bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Concept of Sand Production Prediction: Theory and Laboratory Experiments
Authors: van den Hoek P. J. , Hertogh G. M. M. , Kooijman A. P. , de Bree Ph. , Kenter C. J. , Papamichos E. 
Published: December 2007

SummaryConventional theories of sand production prediction distinguish between compressive (shear) cavity (perforation, borehole) failure, induced by a combination of in-situ stress and drawdown, and tensile cavity failure, induced by the near-cavity pore pressure gradient. In this paper we show, using a global criterion for strain localization around the cavity (i.e., cavity failure), that in most cases the preference for either compressive or tensile cavity failure only depends on the cavity size and on the constitutive properties of the rock, and not on effective near-cavity stress or the pore pressure gradient. It is shown that "large" cavities (e.g., boreholes) always fail in compression rather than in tension failure. Only for sufficiently small cavities (e.g., perforations) in weak, moist sandstones, is compressive failure supressed and tensile failure possible. The above results deviate significantly from previous sand production prediction concepts. They are further supported by laboratory sand production experiments with large cavities, in which sand failure was only observed for near-cavity effective stresses above a certain threshold, independent of applied drawdown (i.e., flow rate). The experiments exhibited no correlation between the (non) occurrence of sand production and drawdown.From these results, it may be concluded that the primary role of fluid flow in sand production is the transport of loose sand (debris) resulting from compressive failure, rather than failure of the intact sandstone itself.
Innovative Real-Time Well-Monitoring Systems (ESP Applications)
Authors: Moffatt Terry , Craig Doug 
Published: December 2007

Abstract
The increasing need for downhole data related to modern production practices has resulted in the growing use of permanent well-monitoring systems (Fig. 1) for both offshore and land-based applications. The development of these technologies has furthered the ability of production and reservoir engineers to make more proactive decisions based on downhole-measured conditions.
This paper takes a cursory look at an innovative technology that has been used in both low- and high-temperature applications. The focus of the paper is on the applications and case studies in which the instrumentation has been employed. Information gathered, education gained, and value of the data is discussed for applications involving electrical submersible pumping (ESP) systems.
Permeability Modification With Sulfomethylated Resorcinol-Formaldehyde Gel System
Authors: Zhuang Y. , Pandey S. N. , McCool C. S. , Willhite G. P. 
Published: December 2007

Summary
The effect of various parameters on the gelation of the resorcinol-formaldehyde (RF) system and a newly developed sulfomethylated resorcinol-formaldehyde (SMRF) system was investigated. The SMRF system was more tolerant of salinity, divalent ion content and pH than the RF system. The SMRF system was tested in laboratory core floods conducted at 41°C (106°F) using Berea sandstone cores, Baker dolomite cores and reservoir rock from the Lansing-Kansas City formation.
SMRF forms strong and stable gels at temperatures between 25 and 52°C (77 and 126°F) and in the pH range between 5 and 8.0. Gel times are a function of pH, salinity, concentration of the chemical constituents and temperature, and can be controlled by appropriate adjustment of these parameters. Laboratory data describing the characteristics of the SMRF system in beaker tests are presented.
The SMRF gel system has a viscosity close to water when the reactants are mixed and is easily injected into porous rock. In core tests, the gel system was injected into short cores and allowed to gel in situ. Permeability to brine after in-situ gelation was determined for each core as well as permeability after several pore volumes of brine injection. The SMRF gel system reduced the permeabilities of Berea and Baker dolomite cores by factors on the order of 10,000. The Lansing-Kansas City reservoir rock was plugged by the gel system.
The SMRF gel system is one of a few gel systems that will form a gel in situ in the presence of the strong buffering that occurs when brine is injected into carbonate rock. The SMRF system has potential for treatments of carbonate matrix rock such as that found in the Lansing-Kansas City formations of central Kansas as well as the low-permeability carbonates found in the San Andres formations in west Texas.
Theoretical and Experimental Studies of Sandstone Acidizing
Authors: Hill A. D. , Lindsay D. M. , Silberberg I. H. , Schechter R. S. 
Published: December 2007

