bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oil Spill Detector for Un-Manned Platforms
Authors: Dalland K. I. , Jouve P. 
Published: December 2007

Abstract
Efficient operation of un-manned oil platforms has given increased demand for new instrumentation. Simrad has together with Elf Petroleum Norge developed a Marine Oil Spill Detector, an autonomous system for detecting oil slicks in the vicinity of the platform. The system should based on the movement of the slick locate its source, and primarily give alarm if the oil comes from the platform itself or any of its subsea installations.
The Oil Spill Detector consist of a standard marine radar antenna interfaced to and controlled by a PC based processing station. It monitors the vicinity of an oil platform to detect the reduction in sea clutter caused by the damping effect of oil on surface waves.
This paper describe two demonstration tests of the system. The system was during the first test located on the roof of our office building close to the waterside in the Bergen harbor where slicks formed by only 5 liters of oil was tracked for more than 20 minutes. The second test was an offshore test conducted by NOFO ( Norwegian Clean Seas Association for Operating companies ) where up to 100 m3 crude oil where spilled and recovered.
Simulation of Well Productivity Losses Due to Near Well Condensate Accumulation in Field Scale Simulations
Authors: Malachowski M. A. , Yanosik J. L. , Saldana M. A. , Batten A. H. 
Published: December 2007

Abstract
Accurate simulation of well productivity losses due to condensate buildup generally requires a finely gridded radial model and either a fully implicit or adaptive implicit solution method. Computer costs for including the grid refinement necessary to capture near well liquid dropout effects in full field, compositional simulations can be extreme even for models with local grid refinement and adaptive implicit capabilities. We propose an alternative simulation method which accurately computes condensate blockage effects in multiwell, full field simulations without local grid refinement. The method is based on the use of correlations of "pseudo skins" which can then be combined with a general well function equation to capture the effects of well productivity losses. The correlations are developed prior to running a full field model by running a series of fine radial grid and coarse Cartesian grid single well simulations to define the relationship between the true wellbore pressure (obtained from the fine grid simulation) and the well block pressure in the coarse grid.
Optimizing Recovery From A Strong Water-Drive West Texas Gas Reservoir Through Integrated Reservoir Simulation Studies
Authors: Hulme J. R. , Colleary W. M. , Van Kirk C. W. 
Published: December 2007

Abstract
This paper presents a field study funded by the Gas Research Institute (GRI) to determine reservoir management and production strategies to economically maximize recovery from the Vermejo/Moore-Hooper strong water-drive gas reservoir in West Texas. The reservoir is greater than 16,000’ deep and contains high pressure sour gas, and it is composed of geologically complex fractured dolomite and chert. The water drive is exceptionally strong, the reservoir has experienced no more than 5 percent pressure depletion during its 20-year history, and late in life the field is beginning to re-pressurize. Detailed Engineering and Geologic studies were performed and reservoir simulation of the field tested the most effective methods to economically maximize recovery.
The management strategies evaluated were comprised of various methods to maximize field productivity, reduce bottom-hole flowing pressure, improve the ability of the wellbore to unload water and reduce/retard aquifer influx. Specific strategies that were tested included the drilling of an infill well, placing the wells on compression, installation of coiled tubing, installation of gas lift, installation of an optimal tubing string, injection of a permeability barrier into the reservoir and de-pressuring the aquifer by downdip water production.
It was concluded that the most economic method to deplete the field was to place the remaining wells on compression at 200 psia wellhead pressure and to install coiled tubing when the wells begin to experience water load-up problems. The gas-lift and optimal tubing cases predicted higher recoveries, but were economically less favorable. The methods tested to reduce aquifer influx to the reservoir actually decreased recovery of gas reserves. The study also identified the need for a multiphase flow correlation which fully handles the complexity involved with high water-gas-ratio systems (up to 10 stb/mscf).
A NEW GENERATION SOLUTION ADAPTIVE RESERVOIR SIMULATOR
Authors: Deb Manas K. , Reddy Mahender P. , Thuren John B. , Adams Wilton T. 
Published: December 2007

