bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production Data Integration Using a Gradual Deformation Approach: Application to an Oil Field Offshore Brazil
Authors: Reis L. C. , Hu L. Y. , de Marsily G. , Eschard R. 
Published: December 2007

Abstract
History matching of geostatistical reservoir models requires efficient tools for coherently modifying model realizations. In recent years, the gradual deformation approach has been developed and successfully applied to several simple (synthetic or pseudo-real) cases. This paper presents the application of the gradual deformation method for history matching to a real oil field located offshore Brazil.
The oil reservoir consists of turbiditic sandstones interbedded by shales and marls. The data set includes 47 wells with lithofacies description and 15 years production history. A fine scale geostatistical lithofacies model was built using the non-stationary truncated Gaussian approach. The model is conditioned to the lithofacies data at wells and takes into account the non-stationary distribution of the lithofacies. The sensitivity of the dynamic behavior with respect to the model realizations was studied. Preliminary results of using gradual deformation method for improving history matching are presented.
Multiscale Data Integration Using Markov Random Fields
Authors: Lee Sang Heon , Malallah Adel , Datta-Gupta Akhil , Higdon David 
Published: December 2007

Abstract
We propose a hierarchical approach to spatial modeling based on Markov Random Fields (MRF) and multi-resolution algorithms in image analysis. Unlike their geostatistical counterparts that simultaneously specify distributions across the entire field, MRFs are based on a collection of full conditional distributions that rely on local neighborhood of each element. This critical focus on local specification provides several advantages: (a) MRFs are computationally tractable and are ideally suited to simulation-based computation such as MCMC (Markov Chain Monte Carlo) methods, and (b) model extensions to account for non-stationarity, discontinuity and varying spatial properties at various scales of resolution are easily accessible in the MRF framework. Our proposed method is computationally efficient and well suited to reconstruct fine scale spatial fields from coarser, multi-scale samples (e.g., based on seismic and production data) and sparse fine scale conditioning data (e.g., well data). It is easy to implement and can account for the complex, non-linear interactions between different scales as well as precision of the data at various scales in a consistent fashion. We illustrate our method using a variety of examples that demonstrate the power and versatility of the proposed approach. Finally, a comparison with Sequential Gaussian Simulation with Block Kriging (SGSBK) indicates similar performance with less restrictive assumptions.
Fractured Reservoir Characterization Using Streamline-Based Inverse Modeling and Artificial Intelligence Tools
Authors: Barman Indranil , Ouenes Ahmed , Wang Mokiang 
Published: December 2007

Abstract
A new approach that combines the use of static and dynamic data in fracture modeling has been developed. The approach provides the unique opportunity to constrain the fractured models to an effective permeability derived by automatically matching well performances using a streamline-based inverse approach.
The effective permeability derived from well performances reflects the stress changes induced by fluid injection, and takes into account the increase of fracture conductivity along the present day maximum horizontal stress. Given the simplicity, robustness, and speed of the streamline based inversion, the estimation of effective permeability is proposed as an alternative to the tedious and often unreliable process of fracture modeling using stress measurements.
Because of the availability of a true integrated fracture modeling framework, where any type of data could be used when deriving fracture models, the use of effective permeability derived by inversion is able to reduce the uncertainties by providing models with better fracture prediction capability, as illustrated on a carbonate reservoir.
Effective Petrophysical Fracture Characterization Using the Flow Unit Concept-San Juan Reservoir, Orocual Field, Venezuela
Authors: Rincones J. G. , Delgado R. , Ohen H. , Enwere P. , Guerini A. , Márquez P. 
Published: December 2007

Abstract
The San Juan Formation is one of two producing reservoirs in the Orocual field of Venezuela. Past efforts to define a petrophysical model failed to predict fracture zones, which have been identified to be the primary source of production. The current model has used both routine and special core analysis to calibrate the logs and neural-network processing has been used to fill curves where data is lost or of unusable quality. The resulting model is based on hydraulic flow units, identified as unique and individual relationships of porosity and permeability based on lithology and derived from capillary pressure curves. The model is tuned to predict fractures in this very tight matrix sandstone reservoir and is used for geostatistical and general integrated study uses.
A Successful Completion/Perforation by Use of a Downhole Lubricator Valve: A Case Study from the Siri Field, Danish Sector, North Sea
Authors: Svendsen Ove B. , Bjørkesett Halvard , Quale Eileen A. , Gudmundseth Marianne , Malmo Bernt , Brown Irvine 
Published: December 2007