AbstractThe matrix acidization of sandstone by a hydrochloric/hydrofluoric acid mixture is described through use of a capillary model. The model was solved first in linear coordinates so that it could be compared with the results of coreflood experiments performed on Berea sandstone. The model predictions showed reasonable agreement with the experimental data and yielded specific information about the reaction characteristics of the sand-stone/HCl/HF system.The acidization model then was applied in radial coordinates to generate design curves for a matrix acidization treatment. While these curves strictly apply only to those sandstones having similar mineral compositions, the approach is general. It is based on matching the location of the HF reaction front to the depth of a damaged zone. This method introduces the concept of an optimum injection rate and, in this regard, differs from other design methods reported in the literature.
Adaptation of Friction Factors to the Flow of Fluids Through Consolidated Formations
Authors: Stutzman L.F. , Thodos George 
Published: December 2007

Abstract
The friction factor plot presented by Cornell and Katz and developed for the flow of fluids through consolidated formations has been directly adapted for handling fluid flow problems involving both linear and radial flow. In this adaptation the friction factor plot is used directly for the solution of problems and thereby eliminates the use of conventional equations which are specific to laminar (Darcy) or turbulent flow. This approach overcomes the disadvantages inherent in the use of these conventional equations. It eliminates the necessity of checking the type of flow occurring in order to identify the specific equation which must be used. In radial flow problems, because of the increasing mass velocity of the fluids as they approach the wellbore, the type of flow may no longer remain laminar. Consequently, it is necessary to use more than one equation in a problem and to identify the range over which each equation should be applied. Finally, in practice it has been found that much of the flow of gases through consolidated media occurs in a range that is neither laminar or turbulent. For this transitional region, no convenient equations are available. The method and presented friction factor plot are applicable to both liquids and gases.

Introduction
The flow of fluids through unconsolidated media in packed beds has been treated extensively by a number of investigators. Most of these studies present friction factors as a function of modified Reynolds number similar to those developed for conventional fluid flow through pipes. These friction factor plots are presented for linear flow; however, Elenbaas and Katz have extended these concepts to apply to radial flow. All of these studies on unconsolidated materials require a knowledge of packing properties such as sphericity, porosity, and particle diameter. Sphericity and particle diameter cannot be defined at the present time for consolidated formations such as those commonly found in gas or oil reservoirs. As a result many investigators have not utilized friction factors and Reynolds number in the study of fluid flow through consolidated media.
Journey From Well Logs/Cores to Integrated Geological and Petrophysical Properties Simulation: A Methodology and Application
Authors: Bahar A. , Kelkar M. 
Published: December 2007

Summary
Reservoir studies performed in the industry are moving towards an integrated approach. Most data available for this purpose are mainly from well cores and/or well logs. The translation of these data into petrophysical properties, i.e., porosity and permeability, at interwell locations that are consistent with the underlying geological description is a critical process. This paper presents a methodology that can be used to achieve this goal. The method has been applied at several field applications where full reservoir characterization study is conducted.
The framework developed starts with a geological interpretation, i.e., facies and petrophysical properties, at well locations. A new technique for evaluating horizontal spatial relationships is provided. The technique uses the average properties of the vertical data to infer the low-frequency characteristics of the horizontal data. Additionally, a correction in calculating the indicator variogram, that is used to capture the facies' spatial relationship, is provided.
A new co-simulation technique to generate petrophysical properties consistent with the underlying geological description is also developed. The technique uses conditional simulation tools of geostatistical methodology and has been applied successfully using field data (sandstone and carbonate fields). The simulated geological descriptions match well the geologists' interpretation. All of these techniques are combined into a single user-friendly computer program that works on a personal computer platform.
Interference Testing in Reservoirs With Conductive Faults or Fractures
Authors: Abbaszadeh M. , Asakawa K. , Cinco-Ley H. , Arihara N. 
Published: December 2007