AbstractThis paper describes a new general purpose three – dimensional multi-phase reservoir simulator that uses fully unstructured curvilinear meshes and employs dynamic mesh adaptivity based on a flow solution. The simulator is based on an unconventional finite element framework called hp finite elements (where h refers to the local mesh size and p refers to the order of the local polynomial approximation). The simulator is coded as an application layer on top of a general-purpose solution-adaptive hp-finite element kernel. This kernel incorporates advanced object-based data structures that allow simultaneous manipulation of h (via refinement/unrefinement) as well as p (via enrichment/ unenrichment).The simulator supports both IMPES as well as fully implicit schemes. It offers an automatic time stepping strategy. The numerical difficulties associated with advec-tion terms and presence of solution near-discontinuities are overcome using SUPG (Stream-wise Upwind Petrov Galerkin) method with a discontinuity capturing (DC) operator. The simulator achieves higher computational efficiency by anisotropic hp-type mesh adaptation. It does not use a predetermined well model (such as Peace-man’s well model). Instead the wells are represented exactly and modeled right up to (and sometimes including) the well bore. The simulator is equipped with both direct and iterative solvers. The iterative solvers are also parallelized. Several validation and demonstration cases solved using this simulator are presented in the paper. It is anticipated that this simulator will provide unprecedented computational advantages when handling geologically complex reservoirs with non-trivial and non-traditional well shapes and perforations.
Reservoir Management and Optimization of the Mitsue Gilwood Sand Unit #1 Horizontal Hydrocarbon Miscible Flood
Authors: Winter B. T. , Edwards K. A. 
Published: December 2007

Abstract
The performance of a two-stage hydrocarbon miscible flood project at the Mitsue field, Alberta, Canada is updated. The reservoir management issues pertaining to the miscible flood project are also discussed, particularly the use of a relational database to store and manipulate the large quantities of data associated with the miscible flood project. Lastly, the chase gas optimization efforts undertaken since original project design are discussed. The Hybrid finite-difference/streamtube technique has been used to modify the chase gas injection slug size and WAG ratio.
A Study of Adsorption of Gases in Tight Reservoir Rocks
Authors: Satik Cengiz , Horne Roland N. , Yortsos Yanis C. 
Published: December 2007

Abstract
In this work, we studied adsorption in tight porous solids using both experimental and numerical methods. We conducted adsorption experiments for geothermal reservoir rock samples and studied the scanning behavior of the steam sorption hysteresis loop. The results of the sorption experiments show that temperature has an important effect on desorption, such that hysteresis becomes more pronounced as the temperature increases. Using a pore network model to represent porous media we investigated adsorption-desorption processes over the range of the relative pressures, highlighting in particular capillary condensation. The numerical model incorporates recent advances from density functional theory for adsorption-desorption in narrow pores (of order as low as 1 nm), which improve upon the traditional multi-layer adsorption and Kelvin’s equation for phase change and provide for the dependence of the critical pore size on temperature. Comparison of the numerical results with the experimental findings showed a good agreement. The hysteresis in the adsorption-desorption cycle is interpreted in terms of blocking of larger pores, where adsorbed liquid is allowed to but cannot desorb, by smaller pores containing liquid that may not desorb. The hysteresis also increases if the porous medium is represented as a fractured (dual porosity) system.
Pore-Network Studies of Steam Injection in Porous Media
Authors: Satik Cengiz , Yortsos Yanis C. 
Published: December 2007

Abstract
Conventional approaches in modeling steam injection (or other vapor-liquid flow) in porous media are based on relative permeability and capillary pressure formalisms borrowed from isothermal, two-phase flow. When phase change is involved, however, additional phenomena, such as heat transfer and condensation must be accounted for. In this paper, we present a theoretical and numerical study to test the validity of this approach. The theory predicts the existence of a compact pattern at conditions when heat transfer predominates. This regime is consistent with the very small residual saturations, typically observed in steam displacements. Heat transfer and phase change also lead to smaller values for the effective mobility ratio, Meff, and the capillary number, Ca. Such displacements can be portrayed in a three-dimensional phase diagram with coordinates Meff, Ca and StPe−1&gt; where St is the Stefan number and Pe the Peclet number. A pore network simulator is next presented. Depending on the location in the parameter space, displacement patterns are shown to lie in the compact, percolation or viscous fingering regimes. The theory was found to be in general agreement with the numerical simulations. Observations from experiments in micromodels also support the general findings.
Three Phase Oil Relative Permeability Determination as a Key Point in the Evaluation of a Tertiary Gas Drainage Gravity Project
Authors: Chalier G. , Giry V. , Madaoui K. , Sakthikumar S. , Maquignon Ph. 
Published: December 2007

Abstract
For several years a dual energy gamma-ray absorption measurement apparatus has been routinely performing in situ three phase saturation monitoring during coreflood experiments in reservoir conditions. This paper presents this sophisticated equipment and the application of the technique to determine the three phase oil relative permeability at low oil saturations during a tertiary gas gravity drainage experiment. The oil relative permeability was thought to be a crucial point to validate the economic feasibility of this tertiary oil recovery process for a waterflooded reservoir in the Far East.
Using the gamma-ray absorption technique it was possible to visualize the fluid saturation distribution in the core as a function of the volume of gas injected. The production of tertiary oil by gravity drainage was put into evidence at the top of the core. The three phase oil relative permeability curve was deduced from the oil saturation profdes using an analytical calculation.
The experiment was finally correctly reproduced with a generalized compositional simulator, emphasis being put on the match of saturation profiles. A triphasic relative permeability model was then validated.
Water Control Diagnostic Plots
Authors: Chan K. S. 
Published: December 2007

