bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application on Horizontal - Test Methods
Authors: Donoso Jose Maria , Daniel Guillermo Alberto 
Published: December 2007

ABSTRACT
The build-up performance for a vertical and two horizontal welltests in the same formation are investigated in this paper. Real time pressure and temperature acquisition were performed with a strain gauge and a downhole cable operated shut-in valve for all three tests. Unfortunately, the amount of time necessary for the horizontal test interpretation analysis to yield unique reservoir and well parameters is found to be insufficient.
Thus, external "information such as core analysis, deviation surveys and geological modeling is used in order to confirm all the available information. The proposed interpretation methodology is to match the actual data to an analytical solution of pressure and its derivative behavior. This is done by adequately combining this external knowledge of the well and reservoir with the calculated parameters from the well test analyses.
The values obtained in this way serve the purpose of checking this peripherical information against well testing interpretation and observe their combine results consistency.
New Slurry Mixer Improves Density Control in Cementing Operations
Authors: O'Neill Eamonn , Téllez Luis E. 
Published: December 2007

Abstract
Poor slurry density control in cementing operations leads to a failure to reproduce laboratory designs at the field level. Adverse consequences include poor bonding, incomplete fill-up, inefficiency of cementing additives, lower compressive strength, erroneous thickening time, and possible inability to control formation pressures.
In three locations worldwide, field testing of a new closed-loop control slurry mixer has demonstrated that density control can be achieved while mixing and pumping direct to the well. There is no need for batch-mixing facilities, because the entire slurry is pumped at the correct density.
The test installations, types of jobs and slurries pumped during the first 12 months, and the parameters recorded to measure the effectiveness of the mixer are discussed in this paper.
The results and conclusions demonstrate that the mixer can automatically control density during mixing within 0.1 lb/gal. Other results include improved field slurry rheology, capacity to mix conventionally problematic slurries, and shorter operational time.
Sucker Rod Centralizers for Directional Wells
Authors: Rivas O. , Newsky A. , Cedeno M. , Rivera P. 
Published: December 2007

ABSTRACT
The industry trend towards directional and horizontal wells demands development and use of new equipment to solve the problems raised by the well deviation angle. Perhaps, the strongest limitation for the use of sucker rod pumping in directional and horizontal wells is the early failure of the tubing and sucker rod string. This is caused by the severe wearing of these components due to the continuos friction between them. The life of the subsurface pump life is strongly affected by stem misalignment All these problems are seriously increased if the well has been steam injected.
A Sucker rod centralizer, has been developed to reduce the wearing of the tubing, sucker rod string and subsurface pump. So far, centralizers have been installed in seven deviated wells in the Orinoco Belt Field. The use of these centralizers has resulted in a 300% increase of the active life of tubing, sucker rod string and subsurface pumps. These seven wells were steam injected and are producing under an emulsion scheme.
History Matching of Unsteady - State Corefloods for Determining Capillary Pressure and Relative Permeabilities
Authors: Grattoni Carlos Atilio , Bidner Mirtha Susana 
Published: December 2007

ABSTRACT
A method for the simultaneous determination of capillary pressure and relative permeability curves of oil/water systems from coreflood experiments is presented. The Levenberg-Marquardt optimization technique is used to match results from a numerical simulator to laboratory coreflood data by applying a nonlinear least-squares procedure. The simulator is an IMPES finite-difference program which models the simultaneous one-dimensional flow of oil and water through a core. Exponentional functions are used to describe relative permeabilities and capillary pressure curves.
Results show that relative permeabilities can be in error when capillary pressure terms are neglected and that the adjustment of a variable which combines oil and total flow rate output data leads to better matches than the adjustment of cumulative oil recovery.
Well Testing Design Under Harsh Environment
Authors: Borges Fernando Assumpção , Felix Márcio , Bezerra Carvalho 
Published: December 2007

ABSTRACT
The oil industry's search for new hydrocarbon accumulations has led to the drilling of ever deeper wells, normally under harsh conditions that involve high pressures, temperatures and mechanical strengths as well as sour gas production. In order to perform drill-stem tests (DSTs) safely, these constraints must be overcome.
PETROBRÁS, the Brazilian state owned oil company, has been drilling wells in ever deeper horizons, reaching up to 18,000 ft (5,500 m). During the last five years some important areas have been discovered, especially offshore, of which the Tubarão Field in Southern Brazil is one example. Based on well-testing experiences in the North Sea, as well as the company's own experience, PETROBRÁS has developed a new approach for testing deep wells: the use of a simple and reliable test-string assembly, achieved by reducing and replacing components, and the adoption of extremely rigorous safety standards and careful selection of materials suitable for use in the presence of hydrogen sulphide.
This paper presents a field-proven well-testing design, whose main concerns are offshore safety and environmental quality.
Special Operations Integrated System
Authors: Lopes D’Almeida Albino 
Published: December 2007

