bluuebunny/crossref_metadata_2025_split huggingface dataset:
Visual Investigation of Multiphase Flow and Phase Interactions Within Porous Media
Authors: Peden J. M. , Husain M. I. 
Published: December 2007

ABSTRACT
The dynamics of multiphase flow in porous media are extremely complex when compounded with the thermodynamic behaviour of multicomponent reservoir fluids and the potential phase interactions. Continual changes in the phase compositions will result in variations in the physical properties and flow characteristics of the phases.
A further complication is that these fluid flow mechanisms, occuring at the microscopic level, have to be extrapolated to the macroscale for application to field studies.
To grasp the essential phenomena involved in such flow situations, an experimental system has been developed that enables displacements to be carried out at simulated reservoir pressures and temperatures of up to 41. 4 MPa (6000 psi) and 150°C. This system incorporates a specially designed high pressure visual micromodel cell in parallel with, optionally, either a slim tube or a long core holder. Such an approach aims at complementing the viusal information obtained at the micro level with quantitative data from the larger scale flow studies.
Visual models have been constructed of realistic scale, geometry and topology which operate at high pressures and temperatures. This paper reviews the characteristics of previously used models and describes the developments in the microprocessing technique and the approach to the application of micromodels which were developed in the present study.
The paper also reports on the application of a range of homogeneous and heterogeneous models to investigate the potential deposition of heavy hydrocarbon fractions within the pore space of reservoirs subjected to gas injection processes. The heterogeneous models were produced from real rock micrographs. The interaction between CO2, N2, hydrocarbon gases and a specific North Sea crudes have been studied. Observations obtained from video recordings, along with measurements made during these experiments, are presented.
In conclusion, the processes associated with the observed phase interactions and the role of micromodel experiments to such studies are discussed.
Pressure Transient Behavior of the Composite Reservoir
Authors: Brown L. P. 
Published: December 2007

ABSTRACT
The composite reservoir, representing a variety of important reservoir configurations, has been studied using a semi-analytical method to determine the characteristics of its pressure transient response. This study extends the work of a previous semi-analytical study1 whose primary concentration was on the pressure transient response in the "altered zone", the zone nearest the wellbore. Important conclusions regarding the nature and duration of the transition period between the altered and unaltered zones are given. This study also presents information which corrects conclusions given in a previous study2 done with a numerical simulator. Specifically, this study shows that the slope of the semilog straight line representing the unaltered zone is independent of the storage ratio.
The study presents equations for calculating mobility in the altered and unaltered zones, for calculating the radius of the altered zone using traditional graphical analysis of well test data and for calculating the skin factor.
Formation Damage Index Number: A Model for the Evaluation of Fluid Sensitivity in Shaly Sandstones
Authors: Basan P. B. 
Published: December 2007

ABSTRACT
Formation Damage Index (FDI) is a number determined by petrographic techniques to classify the potential for formation damage in shaly sandstones. The numbers, which indicate increasing tendency toward damage, represent a formation condition model that is based on ten (10) generic reservoir lithologies. They are: 1) sandstones with less than 5% clay and where clay is part of the matrix; 2) sandstones where more than 10% clay is from structural or laminated shale; 3) sandstones with less than 10% clay and where clay is authlgenic pore-fill; 4) sandstones with varying amounts of clay and where organic content is high; 5) sandstones with varying amounts of clay (10-15±%) and where clay is dispersed matrix but not the primary cement; 6) sandstones with less than 10% clay and where clay is authigenic grain attachments; 7) sandstones with more than 10% clay and clay is homogenized by bioturbation; 8) sandstones with less than 10% or more clay and where clay is authlgenic grain coating; 9) sandstones with 10% or more clay and where clay is the primary binder; and 10) sandstones with less than 10% clay that are semi-or unconsolidated.
Rock-related damage, as opposed to other types of wellbore damage, is best understood where the potential triggering mechanism can be identified. Although there are a few minor mechanisms that contribute to damage, the important ones are: 1) dispersion/migration; 2) particle migration; 3) mineral precipitation; 4) lattice expansion; and or unconsolidation. Each number in the FDI model has an increasing potential to one or more of these mechanisms. Overall, the most fluid sensitive rocks are those that have a small .pa amount of clay (less than 10%) that occurs in a form that produces a high surface area to pore volume. Where clay is responsible for formation integrity, there is a high potential for formation unconsolidation.
Flash X-Ray Analysis of the Interaction of Perforators With Different Target Materials
Authors: Aseltine C. L. 
Published: December 2007

