bluuebunny/crossref_metadata_2025_split huggingface dataset:
System Design for the Measurement of Downhole Dynamic Rheology for Foam Fracturing Fluids
Authors: Spörker H. F. , Trepess P. , Valkó P. , Economides M. J. 
Published: December 2007

Abstract
To investigate the rheology of multi-phase fluids and especially foams under realistic field conditions a downhole flow loop has been constructed and tested. The interactions between gravitational, frictional and other (e.g. gas solubility) factors have been investigated and isolated in a series of experiments. Here the system design of the multi-phase fluid flow loop and the special considerations of the design and their justification are described. To evaluate the data a new two-phase flow equation and a methodology of interpretation are outlined. Applications of the methodology in the treatment of sample data are also presented. The choice of a vertical instead of a horizontal apparatus is justified from the fundamental treatment in this work. It shows that the presence of the gravitational effects magnifies the frictional effects, allowing their more accurate estimation.
Using a Simulated Bidirectional Associative Neural Network Memory with Incomplete Prototype Memories to Identify Facies from Intermittent Logging Data Acquired in a Siliciclastic Depositional Sequence: A Case Study
Authors: Baldwin J. L. 
Published: December 2007

ABSTRACT
This case study compares core photographs, core analysis, a geologist’s facies analysis, sequence stratigraphie analysis, and a description of cores to facies identified by a Simulated Neural Network (SNN). The SNN operates by mimicking human-like reasoning-under-uncertainty from incomplete and partial inputs. The facies identified by the neural network matched those in the geologist’s facies description. The well from which these data were taken penetrates intertidal, lower shoreface, and shelf-to-lower shoreface sequences containing sandstones, siltstones, shales, mudstones, coal, and minor sandy-dolomite beds. Siltstones and mudstones are at times highly interbedded, burrowed, calcareous, and contain organic matter. The log database’s 1/4-foot depth increment currently limits the neural network’s resolution. However, the network’s resolution will be enhanced if dipmeter data is also input. In this case study, the network rapidly and accurately identified 11 lithofacies in the test interval.
Operation of this neural network does not require knowledge of geology or experience as a geologist, although assigning a name to the facies identified does require knowledge of the local geology. For this case study, a petrophysicist unskilled in geology performed all parameter selections.
Log analysts routinely adjust their log correlations and descriptions to incorporate the fact that log data are sometimes missing. In this study, acoustic shear waves could not be measured in facies composed of very soft rock. The neural network’s method of operation automatically accounted for the fact that shear data are missing across some intervals.
The SNN program used for this case study, as implemented on an affordable, highly accessible PC platform (but not restricted thereto), is suitable for depositional environment studies, facies identification, sedimentation studies, and well-to-well facies correlation. Additional applications include identification of productive intervals, and fracture identification.
Modeling and Laboratory Investigation of Microbial Transport Phenomena in Porous Media
Authors: Chang M-M. , Chung F. T-H. , Bryant R. S. , Gao H. W. , Burchfield T. E. 
Published: December 2007

ABSTRACT
Simulation and experimental results on the transport of microbes and nutrients in one-dimensional coreflooding experiments are presented, and the development of a three-dimensional, three-phase, multiple-component numerical model to describe the microbial transport phenomena in porous media is described. The governing equations in the mathematical model include net flux of microbes by convection and dispersion, decay and growth rates of microbes, Chemotaxis and nutrient consumption, and deposition of microbes on rock grain surfaces. Porosity and permeability reductions due to cell clogging have been considered and the production of gas by microbial metabolism has been incorporated. Governing equations for microbial and nutrient transport are coupled with continuity and flow equations under conditions appropriate for a black oil reservoir.
The computer simulator has been used to determine the effects of various transport parameters on microbial transport phenomena. The model can accurately describe the observed transport of microbes, nutrients, and metabolites in coreflooding experiments. Input parameters are determined by matching laboratory experimental results. The model can be used to predict the propagation of microbes and nutrients in a model reservoir and to optimize injection strategies. Optimization of injection strategy results in increased oil recovery due to improvements in sweep efficiency.
An Improved Model of Mud Acid/Sandstone Chemistry
Authors: Bryant S. L. 
Published: December 2007

