
A combination of all these equipment and techniques has enabled us to drill 5 re-entry well bores and four new wells. The new wells were drilled underbalanced but without directional control.
Team Philosophy, Straight Hole Drilling Device and Performance Based Contracting Strategies Continue to Cut Drilling Costs in Tectonically Active Basin
Authors: Vargas Carlos , Rueda Fernando , Marquez Hugo , Pacione Mario , Cruz Marco 
Published: December 2007

Abstract
Drilling through steeply dipping formations associated with major structural features in the Sub Andina Basin of Northern Argentina presents several unique challenges. Specifically, formations in the upper hole sections (22" and 16") are typically hard, abrasive and prone to bit balling. Historically, these intervals have caused operators working the basin major drilling problems such as low penetration rates, hole deviation and frequent drill string failures.
Recently, the use of a Straight Hole Drilling Device (SDD) used in conjunction with a team philosophy and performance based contracting strategies has had a beneficial impact on drilling economics. Because prospects in the area frequently require drilling a well on the apex of a very narrow structural feature, there is a high risk of sliding through a high dip formation with very little change in wellbore trajectory. The SDD provides a unique technological solution to this challenging issue. As technical justification to run the tool, a novel commercial arrangement was established by benchmarking performance of wells drilled with conventional equipment. Then, a contract was structured where the operator did not pay for the use of the SDD unless it shortened drilling days to top of reservoir relative to the baseline wells. The tool was used for the first time in Northern Argentina in Macueta field cutting the drilling by 30 days compared with the best offset well in the Basin. Recently it was used again with the same operator in San Pedrito field saving 63 days relative to the last well drilled in this area. This paper will describe that accomplishment and outline how the team plans to incrementally improve on this success by: Introducing lower speed 9-1/2" motor to SDD tool to allow more WOB.Increasing weight on SDD tool from 80 klbs to 100 klbs would be possible due to change to low speed motor.Improve bit bearing life to end premature seal failure.Improving steering capabilities of SDD tool allowing for a 50 % increase in lateral force.Control solids, sand content and LCM to prevent from plugging and washing the tool's pulser and drill pipe screens.Use shock sub where appropriate.
Performance of a Foamy Oil Reservoir in Pseudo-Undersaturated State with Associated Aquifer
Authors: Yrigoyen A. , Carvajal G. 
Published: December 2007

Abstract
Heavy and extra-heavy oil reservoirs, with moderate gas oil ratio have additional primary recovery mechanisms that increase oil production. Morichal-01 reservoir is located close to the Orinoco Oil Belt, approximately 100 km South of Maturin city, Monagas State, Venezuela. This reservoir has a peculiar behavior and shows an additional recovery mechanism called by some researchers as a foamy phenomenon.
Such phenomenon occur, at the bubble point pressure, when the remaining gas in solution comes out of solution forming a dispersed trapped free phase inside the phase oil (as layer, it is not a free movable phase), as a consequence, no pressure drop is observed, i.e. pressure is maintained constant. Also flash GOR is constant. As a result, there is a progressive increase in oil recovery due to internal expansion of the gas bubbles.
This study aims to explain the peculiar behavior of the reservoir making some adjustment on material balance equations in order to find equations of Drive Depletion Index (DDI) caused by solution gas. All this is caused by solutions gas and free gas bubbles in the oil as well as oil compressibility. Some physical equations that govern foamy oil performance, formation oil volume factor, gas oil ratio and trapped free-gas coefficient (a) in the presence of pseudo-undersaturated state, will be presented.
Optimization of a Mature Oil Field by Changing Lifting System
Authors: Prado Pablo , Brarda Mario 
Published: December 2007

Abstract
All wells in Entre Lomas Area, after a initial period of natural flow, requiered an artifitial lifting system. Gas-Lift system suited very properly the field characteristic.
As the reservoir pressure declined and the water-flooding expanded, it became necessary to change the lifting system progressively from Gas-Lift to Sucker Rod Pumping (SRP) or Electrosubmersible Pumping (ESP).
With almost half of the wells already converted, the remaining did not appear economically attractive for conversion at the individual well basis. Therefore, a global conversion project for the remaining wells was considered, which ultimately yielded additional profit that made total replacement affordable.
Field Experiences in Evaluation and Productivity Improvement Using Selective Hydraulic Fracturing in Deep Directional Wells. Orocual Field, Venezuela
Authors: Carvajal G. A. , Ortiz K. , Carmona A. , Parra G. 
Published: December 2007

