bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Use of Observation Wells in Reservoir Management
Authors: Wannell M. J. , Ezekwe E. C. 
Published: December 2007

Abstract
The South Morecambe gas field has benefited from the use of a subsea observation well since 1983. This continues to provide valuable pressure data that have improved both the accuracy and uniqueness of the history match. This paper will concentrate on the use of these pressure data and particularly the use of pressure derivatives to reduce the effect of gauge drift. The paper will also report on the novel subsea technology used, particularly the neutrabaric chamber and acoustic telemetry data transfer. It will contrast results from three electronic gauges, two mounted downhole and one on the mudline.
Measurement of Invasion Using an MWD Multiple Depth of Investigation Resistivity Tool
Authors: Beck G. F. , Oberkircher J. , Mack S. 
Published: December 2007

ABSTRACT
Measurements made with an MWD multiple depth of investigation resistivity tool are compared with wire-line resistivity logs from two wells in the Gulf of Mexico. Where data density permitted, four investigation diameters at three different time intervals were studied using the MWD tool while drilling, the MWD tool after drilling (MAD), and the wireline (WL) logging operations. The MWD tool allowed new information to be gathered about the early stages of invasion, and combined with the WL data, allowed for the study of the invasion process over time.
Both wells encountered gas, oil, and water sands. The observed invasion characteristics were the same as reported elsewhere: invasion volume (on a per foot basis) was relatively constant for a given formation exposure time regardless of formation property or mud overbalance1. A minor exception to this was the higher initial spurt loss observed in gas sands which was attributed to the higher mobility of gas allowing higher initial flow rates into the formation.
Conventional step profile and annular invasion theories cannot explain the observed MWD, MAD, and WL resistivity profiles over time. Instead, a slope profile invasion model with a long salinity transition zone is indicated. The observed data suggests that in the invaded zone hydrocarbons are not flushed to a residual saturation, but at a critical Sw value filtrate flow into the formationis favored over continued hydrocarbon flushing. Therefore, as the invasion volume is spread out over a larger area instead of being concentrated in a small diameter, the actual depth of invasion is greater than those determined by conventional methods that assume a high Sxo value. The resulting effect on log analysis is that conventional models may not accurately determine Rt.
Analysis of Pressure and Rate Transient Data From Wells in Multilayered Reservoirs: Theory and Application
Authors: Bidaux Pascal , Whittle T. M. , Coveney P. J. , Gringarten A. C. 
Published: December 2007

Abstract
A new solution technique is described for the analysis of multi-layered tests. This technique is based on an analytical conversion of a single-layer transient pressure response into a multi-layer response. Formation cross-flow is taken into account and a wide variety of inner and outer boundary conditions are possible. The method is succesfully applied to a field example for which single-layer analysis failed to give consistent results. Regression is used to simultaneously match observed pressures and layer rates. In the absence of measurable layer rate transients, as encountered in the field example, simple flow profile measurements to obtain relative layer production are all that is required to perform a multi-layer analysis.
Buildup Behaviors in Commingled Reservoir Systems With Unequal Initial Pressure Distributions: Interpretation
Authors: Agarwal Bijan , Chen Her-Yuan , Raghavan Rajagopal 
Published: December 2007

ABSTRACT
Pressure behaviors in layered commingled reservoirs that are a consequence of imbalances in initial reservoir pressures are documented. General conclusions concerning the interpretation of wellbore pressures when layer rates are unavailable are noted. A detailed examination of the time period when there is no surface production shows that much information which has a bearing on production performance can be discerned by the observation of pressure behavior during this time period. A number of approximate solutions to aid the analyst in analyzing well responses are documented.
The observations noted here are general in the sense that they can be used to understand long-time shut in behavior even if initial pressures are equal and layers are commingled at different times.
High-Resolution VSP Imaging To Locate Additional Reserves in Producing Fields
Authors: Johnston L. K. , Markowitz Gerald 
Published: December 2007

