bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scale Dissolver Application: Production Enhancement and Formation-Damage Potential
Authors: Jordan M. M. , Graham G. M. , Sorbie K. S. , Matharu A. , Tomlins R. , Bunney J. 
Published: December 2007

Summary
Sulfate scale dissolvers have been applied downhole for many years to remove barium and mixed sulfate scale deposits from the wellbore and from the near-wellbore formation. As well as dissolving mineral scales, these corrosive materials also have the potential to cause some degree of formation damage by the dissolution of reservoir minerals. In this study, three commercial scale dissolver formulations and two laboratory prepared amino car-boxylic acid dissolvers (EDTA and DTPA) were tested to assess their comparative capacity to dissolve barium sulfate and, of more importance in the current study, their potential to cause damage in the near-wellbore formation. The potential formation damage capacity of various scale dissolvers has been assessed by measuring the levels of cation release in static tests on mineral separates and by studying the various effluent profiles from core floods using reservoir sand. Possible damage mechanisms include silicate dissolution, fines generation/migration, mechanical strength reduction and wettability changes. We conclude that, when testing sulfate scale dissolvers for field application, their formation damage potential should be assessed as well as their barite dissolution performance.
Application of Engineering Effort Through Use of Reservoir Analyzers
Authors: Montague K.E. , Noble M.D. , Buchanan F.E. 
Published: December 2007

Abstract
This paper contains a review of the position which the reservoir engineer occupies in the industry today. His work is found to be that of collecting, assembling and analytically treating large quantities of basic data to the end that physical and economic results are optimized.
The need for methods to simplify and speed the data collecting and analytical processes of reservoir engineering is discussed. An organization utilized by one company to speed these processes is described.
A general discussion of the use of analog computers and the result of six years' experience with this approach is given. It has been found that the reservoir engineer can quickly and easily adjust himself to the use of computers as a routine part of the solution to the over-all problem. In so doing, the burden of manual computation and data processing has been considerably lightened, thereby allowing him to devote more time to original and creative work in planning the basic approach and executing and applying economics to the end result.

The Problem
The industry has long recognized the intricate complexities of the business called reservoir engineering. The application of the fundamental principles established to date has resulted in a large accumulation of raw data from drilling production and laboratory operations. A normal development program yields voluminous records of electric logging, core analysis, drilling data, laboratory analyses of gas, oil and water, reservoir production of gas, oil and water, reservoir pressures, gas plant reports, etc. The engineer must analyze this information and blend it into the complex array of conservation rules and regulations and general cost and profit economics in order to design the most economic oil recovery process. Faced with this duty, the engineer must find time to perform it responsibly. Routine work must be minimized as much as possible.
Spatial Distribution of Oil and Water in Horizontal Pipe Flow
Authors: Soleimani Arash , Lawrence C. J. , Hewitt G. F 
Published: December 2007

SummaryIn this paper we report a series of experiments to quantify the spatial distribution and identify the flow pattern of liquid-liquid flow in a horizontal 25.4-mm (nominal 1-in.) tube. Experimental results are presented for kerosene (EXXOL D80) and tap water at room temperature. Two different measurement techniques (a high frequency impedance probe and a gamma densitometer system) were applied for measuring the volume fraction distribution across the tube and to obtain tomographic results for phase distribution. The use of the gamma densitometer system to obtain the tomographic results in liquid-liquid cocurrent flow is believed to be the first in this field. These methods are more precise than other techniques such as visualization and help to distinguish certain differences in flow patterns for different superficial velocities and liquid fractions. The two sets of measurements were compared and it was concluded that the gamma densitometer system was a more reliable method by which to measure the volume fraction. Two important phenomena in liquid-liquid flow were observed: oil encapsulation by water at low mixture velocity and droplets concentrated at the center of the pipe in the dispersed flow regime. Some possible explanations are given regarding these phenomena.
Field Applications of Abrasive-Jetting Techniques
Authors: Ousterhout R.S. 
Published: December 2007

Abstract
Interest in abrasive-jetting techniques for perforating and cutting well casings, cement and formation rocks has increased rapidly since 1958. This renewed interest in an old process has been due mostly to the development of a jetting tool of longer life and higher efficiency. Present-day jet-orifice nozzles are made of extremely hard materials that have a working life of more than three hours, compared to several minutes in the early days of abrasive jetting. Also, new efficient nozzle design has greatly increased jet speed and depth of penetration.
These improvements in design and materials of construction, coupled with improved operating techniques, have resulted in many widespread and varied applications of abrasive jetting. Jobs have been performed, using this process, that would have much more expensive or even impossible with conventional methods.
Several case histories are presented in this paper to illustrate applications and performance of abrasive jetting.
Correlations for Fluid Physical Property Prediction
Authors: Vasquez M. , Beggs H.D. 
Published: December 2007