Abstract
Until 1998, eleven vertical wells had been drilled in Deep Orocual Field in Eastern Venezuela for a total of 16 completions to produce light oil and condensate. By hydraulically fracturing these wells, the productivity improved up to three times compared to the initial rates. The use of new technologies in drilling directional wells allowed the construction of three of these wells wells in the San Juan Formation.
This paper resumes the experiences associated to three wells in the Orocual Field, the evolution of operational practices and data acquisition that had to be implemented in order to, in some cases, overcome the effect of early stage screenouts and properly evaluate the productivity of such wells. Additionally said, experiences allowed the comparison of the fracturing techniques applied in these case studies, with the conventional designs used in the past and to establish the best evaluation and stimulation techniques for the San Juan Formation wells.
Improved Reservoir Permeability Models From Flow Units and Soft Computing Techniques: A Case Study, Suria and Reforma-Libertad Fields, Colombia
Authors: Soto B. R. , Torres F. , Arango S. , Cobaleda G. 
Published: December 2007

Abstract
This paper presents a methodology that looks to solve the inverse problem of predicting reservoir properties on uncored intervals/wells, using soft computing techniques (neural networks and fuzzy logic), multivariate statistical analysis and hydraulic flow unit concepts.
Our methodology to improve the prediction of permeability in Suria and Reforma-Libertad fields in Colombia is the following: Data quality control. We apply multivariate statistical analysis for quality control of core and log data: 95% confidence ellipses and Q-Q plots are used for that purpose.Rock type identification. We use poral geometry analysis to identify rock types in cored wells. Then, fuzzy logic, core and log variables are used to develop a rock type model to be used in solving the inverse problem, predict the rock type in uncored intervals/wells.Hydraulic flow unit classification. For that purpose, we use the technique based on a modified Kozeny-Carmen equation to calculate the reservoir quality index, RQI=0.0314(K/φ) ½, flow zone indicator, FZI=RQI/(φ/(1-φ)) and φz=φ/(1-φ). The basic idea of hydraulic flow unit (HFU) classification is to identify classes that form unit-slope straight lines on a log-log plot of RQI vs. φz with similar but not identical FZI value. Each class or hydraulic flow unit has a mean FZI value at the intercept with φz=1, and a maximum and a minimum FZI values. We use log data and the fuzzy logic rock type variable to develop a neural network FZI model to be used in solving the inverse problem, predict FZI in uncored intervals/wells. The HFU for each uncored interval is determined with its FZI value that falls on a range between maximum and minimum values of FZI. Finally, permeability is calculated knowing its porosity and FZI values.
In the literature, the HFU is first determined by Bayesian inference assigning a probability distribution of log values to each HFU and identifying to which population the given set of log readings most likely belong. Then, permeability is estimated from porosity and mean FZI values ignoring the scatter data for each HFU.
Permeability estimations from our approach are compared from other conventional techniques to demonstrate that this is a better way to get confident permeability models and to show how to used soft computing techniques to improve reservoir description.
Cyclic Steam Injection Pilot, Yacimiento Los Perales
Authors: Pascual M. R. 
Published: December 2007

Abstract
This paper describes the studies, implementation and results of the first cyclic steam pilot project in the Los Perales Field located in the San Jorge Basin, in the province of Santa Cruz, Argentina. The presentation also includes a brief description of the usual steam injection methods; these methods are widely used in the on-going thermal operations around the world.
Preliminary studies showed the feasibility of injecting steam in intervals with heavy oil located in the Bajo Barreal formation at a depth of 3300 ft.
Some reservoir characteristics are: Fluvial systems with multi-layer reservoirs mainly conformed by packages of four layers and three packages by well on average. The distance between these packages can vary from 262 to 328 ft.Viscosity ranges from 300 to 10000 cp, which varies from well to well and layer to layer.
The pilot project consists of four new wells that were designed and drilled specifically for steam injection. After injecting the pilot wells we decided to stimulate an old reconditioned well with the intention of evaluating the possibility of stimulating this type of wells.
The surface equipment includes a 25 MMBTU/h steam generator at a pressure of 2500 psi.
The steam injection started at the beginning of 1999 in well 804, with the following characteristics: Injection periods: 18 days with flow rate and pressure of 820 bbl/d (cold water equivalent, CWE) and 1800 psi (wellhead pressure, WHP). Steam temperature of 625 deg-F (wellhead temperature) and a steam quality of 65-70% at the sandface.Soak Period: after the injection period, the well was shut-in for 1 week.Peak oil and water production rates occurred within 1-3 weeks, being the initial response three times the primary production with a maximum rate of 27 m3/day in the well 804. The well produced almost a year before it reached the forecasted primary oil production. The history match had a good fit with the Gontijo & Aziz(1) analytical stimulation model that was prepared by the people of Repsol YPF.The well is being prepared for the second cycle.
Throughout 1999, the rest of the wells were steamed, the individual characteristics are being analyzed in detail.
A Web-Based System to Link Asset Tracking to Performance Improvements in Oilfield Operations
Authors: Slezak M. Steven , Prather Floyd 
Published: December 2007