ABSTRACT
Recent investigations have shown that target size and boundaries have a significant effect on the overall penetrating ability of perforators. This paper presents results of X-ray studies that were conducted in an effort to understand the physical mechanisms that caused the observed changes in penetration depth. These preliminary studies are necessary in order to develop a model for downhole penetration.
This paper deals with the interactions that occur within large- and small-diameter targets, with different target boundaries, and with different target materials such as concrete, Berea, and limestone. The difference in performance for perforators shot into cores with kerosene rather than air in the pores is correlated with disturbances within the jet passing through the previously penetrated portions of the core. The X-rays show the origin of the interactions within the core and the resulting effect on the remaining portion of the jet.
A Study of How Heavy-Weight Drillpipe Affects Jarring Operations
Authors: Lerma M. K. 
Published: December 2007

ABSTRACT
In order to optimize jar placement in a drilling string, the force transmitted to the stuck point when the jars are tripped must be determined. Skeem's1 average force method determines this and can be used to evaluate the effect of using heavy weight drill pipe above the jars instead of drill collars. This paper applies Skeem's method to compare two cases for jar effectiveness: (See Figure 1) Drill Collars (DC) are used above the jarsHeavy Weight Drill Pipe (HWDP) is used above the jars
Flame-Jet Induced Thermal Spallation as a Method of Rapid Drilling and Cavity Formation
Authors: Rauenzahn R. M. , Tester J. W. 
Published: December 2007

ABSTRACT
The recent, favorable results of field testing of spallation drilling have directed new research into the rock mechanics and jet dynamics associated with rock spallation under high heat fluxes. Wei-bull's statistical theory of rock failure has been applied to define the mechanics of spallation of brittle materials. A reasonable spallation temperature of 500°C at the rock surface can be computed using typical physical property values for granite, neglecting any temperature dependence of the Weibull parameters because of additional microcracking upon heating. A numerical simulation of the jet dynamics and rock cutting has been formulated to model the spallation drilling process. Conservation equations for the heat, mass, and momentum of the gas jet with appropriate models of turbulent transport phenomena are used to estimate rock spallation rate and steady-state hole geometries as a function of heat flux and position of the drill. The predicted trends in drilling performance with changes in flow input are reasonable in comparison with field data but require future verification. Experiments with well-characterized granites are proposed to test both the Weibull fracturing theory and the dynamic simulation results. Specific tests involve the use of high-speed videotaping to measure spallation times under defined heat flux conditions with laser and gas-jet heating. Quarry-face drilling will also be attempted with a scaled-down jet penetrator. Results of all experiments will be presented at the conference.
Further Development and Application of Simulated Distillation for Enhanced Oil Recovery
Authors: MacAllister D. J. , DeRuiter R. A. 
Published: December 2007

ABSTRACT
Simulated distillation by gas chromatography is useful for determining compositional changes in crude oils undergoing enhanced oil recovery. Area counts generated by simulated distillation are shown to correspond to weight rather than volume fractions by comparing simulated distillation results to true boiling point results for three oils. Recent applications of simulated distillation are discussed including light end enrichment of crude oil in a CO2 pilot, determination of visicracking in thermal laboratory studies, and contamination of heavy oils. The use of an internal standard to calculate the noneluted, heavy fraction of the oil has proven useful and reasonably accurate for a wide variety of applications.
The Use of Microorganisms To Increase the Recovery of Oil From Cores
Authors: Raiders R. A. , Freeman D. C. , Jenneman G. E. , Knapp R. M. , McInerney M. J. , Menzie D. E. 
Published: December 2007

