bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phase Change in Binary Systems in Porous Media: Application to Solution-Gas Drive
Authors: Yortsos Y. C. , Parlar M. 
Published: December 2007

ABSTRACT
In this paper, a study of the liquid-to-vapor phase change by pressure decline in porous media is presented. A simplified solution gas drive system is taken as a representative example. The issues of nucleation, critical supersaturation, and vapor phase growth in porous media are critically examined. At low supersaturations a percolation approach is proposed that allows for the estimation of critical gas saturation and relative permeabilities from nucleation and pore structure characteristics.
Horizontal Wellbore Stability for Openhole Completions
Authors: Fuh G-F. , Loose P. K. 
Published: December 2007

Abstract
Horizontal well drilling and production have been increasingly important to the oil industry in recent years. The potential of significant increase in oil or gas production from a horizontal well will be very attractive as drilling and completion costs diminish and new technologies are developed to address problems concerning wellbore stability and formation damage. This paper presents a successful case analysis on borehole stability conducted before an openhole recompletion was performed in an existing cased hole for increased oil production.
The North Sunshine May No. 4 well located in the Big Horn Basin of Wyoming, was originally completed as a vertical well in 1977. In late 1987, the well was sidetracked and laterally extended to a nearly horizontal wellbore. The 1000-ft lateral extension exposed 850 ft of the reservoir sands for production. The pay zone was cased with 4-1/2" liner. However, the production rate was not as high as originally anticipated. A decision was made to explore the possibility of pulling the slotted liner from the well and leave as an openhole completion after cleaning the reservoir portion of the hole. Based on rock mechanics principles, we conducted openhole stability analysis using high-angle drilling and core recovery data from the well. The analysis also considered the effect of reservoir depletion on openhole stability. The results predicted that the rock strength for the reservoir sands was great enough to keep the horizontal section open with little or no formation support during oil production, following the openhole recompletion operation. Field results after removal of the slotted liner have confirmed this finding. Some detail about the completion for oil production is also described herein.
Gravel Pack Quality Control by Neutron Activation Logging
Authors: Olesen J.-R. , Hudson T. E. , Carpenter W. W. 
Published: December 2007

ABSTRACT
A successful gravel-pack is hard to achieve in wells that have highly deviated boreholes and long completion intervals. The primary difficulty in such wells is placing the pack material in the screen/casing annulus and in the perforations without leaving void areas. Using a low-density particle for packing will help prevent void area in allowing the use of the matched-density concept, where the particle density equals the density of the carrier fluid.
Since most gravel pack quality control devices rely on the usually sizable difference of density between borehole fluid and packing material, they may not be suitable for gravel-pack operations involving high-density borehole fluids and/or low-density gravel packing material.
This paper introduces a new application of existing logging devices to provide a quantitative evaluation of the packing quality. The method is based on neutron activation of particular elements contained in the gravel pack material and applies to standard gravel as well as to new low-density materials. The technique is relatively insensitive to formation characteristics because the depth of penetration of the activation neutrons is shallow. A base pulsed neutron capture log can be recorded simultaneously with log for gravel-pack quality control. The lack of sensitivity of the formation capture cross-section measurement to the presence of the gravel material, whether conventional or lightweight, has been demonstrated.
The logging procedure was developed using a series of laboratory measurements in formations with a simulated gravel-pack completion. Field results obtained with different types of gravel-pack material are compared to a density-based log when the density contrast of the packing material and completion fluid permits the use of the latter logging technique.
Fluid-Loss Control Using Crosslinkable HEC in High-Permeability Offshore Flexure Trend Completions
Authors: Blauch M. E. , Broussard G. J. , Sanclemente L. W. , Weaver J. D. , Pace J. R. 
Published: December 2007

ABSTRACT
An alternative system to conventional HEC (hydroxyethylcellulose) and particulate fluid loss materials has been developed for fluid loss control in high permeability Gulf of Mexico Flexure trend completions. In offshore operations, the problem of controlling fluid loss to the formation is critical in achieving successful gravel pack completions. The problem is magnified in this environment because of the use of expensive high density brine, lost rig time, and increased standards for well control and safety. A newly developed fluid loss system which consists of a crosslinkable, derivatized HEC incorporating a branched functional group oh an HEC backbone has been evolving in the industry. The functional group provides a nonionic reaction site which allows the polymer to be crosslinked at a low pH, and broken in a controlled manner using a newly developed breaker.
Other fluid loss control systems used in Flexure trend completions exhibit specific problems which can be attributed to (1) physical properties of the particular material, and (2) the method of application. For instance, in many high permeability wells, noncrosslinkable HEC pills have proven inadequate for controlling fluid loss to an acceptable level, and in some cases have allowed significant invasion of HEC, thus potentially resulting in permeability impairment. Particulate fluid loss materials present other problems in that they can be difficult to remove from perforations.
Laboratory and field tests demonstrate efficient fluid loss control and potential for reduced formation damage with this new crosslinkable HEC (CLHEC). Internally broken crosslinked gel has shown more favorable return permeability in core tests than regular HEC polymer commonly used in the industry. The CLHEC system deposits a thin, crosslinked polymer filter cake which helps prevent fluid loss, but which can be removed by means of an internal breaker, an acid wash, or both. Subject paper presents laboratory and field data illustrating properties of the new fluid loss control system in high density brine applications.
Improved Methods for the Modeling and Conduct of Vertical Interference Tests Across a Tight Zone
Authors: Stewart G. , Jaafar M. D. , Du Kui Fu 
Published: December 2007

