bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Large Scale Geostatistical Study: the Bachaquero 2 Field
Authors: de Lestang A. Pelgrain , Cosentino L. , Lopez D. , Gonzalez J. E. 
Published: December 2007

Abstract
A geostatistical study has been performed in the framework of the Integrated Reservoir Study of the giant Bachaquero 2 oil field, located in the Maracaibo lake, Venezuela. The objective of the study was to take advantage of the exceptional well density (over 1300 wells) in order to build a detailed and robust 3D model for geological risk evaluation during drilling, as well as further reservoir modelling studies.
The geostatistical database has been built from the preliminary deterministic geological work (3D seismic interpretation, sequence stratigraphy, sedimentological and petrophysical analysis). Stochastic simulations have been run in terms of facies and petrophysical properties, using a pixel based, Truncated-Gaussian algorithm.
The stochastic model has been used in a variety of applications, from optimization of horizontal well trajectories, to infill drilling location and the construction of local scale numerical simulation models.
Electrofacies Characterization and Permeability Predictions in Carbonate Reservoirs: Role of Multivariate Analysis and Nonparametric Regression
Authors: Lee Sang Heon , Datta-Gupta Akhil 
Published: December 2007

Abstract
We propose a two-step approach to permeability prediction that utilizes non-parametric regression in conjunction with multivariate statistical analysis. First we classify the well log data into electrofacies types.This classification does not require any artificial subdivision of the data population but follows naturally based on the unique characteristics of well log measurements reflecting minerals and lithofacies within the logged interval. A combination of principal component analysis, model-based cluster analysis and discriminant analysis is used to characterize and identify electrofacies types. Second, we apply non-parametric regression techniques to predict permeability using well logs within each electrofacies. Three non-parametric approaches are examined viz. alternating conditional expectations (ACE), generalized additive model (GAM) and neural networks (NNET) and the relative advantages and disadvantages are explored.
We have applied the proposed technique to a highly heterogeneous carbonate reservoir in the Permian Basin, west Texas: Salt Creek Field Unit (SCFU). The results are compared with three other approaches to permeability predictions that utilize data partitioning based on reservoir layering, lithofacies information and hydraulic flow units. An examination of the error rates associated with discriminant analysis for uncored wells indicates that data classification based on electrofacies characterization is more robust compared to other approaches. For permeability predictions, the ACE model appears to be the best among the three non- parametric approaches.
Use of Formed Metal Technology to Provide Low-Risk Solutions to High-End Multilateral Completion Challenges
Authors: Hogg W. C. , Mann T. A. , Helmer K. M. , Pieroni A. R. 
Published: December 2007

Abstract
A newly developed multilateral junction system utilizing formed metal technology led to the installation of the world's first Level 6 multilateral completion in the South Belridge Field near Bakersfield, California. This multilateral system provided a hydraulically sealed junction that, during installation, had an effective outside diameter less than the sum of the junction's two lateral casing legs. The junction was capable of running through standard casing and hole sizes as a result of this reduced diameter. Downhole, the junction was reformed using swaging technology. This multilateral system used conventional casing, cementing and drilling systems. In addition, no milling was required and therefore no debris was created. As a result, the overall process of creating the multilateral was simplified and associated risks minimized.
In this paper, the authors will discuss this level 6 multilateral completion including an operational description of the junction system itself. The authors will outline how the system was installed and operated, including the difficulties encountered and how lessons learned from the first installation are being applied to improve performance and process in future applications. The authors will also explain how the service company and operators worked together to finance this multilateral system such that it could be applied in a low cost, low risk environment prior to application in very high cost, high risk, environments.
Continuity Assessment through Flow-Test and Production Data in a Volcanic Formation
Authors: Nomura Masahiko , Sato Kozo 
Published: December 2007