Abstract
In southern Louisiana many of the mature oil and gas fields are piercement salt domes where geologic structure often results in fragmented, although prolific, reservoirs throughout the fields. Surface seismic and geological data have proven reliable for exploration drilling in these reservoirs. This information, however, is not adequate to define the small fragmented reservoirs encountered in development drilling.
The use of borehole seismic imaging to define structure in exploration wells is a common practice. However, these surveys have typically lacked the accuracy to be used reliably in a development environment. Traditional borehole seismic surveys were adjusted to run inside tubing and inside casing while enhancing the resolution required to make development drilling decisions. By defining the reservoir extent, an operator can confirm economics before additional development drilling.
A case study examines the specific seismic imaging technologies used to define the updip limit of a reservoir from an existing production well. A three-component, multireceiver tool and marine vibroseis source technology were applied with advanced wave field processing to provide the resolution required to meet the objective of defining reservoir extent.
Relating Static and Ultrasonic Laboratory Measurements to Acoustic Log Measurements in Tight Gas Sands
Authors: Tutuncu A. N. , Sharma M. M. 
Published: December 2007

Abstract
A comparison of Young's moduli and Poisson's ratios obtained from ultrasonic laboratory measurements with static moduli obtained under identical stress conditions shows that the Young's moduli are 1 to 6 times higher under ultrasonic loading conditions. A comparison of these two laboratory measured quantities with log derived moduli measured at 20 KHz indicates that Eultrasonic&gt; Esonic &gt; Estatic, The clay content and porosity of the samples varied from 1 % to 54.5% and 3% to 17.5%, respectively. This clearly suggests that a wide variety of sandstones behave in a viscoelastic manner. The magnitude of the variation with frequency is a function of the clay content, grain size, shape of intergranular contacts, mineralogy and fluid saturations. A model is presented that describes this observed viscoelastic behavior.
The measured static moduli are a function of the sample length. This effect is investigated in some detail. The reported static moduli were obtained at L/d ratios of 2. When comparing log measurements to core, two inherent problems were encountered: depth correlation and sample size. These effects need to be properly accounted for when comparing logs with cores.
Defining Flow Units in Dolomitized Carbonate-Ramp Reservoirs
Authors: Lucia F. J. , Kerans Charles , Senger R. K. 
Published: December 2007

ABSTRACT
The problem of defining flow units in carbonate reservoirs has been investigated by integrated geological, petrophysical, and geostatistical outcrop studies. Results show that flow units (mappable intervals with similar petrophysical properties) can best be defined in terms of rock-fabric fades. Geostatistical analysis indicates that the different rock-fabric facies defined are significantly different but that within rock-fabric facies the petrophysical properties are near random. Detailed outcrop mapping shows that rock-fabric units are systematically arranged within genetic packages that have predictable stacking patterns within a sequence stratigraphie framework.
Anguille Marine, a Deepsea-Fan Reservoir Offshore Gabon: From Geology to Stochastic Modelling
Authors: Massonnat G. J. , Alabert F. G. , Giudicelli C. B. 
Published: December 2007

ABSTRACT
The ANGUILLE MARINE field has been produced for 25 years. Implementation of water injection soon revealed complex reservoir mechanisms controlled by severe sedimentary heterogeneities.
The ANGUILLE Formation has been deposited in a deep-sea-fan environment (slope apron) with a low sand/shale ratio. In such an environment, the geometry of sandbodies controls the reservoir connectivity. Knowledge of this parameter is therefore critical in understanding flow mechanisms.
This paper deals with a multi-scale analysis of the heterogeneities (5 scales were studied), and the research of the best way to represent all the scales in the 3D modelling.
Sequence stratigraphy principles are applied successfully and allow the reconstitution of the ANGUILLE Formation history. In each defined time unit, a sequence analysis log data is used to divide the reservoir into four main types of turbiditic geometries (channels, lobes, slumps, laminated facies). Isovalue maps of lobe and channel frequency slow clearly the paleo-directions of sediment supply. These, together with the well data, constrained the generation of fine 3D models of heterogeneities (more than 2 millions gridblocks) using geostatistical techniques. The generated models proved to efficiently represent the reservoir, as confirmed by the drilling of a new well in the northern part of the field, and by the results of the full-field flow simulations.
An attemptto use more precise sedimentary bodies dimensions in the matching of the actual data was carried out, and proved that this characteristic could become one of the usable parameter to match the reservoir performance.
Pressure Transient Parameter Estimation in the Laplace Domain
Authors: Wilkinson D. J. 
Published: December 2007

