bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Continuous Circulation System: An Advance in Constant Pressure Drilling
Authors: Jenner J. W. , Elkins H. L. , Springett F. , Lurie P. G. , Wellings J. S. 
Published: December 2007

AbstractIn late July 2003, for the first time since rotary drilling was introduced, a section of hole was drilled without interrupting circulation while new joints of drill pipe were added to the drill string. This was made possible by the use of the Continuous Circulation System (CCS), developed over the previous three years by a Joint Industry Project (JIP) managed by Maris International, funded by six major oil companies (Shell UK, BP, Statoil, BG, Total and ENI), Coupler Development Ltd (CDL) and Varco and supported by the UK's Industry Technology Facilitator (ITF). The field trial of the CCS was carried out on a land well being drilled in Oklahoma, USA. Its success marked the end of the JIP and the commencement of commercial development of the system.The CCS is a new and enabling technology, the potential benefits of which are: Elimination of negative and positive pressure surges when stopping and starting circulation to make a connectionNo rig downtime to circulate out cuttings to clear the bottom hole assembly before making a connectionImproved drilling fluid managementElimination of kicks on connectionsImproved control of Equivilent Circulation Density (ECD)Reduced Total Connection Time (TCT)Reduced chance of stuck pipe during a connectionNo downtime in HPHT wells to circulate out connection gasReduced wellbore "breathing" or "ballooning"Overall improvement in hole conditionImproved safety around the rig floorPotential applications of the system are in drilling: Extended reach (ERD) and horizontal wellsHigh Pressure/High Temperature (HPHT) wellsNear or underbalance (UBD) wellsDeepwater wellsThe CCS is also a potential contributor in achieving the "One Trip Well", Journal of Petroleum Technology (JPT) May 2004. The concept was presented in the paper "Continuous Circulation Drilling" by L. Ayling at the Offshore Technology Conference in May 2002.
Information is Costly, but How Valuable is It?
Authors: Wills Hector A. , Graves Ramona M. 
Published: December 2007

Abstract
This paper presents a method for economic resource allocation for additional data acquisition using the value of information concept. To apply it, the basic condition is that at decision time the available information does not describe conclusively the state of nature. Consequently, the new information might lead to a change in the decision to be made because it has the ability to modify positively the prior perception about the state of nature. The maximum value of the new information comes from how well this perception, in probabilistic terms, is modified from its original value towards the probability of conclusive or perfect information value. The new information value is calculated before acquiring it; using Bayesian theory, with decision tree methodology in conjunction with Monte Carlo simulation applied to the estimated ultimate recovery (EUR) algorithm. A sensitivity analysis on the Bayes' conditional probabilty term is performed, and the results are presented in graphic form as the information surface, its 2-D projection and the Information index plot.
The model was built on spreadsheet based commercial software.
Self-Organizing Maps for Lithofacies Identification and Permeability Prediction
Authors: Stundner Michael , Oberwinkler Christian 
Published: December 2007

Abstract
Methods of Artificial Intelligence like Back-Propagation Neural Networks (BPNN) have become popular software tools to predict permeability and porosity from well logs during the last several years.
Similar to Multiple-Linear Regression models, Back- Propagation Neural Networks are trained with a set of target values from core measurements.
The Self-Organizing Map (SOM) Neural Network method applies an unsupervised training algorithm. Until now this approach has mainly been applied for clustering purposes only, not for predicting reservoir properties.
In a new application, SOM technology has been merged with statistical prediction methods to derive the following types of information from well logs and core measurements in one step: Synthetic lithofacies system (clustering)Porosity and permeability (prediction)
SOM technology also provides a data visualization tool which allows evaluating relationships between input variables (well logs) and output variables (reservoir properties).
SOM models can also be combined with BPNN in order to subdivide the entire set of well log patterns into different lithofacies and run individual BPNN models for each facies.
Application of this method showed increase in prediction accuracy and significant timesavings.
This paper should be viewed and printed in color.
A Unique Design for Deep-Set Tubing-Retrievable Safety Valves Increases Their Integrity in Ultra Deepwater Applications
Authors: Vinzant Mike , Vick James , Parakka Anthony 
Published: December 2007