SummaryThis paper addresses interference testing in reservoirs with conductive faults allowing fluid flow along and across the fault plane. An altered skin region around fault thrusts is also included. It is found that the classical line-source solution does not apply. When active and observation wells are located across a fault, the interference behavior resembles that of a hydraulically fractured well with bilinear flow characteristics. However, different flow regimes are developed on the pressure derivative when the well pairs are situated at the same side: initially, the basic line-source behavior; then, constant pressure effect from the fault represented by a negative unit-slope line; and, finally, bilinear flow. Interference type curves for various regions in the reservoir are developed and practical guidelines are provided for interpretation of these tests. Field data from an interference test in a faulted carbonate reservoir are analyzed and fault parameters are estimated.
A New Approach for Accurate Prediction of Loading in Gas Wells Under Different Flowina Conditions
Authors: Nosseir M. A. , Darwich T. A. , Sayyouh M. H. , Sallaly M. El 
Published: December 2007

Summary
Several authors have introduced various mathematical equations to calculate the critical flow rate necessary to keep gas wells unloaded. The most widely used equation is that of Turner et al.1 However, Turner's equation required empirical adjustment with different ranges of data which made the application rather questionable. In this paper we present a new approach for calculating the critical flow rate necessary to keep gas wells unloaded. This approach still adopts Turner's basic concepts, but considers different flow conditions that result in different flow regimes. Hence it explains the previous discrepancies of Turner's equation (the droplet model) with different data ranges, and presents a new set of equations that eliminates the need for empirical adjustment and better matches actual data records.
Long-Term Hydraulic-Fracture Conductivities Under Extreme Conditions
Authors: Cikeš Marin 
Published: December 2007

Summary
Proppants for hydraulic fracturing are subjected to very severe conditions of stress, temperature, and chemical environment while they are expected to maintain their structural integrity for a period of many years. The performance of these proppants over time at simulated in-situ conditions has been a topic of laboratory investigation for several years, but in many cases the real conditions exceed the capabilities of the laboratory apparatus. To determine the proppant behavior under real reservoir conditions, production history and pressure buildup tests of four fractured wells have been analyzed. The reservoir conditions of these wells are so severe, that it was almost impossible to simulate them in the laboratory. The formation temperature is 179 to 195°C [354 to 383°F], while the reservoir pressure varies between 44.5 and 50.0 MPa [6,453 to 7,250 psi]. The producing fluid is large gravity sour gas, while the producing water is practically deionized. The proppants are mainly high-strength zirconium oxide and sintered bauxite that injected amount varies between 164 and 628 tons [3.6E + 05 to 1.38E + 06 lbm]. During the production time of six to eight years, the effective closure stress reached the values in the range of 32 to 51 MPa [4,640 to 7,395 psi].
More Than 12 Years' Experience With a Successful Conformance-Control Polymer-Gel Technology
Authors: Sydansk R. D. , Southwell G. P. 
Published: December 2007

SummaryIn this paper, we discuss and describe our extensive experience with the widely applied and quite successful Cr(III)-carboxylate/ acrylamide-polymer (CC/AP) gel technology for use in oilfield conformance-control, sweep-improvement, and water and gas shutoff treatments. Chromic triacetate is the often preferred chemical crosslinking agent used in conjunction with this polymer-gel technology. The CC/AP gel technology is characterized as having a robust gel chemistry and as being highly insensitive to petroleum reservoir environments and interferences. This gel technology, as of May 1998, has been employed in over 1,400 conformance-control treatments worldwide. Highlights of illustrative field applications and results involving the CC/AP conformance-control gel technology are presented. An overview of what a decade plus of experience in applying the CC/AP gel technology has taught us is discussed. This includes discussion of classifying and distinguishing conformance problems and treatments, attributes of good candidate wells and well patterns for gel conformance-control treatments, requirements that must be met in candidate wells and well patterns in order to achieve success, gel treatment elements that must be successfully implemented to achieve success, guidelines as to where polymer-gel conformance treatments are most successfully applied, risks and pitfalls of gel conformance treatments, and quality control issues.
Simulation With a Full-Tensor Coefficient Velocity Field Recovered From a Diagonal-Tensor Solution
Authors: Edwards M. G. 
Published: December 2007