Abstract
It has become customary to compute pressure transient model solutions in the Laplace domain. This is because it generally simplifies the solution, and allows easy incorporation of wellbore storage, commingled systems or dual-porosity formations. On the other hand, the convolution and parameter estimation are usually done in the time domain. Thus, when the solution is used as the forward model in an optimization scheme, each forward evaluation requires a Laplace inversion of the model (using the Stehfest algorithm) and a time domain convolution. Here we explore the alternative of transforming the data into the Laplace domain (a one-time operation) and then doing the fitting in the Laplace domain. The chief new result is a self-consistent prescription for dealing with the fact that the data are available only over a finite time interval. The technique is illustrated for the case of a conventional well test which reaches radial flow on the time scale of the test, a situation for which the method is particularly efficient.
Effects of Properties in Seismic Data on Reservoir Characterization and Consequent Fluid-Flow Predictions When Integrated With Well Logs
Authors: Araktingi U. G. , Bashore W. M. 
Published: December 2007

ABSTRACT
A reservoir model was generated to quantify the enhancements in reservoir description resulting from the incorporation of seismically-derived information with well-based data and to study how the quality of the seismic data affects those reservoir descriptions. The reservoir model was created from 56 well logs with a predetermined spatial correlation using geostatistical techniques. A regular grid of traces was extracted from this model and transformed into 3D seismic surveys which were then inverted to produce acoustic impedance logs. Several seismic data parameters such as frequency bandwidth, waveform phase estimation error, and correlation coefficient between seismic and well data were varied to study their relative importance on reservoir description and subsequent flow results. These differing seismic datasets were finally integrated with the original well-log data again using geostatistical methods.
Comparative fluid displacements were performed on all reservoir realizations using an all-purpose flow simulator to quantify the flow behavior differences. The results, based on breakthrough time and oil recovery predictions, show that even marginal increases in frequency bandwidth (e.g., increases of 10 Hz in the upper frequency) provide significant enhancements to the reservoir model. Also, estimation of waveform phase to within ±20° of the true value is shown to be sufficient to capture much of the interwell heterogeneity contributed by the seismic data and thus does not significantly affect fluid-flow results. Finally, even for correlation coefficients as low as 0.4, which initially was considered quite low, sufficient positive contribution from the seismic data still warrants integrating it with the well-log data.
Outlook For Oil: The Problems And The Promise
Authors: Ballou George T. 
Published: December 2007

Good afternoon, gentlemen…..
I am honored by your invitation to address this distinguished meeting, especially since it gives me an excuse to visit this great producing region once again.
San Francisco and Los Angeles and Chicago and New York are wonderful cities and excellent places to conduct business. But to see the oil business in true perspective you have to return to the San Joaquin Valley or the Permian Basin, or one or the other places where the blood and bone or the industry is formed.
Sometimes I think oil men are like the legendary Greek wrestler, Anteus. He was unbeatable as long as he stayed in contact with the earth—-in other words, as long as he kept his feet on the ground. It wasn't until he allowed himself to be lifted into the air that his opponent, Hercules, was able to do him in.
In the same way, the oil fields—-where the real work or finding and producing oil is done—-are the industry's source or strength. Only by understanding what happens here can the oil business keep its feet on the ground, and be ready for all challenges.
A Coiled-Tubing-Deployed Downhole Video System
Authors: Rademaker R. A. , Olszewski K. K. , Goiffon J. J. , Maddox S. D. 
Published: December 2007