Introduction
The evaluation of physical properties of hydrocarbon mixtures is an important step in the design of various stages of oilfield operations. The fluid properties, which change as pressure and temperature change, must be evaluated for both reservoir engineering and production design operations. For example, the production design operations. For example, the calculation of two-phase flowing pressure gradients occurring in piping systems requires prediction of fluid properties such as dissolved gas, formation volume factor (FVF), oil compressibility, and viscosity at various locations in the pipe, Even though laboratory measurements of these properties may be available as a function of pressure, the measurements usually are made at reservoir temperature only. The behavior of these properties with temperature change usually is predicted empirically.
Increasing emphasis is being placed on the necessity of having accurate estimates of fluid physical properties in advance of laboratory PVT physical properties in advance of laboratory PVT analyses of the reservoir fluids. Many times these properties are required at a time when the only properties are required at a time when the only information available consists of oil and gas gravities and reservoir pressure and temperature. The purpose of this study was to utilize a large base of laboratory. measured PVT data to develop improved empirical correlations to replace those commonly in use. Many of the presently used correlations were developed many years ago from limited data and are being used beyond the range for which they were intended.
JPT
P. 968
Screenless Completions: Cost-Effective Sand Control in the Adriatic Sea
Authors: Pitoni E. , Devia F. , James S. G. , Heitmann N. 
Published: December 2007

SummaryMany gas reservoirs in the central Adriatic Sea, offshore Italy, are formed of laminated, low-permeability, dirty sandstones, with as much as 50% clay content. Initially, wells were completed with gravel packs, but the nature of the formations caused productivity to decrease in some gas fields because fines plugged the gravel packs. In the past few years fracpacks have been used to alleviate the fines migration problem. However, there are many gravel-packed wells which are either sanded up and shut in or underperforming because fines have plugged the gravel-pack screens. These wells do not currently justify the expense of an immediate full rig workover.A candidate zone was selected to evaluate the viability of a screenless completion technique for competent sand control. We placed a highly conductive tip-screenout fracture in the zone, using recent innovations in fracturing fluid technology and proppant flowback control additives, to eliminate sand production. Successful implementation of this technique was confirmed by posttreatment production more than 2.5 times the normalized rate of the initial gravel-pack completion. No formation sand or proppant was produced back to surface during production. The screenless completion technique provided a cost-effective and reliable rigless rehabilitation technique.
Observation of Asphaltene Destabilization at Elevated Temperature and Pressure
Authors: Wang J. X. , Brower K. R. , Buckley J. S. 
Published: December 2007

Summary
An optical observation cell was added to a mercury-free pressure/volume/temperature apparatus to extend studies of the onset of asphaltene precipitation to elevated temperatures and pressures. Observations for asphaltic, paraffinic, and light-to-medium gravity crude oils are reported as a function of temperature, pressure, and mixing time. Precipitants ranged from heptane to propane.
Studies at ambient conditions have shown that the refractive index at the onset of precipitation is an important characteristic of oil/precipitant mixtures. Calculated values of refractive index as a function of temperature, pressure, and composition are being correlated to observations of asphaltene separation at elevated temperature and pressure, as a predictive test.
Temperature Effect on Formations During Jet Perforating
Authors: Robinson Reginald L. 
Published: December 2007

Abstract
An investigation into the thermal reactions during jet perforating has been conducted over a period of years. Theoretical considerations have been investigated and correlated to experimental laboratory tests. The tests have been conducted under a variety of simulated well conditions and into sandstone, limestone, and dolomite cores. Various well fluids were used in the tests. Jet charges contained in steel guns and self-contained or directly exposed jet charges were both used in this investigation.

Introduction
For almost a decade now jet perforating has been used in well completions. With the introduction of this radically different tool, misconceptions as to its method of penetration arose. In some instances it was thought that the jet stream itself burned its way through the casing, cement and into the formation. This, of course, was a misconception. Numerous surface tests have indicated no burning action. The mechanics of penetration of a formation or target is altogether a different subject and is not covered in this paper.
A direct mathematical explanation of the thermal aspects of jet perforating, especially the heat transfer relations, is very complicated. It is probably for this reason that very little work has been done on this problem. With the ever increasing use of jet perforating, the question of what happens to the formation during perforating is of interest to the petroleum industry.

Theoretical Considerations
The nature of an explosion or decomposition of a high explosive is a complex phenomena and entails unusual heat flow conditions.
Actual well conditions present many variables that vastly complicate the calculations by having multiple explosions occurring with the jet charges cased in various materials in both dry and in fluid filled holes. These extremely complex conditions result in laboratory measuring methods as a practical approach to temperature reactions.