Abstract
Many oilfield service companies as well as oil producers have manually tracked assets over the years for a variety of reasons. The service companies have tracked assets such as pumps, packers, or other products to assist in R&D efforts. Being able to collect the data and compile statistics on run times and component failures enables the service companies to evolve and improve current products as well as design new products. From a producers perspective, compiling the same or similar data allows for the development of "best practices" in operating procedures and processes. Software products developed to address these needs have evolved with time to provide more functionality. However, many systems implemented to handle the total process of data acquisition, warehousing, querying, and reporting to achieve improved operating results have become more difficult and expensive to support than the value added.
The value of the information has not diminished, but increased due to the fluctuations in oil prices and the continuing efforts to reduce lifting costs through design and process enhancements. The recent development of a web based tracking system incorporates workover management, downhole equipment, and chemical usage while enabling the operator and service provider the ability to easily enter and access the data. The system reduces the problems of database synchronization, multiple entries of the same data, and provides a common means through the Internet to interface with the information. The system links the operator in the field, the service company providing equipment or chemicals, and the district office together through a common database that each has access to.
The system allows a technician in a pump shop, workover foreman in the field, or chemical sales person to easily enter data into the system using a laptop computer or touch screen technology. The data is brought back to the service provider's local office and is accessible to the operator through the Internet. Wells, well equipment, and equipment components can be tracked for run life and root cause of failure. The operation becomes an information network that uses the same data to accomplish different tasks but with a common objective of reduced costs and improved profitability.
Evaluation of Displacement Efficiency in Volatile Oil Reservoirs under Nitrogen Injection
Authors: Rivera de la Ossa Juan E. , Correa Castro Juan C. , Mantilla Uribe Cesar A. , Duarte Prada Cesar Augusto 
Published: December 2007

ABSTRACT
It nitrogen injection has been proven as a competitive alternative for volatile oil reservoirs lately found in Piedemonte area of Colombia, taking into account the reservoir fluid nature and the reservoir conditions. A laboratory study was carried out by the authors in the Enhanced Oil Recovery Laboratory of Colombian Petroleum Institute.
Three corefloods were carried out using Berea sandstone and volatile oil samples from the Piedemonte area and nitrogen as displacing agent. One of these corefloods was conducted in a long Coreflooding apparatus, and the other ones, in a short Coreflooding apparatus connected with a slim tube in a order to achieve miscibility conditions. The main variable studied was the flow rate, which represents three different flow regimes. The scaling criteria taken was a dimensionless group, which relates viscous and gravity forces, called gravity number.
Displacement efficiencies determined were around 50%, 65% and 80% for each one the tests. The results of these corefloods were compared to determine the best scheme of nitrogen injection. Results have successfully confirmed the effectiveness of nitrogen as displacing agent for this kind of oils and the better swept efficiency given by the equilibrium between the governing forces.
Gas Coning in Vertical and Horizontal wells, a Numerical Approach
Authors: Benamara Ahcene , Tiab Djebbar 
Published: December 2007

Abstract
In the presence of gas cap, production from a well is limited by the maximum, critical oil flow rate. If oil production rate is above this critical value, gas breakthrough occurs. After the breakthrough, the gas phase may dominate the total production rate to the extent that further operation of the well becomes uneconomical and the well must be shut in. In the oil industry this phenomenon is also referred to as "gas coning."
Until recently, several techniques have been used by the industry to prevent gas breakthrough due to coning. These methods include: keeping production rates below the critical value, perforating as far from the initial gas-oil contact (GOC) as possible, or creating a gas-blocking zone around the well by injecting crosslinking polymers or gels. Unfortunately, all these conventional methods do not solve the gas breakthrough problem.
It is usually uneconomical to keep production rate of a well below the critical rate. Perforating far above the GOC reduces the length of the perforation interval and, thus, increases pressure drawdown around the well. The increased pressure drawdown may enhance gas coning.
Despite the fact that the coning has been studied extensively since the fifties, it is still difficult to answer to the following two questions:
How to perforate a well subjected to the coning? What is the optimum oil flow rate of the well?
In this paper a numerical approach is used to study the gas coning using a 3-D radial model, and gas dipping using a 3-D irregular cartesian model, where well A, from Hassi-R'mel field in Algeria, is chosen for a case study.
In the first part, a sensitivity study was performed to analyze the most relevant parameters that affect the coning. In the second part, a new technique is proposed to interpret the variation of the different parameters that affect gas coning. It consists in plotting the free gas oil ratio (GOR-RsBHP) against the cumulative oil production on a log-log scale. This model reveals straight lines that occur after gas break through. In the last part of this study, regression analysis was performed to develop empirical gas coning correlations to predict critical oil rate, gas breakthrough time and gas oil ratio (GOR) after breakthrough for both vertical and horizontal wells.