Abstract
To be able to lubricate long perforating assemblies (guns) in horizontal wells, and to retrieve them without killing the well has always been attractive for many reasons, both from an operational point of view and to minimise formation damage.
This paper describes a case study from the Siri Field where lubricating long gun assemblies against a tubing-retrievable downhole lubricator ball valve (DHLV) enabled running up to 1000 m of 3.5" perforation guns in two runs in a live well. This was performed without the use of a surface deployment system, and without exposing the tubing-retrievable surface controlled subsurface safety valve (TRSCSSV) to potential damage in the event of inadvertently dropping the perforation guns during completion.
Use of this equipment gives also the added benefit of considerably reducing the equipment rigup heights for Siri in the future life of the field, after the jackup drilling rig has moved off location.
Well Construction and Completion Aspects of a Level 6 Multilateral Junction
Authors: Ohmer Hervé , Follini Jean-Marc , Carossino Ricardo , Kaja Mirush 
Published: December 2007

Abstract
Multilateral applications have been historically constrained by the complex construction process of the junction, and the fact that the overall mechanical integrity and detailed geometry of the junction is not always known and predictable for the lifetime of the producing reservoir.
In particular, Level 61 junctions, as defined by the Technology Advancement-Multi Laterals (TAML) forum, must provide both mechanical and hydraulic integrity.
A pre-formed dual-leg Level 6 junction has been developed The design is based on an integrated geometry that increases the branch/parent diameter ratio compared to a non-formed junction using a novel metal forming technique.
The junction construction process starts when a compressed shape dual-leg junction is run in the hole at the bottom of the parent casing. Afterwards, a wireline-conveyed expansion tool post-forms the junction in a fully controlled and closely monitored process. The result of this simple construction process is a junction with an overall mechanical integrity and a known geometry.
In this paper we first describe the dual-leg junction and process related system tools, then we provide the full construction process of a multilateral well using the preformed dual-leg Level 6 junction, and finally we present the results of the successful first field installation of the system.
Optimal Control Strategy and Experimental Investigation of Gas-Liquid Compact Separators
Authors: Wang S. , Mohan R. , Shoham O. , Marrelli J. D. , Kouba G. E. 
Published: December 2007

Abstract
The deployment of the new technology of gas-liquid compact separators such as Gas Liquid Cylindrical Cyclone (GLCC©1) requires dedicated control systems for field applications. The control strategy implementation is crucial for process optimization and adaptation, especially when GLCCs are operated at wide range of liquid and gas flow conditions. In this study, a unique and simple control strategy, which is capable of optimizing the operating pressure and adapting to liquid and gas inflow conditions, has been developed. Detailed simulations and experimental investigations have also been conducted to evaluate the performance of the proposed control systems. The significant advantages of this strategy are: the system can be operated at optimum separator back pressure; the system can adapt to the changes of liquid and gas flow conditions; and the strategy can be easily implemented using simple PID controllers available in the market. This provides the oil and gas industry a simple, robust compact separator control technique which has the potential for offshore and subsea applications.
Oilfield Paraffin Treatments: Hot Oil and Hot Water Compared to Crystal Modifiers
Authors: Becker J. R. 
Published: December 2007

Abstract
Crystal Modifier chemicals have been successfully applied in several areas of the world to control deposition of paraffin waxes in production strings, pipelines, and refinery storage facilities. However, the use of these chemicals requires that they be protected from cold weather to prevent them from freezing, thus making them impossible to pump. Therefore, the practices of hot oiling and hot watering remain the main methods of paraffin wax remediation. Over the past two years advances in the technology of crystal modifier formulation have succeeded in producing modifiers that are suitable for year-round application. This new technology has made it possible to compare the effectiveness of crystal modifiers versus hot oiling and hot watering for a large sampling of production areas. Three large and geographically distant areas of production, previously on hot oiling and hot watering programs, were placed on a program of solvent cleanup and continuous and batch treatment with crystal modifier products. Case histories for these three fields are presented in this paper. Additionally some theoretical topics are also covered including the description of paraffin crystal modification and its affect on the behavior of crude oil fluids.
Low-Frequency Downhole Vibration Technology Applied to Fishing Operations
Authors: Stoesz Carl W. , DeGeare Joe P. 
Published: December 2007