ABSTRACT
A new technique to determine excessive water and gas production mechanisms as seen in petroleum production wells has been developed and verified.
Based on systematic numerical simulation studies on reservoir water coning and channeling, it was discovered that log-log plots of WOR (Water/Oil Ratio) vs time or GOR (Gas/Oil Ratio) vs time show different characteristic trends for different mechanisms. The time derivatives of WOR and GOR were found to be capable of differentiating whether the well is experiencing water and gas coning, high-permeability layer breakthrough or near wellbore channeling.
This technique was applied on wells in several fields in Texas, California, the Gulf Coast and Alaska. Plots using the actual production history data determined the production problem mechanisms. Together with well tests and logs, the technique was used to select well treatment candidates and to optimize treatments to enhance the return of investment.
Waterflood Recovery and Fluid Flow Upscaling in a Shallow Marine and Fluvial Sandstone Sequence
Authors: Ciammetti G. , Ringrose P. S. , Good T. R. , Lewis J. M. L. , Sorbie K. S. 
Published: December 2007

Abstract
Detailed reservoir characterisation and modelling has been an active area of petroleum technology development for several years now, but incorporating and scaling up these geologic models into fluid flow and production simulations is a major challenge. The objective of this study is to properly incorporate all relevant levels geological heterogeneity identified in a detailed outcrop reservoir description into a flow simulation of an hypothetical reservoir. We apply the "geopseudo" upscaling methodology to the geological description of a shallow marine sequence exposed in the Book Cliffs. The study identifies which features are important for field-scale fluid flow and recovery for a waterflood.
A cross section waterflood flow simulation, using the geopseudo upscaling technique, was carried out on an interpreted cross-sectional panel through a portion of the Book Cliffs outcrop in Utah. The section consists of the following lithofacies: Undifferentiated Upper Shoreface deposits, Hummocky Cross Stratified sands, the Swaley Cross Stratified sands, Fluvio-Tidal Channel Sandstones and two units of Heterolithics. A grid block size of 10 metres by 1 metre was used, with two stages of upscaling to account for the effects of small-scale heterogeneities. The thin beds of shales were accounted for using vertical and horizontal transmissibility multipliers between grid blocks. Sensitivity runs were carried out to assess the relative contribution of different geological parameters to the waterflood performance.
Comparison of Flash Calculations in Compositional Reservoir Simulation
Authors: Wang Peng , Barker John W. 
Published: December 2007

Abstract
This paper compares several recent flash algorithms in the context of compositional reservoir simulation. We evaluate three reduced equation methods: 1) the 3-equation flash of Michelsen (1986), which applies only when all binary interaction coefficients (kij) are zero; 2) Hendricks and van Bergen (1992); and 3) Kaul and Thrasher (1993). We also evaluate: 4) the non-iterative flash (Stenby and Wang, 1993); and 5) the method of Young (1991). We find that these last two methods, which are similar in concept, work well for reservoir simulation where the flash must be closely coupled with the solution of the pressure equation, and where a good initial guess is generally available. The reduced equation flashes offer no significant improvement over these other methods; this is true even for the 3-equation flash which solves a simpler problem (with kij = 0).
Optimization of Pseudo-Component Selection for Compositional Studies of Reservoir Fluids
Authors: Joergensen M. , Stenby E. H. 
Published: December 2007

Abstract
Twelve different lumping procedures were compared with the objective of formulating a generalized set of rules for pseudoization of reservoir fluids. These twelve methods consisted of three different grouping methods, and four different property calculation methods.
The lumping procedures were tested by simulating phase equilibria and PVT experiments for three different synthetic fluids. None of the tested methods performed significantly better than others, but some of the methods proved to perform worse than the majority of the methods.
It has been found that most experiments can be simulated with a reasonable accuracy (deviations less than two percent) when eight or more pseudo-components are used in the fluid description.
An Algorithm to Predict Pressure and Temperature Profiles through a Coiled Tubing.
Authors: Pilo S. 
Published: December 2007

Abstract
The scope of this work is to develop an algorithm to predict the temperature and pressure profiles in a compressible flow through a coiled tubing, taking into account both friction losses and heat transfer simultaneously. The algorithm combines the theory of gas dynamics (heat transfer process) and thermodynamics (energy balance) to predict pressure, temperature, density, velocity and Mach number profiles for either horizontal, inclined or vertical strings.The results of the algorithm were compared with the Cullender & Smith method, which is the standard correlation used for downward gas flow calculations. A strong agreement between them was obtained. The algorithm presented allows more reliable results because it only needs for start-up, gas data that is usually very precisely known in real conditions.
Filtration Control, Mud Design and Well Productivity
Authors: Leerlooijer K. , Kuijvenhoven C. A. T. , Francis P. A. 
Published: December 2007