ABSTRACT
The chemical reactions between mud acid (HF/HCl mixtures) and sandstone minerals are numerous and complex. To obtain tractable models of mud acid treatments it is common practice to approximate the chemistry as the dissolution of two "lumped" minerals. Examination of coreflood data shows that this approximation does not consistently account for HF consumption. In particular, this approach cannot account correctly for the effect of flow velocity. Consequently this model cannot reliably extrapolate laboratory data to different operating conditions. Neither can it be used with confidence in the simulation of well treatments, since local flow velocity decreases with distance from a well.
This paper presents an improved chemistry model that includes a secondary dissolution/precipitation reaction recently established in the literature. The improved model provides a consistent prediction of acid consumption. Thus this model provides a more reliable basis for extrapolating laboratory data and for simulating matrix acid treatments. The improved model also accounts for porosity changes more reliably, thereby providing a stronger basis for calculating productivity changes using permeability/porosity correlations.
Identification of a Desaturated Zone and Its Effect on Steamflood Performance/Development at Lost Hills, California
Authors: Kerns J. R. , Kirst T. L. 
Published: December 2007

ABSTRACT
The Etchegoin B sand contains significant thermal recovery potential, but core data at Mobil’s Lost Hills 2 lease indicated unusually low oil saturations in the upper third of the reservoir. The geology of the B sand and its affect on fluid saturations is discussed. A pilot was designed and implemented to test steamflooding the B sand, and 16 months of performance data are presented.
Measurement of "Rock Properties" in Coal for Coalbed Methane Production
Authors: Gash B. W. 
Published: December 2007

Abstract
Standard laboratory techniques for measurement of rock properties (porosity, permeability and gas-water relative permeability) must be modified when applied to coal for use in coalbed methane reservoir engineering studies. Coal is unlike most conventional reservoir rock in that fluid flow occurs in a network of naturally occurring microfractures or cleats. Drying coal alters the cleat structure. Therefore, a miscible displacement technique, in which coal cores are not dried, was used to determine an upper limit for cleat porosities of around 2% for cores from coalbed methane wells. There is no significant difference between the cleat porosity measured with the miscible displacement technique and the mobile water porosity for a coal core, indicating there is little or no irreducible water saturation in the cleat network. (The mobile water porosity is the volume of water which is driven out of a water-saturated core by helium injection divided by the bulk volume of the core.) Absolute permeability to water in coal cores can decrease with continued flow by an order of magnitude, probably due to fines migration. Unsteady-state gas-water relative permeability techniques can be modified to handle both the small volumes of water produced from cores with less than 2% porosity and the decreasing absolute permeability. Representative unsteady-state gas-water relative permeability curves for San Juan and Warrior Basin cores which have been used in coalbed methane reservoir engineering studies are presented. In steady-state gas-water relative permeability measurements using sodium iodide as a tracer, sodium iodide adsorption on the coal surfaces will result in systematic error in saturation values. However, within the experimental error with which saturations in the cleat networks can be determined, unsteady-state and steady-state with sodium iodide gas-water relative permeability measurements yield the same results.
Simulation of a Gas Naturally Fractured Reservoir: A Case History
Authors: Au A. D. , Franks L. N. , Aguilera R. 
Published: December 2007

ABSTRACT
This case history discusses the Palm Valley gas field in Central Australia. Production is obtained from a naturally fractured sandstone characterized by a very low matrix permeability (km &lt;0.1 md).
An integrated study including detailed geology, core and log analyses, well testing and numerical simulation led to a good history match of a 33 hour interference test and over 7 years of production.
The conclusion was reached that 98% of the gas was stored in a very tight matrix and that the prolific production was only possible via a network of natural fractures.
The methodology used to reach a history match in this case history is presented in detail together with discussions of critical parameters such as fracture spacing, fracture porosity, and fracture permeability.
Quantifying Horizontal Well Logs in Naturally Fractured Reservoirs—II
Authors: Svor T. R. , Meehan D. N. 
Published: December 2007

ABSTRACT
Naturally fractured reservoirs are the most significant target for horizontal wells in the U. S. While most of the horizontal wells drilled to exploit naturally fractured reservoirs are not logged, substantial useful information can be obtained by logging such wells. A previous paper1 contrasted various logging technologies including acoustic televiewers, sonic logs, and oriented microresistivity devices. Union Pacific Resources (UPRC) has logged 42 of the 120 horizontal wells drilled to date; 38 of these wells have been logged with Schlumberger’s Formation MicroScanner (FMS), an oriented microresistivity device. Extensive analysis of these logs on UNIX-based workstations and correlation with horizontal well performance has resulted in a correlation between the horizontal well fracture index (RFI) and horizontal well fluid Productivity Index (PI). Attempts to correlate RFI with ultimate oil or oil and gas recoveries have been unsuccessful; however, a correlation with ultimate fluid (oil+water) recoveries has been developed. These correlations have been used to integrate FMS information with artificial lift, stimulation, isolation, and repair decisions as well. Example cases are used to illustrate these decisions. Further, the quantified data have been used in making development, exploitation, and spacing decisions. Geostatistical techniques used in reservoir characterization efforts have also incorporated the spatial distribution and correlation of RFI density.
The Assessment of Geological Uncertainties in Development Project Planning
Authors: Bléhaut J-F. 
Published: December 2007