ABSTRACT
A method for oil recovery enhancement by stimulating the growth of indigenous microbial populations in sandstones by nutrient injection was investigated. Incremental oil recovery from the cores ranged from 10–38% of the original oil in place. Volumetric and microscopic sweep efficiency was improved by the microbial selective plugging process. Biogenic gas production accompanied the oil produced from the cores. The combination of stratification correction, gas production, and pressure increase assisted in recovery of previously trapped oil.
Murchison: A Review of Reservoir Performance During the First Five Years
Authors: Massie I. , Beardall T. J. , Hemmens P. D. , Fox M. J. 
Published: December 2007

ABSTRACT
The first five years of the Murchison Field Reservoir Development have been a success. The field has produced 50% of its recoverable reserves and despite the sands having marked permeability contrasts, the water cut is just 26%, considerably lower than similar water floods nearby. Results of three delineation wells in 1976 led to a development plan of initally perforating wells in the lowest productivity sands. At the start of development drilling the need for an extensive data acquisition programme was recognised and planned with full management and partner support.
Powell Pressure Maintenance Unit Enhanced Recovery Project That Is Providing Liquid Sales in a Limited Gas Market Environment
Authors: Heath L. B. , Bross R. E. , Givens W. A. , Morrow R. J. 
Published: December 2007

ABSTRACT
A retrograde condensate Frontier reservoir in Wyoming's Powder River Basin is proving amenable to pressure maintenance through injection of dry hydrocarbon gas. The Powell Pressure Maintenance Unit, operated by Woods Petroleum Corporation, is successfully producing substantial condensate and natural gas liquids without the threat of curtailment due to gas market limitations, while providing approximately a three-fold increase in recoverable liquid hydrocarbon reserves through pressure maintenance. Difficulties encountered in unitizing this field during its development were overcome by establishing equitable expansion provisions in the unit agreements. This was made possible by the cooperation of the owners with the state and federal regulatory bodies. Centralized facilities were designed and constructed prior to unitization to maximize liquid recoveries and reduce operating costs.
Evaluation of Naturally Fractured Gas Reservoirs Through Pressure Transient Testing
Authors: Samaniego-V. F. , Cinco-Ley H. , Montiel-H. D. 
Published: December 2007

ABSTRACT
Field cases are presented of naturally fractured gas reservoirs where the main storage capacity is in the fractures, since the matrix permeability is negligible for practical purposes. Wells in these reservoirs initially exhibit high productivity. These fields are located in the north of Mexico. Upon completion of the exploratory wells a set of multiple rate tests were carried out in open hole conditions. All information available indicates that the reservoirs are located in strati graphic traps in uniformly fractured packstone formations of Cretaceous age. Peculiar to these cases is the fact that pseudosteady-state flow conditions are reached in a very short time (about 2 to 4 hours). Both formation flow conductivity kh and pore volume were estimated for each case. Results indicate that fracture pore volume were exceedingly small for the reservoirs to be developed. Estimation of pore volume from pseudosteady-state pressure data shows a good agreement with those obtained from material balance calculation as applied to reservoir performance.
Gulf Coast Geopressured Gas Reservoirs: Drive Mechanism and Performance Prediction
Authors: Bernard W. J. 
Published: December 2007

ABSTRACT
A new, simple method is presented for estimating reserves and predicting the performance of abnormally-pressured (geopressured) natural gas reservoirs. The method is applicable for reservoirs undergoing either depletion drive or very limited water drive. Reasons for the differences in performance between normally-pressured and abnormally-pressured gas reservoirs are discussed.
Reserve Determination Using Pseudosteady-State Techniques in a High-Pressure Sour Gas Field: A Case History
Authors: Lewis R. C. 
Published: December 2007