ABSIBACT
A distributed processing system was designed to monitor and control special drilling operations. It is fed by five regional centers located across Brazil; all information is also available at the head offices in Rio de Janeiro, where data are grouped. This user-friendly system deals with technical, cost, equipment, and personnel data pertaining to fishing, core sampling, drill-stem testing, and cementing assembly operations.
It can generate consolidated reports containing statistical data as well as operation reports. The system monitors equipment service life and performs preventive maintenance tasks. Through the computer network, specific operations may be accessed and records transferred to accompany movement of personnel and tools.
Static Hydrocyclones: A Cost Effective Alternative for Produced Water Treatment
Authors: Choi Michael S. 
Published: December 2007

ABSTRACT
Ever increasing water production and more stringent environmental standards have driven up the cost of produced water disposal. What was once a small consideration in the design of production facilities has become a high profile and costly component of offshore production projects. The large space and weight requirement for conventional produced water treatment (PWT) systems (skim tanks, CPI's and flotation cells) could have a large negative impact on the overall economics of a deep water development.
Recent advances in static hydrocyclone technology for PWT has added an attractive alternative to conventional systems. Within certain operating limits, hydrocyclones have proved to be effective in reducing oil-in-water content to environmentally acceptable levels. In contrast to a conventional PWT system, hydrocyclones provide offshore operators the benefits of light weight, compact size, easy and reliable operation, low maintenance, complete insensitivity to platform motions, low utility requirements and highly predictable capacity. In many cases, good performance is achieved without the use of chemicals. As water production increases, additional hydrocyclones can be added without extensive piping modifications or costly construction barge time. This unique feature allows operators the flexibility to phase in PWT capacity as it is needed. All this often adds up to lower costs for a non revenue producing function, and provides a cost effective alternative for meeting stringent corporate guidelines and environmental standards.
A Fully Implicit, Three-Dimensional, Three-Phase Simulator With Automatic History-Matching Capability
Authors: Tan T. B. , Kalogerakis N. 
Published: December 2007

ABSTRACT
The reservoir simulator described in this paper has the capability of automatically determining parameter values of reservoir properties in specified zones that will best match observed data. The observed data can be grid cell pressures, water-oil ratios, gas-oil ratios and flowing well bottom hole pressures. A modified Gauss-Newton approach is used that significantly reduces the computational time in generating new parameter estimates. As a test problem, the Second SPE Comparative Problem which is a numerically difficult three phase coning problem, was chosen. The proposed algorithm was able to converge to the original values of permeability and porosity from a wide range of initial guesses and the computational effort was equivalent to performing a few typical simulator runs.
Estimating Relative Permeabilities by Automated History Matching Using Linear Modeling Techniques
Authors: Labban Z. S. , Horne R. N. 
Published: December 2007

ABSTRACT
This paper presents a novel approach for estimating relative permeabilities through an automated history matching procedure which makes use of linear models. The new technique makes use of linear relationships which are found to exist between simulation runs for the same points in time.
Linear models relating phase relative permeabilities with reservoir fluid properties, pressure and production data are developed. The linear relationships are used in an iterative procedure to estimate relative permeability-saturation relationships for use in simulation models.
Several cases are presented to determine the validity of both the linear models as well as the new procedure.
A case is presented which shows the new method to have promising applications in scaling of rock relative permeabilities to coarse grid simulator interblock relative permeabilities directly from observed production and pressure data.
A New Parallel Iterative Linear Solution Method for Large-Scale Reservoir Simulation
Authors: Wallis J. R. , Foster J. A. , Kendall R. P. 
Published: December 2007

ABSTRACT
Throughout the more than four decades of the existence of numerical reservoir simulation, computer hardware has been a strong driving force in the evolution of modeling capabilities. Advances in the architecture of computing platforms invariably stimulate advances in simulation technology. The principle underutilized hardware resource available today is the capability of many machines to perform concurrent or "parallel" processing. Within the family of algorithms comprising a reservoir simulator, numerical linear algebra is a long-standing bottleneck. Robust iterative linear solvers typically utilize recursive preconditioning methods and involve conjugate gradient-like computations such as dot products which are "fine" grained and are not ideally suited to the parallel processing environment.
This paper will describe a robust, high-performance linear solver formulated specifically for parallel computers with shared memory and a relatively small number of sophisticated processors (e.g. IBM 3090-400S, CRAY Y-MP). In particular, this paper will address the parallel iterative solution of the pressure equation although the method can be adapted to the fully implicit case. A new preconditioning based on the application of domain decomposition to a variant of Nested Factorization is described. A new variation of the Generalized Conjugate Residual (GCR) method better suited to parallel computation is also presented. Even for a "small" waterflood model with two layers and 8,164 active cells, a speedup of 3.9 was experienced on a four processor CRAY Y-MP; 3.3 on an IBM 3090-400S. Larger models exhibit almost ideal performance. Results are presented for up to eight processors (CRAY Y-MP). These results confirm our view that the performance potential of the parallel processing environment can be realized by reservoir simulation.
Towards a More Effective Parallel Reservoir Simulator
Authors: Meijerink J. A. , van Daalen D. T. , Hoogerbrugge P. J. , Zeestraten R. J. A. 
Published: December 2007