Abstract
Tubing-retrievable safety valve (TRSV) performance has been improved drastically over the last decade as a result of simplified design concepts, increased use of non-elastomeric and metal-to-metal (M-t-M) sealing materials, and enhanced validation testing. Unfortunately, the demands imposed by deep-water applications have also increased, and in spite of continuing improvement in safety-valve technology, equipment continues to be pushed to its limits. Higher valve-opening pressures associated with deep-set applications have emerged, and to address these needs, conventional solutions have focused on balancing the wellbore and its reaction to the hydraulic piston area using mechanisms that require additional seals and/or gas-charged chambers. These solutions are heavily dependent on elastomeric seals and/or the permanent, long-term containment of a dome charge or pressure counterbalance, to maintain reliability. Unfortunately, dynamic elastomeric seals have posed a major limitation when design intent tries to focus on equipment that will provide life-of-the-well reliability.
This paper will review a unique TRSV design that is a revolutionary new concept. This design incorporates a floating-magnetic-coupler mechanism that allows the hydraulic actuator to be positioned in a dedicated chamber isolated from contact with well fluids and pressure. Since the hydraulic actuator has been separated from the tubing wellbore, this new valve is the first in the industry to have 100% M-t-M sealing with no moving seals within the tubing wellbore. The low hydraulic operating pressure of the valve also simplifies the complexity of the pressure source equipment and completely eliminates the need for high-pressure operating equipment. This is significant when considering both safety and cost; furthermore, it could completely eliminate use of high-pressure equipment and associated umbilical line, often more costly than the TRSV in a subsea application.
The new intrinsically simple design: Increases environmental and personnel safetyReduces system costsReduces sealing requirementsProvides an extremely reliable tubing retrievable safety valveIncreases life-of-the-well.
Improving Support Vessel Utilization on Subsea Operations Using Novel Underwater Pipeline Data Acquisition and Transmission Equipment
Authors: Johnston Neil , Sergeant Paul 
Published: December 2007

Abstract
During sub-sea pipeline commissioning operations using a surface support vessel, a substantial amount of non-productive time is endured during the hold period of pipeline hydrotesting. During this time, which may last up to several days, instruments on the support vessel monitor the pipeline pressure and temperature using long hoses and cables. The vessel is unable to move away and perform more productive operations elsewhere. In addition, adverse weather conditions may force the vessel to disconnect and move off station causing data loss and the requirement for a retest. With vessel day-rates in the tens, or even hundreds, of thousands of dollars per day, it is apparent that freeing the vessel during the hydrotest substantially reduces overall project costs and saves time.
This paper describes the development of an electronic sub-sea data acquisition and transmission system which achieves these goals by transmitting data to the surface using through-water two-way acoustic communications. Even if surface data collection becomes impossible due to the vessel moving out of range, or a deterioration in the acoustic environment, successful test verification is still possible as the data is permanently recorded in a non-volatile memory card sub-sea.
The paper also describes a number of challenges to successful acoustic data transmission in the offshore oil & gas marine environment. These include the naturally varying properties of the water column (water density, salinity, temperature and seasonal variations) as well as the relatively large horizontal displacement with respect to the shallow water depth (commonly found in many producing offshore fields) which lead to a heterogeneous acoustic velocity profile and multi-path effects. In addition, significant vessel-produced noise requires the use of advanced signal processing techniques to provide successful communications. It is believed that this technique could be applied to other sub-sea applications requiring remote monitoring & effective data acquisition.
Role of Critical Gas Saturation in Methane Production from Hydrate Dissociation at the Pore-Network Scale
Authors: Tsimpanogiannis Ioannis N. , Lichtner Peter C. 
Published: December 2007

Abstract
Hydrates are crystalline structures that are formed under conditions of low temperatures or high pressures and consist of a lattice made up of hydrogen-bonded water molecules, containing cavities. These cavities can be stabilized by van der Waals forces if occupied by certain types of guest molecules (e.g. CH4). Hydrates are very important compounds due to their capacity to store large volumes of gases. They are studied as a possible source of energy, since an enormous reservoir of carbon is deposited in worldwide accumulations of hydrates, containing predominantly methane, both on-shore (under the permafrost), and off-shore (in marine sediments).
In this study, a 2-D pore-network simulation based on concepts from Invasion Percolation in a Gradient is discussed to study the dissociation of methane hydrate in porous media. By using reported experimental values of porosity and permeability that are found in oceanic sediments we reconstruct a porous medium with similar properties by varying appropriately the size range of throat radii and the ratio pore/throat radii. The reconstructed porous medium can be either fully or partially saturated with hydrate. In this work emphasis is placed on examining the patterns formed by the release of methane gas in a partially saturated porous medium following hydrate dissociation. We investigate how the various patterns are affected by parameters such as the viscous pressure drop applied to the system, the size range of throat radii, hydrate saturation, and pore size distribution. Note that in order for the methane gas to be produced from the system, the critical gas saturation (defined as the volume fraction of the gas phase at the onset of bulk gas flow) must be reached. This is an issue of significant importance that delineates the possible range of parameters where methane production can be economically viable. For the critical gas saturation to occur the produced gas clusters must: either (i) connect to each other forming a sample-spanning gas cluster through which the gas phase can be produced, or (ii) be mobilized by the presence of viscous or buoyancy forces and thus arrive at the producing end of the network (this is a limiting case where continuum models may break down because of the formation and mobilization of gas bubbles). In order to obtain a better understanding of the production efficiency for the commercial development of hydrate deposits we address the significant question whether the resulting dissociating system (at lower hydrate saturation values) is below or above the critical gas saturation and how the aforementioned parameters affect the value of the critical gas saturation.
High-Resolution Near-Wellbore Modeling and Its Applications in Formation Testing
Authors: Liu Wei , Hildebrand Margaret A. , Lee Jaedong , Sheng James 
Published: December 2007