ABSTRACT
The application of pseudo-steady-state techniques to assist in reserve determination is presented for three high pressure sour gas reservoirs. The techniques discussed in this paper utilize stabilized flowing wellhead pressures, gas production rates, and pressure adjusted gas well performance coefficients to calculate a representative average pressure for the reservoir. Original gas-in-place and recoverable reserves are determined using the calculated average pressures and gas material balance equation.
As of publication date, various bottom-hole pressure measurements, cumulative gas recovery, and current gas well deliverabilities have supported reserve estimates based on the procedure. These techniques have been successfully applied to other reservoirs in the south Texas area to enhance gas reserve estimates in the absence of shut-in, bottom-hole pressure data.
The Effects of Permeability Variations on Flow in Porous Media
Authors: Giordano R. M. , Salter S. J. , Mohanty K. K. 
Published: December 2007

ABSTRACT
By using a compositional simulator together with experiments, we analyze the physical processes that control the initiation and propagation of fingered fronts in porous media which contain permeability variations. Miscible displacements at both favorable and unfavorable mobility ratios are studied and the effects of the standard deviation and spatial variability of the permeability on these displacements are discussed. A developed-miscible process is also studied and the interplay of capillary pressure with permeability variations is presented.
To represent the spatial and frequency distribution of the permeability in the simulator, we have taken 1600 (40 × 40) surface permeability measurements on each of two 2 ft by 2 ft slabs of Berea rock and entered these numbers directly into the simulator. Displacement experiments at various mobility ratios were then conducted in this rock and the results compared to the simulations.
Although only laboratory-scale systems are studied, the concepts and insights which we present can help interpret larger-scale systems. The results can be used not only to judge the degree of detail needed to simulate permeability variations for a given process, but also to gauge the robustness of a process to permeability variations.
Steam Diversion by Surfactants
Authors: Gall J. W. 
Published: December 2007

ABSTRACT
A large problem associated with steamflooding is the overriding or bypassing of the oil by the highly mobile steam. Surfactants have often been injected along with the steam in attempts to create a foam that would inhibit the flow of steam in these depleted zones or channels. Laboratory studies have shown that the magnitude of resistance to the flow of steam through a porous medium containing foam was directly related to the permeability. Because of these higher resistance factors in higher permeability zones, the relative amount of fluid flowing through zones of differing initial permeability can actually be reversed. Results with several surfactants will be discussed.
Experimental techniques developed to permit determination of the amount of steam diverted from one zone to another enabled the examination of variables related to foam diversion processes such as surfactant type, surfactant concentration, slug size and most importantly, permeability. A description of these experimental techniques and the data analysis will be discussed.
Some Experiences With a Critical Reservoir Fluid
Authors: Huang W. W. 
Published: December 2007

ABSTRACT
Fluid properties and composition in a naturally occurring near critical reservoir show significant variations between samples. Highly undersaturated volatile oil and rich condensate gas coexist in the same reservoir without a gas-oil contact. Producing gas-oil ratios (GOR) at undersaturated reservoir conditions have been observed to vary up to more than two fold among wells. An equation of state (EOS) reservoir simulator was used to predict performance of nitrogen injection into this reservoir where fluid variation is the rule, not the exception. Phase behavior of the fluid samples predicted by the EOS is sensitive to their plus fraction characterizations. Estimated characterization parameters such as Watson's factor and Whitson's1 molar distribution parameter a differ among the reservoir samples. Values of these characterization parameters decline generally with producing GOR of the sampled well, indicating richer fluids tend to be more paraffinic and higher in heavier components. Variations in heptanes plus (C7+) properties correlate better with producing GOR than with depth. Saturation pressure does not exhibit clear correlations with GOR or depth. It is difficult to explain by the gravity-thermodynamic equilibrium theory of Schulte2 and Hirschberg3. To account for observed GOR variation in the field, reservoir fluids are thought to vary areally rather than vertically in the oil/gas column.
An EOS tuned for one sample usually gives unsatisfactory predictions of phase behavior of other samples. Describing these property variations and the effect of injected nitrogen with an EOS becomes a challenging task. This study uses calculated Watson characterization factor in regression to improve the match of extensive PVT cell data and to treat changing fluid characterization. This procedure was found to improve the PVT match significantly when the common regression practices yield unsatisfactory results and extended analyses of the plus fraction are unavailable.
This paper addresses compositional grading occurred in the near-critical reservoir and a method to account for it in an EOS reservoir model. Interfacial tension effects associated with the critical fluid are also discussed briefly.
Imaging of Wetting and Nonwetting Phase Distributions: Application to Centrifuge Capillary Pressure Measurements
Authors: Wunderlich R. W. 
Published: December 2007