Abstract
A layered model without formation crossflow can reproduce anomalous pressure behavior of well tests conducted in a volcanic gas formation. This model, however, fails to simulate production-logging and/or long-term production data for some wells, implying that interlayer crossflow cannot be neglected.
To construct a layered model with formation crossflow, horizontal permeability of not-completed intervals is predicted through log responses and vertical permeability between layers is evaluated by sensitivity studies. Resultant reservoir models can reproduce pressure-transient, production logging, and long- term production data for 20 wells. During the analyses, it is recognized that long-term production data must be honored to obtain proper estimation of lateral extents of individual layers.
The layer parameters obtained in the analyses are used to assess the degree of reservoir continuity. This information is of use in characterizing the reservoir and for a future development plan.
A Comparison of Forecasting Methods for Gas Production
Authors: Caswell G. R. , Mogensen A. C. , Trick M. D. 
Published: December 2007

Abstract
As the demand for natural gas has increased, so has the need for accurately forecasting reservoir deliverability. Some common methods for forecasting include (a) production decline analysis; (b) a tank type reservoir model linked to a surface network model; and, (c) a reservoir simulator linked to a surface network model. The selection of the most appropriate method should consider the economic risk associated with the forecast and the availability of pertinent data necessary for the method being applied. In reality, other considerations such as time constraints, availability of certain in-house models, or the familiarity the engineer may have with one or more forecasting methods may be the governing factor in deciding which method might be applied. The paper compares the production forecasts generated for the three forecasting methods referenced evaluating such parameters as reservoir permeability and geometry and the effect of changing backpressure and well spacing. An assessment of the impact of these parameters and the relative magnitude difference of the forecast are presented to help provide guidelines for selecting a method, and appreciating the accuracy of methods in certain circumstances.
This study found that production decline analysis generates the most conservative forecast of the three methods unless information is available to characterize the transient period in advance of the depletion decline. Production decline analysis, by virtue of its inherent assumptions, is unable to accurately predict the changes in volumes that result from changing surface operating conditions. A tank reservoir model linked to a surface network model is a good tool for field optimization, as long as the reservoirs are homogeneous and have good permeability. However, reservoir geometry can severely influence the interpreted results from such models, leading to erroneous conclusions. A reservoir simulator linked with a surface network model is the preferred choice for forecasting and optimizing the system for heterogeneous and/or low permeability reservoirs as long as sufficient reservoir data are available.
Optimizing Horizontal Laterals in a Heavy Oil Reservoir Using LWD Azimuthal Measurements
Authors: Rasmus J. , Bornemann Ted , Farruggio G. , Low S. 
Published: December 2007

Abstract
Over 100 horizontal laterals averaging 4,600 feet in length have been drilled in a shallow, heavy oil reservoir in Eastern Venezuela. Measurement While Drilling (MWD) continuous directional measurements and Logging While Drilling (LWD) azimuthal measurements are used to steer the wells through the reservoir, along a specific well path chosen from vertical stratigraphic wells for each pad and 3 Dimensional (3D) seismic which covers the field area.
Experience from drilling the horizontal wells has shown that this reservoir is laterally discontinuous between the vertical stratigraphic wells and that this discontinuity is not always predicted from the surface seismic. However, the LWD azimuthal measurements, presented in the form of a 3D image is able to give the orientation of the wellbore relative to the geometry of the channels. Another use of the azimuthal images is to identify the numerous shale stringers that are only a few inches thick. These stringers are not detectable on the vertical stratigraphic wells due to the limited bed resolution of the wireline logging tools run in these wells. These stringers in the laterals greatly reduce the non-azimuthal resistivity measurements and give a false indication of an approaching reservoir bed boundary.
FPSO Trends
Authors: Ronalds B. F. , Lim E. F. H. 
Published: December 2007