Abstract
Formation Testing (FT) can collect high-resolution data sufficient to capture small variations in fluid and formation properties. Unfortunately, conventional interpretation techniques are rarely capable of processing the data from complex tool configurations and formation properties. Studies have shown that numerical simulation can replicate the complex physics of multiphase fluid flow but often not at the level of detail needed for high-resolution data interpretation.
In this paper, we propose a general three-dimensional and multiphase numerical model to incorporate various wellbore and/or tool factors. Unlike the analytical source representation of a well commonly used in reservoir simulation, the proposed model establishes the internal boundary of a well, generally involving the pressure and flow rate at the sandface, where the size of the wellbore or tool configuration is equivalent to or smaller than that of the grid cells. This fully coupled and fully implicit model at a fine spatial and temporal scale is advantageous in revealing further potentially useful information and realizing the synergy across a spectrum of FT applications. As a result, wellbore and/or tool factors, particularly the tool storage effect, can be integrated at a level of detail not previously possible in the absence of a comprehensive wellbore model.
The mathematical formulations and numerical schemes are presented. Simulation studies include the primary FT applications in the field, i.e., pressure transient testing and fluid sampling for both oil-based and water-based mud filtrate. These examples show that the proposed near-wellbore high-resolution modeling approach with non-negligible wellbore and/or tool factors permits new insights into fluid flow in FT applications.
Improved Reservoir Simulation With Seismically Derived Fracture Models
Authors: Ouenes Ahmed , Zellou Abdel M. , Robinson Gary C. , Balogh David R. , Araktingi Udo G. 
Published: December 2007

AbstractHistory matching and simulation of naturally fractured reservoir is a recurring challenge to many oil and gas companies seeking to manage and develop fractured reservoirs. Several techniques have been applied in the past to match past production and pressure history that have been proven unreliable. This paper describes a methodology to improve the simulation of fractured reservoir using seismically driven reservoir characterization.The methodology presented in this paper uses the integration of geophysical, geologic, and engineering data simultaneously to improve the reservoir description. At the root of the reservoir characterization lays the more and more accurate seismic data collected on most of the reservoirs around the world. The initial use of this seismic information is made possible through high-resolutioninversion and spectral imaging. These two processes allow a better imaging of key reservoir properties that have an important impact on fracturing. Based on this seismically driven reservoir characterization, the reservoir properties necessary as inputs to the reservoir simulator, i.e. fracture porosity and permeability, are generated using artificial intelligence tools and core measuremenst as fracture indicators.The usefulness of the derived seismic attributes is illustrated on a specific reservoir where a new well was recently drilled. The drilling results indicate that the derived seismic attributes can be used successfully to locate highly fractured areas. Using the generated seismic attributes in an integrated fracture modeling approach allows for a better modeling of the "plumbing" of the reservoir through a correct estimation of the fracture permeability and porosity. These improved fracture properties lead to a history match of the well performances. Examples of such history matches are given for illustration purposes.
Case Studies in Production Optimization Using Chosen Information Sources and Information Technology
Authors: Leshchyshyn Tim , Rieb Brad 
Published: December 2007

Abstract
Well data for oil and gas wells drilled in the Western Canadian Sedimentary Basin (WCSB) exist in many places and multiple formats with ranging detail. Multiple data sources, both internal and external, are needed to optimize the well stimulation and the production optimization process. Public production and well data in the WCSB is considered high in quantity and quality for reservoir description. This data repository exists due to royalty and tax reasons and is strictly enforced by government legislation. Unfortunately, detailed completion data are not part of the public database records. However, companies whose core business include drilling and completion field services usually keep a comprehensive and detailed collection of data. These pumping service companies often have data that are unavailable in the public databases.
This paper outlines the first steps in developing a synergistic approach to integrating publicly available production and well data with detailed completion data from private sources. The case study presented shows the effectiveness of combining internal detailed completion data with external third party data.
Case study #1 evaluates various fracture fluid systems and size on production in the Medicine Hat gas of southeast Alberta, Canada. Case study #2 evaluates stimulations in the Horseshoe Canyon Coal Bed Methane (CBM), fairway in south central Alberta, Canada. Production impact of current industry stimulation practise and some alternatives are examined.
The Tengiz Field History Matching Problem Revisited
Authors: Gao Guohua , Zafari Mohammad , Reynolds A. C. 
Published: December 2007