Abstract
This paper describes some of the results obtained in a large operating company after the implementation of new procedures for reserves calculations in development projects. A number of inconsistencies in historical trends of hydrocarbon-inplace volumes, together with an evolving business environment, justified the introduction of a new methodology where a more realistic assessment of geological uncertainties is emphasised. The experience gained so far indicates that, although the new approach is more manpower intensive, the benefits justify the extra effort. In particular, expectation reserves figures are positively affected, and the general quality of geological interpretations is enhanced. The economics of a few projects appear not to have taken sufficient account of geological risk. Finally, a worthwhile compromise between theory and practical use can be achieved without resorting to excessively sophisticated techniques.
An Improved Wireline Formation Fluid Sampler and Tester
Authors: Crocker H. 
Published: December 2007

Abstract
Research has been undertaken in the development of an improved wireline formation fluid sampler and tester. Formation fluids are pumped from the formation to the well bore at surface controlled rates. The formation fluid characteristics are measured and surface monitored. When the mud filtrate has been removed a sample may be taken. The resistivity, conductivity and temperature are measured and hence the formation water salinity may be determined.
Flowing fluid density is measured and thus oil, gas and condensate may be distinguished and the API gravity estimated. There is almost no theoretical limit to the number of samples that may be taken and therefore the entire well may be tested and the salinity and pressure profiles recorded. The use of controlled flowrates to match the reservoir deliverability and the surface recording of flow pressures allows multi-rate testing, the determination of permeability and formation damage. Since the reservoir pressure may be measured after repeated small fluid volumes are taken, the problem of supercharging or depletion, that often invalidate present wireline measured pressure profiles in low permeability formations, may be avoided. An isolation valve is used to trap a known volume of hydrocarbons, taken under minimum drawdown, which is then expanded to determine the compressibility and bubble-point. These tests may be repeated to ensure accuracy.
Formation Damage in Heavy-Oil Formation During Steamflooding
Authors: Okoye C. U. , Onuba N. L. , Ghalambor A. , Hayatdavoudi A. 
Published: December 2007

Abstract
An experimental study was undertaken to examine formation damage due to plugging caused by precipitates and scales generated from the dissolution of silicate compounds and associated minerals. The experimental tests include: roller oven tests, petrographic, SEM and EDEX studies. The tests were carried out at various temperatures (200°F to 500°F) and steam alkalinity in order to ascertain the factors and conditions that lead to formation damage and wellbore erosion during steam injection.
The results from this investigation indicate that elevated temperatures (above 200°F) as a factor can cause irreversible formation damage because of hydrothermal effects. Also high PH causes irreversible formation damage mostly due to hardness precipitation from divalent ion exchange processes. The combined effect of temperature and alkalinity increases the degree of formation damage at low temperatures (below 200°F). However, at high temperatures, the more severe formation damage caused by increased alkalinity can be reduced by thermal effects. Formation crystals and precipitates seems to be hindered at temperatures above 300°F. SEM, X-Ray, EDEX and petrographic analyses show pseudo-hexagonal stacks of mineral overgrowth which blocked pore throats. The SEM micrographs show the dissolution of certain minerals such as kaolonite and the precipitation of aluminosilicate compounds such as zeolite.
Application of Fractal Geostatistics to Miscible Flood Performance in Heterogeneous Reservoirs
Authors: Taggart I. J. , Pitkin M. , Gray T. A. 
Published: December 2007

Abstract
This work outlines an improved method of generating anisotropic fractal property maps using Fourier techniques. These maps are used as input data to enable the numerical prediction of large scale dispersivity behaviour of miscible flooding in vertical cross sections. By varying the ratio of inter-layer as opposed to intra-layer variation, the impact of layering can be assessed. Results suggest that when the ratio of horizontal to vertical variance of property values is low, that the benefit of fine scale conditional simulation is often due to the improved resolution of layering alone.
Marangoni Flooding With Water Drives: A Novel Method for EOR?
Authors: Pratt H. R. C. 
Published: December 2007

Abstract
Trapped solvent droplets within a water-filled column packing can be liberated by injection of a partitionable solute which induces coalescence to form larger, easily-deformable droplets. This result, an outcome of the Marangoni effect, is normally much more marked when the solute transfers from solvent into aqueous phase; however, some solutes can be effective in both directions of transfer. A proposal is made for a novel method of utilising the Marangoni effect to achieve EOR by solute flooding, followed by a repeated water (or gas) drive; unlike a previously reported, unsuccessful study, this takes advantage of the non-equilibrium nature of the effect.
The Potential Benefits of Remote Intervention Technology for Australasian Subsea Developments
Authors: Wayman S. J. 
Published: December 2007