Abstract
A review of trends in floating production, storage and offloading (FPSO) technology is presented, using an extensive database of past, current and planned developments around the world. The review commences with the first FPSOs in the mid-1970s, explores the stimuli for FPSO development in Asia, in particular, over the next two decades and their widespread acceptance in the North Sea in the late-1990s. Current and future FPSO innovations in both hardware and applications are discussed against this background.
New Wireline Formation Testing Tool with Advanced Sampling Technology
Authors: Proett Mark A. , Gilbert Gregory N. , Chin Wilson C. , Monroe Myrick L. 
Published: December 2007

Abstract
A recently introduced wireline formation-testing tool incorporates new digital control technology to significantly improve formation fluid sampling and pressure testing. A primary focus of the new technology is improving the quality of reservoir fluid samples. An innovative pump-out design using a digital control feedback system enables the tester to continuously monitor the fluid sampled and to make precise adjustments to the rate and pressure at which the fluid is withdrawn from the formation and injected into a sample chamber. Because the tool design incorporates a powerful pumping-system motor and an efficient hydraulic system, invaded fluids surrounding the probes, such as mud filtrate, can be flushed 50% faster than other wireline test tools, thereby enabling quicker sampling of virgin formation fluids. Sample chambers can be filled against hydrostatic pressure to insure pressure-volume-temperature (PVT) quality samples, and additional pressure can be applied to minimize phase changes that might otherwise occur because of temperature gradients in the borehole. The new system can also be used to perform a closed-chamber PVT test for the bubble point of the fluid sampled.
Closely spaced dual probes are simultaneously deployed for pressure testing and fluid sampling. Besides increasing tool reliability through redundancy, the two probes allow for advanced pressure-testing techniques. For example, formation anisotropy can be determined with an interference test between the two probes. Alternatively, a new pressure-pulsing technique can be used, which uses time delays between the probes’ measured pressures to determine additional hydraulic diffusive properties of the formation. The drawdowns can be rate- or pressure-controlled from either probe.
The new tester is combinable with existing openhole logging tools and tester tool sections are interchangeable. This combinability permits a complete wireline toolstring to be configured to meet particular openhole formation evaluation and testing needs in a single trip into the well. Current tool sections for the new tester include a dual-probe section (DPS), flow-control pump-out section (FPS), precision quartz gauge section (QGS), chamber valve section (CVS) for two sample chambers (1 to 5 gallon), and a multi-chamber section (MCS) with 1,000-cm3 chambers. The MCS chambers are compatible with hydrogen sulfide (H2S) with NACE approved materials and have an exemption with the U.S. Department of Transportation (DOT) for common-carrier transportation.
This paper details operational features of the new tester and introduces new pressure-testing and sampling interpretation techniques. Field-test results are used to demonstrate these features and techniques.
An Analytic Model for a Flowing Bundle System
Authors: Danielson Thomas J. , Brown Lloyd D. 
Published: December 2007

Abstract
As bundled pipelines have become more common in offshore operations, several tools have appeared to aid in the modeling of such systems. One such tool is the Conoco bundle model, developed for use with the OLGA transient multiphase code, and used extensively on Conoco's Britannia bundle system (SPE 36610)1 and commercialized by Scandpower. However, if the numerical grid is not sufficiently fine in regions of large axial temperature gradients, the temperature profile in the bundle lines will not be adequately captured. This can result in a significant over-prediction of minimum line temperatures (and possible formation of hydrates and paraffin), and significant under-prediction of thermal stresses.
Many times, a steady-state analysis is adequate to capture most of the salient features of a bundle system. With minimal simplification, an analytic solution for a steady-state bundle system containing up to 3 internal lines (e.g., the production and test line, and heating medium return line) can be formulated.
The Conoco Analytic Bundle Model has the advantage that it is not grid-sensitive, as the numerical model is. In addition, unlike the numerical model, it is extremely fast (essentially instantaneous) and easy to set up. For this reason, it is an excellent tool for performing sensitivity analyses on variables which cannot be predicted with great accuracy, e.g., the film heat transfer coefficient in the bundle heating medium.
Downhole Water Sink (DWS) Completion Enchance OIL Recovery in Reservoirs with Water Coning Problem
Authors: Wojtanowicz A. K. , Shirman E. I. , Kurban H. 
Published: December 2007