Summary
Commercial simulators generally assume that the pressure equation always has a diagonal-tensor permeability field. However, cases that involve the use of non-Cartesian grids, crossbedding, or upscaling (or any combination thereof) will give rise to a full-tensor coefficient velocity field. Discretization of a full tensor increases the scheme stencil, simulation cost, and complexity of implementation. The focus of this paper is on the development of fully implicit finite-volume schemes that can allow full-tensor fluxes while retaining standard-matrix inversion.
Estimating Relative Permeability From Production Data: A Streamline Approach
Authors: Kulkarni K. N. , Datta-Gupta Akhil 
Published: December 2007

SummaryWe present a streamline-based approach for estimating relative permeabilities from production data. The streamline approach offers two principal advantages. First, we can analytically compute the sensitivity of the production response with respect to relative permeability parameters. The approach is extremely fast and requires a single streamline simulation run. Second, we can exploit the analogy between streamlines and seismic ray tracing to develop a formalism for efficient inversion of production data. For relative permeability representations we have used the commonly used power functions and also a more flexible representation through the use of B-splines. The relative advantages of these representations are examined through inversions of water-cut data from a nine-spot pattern. Finally, we address the underlying challenges associated with the simultaneous estimation of absolute and relative permeabilities from production data. We systematically investigate the nonuniqueness associated with the inverse problem and quantitatively evaluate the role of additional data such as pressure response in addition to water-cut history at the wells.
The Application of an Electronic Computer to the Calculation of the Recovery of Natural Gasoline by Refrigeration
Authors: Roberts S.M. 
Published: December 2007

Abstract
A study of the recovery of natural gasoline from natural gas by refrigeration was made with the aid of an IBM 650 computer. A form of the familiar "flash" equation, chosen to minimize calculation time, was employed to determine the natural gasoline recovery. An eight-component system can be solved in about 30 seconds for each pressure and temperature combination.
The ranges of the variables studied aregasoline content (isobutane and heavier) of the wet gas, 0.891 to 3.293 gal/Mcf,pressure, 50 psia to 1,000 psia, andtemperature, −20 degrees F to +40 degrees F.
For the gases considered the gasoline content of the discharge gas decreases more or less linearly with pressure to about 300 psia and then levels off. For all but the leanest gas, the gasoline content of the discharge gas can be reduced to 0.45 gal/Mcf at 400 psia and 0 degrees F. Under certain conditions of pressure and temperature the gasoline content can be reduced to as low as 0.25 gal/Mcf. In this case a large penalty is paid in the excessive recovery of propane and lighter in the liquid, The extraction efficiency is often a more satisfactory measure of the utility of the process than is the gasoline content of the discharge gas. The extraction efficiency increases more or less linearly to about 300 psia and then levels out beyond 600 psia. For all but the leanest wet-gas the isobutane and heavier extraction efficiency exceed 70 per cent at 400 psia and 0 degrees F. Under certain conditions the efficiency may exceed 90 per cent. At a given pressure and temperature, the richer the wet gas, the higher is the extraction efficiency.