Abstract
There are two main motives which prompt an Operator to consider diverless technology for installing and maintaining subsea production systems – namely, physical and economic. This paper traces the history of subsea production in the Australasian region, and evaluates worldwide progress in remote intervention by reference to several landmark projects. Present trends indicate a growing preference towards diverless intervention, especially where this is favoured by local physical and economic factors such as those in the Australasian province. A comparison of typical life cycle costs for manned and unmanned intervention systems illustrates the long term potential benefits of remote technology for this area.
A Continuum Approach to Contemporary Shaly Sand Evaluation
Authors: Worthington P. F. 
Published: December 2007

Summary
The electrical behaviour of fully electrolyte-saturated reservoir rocks has been represented through verified type curves as a continuum across a range of electrolyte resistivity. The type curves can be used with core and log data to infer whether a reservoir rock is behaving as effectively clean or shaly. In the case of effectively shaly sands, a single-point value of excess conductivity can be evaluated from log data alone.
More generally, the type curves allow different reservoirs to be compared in terms of their electrical behaviours. Where these are similar, it is reasonable to assume that the petrophysical interpretation procedures will be similar. Thus, the type curves allow a given reservoir-rock to be evaluated within the "big picture" of electrical behaviour. This, in turn, allows experience gained elsewhere to be brought to bear on the current appraisal, especially in terms of the suitability of available interpretation models.
Application of a Layered Resistivity Model for Deriving True Resistivity of Thin Dipping Sands in the Asia Pacific Region
Authors: Gill S. , Brink K. , Patterson D. , Hitchcock S. 
Published: December 2007

Abstract
The application of a one foot layered resistivity model that includes apparent dip magnitude and produces a solution of Rt in dipping beds is presented. This approach is numerically simulated to illustrate the problems and confusion created over conventional devices with various depths of investigation which are magnified by the effects of dip. A field example from the Asia Pacific Region is presented.
The Effect of Reservoir Conditions and Wettability on Electrical Resistivity
Authors: Sondenaa E. , Bratteli F. , Normann H. P. , Kollveit K. 
Published: December 2007

Abstract
Archie saturation exponents have been determined on sandstone core plugs from three North Sea reservoirs from capillary pressure measurements using the porous plate method.
Traditionally, restored or native state samples are compared with cleaned samples in studies of the effect of wettability on the electrical properties of porous media. In this study cleaned samples were restored during a capillary pressure drainage test. This is supposed to be more similar to the process taking place during migration of the oil in the reservoir.
Archie saturation exponents, from experiments where brine was displaced with refined oil at reservoir and ambient temperature, both with ambient pressure and reservoir conditions, (reservoir temperature and pressure), are presented.
Next saturation exponents, crude oil displacing brine, at reservoir and ambient temperature both with ambient pressure are presented.
Finally saturation exponents, live crude oil displacing brine, at reservoir conditions are presented.
The wettability preference of the samples were determined both prior to and after the electrical resistivity tests.
The results from the electrical resistivity measurements at reservoir temperature, show that the relationship between the resistivity index and water saturation is as expected from Archie's equation, when water were displaced with refined oil.
The Archie saturation exponents obtained at reservoir temperature are equal to the Archie saturation exponents obtained at reservoir conditions but lower than the Archie saturation exponents obtained at ambient conditions.
The saturation exponents obtained with crude oil displacing brine are higher than the saturation exponents obtained with refined oil displacing brine, for the measurement at ambient temperature.
The results from the electrical resistivity measurements with live crude oil at reservoir conditions, (reservoir temperature and pressure) and the measurement with crude oil show that the relationship between the resistivity index and water saturation is not as expected from Archie's equation. The saturation exponents (n*) increased with decreasing brine saturations. The increase of the saturation exponents can be related to a wettability change.
Large-Scale Integration of Core and Logging Data at the Ocean Drilling Program
Authors: Meyer W. M. 
Published: December 2007

Abstract
An effort is currently in progress at the Ocean Drilling Program to integrate downhole logging data with the core analyses performed in the laboratory. This process is intended to take place in near real-time during routine drilling operations. The results of this process are tables containing all measurements related to the borehole which are correlated to a single common reference depth. This matrix can be loaded into spreadsheets and other software packages for detailed examination by shipboard scientists. Because the data are correlated to a common depth scale, cross plots across the numerous data types are easily accomplished.
This paper will describe the progress made in the following areas:
– Data sharing via a networked fileserver. – Common reference depths for core and logging data. – Strategies for correlating core and logging data. – Exploratory data analysis on integrated datasets.