Abstract
To date, field trials of wells with DWS completions have shown that this new technology could control water coning and increase oil production rate. None of these tests, however, was long enough to show DWS potential to improve process of oil recovery comparing to conventional wells. Presented in this paper are results from a recent project of the R&D consortium of nine companies at LSU – Downhole Water Sink Technology Initiative.
The recovery study involved experiments with the physical model and computer simulation runs. The laboratory results showed that, for the same rate at the top completion, DWS dramatically accelerated the recovery process; A five-fold increase of the oil production rate was reached without changing the rate at the top completion - by adjusting the drainage rate at the bottom completion. The results also showed a 70-percent increase of oil recovery; from 0.521 up to 0.882 for conventional and DWS completions, respectively.
The computer-simulated experiments with commercial reservoir simulator confirmed the thesis on better recovery with the DWS completions by showing a 30-percent increase of recovery factor from 0.61 to 0.79 for conventional and DWS completions, respectively. The results also gave a five-fold reduction of the time required to reach the limiting 0.98 value of water cut. However, accelerated recovery process with DWS required a substantial up to 3.5-fold increase of total water production.
The simulation experiments clearly showed that the main advantage of using DWS is its flexibility of controlling the recovery process. For conventional completions, the recovery could be slightly increased by reducing production rates and largely increasing production times. For DWS, on the other hand, production process could be optimized for maximum recovery, minimum time, or minimum cumulative water produced by seeking a best combination of the top and bottom rates.
Time Lapse Ultrasonic Measurements of Laboratory Hydraulic Fracture Growth: Width Profile and Tip Behaviour
Authors: Groenenboom J. , van Dam D. B. , de Pater C. J. 
Published: December 2007

Summary
In scaled laboratory tests, we perform acoustic measurements in a time-lapse sequence to separate the fracture response from the background signal. Using both compressional waves and shear waves (that are very sensitive to fluid filled fractures) we can not only detect the hydraulic fracture, but also characterize its shape and geometry during its growth. We show the application of the technique to propagation, flowback tests and re-opening of hydraulic fractures.
During fracture growth the acoustic waves excite diffractions at the tip of the fracture. We use the direct compressional and shear diffractions to locate the position of the tip of the fracture. The ultrasonic data show that the diffractions are most strongly excited at the fluid front of the hydraulic fracture. In some cases, a much weaker precursor diffraction can be detected which is interpreted as the dry tip of the fracture. Depending on the acquisition geometry, we detect many events related to surface waves propagating along the fracture. Also, we observe that shear waves detect the migration of the fluid front during re-opening of a pre-existing hydraulic fracture, in contrast with the compressional waves which are insensitive to the fluid front during re-opening.
Observation of transmission signals through the fracture yields a very accurate measurement of the fracture width. In this way we have obtained the full fracture width profile during propagation and closure. Flow back resulted in closing the fracture at the wellbore, while it remained open farther from the wellbore.
Interpretation and Modeling of Time-Lapse Seismic Data: Lena Field, Gulf of Mexico
Authors: Shyeh J. J. , Johnston D. H. , Eastwood J. E. , Khan M. , Stanley L. R. 
Published: December 2007

Abstract
Two 3D seismic data sets from the Lena Field, Gulf of Mexico are analyzed for time-lapse effects. The seismic analysis involves cross equalization and residual migration of the post-stack seismic data, as well as full reprocessing and attribute analyses. The time-lapse differences for the B80 reservoir are compared with production data, geologic models, flow simulations, and forward seismic models. The time-lapse seismic difference anomaly is interpreted to be a region of gas invasion. Areas bypassed by the injected gas are identified from 4D seismic data as opportunities for infill drilling. Successful interpretation of this time-lapse seismic data illustrates the importance of integrating the results of modeling and simulation with seismic processing and interpretation.
Application of Silicate-Based Well Treatment Techniques at the Hungarian Oil Fields
Authors: Lakatos I. , Lakatos-Szabó J. , Tiszai Gy. , Palásthy Gy. , Kosztin B. , Trömböczky S. , Bodola M. , Patterman-Farkas Gy. 
Published: December 2007