ABSTRACT
Vertical interference testing to determine the effective vertical permeability of tight zones is an important part of reservoir characterisation. The analytical model of Bremer has been extended to include the effect of wellbore storage and skin using a real time convolution formula. This appraoch has been validated by comparison with the results of the dual permeability model in Laplace space proposed by Economides. Practical considerations relating to the effective conduct of such tests are given. In particular procedures for pressure testing of packers and eliding sleeve doors are recommended along with good cement bond logs. Reciprocal testing of both layers as active and observation layers gives much improved results. Several field examples have been analysed with success. The depth of investigation of such vertical interference tests is related to the gauge resolution. The effect of wellbore storage on observation layer response can be predicted by analysing the active layer response in the conventional manner. This reduces uncertainty in the determination of vertical permeability. Large negative skin factors due to acid stimulation lead to problems with the Laplace space method. Analytical results have been complemented by numerical simulation to characterise for example the effect of tight zone capacity and extension. Numerical simulation was also used to show up the effect of leaks behind casing on the observation layer response. A distinct change in the character of its signal occurs with a casing leak.
A Fractured Reservoir Simulator Capable of Modeling Block-Block Interaction
Authors: Por G. J. , Boerrigter P. , Maas J. G. , de Vries A. 
Published: December 2007

ABSTRACT
A new simulator has been developed to model displacement processes in fractured reservoirs, in particular the block-block interaction in gravity drainage processes. This block-block interaction forces oil draining from a matrix block into the fracture system to be absorbed by the underlying matrix block whenever this is possible. Otherwise the oil flows through the fracture network. Block-block interaction influences both the initial production rates and the resulting hydrocarbon distribution in the reservoir.
Simulation of fractured reservoirs with this type of interaction between matrix blocks makes high demands upon the simulator, both in terms of memory requirements and speed. The simulator hence uses dynamic memory management and an efficient grid-block partitioning scheme that reduces the memory requirements significantly. In addition, this scheme enables a high degree of vectorisation on a Cray computer.
The simulator can be used for a variety of reservoir geometries: dual porosity, dual porosity/ permeability, reservoirs with block-block interaction and unfractured reservoirs.
Field Study and Modeling of Condensation in a Gas Distribution Pipeline
Authors: Adewumi M. A. , Mucharam L. , Watson R. W. , Campbell L. D. 
Published: December 2007

Abstract
This study pertains to a carefully designed non-intrusive field experiment aimed at generating data for gas condensate pipeline. A compositional two-phase hydrodynamic model is used to analyze the system with a view of validating and tuning the model for field applications. The field test was designed as part of an existing gas distribution system to collect data on gas condensation and pressure drop in gas pipeline. The test section is a 6-inch, 52,000-ft long pipe to which natural gas from three different fields is fed simultaneously. Detailed topographic profile of the pipeline is drawn so as to obtain the various inclination and inclination changes along the test section. 120 inclination changes are present in the test section. The spatial distribution of the pressure and liquid holdup are not monitored so as to keep the normal operation of the distribution system as intact as possible. However, pressure and gas flow rates are monitored at some key points along the test section. In addition, periodic pigging provides total liquid accumulation over a 4-month period. Gas Chromatographic analysis provides the composition of the transported natural gas.
A compositional two-fluid steady multiphase hydrodynamic model developed from fundamental fluid dynamics is used to describe the formation and dynamic behavior of the gas/condensate system. The results of production runs demonstrate the predictive capability of the model in terms of the basic engineering design variables for this system. A number of interesting findings concerning the behavior of gas condensate flow are made. The model can be used for both design and operational purposes.
A New Method for Capillary Pressure and Relative Permeability Curve Matching for Gas/Water Flow
Authors: Choho T. , Pelce V. , Fasanino G. , Picard M. 
Published: December 2007

Abstract
Knowledge of gas-water relative permeability and capillary pressure curves is very important for reservoir engineers. A new mathematical procedure is proposed concerning two-phase flow with one compressible phase.
The method consists in the establishment of a criterion evaluating the difference between a historical record of real pressures and modeling pressures. It then automatically determines the optimum capillary pressure and relative gas and water permeability curves that minimize the criterion. The difficulties remain in the numerical criterion estimate and the gradient calculation.
This method was tested for one-dimensional cases and an example of application shows the efficiency of the algorithm. Validations in 2D and 3D are envisaged.
Feature Selection and Extraction for Well Test Interpretation by an Artificial Intelligence Approach
Authors: Stewart G. , Du Kui Fu 
Published: December 2007