Types of Jet Perforators
A conventional jet perforating carrier has a number of ports or holes in a hollow steel tube with a jet charge arranged to shoot through each port. At the time of firing, all charges in a gun are detonated, resulting in an explosion in each jet charge.
Thermal Reservoir Simulation Model of Production From Naturally Occurring Gas Hydrate Accumulations
Authors: Swinkels Wim J. A. M. , Drenth Rik J. J. 
Published: December 2007

Summary
Reservoir behavior of a hydrate-capped gas reservoir is modeled using a three-dimensional thermal reservoir simulator. The model incorporates a description of the phase behavior of the hydrates, heat flow and compaction in the reservoir and the hydrate cap. The model allows the calculation of well productivity, evaluation of well configurations and matching of experimental data. It shows the potentially self-sealing nature of the hydrate cap.
Production scenarios were also investigated for production from the solid hydrate cap using horizontal wells and various ways of dissociating the gas hydrates. These investigations show the role of excessive water production and the requirement for water handling facilities. A data acquisition program is needed to obtain reservoir parameters for gas hydrate accumulations. Such parameters include relative phase permeability, heat capacity and thermal conductivity of the hydrate-filled formations, compaction parameters and rate of hydrate formation and decomposition in the reservoir.
Realistic Numerical Models for Fractured Reservoirs
Authors: Gurpinar O. M. , Kossack C. A. 
Published: December 2007

Summary
Characterization and forecasting in fractured reservoirs is one of the most challenging topics in the oil and gas industry. Managing such reservoirs requires construction of representative reservoir models that can handle both fracture and matrix systems, and their interaction, correctly. Data integration from all disciplines is required for construction of these reservoir models.
Commercial numerical models capable of handling flow in fractured reservoirs have been present in the industry for quite some time. However, the correct application of those simulators for representative reservoir models is not easy. This paper will discuss parametric ways to improve construction of representative reservoir models. Discussion will focus on transition from single-porosity representation to dual-porosity models and pseudoization of capillary pressure process employed in between.
A fractured reservoir undergoing a waterflood is simulated with a single-porosity formulation, where the matrix blocks are subdivided into core-plug-size gridblocks and the fractures are subdivided into even smaller blocks. The results from this fine grid are considered the "solution" to the displacement in the fractured reservoir. The grid is coarsened and the effects of scale-up are observed. Pseudos are developed for a coarse grid so that the results match the solution. The reservoir is then simulated with a dual-porosity simulator. The sensitivity of the dual-porosity results to the refinement of the numerical grid is studied.
A comparison is made between the solution and the dual-porosity simulator results. Several of the advanced features found in commercial dual-porosity models are tested to see how well they improve the comparison. A scale-up pseudoization is determined that allows the dual-porosity simulation to match the solution. A larger sector model is then simulated with the pseudocapillary pressure to investigate the robustness of the scale-up pseudoization. Recommendations are provided that describe a procedure for using the dual-porosity model to simulate displacements in a fractured reservoir in a more accurate way.
The scale-up process discussed in this paper is just the first step of a two-step procedure. The next step is to scale-up these curves to a field-scale gridblock (i.e., 100×100×20ft or m). If one uses nested matrix blocks for this first step of the scale-up process: the numerical computation problem is much more difficult and expensive and the next step scale-up calculation is confusing and difficult. Thus, this process is preferred in the final analysis.
Alkaline-Surfactant-Polymer Flooding of the Cambridge Minnelusa Field
Authors: Vargo Jay , Turner Jim , Vergnani Bob , Pitts Malcolm J. , Wyatt Kon , Surkalo Harry , Patterson David 
Published: December 2007

SummaryThe Cambridge Minnelusa field alkaline-surfactant-polymer (ASP) flood was an economic and technical success, with ultimate incremental oil of 1,143,000 bbl at a cost of $2.42 per barrel. This success was due to an integrated approach of the application, including: reservoir engineering and geologic studies, laboratory chemical system design, numerical simulation, facilities design, and ongoing monitoring. This paper discusses how each of these was used in the design and evaluation of the Cambridge ASP project.
Discussion and Comparison of Horizontal-Well Performance in Bouri Field
Authors: Jafar A. S. , El-Ageli I. S. , Al-Attar H. H. 
Published: December 2007