Abstract
This paper describes a fiber-optic downhole video system deployed on coiled tubing. A state-of-the-art inspection system has been developed that combines proven coiled tubing components, innovative cable termination methods, and the latest downhole video and fiber-optic cable technology. This new system has the capability to visually inspect horizontal wells, to displace opaque liquids in the desired viewing area by locally injecting clear fluids, and to obtain high resolution video at greater depths than possible with other camera systems. Testing indicates that this system provides improved versatility and video quality. This paper includes a complete description of the components in the downhole video system.
Field Study: Utilizing a Progressing Cavity Pump for a Closed-Loop Downhole Injection System
Authors: Klein S. T. , Thompson Scott 
Published: December 2007

Abstract
The information contained in this paper is based upon the field test of an experimental closed-loop injection system. The basis of the test was to determine both functionality and future feasibility. The system was installed in an existing water flood where the water source zone and the injection zones were completed in the same wellbore. The two zones were isolated by a bottom packer and a second upper packer, installed above the water source zone, which allowed the casing to be pressure tested to meet state regulatory requirements. The pumping system consisted of a sucker rod driven progressing cavity (PC) pump installed below the bottom packer. The sucker rods and pump rotor were driven from the surface by a variable speed hydraulic drive system. Water from the water source zone entered the pump through a perforated sub in the tubing string above the pump and was pumped into the injection zone. Downhole pressure gauges were initially installed to determine the differential pressure across the pump. A downhole flow meter was later installed to determine actual flow rates into the injection zone.
Large-Scale Laboratory Sand Production Test
Authors: Kooijman A. P. , Halleck P. M. , de Bree Philippus , Veeken C. A. M. , Kenter C. J. 
Published: December 2007

ABSTRACT
This paper describes the results and interpretation of a large-scale laboratory sand production test. In the experiment, a real well with multiple perforations was simulated, using an outcrop rock selected to represent core material from a specific field. The objective of the experiment, which was the first of its kind, was to investigate the influence of both effective stress increase and drawdown on sand production behavior, taking into account the influence of the presence of casing and cement and of perforating. An additional objective of the test was to investigate the influence of a water cut on the sand produced. The laboratory well behaved very realistically, in terms of both oil and sand production.
Hydrates Inhibition by Physical Solvents in the Treatment of Natural Gas From Offshore Reservoirs
Authors: Behar Emmanuel , Creagh Louise 
Published: December 2007

Abstract
The transport of natural gas from offshore producing fields presents difficulties not encountered in conventional onshore situations. If the gas is transported untreated, there is a risk of hydrates formation causing blockages in the pipeline.
A possible remedy is to treat the gas before transport using a compact unit in which it is contacted at low temperature by a physical solvent. The treatment consists of removal of condensate from the gas thus avoiding two-phase flow in the pipeline, removal of sour gas components which greatly increase the hydrates formation temperature, dehydration and depression of the hydrates formation temperature resulting from the inhibiting effects of the selected solvent.
After screening several physical solvents, two were retained for an experimental study of their effectiveness in hydrate inhibition, as well as their ability to selectively remove sour gas components while limiting the losses of hydrocarbons to the solvent. Hydrate formation curves were measured for a synthetic natural gas (s.n.g.) in the presence of water and of solutions of the tested solvents in water. For the sake of comparison, the hydrate formation curve was also determined for the s.n.g. in the presence of a methanol solution since this is the standard hydrate inhibitor in gas transport.
Thermodynamic Modeling for Organic Solid Precipitation
Authors: Chung Ting-Horng 
Published: December 2007