ABSTRACT
In 1989 it has been reported how an operational black/volatile oil reservoir simulator of IMPEC type has been successfully parallelised for a medium-scale (10-100 processors) local memory MIMD
architecture1. The present paper reviews the principles underlying the parallelisation and describes the further development of the parallel simulator. Some attention is given to the linear solver which is of conjugate gradient type, with a local, block-wise preconditioner. A novel acceleration method, CGSTAB, for the solution of non-symmetric linear systems is described.
The parallel simulator is now being evaluated in an operational environment. It has been installed on a 90 processor, 5500,000 Meiko M40 that should support two simultaneous job streams, each running at one quarter to one half (depending on the input) of the speed of a 1 processor Cray-XMP.
So, at present, parallel computing leads to a substantial reduction of computing cost. In the very near future however, parallel computing machinery of the same family but based on the latest hardware, will beat traditional sequential computers on absolute performance too.
Field-Scale Simulation of Horizontal Wells with Hybrid Grids
Authors: Collins David A. , Nghiem Long X. , Sharma Ravi , Agarwal Rajeev K. , Jha Kamal N. 
Published: December 2007

ABSTRACT
For an accurate simulation of horizontal-well performance, both flow in the wellbore and in the vicinity of the wellbore have to be modelled. This paper combines a novel technique for simulating horizontal wellbore hydraulics with an elliptic grid refinement around the wellbore to address both issues.
The wellbore is represented by a row of cylindrical gridblocks where the well "permeability" and "relative permeabilities" are adjusted to yield the pressure drop and phase slippage predicted from multiphase flow correlations. With this method of coupling, the wellbore equations have the same primary variable set as the reservoir equations. This allows for a consistent application of the efficient solution techniques developed for reservoir simulation.
For a detailed simulation of flow around the wellbore, a system of fine elliptic and hyperbolic grids is used. It is shown how this grid system is constructed and coupled to the Cartesian coarse grids.
Simulation runs showing the importance of both wellbore hydraulics and flow in the vicinity of the wellbore are presented.
Seventh SPE Comparative Solution Project: Modelling of Horizontal Wells in Reservoir Simulation
Authors: Nghiem Long , Collins David A. , Sharma Ravi 
Published: December 2007

ABSTRACT
This paper reports the results of comparisons of simulation runs performed by fourteen organizations on a problem involving production from a horizontal well in a reservoir where coning tendencies are important. The effect of well length and rates on the recovery is examined. In addition, the paper also reports the techniques used by the different participants to calculate the inflow into the horizontal well and the wellbore hydraulics.
A variety of methods was used by the participants to model the inflow into the horizontal wells ranging from the use of productivity indices to grid refinement. A multitude of techniques was also used to calculate wellbore hydraulics while a few participants selected to represent the wellbore by a constant-pressure line sink.
All participants consistently predict a decrease in the coning behavior with an increase in well length. However, variations in the predictions were observed. Although the modelling methods from different participants can be grouped into different categories, no trend in the predicted results, according to the methods used, could be observed.
An Automatic Ordering Method for Incomplete Factorization Iterative Solvers
Authors: D’Azevedo E. , Forsyth P. A. , Tang Wei-Pai 
Published: December 2007

Abstract
The minimum discarded fill (MDF) ordering strategy for incomplete factorization iterative solvers is developed. MDF ordering is demonstrated for several model non-symmetric problems, as well as a waterflooding simulation which uses an unstructured grid. The model problems show a three to five fold decrease in the number of iterations compared to natural orderings. Greater than twofold improvement was observed for the waterflooding simulation.
Characterization of Mixing Length Growth for Flow in Heterogeneous Porous Media
Authors: Furtado F. , Glimm J. , Lindquist W. B. , Pereira L. F. 
Published: December 2007

ABSTRACT
The scale up problem concerns the prediction of field scale fluid flow properties from smaller scale (laboratory) data. It has been observed from field data that the mixing length for two phase flow has anomalous scaling behavior. Recent theoretical and computational developments have confirmed that anomalous scaling behavior results from multi-length scale heterogeneities not observable at laboratory length scales.
Two main results are presented here. One is a generalization of the fractal analysis of rock and fluid mixing properties, as a first step in moving from idealized self-similar reservoir properties to realistic geology. The other is a refinement of earlier computational results demonstrating anomalous diffusion for flow through reservoirs with weakly decaying fractal correlations.
A Global Optimization Approach to Grid Generation
Authors: Farmer C. L. , Heath D. E. , Moody R. O. 
Published: December 2007