Abstract
The limited memory Broyden-Fletcher-Goldfarb-Shanno (LBFGS) is an ideal optimization algorithm for large-scale automatic history matching problems. In previous work, we applied the LBFGS algorithm to condition a model of the Tengiz reservoir generated from static data to buildup pressure data at 44 wells. The resulting reservoir model displayed regions of extremely high and low permeability values inconsistent with the geologic information. Here, we identify a potential source of this problem, and present an approach which yields a history-matched model that is consistent with the geological/geostatistical model.
A New OCTG Strength Equation for Collapse Under Combined Loads
Authors: Klever F. J. , Tamano T. 
Published: December 2007

Abstract
Wells are becoming more challenging and casing designers are faced with increasing design pressures. Deep hydrocarbon targets lead to requirements for the casing to resist collapse under external pressure while significant internal pressure and axial compression or tension may exist at the same time.
This paper describes the development, and its evaluation, of a new collapse strength equation for oil country tubular goods (OCTG). It is based on a generalization of a model previously proposed by Tamano et al.1. The new model is evaluated through comparisons with both finite element analyses and test data. It is more accurate in dealing with combined internal pressure, external pressure and axial load than, for example, the model currently provided in API Bulletin 5C32.
The joint API/ISO SC5 Work Group 2B tasked with modernizing the API 5C3 property equations has evaluated a number of collapse models available in the literature on their performance against several different collapse databases. As a result the model presented here is recommended for developing collapse ratings in the new ISO 10400 standard.
A Method for Continuous Interpretation of Permanent Monitoring Pressure Data
Authors: Ramakrishnan T. S. , Raghuraman B. 
Published: December 2007

Abstract
We show that a pressure pulse originating in a well is correlated to a pulse observed at a distant well with a characteristic time. The correlation time is directly related to the diffusion time scale arising out of the pressure diffusion equation. The relationship is affected by the source-observer or observer-observer distance but the correction is small for large distances. In practice, further corrections have to be included for finite width pulses. For these pulses, we present a practical scheme for continuous permeability monitoring.
Wellbore storage also has a strong influence on the correlation time-scales. We show a simple forward calculation that removes this effect and allows a direct estimation of reservoir scale permeability. The techniques developed in this paper are simpler to practice than conventional interference testing, and do not require the same level of periodicity or uniformity of pulses.
Up-Gridding from Geological Model to Simulation Model: Review, Applications and Limitations
Authors: Fincham A. E. , Christensen J. R. , Barker J. W. , Samier P. 
Published: December 2007

Abstract
In recent years, several papers have presented methods for choosing an optimal coarse grid suitable for dynamic simulation, given a multi-million cell geological model as starting point. Usually these methods include some technique for measuring how well the coarse simulation grid represents the response of the original fine scale grid.
In this paper, we describe a software package we have produced based on these methods. We discuss some of the difficulties encountered in applying the published methods to realistic reservoir models. We present our experience in using the methods in real case studies, both successfully and otherwise. Finally, we discuss the limitations of this type of approach to up-gridding.
High-Accuracy Wet-Gas Multiphase Well Testing and Production Metering
Authors: Atkinson D. I. , Reksten Ø , Smith G. , Moe H. 
Published: December 2007

Abstract
Dedicated wet-gas flowmeters are now commercially available for the measurement of gas and liquid flow rates. They offer a more compact measurement solution than the traditional separator approach. The interpretation models of traditional multiphase flowmeters emphasize the liquid rate measurements; they have been used to well test and meter mostly liquid-rich flow streams. These models were not developed for the measurement of gas flow rates, particularly those of wet gas.
A new interpretation is described that allows a traditional multiphase flowmeter to operate in a dual mode either as a multiphase meter or as a wet-gas meter in 90% to 100% gas. The new interpretation model was developed for a commercially available multiphase flowmeter consisting of a venturi and a dual-energy composition meter. This combination results in excellent predictions of the gas flow rate, and in addition, liquid rate and water-cut predictions are made with an acceptable accuracy with no additional measurements.
The wet-gas and low-liquid-volume-fraction interpretation model is described together with the multiphase flow meter. Examples are presented of applying this model to data collected on flow loops, with comparison to reference flow rates. The data from the Sintef and NEL flow loops show an error, better than ± 2% reading for the gas flow rate, at line conditions; the absolute error in the measured total liquid flow rate at line conditions of was better than ± 2 m3/h (&lt; ± 300 bpd).
This new interpretation model offers a significant advance in the metering of wet-gas multiphase flows and yields the possibility of high accuracies to meet the needs of gas-well testing and production allocation applications without the use of separators.