Abstract
This paper discusses the development and the recent, successful application of downhole vibration technology as an effective, economical technique for extracting sand- and gravel-stuck tubing, pipe, and liners from wellbores. This paper shows how equipment previously considered immovable can be extracted by applying low-frequency vibration at the point where it is stuck. Furthermore, the paper describes how downhole vibration fills a technological gap between single impact jars, washovers, milling operations, and surface vibration, accomplishing these extractions at considerable cost and time savings over other approaches. Testing and field runs in which liner lengths ranging from 60 to 725 ft were successfully extracted are presented, demonstrating the efficiency of the new technology. Application identification also is addressed.
4D-Ready Towed-Streamer Data and the Foinaven Benchmark
Authors: Morice S. , Svendsen M. , Larsen L. , Kristiansen P. 
Published: December 2007

Abstract
Time-lapse (or 4D) seismic is emerging as a key reservoir management tool, and towed-streamer configurations offer a cost-effective method for acquiring 4D surveys. Successful 4D imaging requires that the non-repeatable noise should be weaker than the 4D signal, however, poor control of repeatability perturbations often masks any changes in the reservoir.
Analysis of the Foinaven Active Reservoir Management (FARM) 4D datasets, comparing permanently-installed sea-bed receivers with conventional towed-streamer seismic acquisition technologies, has revealed much about the factors that influence successful 4D imaging. Data from both the sea-bed-cable surveys and the towed-streamer surveys are very well repeated, with the sea-bed-cable data showing the higher repeatability. We infer that a significant factor in this success is the exacting control of acquisition parameters, and that the improved response from the sea-bed-cable surveys is due to the use of receivers that occupy identical positions in the baseline and repeat surveys.
This paper describes a new acquisition system specifically designed for reservoir characterization and 4D seismic, which enables control of repeatability factors through advances in marine seismic technology. This system will deliver the high-quality 4D seismic data that are needed to reveal subtle reservoir parameters.
So What is the Reservoir Permeability?
Authors: Haddad S. , Cribbs M. , Sagar R. , Viro E. , Castelijins K. , Tang Y. 
Published: December 2007

Abstract
In many reservoirs, permeability values are often available from one or as many as four sources. These permeability sources include core analysis, nuclear magnetic resonance log (NMR), wireline formation tester, and well testing (DST). However, permeability values from these sources often differ significantly. In many cases, this creates confusion as to which value of permeability should be used to best represent reservoir performance and well productivity.
In this paper, permeability values, evaluation methods, scales and applicability of all measurements are discussed and verified with field data. Factors influencing each measurement technique are also discussed.
Available permeability data from the various sources in a deep water Gulf of Mexico sandstone reservoir are considered to demonstrate how they may be used to build a model of well/reservoir performance. An accurate knowledge of permeability is critical to forecasting rates. Production facilities may be over- or under-designed if rates are inaccurately predicted, excessive capital expenditure for an over-designed facility or the inability to deliver at high rates for an under-designed facility can cost an operator and its partners dearly.
Critical Gas Saturation and Relative Permeability During Depressurization in the Far Field and the Near-Wellbore Region
Authors: Egermann P. , Vizika O. 
Published: December 2007

Abstract
Depressurization of a virgin or waterflooded oil reservoir results in the appearance of a solution gas saturation. Above a saturation threshold, this gas becomes mobile and can be produced. Knowledge of the critical gas saturation (Sgc) and the subsequent relative permeabilities (Kr) in the far field and the near-wellbore region has a tremendous impact on gas and oil production forecasts.
The present paper provides a new methodology to obtain representative Kr and Sgc values for a depressurization process. Specific experiments are presented in which undersaturated oil was injected upstream at a fixed rate whereas downstream the pressure was controlled in order to reproduce a drawdown. Evolution of pressure was recorded and in-situ gas saturations measured by CT-scanner. Two initial conditions were considered, fully oil saturated and at irreducible water saturation. Influence of the drawdown scheme was also explored. Transient evolution of the gas saturation profile in the core is clearly shown. Kr are deduced from history matching. They are finally compared to the Kr derived from gas injection experiments.
It is demonstrated that gas/oil Kr shape is strongly affected by the way the gas appears and is distributed in the porous medium. For solution gas drive, oil relative permeability is higher and gas relative permeability is smaller than for gas injection.
Concerning critical gas saturation, the experiments show two types of gas mobility depending on the operational conditions: mobility threshold attained from connection of bubbles or from mobilization of a population of separate bubbles. For the first type, Sgc can be linked to the values obtained through static experiments at fixed depletion rate.
A Fully Compositional Streamline Simulator
Authors: Crane Martha , Bratvedt Frode , Bratvedt Kyrre , Childs Paul , Olufsen Rudi 
Published: December 2007