Abstract
Simulation of heterogeneous reservoirs can require distorted grids to give an accurate model of the reservoir geology with a moderate number of grid cells. In this paper we study grid construction in which grid lines are encouraged to follow either the boundaries between different rock types or regions of different permeability. An algorithm is described which finds a global near-optimal solution, to such problems.
We find that, even with grid controls, good grids can depart from orthogonality. The final part of the paper therefore considers the problem of discretisation on near-orthogonal grids. We describe a mixed finite element approach which is a natural and compact generalisation of the standard block-centred finite difference method.
Simulating Naturally Fractured Reservoirs Using a Subdomain Method
Authors: Beckner B. L. , Chan H. M. , McDonald A. E. , Wooten S. O. , Jones T. A. 
Published: December 2007

ABSTRACT
A subdomain formulation for modeling naturally fractured reservoirs is presented. "Representative Matrix Blocks" are subdivided into rectangular rings and layers to enhance pressure and saturation gradient resolution within the blocks. Improved description of matrix capillary and gravity forces can be achieved through this formulation. A three phase coupled implicit algorithm incorporates pressure dependent gas/oil capillary pressure，fracture permeability, and fracture porosity. Segregated and dispersed fracture fluid options are given, and field-scale simulations of primary depletion, water injection and gas injection are presented.
Naturally fractured simulations with matrix block discrefcizafcion can yield significantly different production forecasts from those without internal discretization. Quarter five-spot, low permeability waterfloods show differences in cumulative oil recovery as large as 35 percent. For small blocks, or moderate matrix permeability, differences in simulated oil rate are less than 10 percent.
The dependence of gas/oil capillary pressure on pressure is shown by example to have a large effect on oil production rate. Jones' relations17 between pressure and fracture porosity and permeability lead to modest changes in oil rate when compared with constant fracture properties. At early times fracture permeability reduction decreases oil rates, while fracture porosity variation leaves oil rates unaffected.
Segregated fluid flow in the fractures leads to smaller matrix/fracture fluid transfer rates, and hence lower oil recovery. A dispersed water phase in the fracture is exposed to larger matrix surface area, creating additional opportunity to exchange itself with oil contained within the matrix block.
Quick Determination of Pressures in Well-Spacing Patterns
Authors: Higgins R.V. , Leighton A.J. 
Published: December 2007

American Institute of Mining, Metallurgical and Petroleum Engineers Inc.

Abstract
A quick method to determine the pressure distribution between wells for various well patterns is presented. In the determinations, patterns is presented. In the determinations, the effect of well diameter may be included. Comparison of the results with potentiometric models presented in the literature showed excellent agreement. By the method presented, it would be easy to obtain quickly the pressure distribution in an entire reservoir.
The computer program uses the flowing well pressures at bottom of wells to calculate the pressures at bottom of wells to calculate the pressure distribution throughout the entire pressure distribution throughout the entire reservoir. The program is relatively short and uses the grid method for solution. It uses the point successive over relaxation technique point successive over relaxation technique [Liebmann accelerator] and has an open subroutine to increase the size of the accelerator if the progress of the computation so requires.
Use of the program saves construction of a potentiometric model. The printed pressure potentiometric model. The printed pressure distribution can be obtained quickly. Another advantage is that the effect of any change in the location of wells or pressures about the wells can be ascertained quickly—average computer time was less than 2 minutes.

Introduction
The literature mentions that a series of steady-state flow equations may be used to mathematically represent unsteady-state flow after the initial withdraw of a small quantity of fluid. As a result, pattern efficiency in reservoirs can be investigated reasonably accurately by assuming steady-state flow during the period of interest. The advantage of steady-state flow is the reduction in time needed to obtain a solution. The results presented in this report are steady-state presented in this report are steady-state solutions except in one instance where an unsteady-state calculation for a slightly compressible liquid was used to obtain well pressures for subsequent steady-state solution of the pressure distribution throughout the reservoir. pressure distribution throughout the reservoir. Streamlines may be drawn on plots of the pressure distributions obtained using this pressure distributions obtained using this method. The shape factors and areas of the cells formed by the resulting flow nets may be calculated and the resulting data used in the prediction of fluid injection performance. However, obtaining the streamlines performance. However, obtaining the streamlines and shape factors are not included in this paper. paper.

THEORY
The solution by finite differences [numerical methods] of the Laplace equation to determine the potential distribution in two dimensions has been reported in the literature.