Abstract
A generalized predictive model which is based on thermodynamic principle for solid-liquid phase equilibrium has been developed for organic solid precipitation. The model takes into account the effects of temperature, composition, and activity coefficient on the solubility of wax and asphaltenes in organic solutions. The solid-liquid equilibrium K-value is expressed as a function of the heat of melting, melting point temperature, solubility parameter, and the molar volume of each component in the solution. All these parameters have been correlated with molecular weight. Thus the model can be applied to crude oil systems. The model has been tested with experimental data for wax formation and asphaltene precipitation. The predicted wax appearance temperature is very close to the measured temperature. The model not only can match the measured asphaltene solubility data but also can be used to predict the solubility of asphaltene in organic solvents or crude oils. The model assumes that asphaltenes are dissolved in oil in a true liquid state, not in colloidal suspension, and precipitation-dissolution process is reversible by changing thermodynamic conditions. The model is thermodynamically consistent and has no ambiguous assumptions.
Deviated Well Fracturing and Proppant Production Control in the Prudhoe Bay Field
Authors: Martins J. P. , Abel J. C. , Dyke C. G. , Michel C. M. , Stewart Graham 
Published: December 2007

ABSTRACT
Over 300 hydraulic fracturing operations have been performed at Prudhoe Bay. The available data have been analysed to examine the effects of well deviation and azimuth on fracture treating pressures, job placement success and, most importantly of all, post-frac well performance. Clear conclusions emerge.
Proppant production is an expensive problem at Prudhoe Bay. Factors affecting proppant production are examined, together with the results of a field evaluation of Resin Coated proppant.
Stochastic Models of Reservoir Heterogeneity: Impact on Connectivity and Average Permeabilities
Authors: Alabert F. G. , Modot Vincent 
Published: December 2007

Abstract
Probabilistic techniques are being increasingly used for modelling reservoir heterogeneity. A wide variety of models are now available, which all differ in their underlying assumptions, range of application, complexity of usage and computer efficiency.
Each technique has its own unconditional supporters. However, for the non-specialist, choosing one method is not trivial. Which method is best suited to a particular modelling context? After all, does it really matters from a practical, engineering point of view?
These are the basic questions we are addressing here.
After a review of current heterogeneity modelling techniques, a few "classical" models are compared on data from a deep-sea-fan reservoir. Fine scale, three dimensional distributions of permeability are generated using Indicator Simulations, Gaussian/Fractal Simulations and Truncated Gaussian Simulations. Common well log data and geological a priori are used for all methods.
The models are then compared in terms of connectivity and distribution of average permeabilities at the scale of full-field flow simulation grid.
Connected pore volume geometry on fine grids is found to be quite sensitive to the modelling technique. After upscaling, large scale permeability distributions remain sensibly different. The choice of the stochastic modelling technique has therefore a potentially important, practical impact on reservoir description.
Single- and Two-Phase Flow in Natural Fractures
Authors: Rossen W. R. , Kumar A. T. A. 
Published: December 2007

Abstract
Understanding and predicting the production behavior of naturally fractured reservoirs requires understanding flow in a single fracture. Individual fractures can be represented as two-dimensional networks of locations of wide and narrow aperture. Percolation theory prohibits two-phase flow in such a network under restricted conditions: that is, the relative-permeability curves cross at a relative permeability of zero. Using the Effective Medium Approximation (EMA), we illustrate the effect of aperture distribution and of gravity on these kri curves. In the absence of gravity effects, as the aperture distribution becomes broader, the cross-over point in the relative-permeability curves approaches zero wetting-phase saturation. On the other hand, straight-line relative-permeability curves obtain if gravity segregation dominates flow. This can occur, however, only if both phases are free to attain gravity equilibrium, which may not be possible given the restriction on local two-phase flow. In fractures, viscous forces become significant at pressure gradients orders of magnitude lower than in rock matrix. Viscous effects would tend to lead to straight-line relative permeability curves, as well.
We present also several simple models for non-Newtonian single-phase flow through fractures. Shear-thinning non-Newtonian fluids make the fracture appear to be wider than in Newtonian flow. In addition, plugging a fracture requires a higher fluid yield stress than expected from characterization of fracture aperture from Newtonian flow. Both non-Newtonian effects are greatest for fractures with broad aperture distributions.