ABSTRACT
An epoxy casting technique has been developed which permits the imaging of wetting and nonwetting phase distributions in porous media. First, a rock sample is saturated with a colored epoxy. Air is forced in at a particular pressure, and after equilibrium has been reached, the epoxy is solidified. The sample is then evacuated and saturated with a different colored epoxy, which is also solidified. Finally, thin sections of the sample are prepared to image the phase distributions.
This method has been applied to study contrasting models for centrifuge capillary pressure measurements. These measurements are usually interpreted in terms of the work of G. L. Hassler and E. Brunner.1 One of their assumptions was that a region of 100% wetting phase saturation always is present at the face of the sample furthest from the axis of rotation. The epoxy casting technique has been used to demonstrate that this assumption fails beyond a critical capillary pressure.
The technique is also being used to identify petrographic controls on the distribution of the wetting and nonwetting phases. For example, the influence of clays on the distribution of the wetting phase between intergranular and intragranular porosity can readily be distinguished.
Areas in which this and similar techniques could prove valuable include studying the pore-level structure of the residual nonwetting phase, and the electrical conductivity of porous media as a function of saturation. Techniques are currently being developed to aid in such studies.
Research on Simultaneous Production Logging Instruments in Multiphase Flow Loop
Authors: Davarzani J. , Sloan M. L. , Roesner R. E. 
Published: December 2007

ABSTRACT
The capability to accurately record log data in multiphase flow was greatly enhanced with the introduction of well logging instruments designed for simultaneous data acquisition. Presented is an overall evaluation of the simultaneous production logging instruments and dynamic flow test results. Investigations of water holdup and water cut and the effects on the response of the downhole logging instruments are presented. Also, the multiphase slip velocities at various fluid compositions, flow rates, and deviation angles are presented in relation to the simultaneous flowmeter measurement data. Derived are recommended logging procedures that will improve log quality in multiphase flow.
Fracture Conductivity Damage Due to Crosslinked Gel Residue and Closure Stress on Propped 20/40 Mesh Sand
Authors: Kim C. M. , Losacano J. A. 
Published: December 2007

ABSTRACT
The commonly used cross-linked fracturing fluids, called gels, were broken in a 20/40 mesh sandpack. The san dpa ck simulated a 2.0 lbm/ft2 propped fracture and was used to test the effects of gel residue and closure stress on fracture con ductivity.
The gel residues that were evaluated in this test were derived from the gels made with hydroxypropyl guar (HPG), guar, and carboxymethyl hydroxyethyl cellulose (CWEC) polymers. The relative gel residue volumes for these polymers were determined. Reduction in sand permeability due to these residue volumes was compared between polymers at given closure stress levels. A linear-flow proppant conductivity test cell was used to measure the permeability of the sand under closure stresses up to 10000 psi. For the HPG polymer, both cross-linked and linear fluids were evaluated.
Among the three polymers evaluated, the CMHEC gel cross-linked with trivalent aluminum caused the least reduction in sand permeability. The borate cross-linked guar gel resulted in the greatest reduction. However, the difference in permeability reduction caused by the borate cross-linked guar and titanate cross-linked HPG gels was small. Test results for the HPG polymer indicated that the reduction in permeability both due to the cross-linked and linear fluids was nearly the same. Sand permeability was continuously reduced with increasing closure stress. However, the permeability reduction above 4500 psi closure stress was inconsistent. An increase of polymer concentration further reduced sand permeability, but the amount of reduction was not directly proportional to the increase of polymer concentration.