Abstract
A new 3-D three phase compositional reservoir simulator based on extension of the streamline method has been developed. This paper will focus on the new methods developed for compositional streamline simulation as well as the advantages and disadvantages of this strategy compared with more traditional approaches. Comparisons with a commercially available finite difference simulator will both validate the method and illustrate the cases in which this method is useful to the reservoir engineer.
Managing Uncertainties in Oman Liquified Natural Gas Gas-Condensate Reservoir Development
Authors: Al-Shaidi Salman M. , Perriman Belinda J. , Vogel Koen 
Published: December 2007

Abstract
Oman LNG upstream project is to deliver a sustainable gas production in excess of 40 Million m3/d (1400 million cuft/d) over a 25 year project life to Oman LNG. The full production, commenced Q1 2000, is planned to come from three deep gas-condensate fields (Saih Rawl, Barik and Saih Nihayda) situated in the Central Oman Area. The three gas-condensate fields contain gas and condensate reserves in excess of 18 tcf, and 0.5 billion bbl respectively. The complex phase behavior of such rich gas-condensate fluid coupled with low reservoir quality has made reservoir development options challenging, sometimes reaching the limit of conventional simulation and stimulation
This paper will present the state-of-the-art multidisciplinary approach followed in managing reservoir uncertainties in Saih Rawl and Barik fields. As a result both static and dynamic uncertainties have been reduced whilst building up capacity to meet contractual requirements.
Comparison of the Performance of Vertical and Horizontal Wells in Gas-Condensate Reservoirs
Authors: Dehane A. , Tiab D. , Osisanya S. O. 
Published: December 2007

Abstract
Properties of gas-condensate reservoirs are particularly difficult to study due to the composition and phase changes of light components that occur during the reservoir depletion. At the first stage of their discovery, these reservoirs behave like gas reservoirs during depletion. Once the dew point pressure is reached at reservoir conditions of pressure and temperature a retrograde condensation phase develops in the reservoir. Liquid condensation in the formation can result in severe loss of well deliverability and therefore of gas and condensate recovery, which will certainly lead to a loss of income.
In this study, the performance of horizontal wells and vertical wells in gas condensate reservoirs is investigated under various depletion schemes. The expected low drawdown pressure for horizontal well, compared to vertical well for the same flow rate, considerably reduces retrograde condensation. A reservoir simulator is used to compare liquid saturation profiles for horizontal and vertical wells in gas condensate reservoirs. The influence of the horizontal well length section and reservoir thickness on horizontal well productivity, and condensate recovery were also studied. Another factor investigated in this study is the effect of drilling a horizontal well in a gas condensate reservoir that has already been developed by vertical wells.
To illustrate the productivity increase due to the use of horizontal wells in gas condensate reservoirs, Djebel Bissa field (Figs. 1 and 2) data are presented and discussed using a compositional single well model (VIP simulator). The main results of this investigation are as follows: A smaller pressure drawdown for a horizontal well compared to that of a vertical well, eliminates or reduces liquid condensation in the reservoir.
Layers with higher capacity (kh) values contain the most liquid accumulations.
Fracture Geometry and Vertical Migration in Multilayered Formations from Inclined Wells
Authors: Sankaran Sathish , Nikolaou Michael , Economides Michael J. 
Published: December 2007

Abstract
Knowledge of the near-well fracture geometry and the connection with the ultimate fracture propagation are of great importance to hydraulic fracture design. This is particularly true in high-permeability reservoirs where the connectivity between the well and the fracture has been viewed as a critical element to the success of the well stimulation. In addition to the fracture geometry difficulties, fracture height migration, that is the vertical fracture growth outside of the target interval is, invariably, an undesirable occurrence (unless the fracture is designed to penetrate a multi-layered formation.) When the fracture propagates through adjoining-to-the-target layers, there arises an impending danger of proppant screen-out leading to excessive pressurization and subsequent termination of the process. Therefore, it is essential to control and contain a hydraulic fracture within its target layer and to minimize geometry complexities in the near-well zone. Because inclined wells are drilled frequently in the petroleum industry, this work aims at developing a model for predicting fracture migration heights and the crack paths in multi-layered formations penetrated by such wells. The dependence of fracture initiation conditions on well inclination and mechanical properties are used to predict the migration of fracture height into adjacent layers using fracture mechanics models. The model predictions can be used beneficially in planning hydraulic fractures and in anticipating fracture geometry, thus, providing drilling trajectory guidelines. By controlling the fracturing fluid pressure gradient it is possible to affect the fracture geometry. A multi-layer approximation approach is presented to provide a formulation of the inclined well problem. The effects of well inclination and stress contrast on fracture height migration are studied and guidelines are offered on the desired well trajectories in view of property contrasts among layers for acceptable fracture geometries.