Abstract
Filtration control has a considerable impact on drilling fluid properties & performance, on drilling costs and on well productivity. The requirements for filtration control, with regard to optimisation of the various stages of drilling a well, are ambiguous. This is largely due to the lack of understanding of the functionality of the mud components and on imprecise definition of demands.
Multi-Core Dynamic Filtration equipment has been designed to study static- and dynamic filtration (including spurt loss conditions) and assess their effect on return permeability for up to 4 core samples at a time. Several core samples in one experiment will enable us to evaluate the effect of permeability variation on clean-up efficiency. In another development, equipment has been designed for continuous measurement of cake thickness during filtration.
Polymer systems have been identified that effect acceptable fluid loss without solid particle additions. Apparently, the micelles formed have the dual functionality of solids to plug the pores and polymers to reduce cake permeability. This line of investigation may have potential in the development of truly solids free drilling fluid systems based on high density brines (e.g. Formates).
Effects of Various Parameters on Perforation Plugging and Perforation Cleanup
Authors: Han Liqun , Peden Jim M. , Ford John 
Published: December 2007

Abstract
Formation damage caused by kill fluids invasion and filter cake deposition in the perforation tunnel has rarely been addressed in the scientific literature. In this paper, a systematic experimental program using CaCO3-HEC slurry to kill perforated wells is presented. The perforation target is simulated using a cylindrical core with a drilled perforation, and borescope has been used to observe the distribution of filter cake in the perforation tunnel. Important parameters affecting perforation plugging and cleanup have been identified. The effectiveness of perforation cleanup methods, such as backflush and backsurge have been studied and the mechanism of filter cake removal investigated.
Experimental results show that among the various damage parameters investigated, only core permeability and fluid viscosity have big effects on Perforation Flow Efficiency (PFE), which is the comparative flow capacity of a damaged perforation to that of a clean perforation. Perforation Flow Efficiency decreases with increasing permeability.
The mechanism of filter cake removal strongly depends on the perforation cleanup techniques. When backflush is used to clean the plugged perforations, a threshold differential pressure has to be reached before flow can be initiated and a minimum volume of fluid must be flowed to achieve optimum PFE. Depending on the damage and cleanup conditions, plugged perforations may be partially or completely cleaned by backflush. Sequential backflush is advantageous over single constant rate backflush for high permeability core, where matrix damage is severe. Increasing backflush rate increases PFE. When backsurge is used, all the filter cake deposited can be removed instantaneously, and the PFE obtain is very high. Backsurge pressure is more important than backsurge volume.
The results obtained in this study will be very helpful in the design of kill pills and the design of perforation cleanup methods in the field.
Stability of Proppant Pack Reinforced with Fiber for Proppant Flowback Control
Authors: Romero J. , Feraud J. P. 
Published: December 2007

Abstract
A new method has been developed to prevent proppant flowback from a propped hydraulic fracture. The method consists of mixing the proppant with fiber elements before pumping the proppant into the fracture. The results of an experimental program, in which the goal was to better understand the mechanics of the reinforcing fiber on the proppant pack, are presented. The effects of fiber and sand properties on sandpack strength have been studied for an optimal use of the fiber. A macroscopic model has also been developed based on fiber and proppant properties. Laboratory tests on proppant with a low fiber content indicate a favorable agreement between the model prediction and the flowback tests.
Assessment of Formation Damage using Artificial Neural Networks
Authors: Kalam M. Z. , Al-Alawi S. M. , Al-Mukheini M. 
Published: December 2007

Abstract
Artificial neural network (ANN) models are designed to emulate human information processing capabilities such as knowledge processing, speech, prediction and control. The ability of ANN systems to spontaneously learn from examples, reason over inexact and fuzzy data, and provide adequate responses to new information not previously seen, has generated increasing acceptance for this technology in the engineering field and resulted in numerous applications. A preliminary investigation into the use of this novel technology is presented towards predicting formation damage by quantifying wettability and two-phase relative permeability of oil reservoirs.
An artificial neural network model based on the Back Propagation technique is trained with a number of variables from experimentally established relative permeability (relperm) curves. The reservoir core input data covers an extensive range of porosities and permeabilities from different lithologies having diverse wettabilities. The trained model is then tested with only a couple of easily obtainable input variables such as the Swc and Sor and predictions are made on the wettability and relperm curves. A change or shift in the relperm curves is associated with changes in wettability, and perhaps to formation damage in the drilling process.
The wettabilities of the rock-fluid system are predicted to within 90 % of the experimentally determined values. The relperm curves, particularly the end-points are predicted to within 85 % of the measured results. The accuracy of the predictions are significantly enhanced with model training using more precise reservoir data and better defined formation lithologies. Neural networks have immense potential in predicting relperm curves and thereby assessing formation damage in reservoirs.