Summary
Seven horizontal wells were drilled in Bouri field, offshore Libya, and put on production between 1989 and 1992. This paper presents the experience gained in producing and monitoring these wells over the past few years. Comparison of well basic characteristics and performances with offset conventional wells indicates their higher productivity and general superior performance. Different monitoring activities conducted on these wells are discussed, including transient test analyses and production logs. Free gas production was found to be related to the combined phenomena of coning and fracture flow mechanism. These discussions show that, in most of the cases, production of water and gas is inevitable as long as economic oil rates are to be maintained. The targets set for these wells in terms of recovery increase and production troubles reduction were at least partially fulfilled.
Advanced Rheological Techniques for Optimizing Borate-Crosslinked Fracturing Fluid Selection and Performance
Authors: Power David J. , Paterson Lincoln , Boger David V. 
Published: December 2007

Summary
The complex rheological behavior of crosslinked fracturing fluids is a function of shear history, temperature, and chemistry. Understanding the relationship between these variables and the downhole properties of the fracturing fluid is a challenging task. Rheological measurement techniques are presented that unravel some of the mystery associated with crosslinked fracturing fluids. The concept of a physical gel-point for fluids undergoing crosslinking is introduced and shown to correlate strongly with the proppantcarrying ability of the fluid. The gel-point variation with temperature and chemistry is discussed. This variation can be studied in the laboratory to provide an in-situ field performance evaluation without the need for expensive proppant-transport flow loops. The limitations for newly developed, low-concentration polymer fluids are also discussed. The fluid system chosen for analysis was the pH-activated, borate-crosslinked hydroxypropylguar (HPG) fluid.
Processing of Multi-Acquisition NMR Data
Authors: Slijkerman W. F. J. , Looyestijn W. J. , Hofstra P. , Hofman J. P. 
Published: December 2007

Summary
Crucial issues in formation evaluation are the determination of porosity, permeability, hydrocarbon volumes, and net-to-gross ratio. Nuclear magnetic resonance (NMR) logging provides measurements that are directly related to these parameters. The NMR response of fluids contained in pores is governed by their T2- and T1-relaxation times, diffusion coefficient, and whether or not they wet the rock. In the case where fluids possess a sufficiently large contrast in these properties and NMR data have been acquired with suitably chosen acquisition parameters (i.e., wait times and/or inter-echo times) a separation of water, oil, and gas NMR responses can be made. From these separate NMR responses the hydrocarbon volumes, porosity, and permeability estimates are subsequently calculated. Key in these applications is the ability to include all the acquired log NMR data into the processing towards the desired end result.
Methods exist to derive hydrocarbon volumes from T2 distributions or from echo decay data. However, these are all methods in which the difference between just two acquisitions that only differ in either wait time or inter-echo time are considered. Over the past years we have developed, tested, and employed an alternative processing technique named multi-acquisition NMR (Mac-NMR). MacNMR takes any number of log acquisitions (wait time and/or inter-echo time variations) and simultaneously inverts them using a rigorous forward model to derive the desired water and hydrocarbon T2 distributions. In this paper, we discuss the concepts of MacNMR and demonstrate its versatility in NMR log processing. An example will illustrate its benefits.
Well Formation Characterization by Residual Hydrocarbon Analysis
Authors: Maness Mabre 
Published: December 2007

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Introduction
Information supplied by current wellbore evaluation methods often is insufficient for optimum well completion. Recent developments indicate that additional data useful for this application may be obtained from the composition of residual hydrocarbons in drill cuttings. As early as the mid-1950's, Smith and Evans demonstrated that residual hydrocarbons could be used to characterize some geologic formations. The general principles involved later were extended by Reed and Warren and Scrima to oil shale formations using pyrolysis techniques and thermal chromatography. In pyrolysis techniques and thermal chromatography. In 1974, Baker expanded their work to include petroleum source-rock evaluations. Other investigators during this period experienced only limited success in modifying the technique for use in wellbore evaluations. This paper describes a pyrochromatographic analysis that has proved useful when characterizing the producing potential of certain types of wells. potential of certain types of wells. Description of Method
Our method involves the premise that not all hydrocarbons in bits of formation rock are lost when these samples are brought to the surface during normal drilling procedures. Phase behavior and formation permeability procedures. Phase behavior and formation permeability phenomena responsible for residual hydrocarbons in these phenomena responsible for residual hydrocarbons in these samples have been well documented. Relationships between residual hydrocarbon saturations and formation production potential also have been well established. Our method potential also have been well established. Our method uses these relationships to correlate characteristics of test sample hydrocarbon with well production potential.
The analyzer used was composed of a low dead-volume pyrolysis unit attached directly to a flameionization gas pyrolysis unit attached directly to a flameionization gas chromatograph. A large pyrolysis chamber (1 m1 in volume) was developed to allow the testing of larger, more representative formation samples.
Fig. 1 - Carbon-number distribution for nonproductive formation.
Fig. 2 - Cumulative percent curve for nonproductive formation.
JPT
P. 118