Abstract
By joint application of silicates and polymers or humates, a multifunctional, self-controlling chemical system is usually formed which works spontaneously even under harsh reservoir conditions, meanwhile the methods remain inexpensive, flexible and adaptable to any production technology. A concise summary of the diverse techniques, their principle and mainly field projects are discussed in the paper. It was shown that the silicates, combined with polymers and humates offer unique opportunity to cure numerous production/injection problems including water-shut-off, profile correction, clay stabilization, etc. in oil and gas fields and underground gas storage. Between 1980 and 1998 the field projects, comprising more than hundred well treatments, yielded substantial additional oil production, life time of wells were extended and the overall profitability of fields was significantly increased, meanwhile environmentally friendly chemicals were used. Therefore, the Hungarian experts are convinced that the silicate-based methods as reasonable alternatives wherever and whenever the application of bulk or surface gelation or deposition is arising.
Fully Automatic Procedure for Efficient Reservoir Fluid Characterization
Authors: Liu K. 
Published: December 2007

Abstract
The EOS has been widely applied to characterize reservoir fluids. On the other hand, an EOS is generally not predictive without tuning its parameters to match relevant experimental data. Since the manual EOS-tuning process is artistic and strongly dependent on an engineer's past experience, different engineers may get completely different results and few engineers could obtain the satisfactory results without certain tries and guesses. Problems include what the minimum number of components should be used, how the original system should be lumped, how many and what kinds of regression variables should be included into the regression variable set, and so on. This paper presents a fully automatic technology to efficiently perform the reservoir fluid characterization. A method to handle multiple fluid samples, a fully automatic tuning procedure, a best lumping algorithm, and the fully automatic determination of the minimum number of components will be described. Some applications will be summarized.
Gradient-Based History-Matching with a Global Optimization Method
Authors: Gómez Susana , Gosselin Olivier , Barker John W. 
Published: December 2007

Abstract
We investigate the application of a global optimization algorithm called the Tunneling Method to the problem of history-matching of petroleum reservoirs.
Results are presented for two test cases. The first is a small synthetic case in which the global minimum is known. The second is a real field example. In both cases, a series of minima was found. The computational cost of each tunneling phase is found to be comparable with the cost of each local minimization.
It is concluded that the Tunneling Method may have a practical application in history-matching as an alternative to immediate reformulation of the problem if the first minimum found does not represent an acceptable match.
Time-Dependent Coupled Processes in Wellbore Design and Stability: PBORE-3D
Authors: Abousleiman Y. , Ekbote S. , Cui L. , Mody F. , Roegiers J. -C. , Zaman M. 
Published: December 2007

Abstract
It is well established that time-dependent processes are responsible for stability and failures in wellbore drilling. Stability problems account for a significant amount of lost drilling rig time and substantial costs during drilling. The coupled time-dependent processes are well described in the realm of the poroelasticity theory and some of their solutions and applications to the inclined wellbore problem in the general three-dimensional state of the in-situ stress have been published. In this paper, in addition to the analyses conducted on the previously derived solutions, thermal and pore fluid diffusion, the time-dependent solution for stresses and pore pressure for the inclined wellbore taking into account the mud and formation shale activities, are also derived. The aforementioned solutions are implemented in the user-friendly software, PBORE-3D, which can perform analyses of stress/pore pressure, formation failure, mud weight and mud salinity design for drilling in shale formations. Also included in this software are the thermal and viscous effects.