Introduction
The recovery of natural gasoline from natural gas by refrigeration is a special field processing method. A study was made to establish the area of application of the method. The first step was to determine the ultimate physical recovery of liquid product, and the second step, to determine the economic recovery of liquid product. This paper will deal only with the first step. It describes in some detail the program for solving the flash equation with the aid of the IBM 650 computer and reports the calculated results. A somewhat similar study has been reported by Stamm, McCarty, Allen and Moore, but for a more limited range of wet-gas compositions and operating conditions.
The Impact of Compression Forces on Casing-String Designs and Connectors
Authors: Jellison M. J. , Brock J. N. 
Published: December 2007

Summary
The effect of downhole axial compression forces on casing string designs and connectors is a major concern to engineers designing high-temperature, high-pressure, extended reach, and horizontal wells. Widespread concern regarding the significance of compression loads on casing string design is relatively recent. For decades engineers were either not aware that high-compression loads may occur or were not concerned about the effect of compression on the casing.
This paper discusses the sources of axial compression forces in straight and directional wells. Methods to analyze casing subjected to compression and bending loading are presented including the effect of compression and bending on the von Mises equivalent stress state of the pipe.
Connector selection for casing applications where high axial compression loads are anticipated is critical. Compression ratings for API casing connectors have never been addressed in API standards. The paper offers methods to evaluate API connectors for applications with significant compression loading. Compression ratings for premium casing connectors are generally available, but the justification for these ratings varies substantially from one manufacturer to another and the basis for the compression ratings may not be well documented. The paper discusses compression rating methods for various premium connector configurations including threaded and coupled, flush and near flush. Desirable and undesirable premium connector features that relate to compression capacity are reviewed. Results from compression testing of premium connectors are also presented.
The paper benefits engineers involved in the design of casing strings for applications with high compression and bending loading.
Case History of Complex-Fracture Behavior in the Hanoi Trough, Vietnam
Authors: Cipolla C. L. , Mayerhofer M. , Wilson B. L. 
Published: December 2007

Summary
In this paper we present a detailed case history of complex fracture behavior in exploratory wells in the Hanoi Trough, Vietnam. The target formations are stacked fluvial channel deposits that occur at depths of 10,000 to 12,000 ft. The initial three wells were drilled from the same pad, with bottomhole locations about 3,000 to 5,000 ft apart and a probable fault between the No. 1 and No. 3 well. The gas reservoirs encountered were slightly overpressured and varied significantly in quality, with permeability ranging from 0.01 to 1 md. The first three wells were fracture stimulated in an attempt to improve deliverability. However, only one of the three treatments was successful due to complex fracture behavior. A comprehensive data set consisting of core analysis, rock mechanical tests, pre- and post-fracture logs, geochemical analyses, pre- and post-fracture well tests, and detailed fracture modeling was compiled to understand fracture performance in this complex environment. Without such a complete data set, identifying the cause of the treatment failures would probably not have been possible.
Particulate Invasion From Drilling Fluids
Authors: Bailey Louise , Boek E. S. , Jacques S. D. M. , Boassen Tony , Selle O. M. , Argillier J. -F. , Longeron D. G. 
Published: December 2007

SummaryWe investigate the invasion of solids and their mobility during cleanup. We study the effect of weighting agent particle size on rock substrates of varying permeabilities. We find permeability damage increases but flow initiation pressures decrease with increasing substrate permeability.We obtain quantitative profiles of solids invasion by scanning electron microscopy/x-ray mapping and synchrotron energy-dispersive x-ray diffraction tomography. We compare these profiles to core sectioning data. We find invasion profiles drop steeply but fines are observed deep within the core. We examine the effect of backflooding on the invasion profile. Near-surface damage is reduced but deeply invaded fines are unaffected by backflow.We develop a deep bed filtration model for solids invasion and consequent permeability reduction. This model is compared to the profiles obtained in the invasion experiments. We find that we can fit the experimental invasion profile for monomodal particles using a single trapping coefficient. Backflow is modeled by reversing the flow rate. We postulate a phenomenological rate of erosion to untrap particles in line with experimental observations (30%). When erosion is included in the model, a peak in the backflow pressure is found. This peak may be correlated with the experimentally observed flow initiation pressure.