ABSTRACT
A technique for the automatic selection and extraction of features from a well test interpretation curve is described which provides a means for transforming a well test signal into a symbolic context; this is regarded as a first step in developing an automated or knowledge-based approach to interpreting transient pressure tests [9]. It uses novel methods paralleling those frequently employed in solving artificial intelligence problems such as vision processing.
The library of recognized features has been chosen by careful observation of a wide variety of well test responses. The criteria of feature selection and extraction are based on the special attributes considered by human experts during the visual diagnosis of an interpretation model and the definition of flow regime. The implementation of feature selection and extraction is carried out by the following steps: Data preprocessingSegmentationGroupingRepresentation relationships between the segmented elements
At the end of this process, a digital signal has been translated into a symbolic string which will be used as a basis for the further analysis e.g. model selection, using knowledge-based methods.
New Methods for the Analysis of Drillstem Test Data
Authors: Peres A. M. M. , Onur M. , Reynolds A. C. 
Published: December 2007

Abstract
This paper presents new procedures for analyzing pressure buildup data obtained from drillstem tests. The new methods apply for cases where the produced fluid does not reach the surface during the flowing period so that, the flow period represents a slug test. The combined effects of variable flow rate, short producing time and changing wellbore storage generally make it difficult to apply conventional analysis methods to DST buildup data. Two new straight-line methods for analyzing buildup data presented in this work account for both the variable rate during the flow period and producing time effects. If the buildup well-bore storage-skin group Csd exp(2s) is small, then shortly after shut-in, a well-defined straight line is obtained for both methods. Using the slope of the straight line obtained by either method, it is shown that the flow capacity (kh), the skin factor (s) and the initial reservoir pressure (pi) can be determined. If the group Csd exp(2s) is large, longer shut-in times are needed before the proper straight line can be obtained. However, for the latter case, it is shown that a multi-rate equivalent time can be constructed so that standard type-curve matching can be performed to obtain estimates of the flow capacity and the skin factor. A field example is presented to illustrate the applications of the proposed methods.
Applications of Cross-Borehole Seismic Tomography To Monitor EOR Displacement Fronts in Heavy-Oil Fields of Kern County, California
Authors: Hutt P. R. , Justice J. H. , Vassiliou A. A. , Cunningham P. S. , Singh S. , Bulau J. 
Published: December 2007

Abstract
Cross-borehole seismic tomography has been applied to assist in the monitoring of an EOR displacement front in a heavy oil field located in Kern County, California. Results from this survey indicate that tomographically processed cross-borehole seismic surveys can image variations in the velocity field of the subsurface. Several factors including the temperature, type, and physical state of the pore filling material strongly affect the velocity field of a reservoir. Cross-borehole velocity profiles, referred to as tomograms, are interpreted to provide insight into the physical changes taking place in the reservoir as an EOR process progresses.
A cross-borehole seismic survey is acquired by placing a downhole seismic source system into one wellbore and a downhole seismic receiver system into an adjacent wellbore and recording seismic wavefield information for a series of "shots" from the source to the receiver. The time it takes the wavefront to propagate from the source to the receiver is associated with a raypath. When an adequate number of wavefronts are recorded to properly sample the subsurface profile from source well to receiver well, they may be tomographically processed to provide a velocity profile between the two wellbores.
A tomographic survey acquired in a reservoir undergoing cyclic steaming stimulation resulted in a data set of both compressional and shear wave velocity profiles. These data were combined to produce a Poisson ratio tomogram for one of the two well-to-well surveys. The P-wave, S-wave, and Poisson ratio tomograms are interpreted to demonstrate variations in the type and physical state of the pore filling material of the reservoir. The data may be revealing information with respect to heavy oil saturations as well as highlighting zones of thermally heated reservoir. The interpretations are highly qualitative and require further acoustic core analysis to confirm and quantify the findings.
Drilling Contracting in the Nineties
Authors: De Wardt J. P. 
Published: December 2007

ABSTRACT
The paper will review the construction and content of a new document format which has been selected for use in Shell drilling operations contracting. The review of content will cover a range of items including liabilities, obligations, scope of work, specifications and equipment requirements. The application of the new format to incentive and turnkey drilling operations will be reviewed together with the implications on Operator/Contractor roles in the execution of these types of contract.
The desire to increase operator efficiency is leading a change from supervising the contractor to managing the contract. The implementation of this change will be discussed.
Quality assurance leads to more cost effective operations. The application of QA to drilling operations contracts will be introduced.
Managing Safety
Authors: Stewart D. A. , Young L. P. 
Published: December 2007

ABSTRACT
The objective of this presentation is to highlight the major vehicles of an accident prevention program that allowed the subject company to improve their incident rate by 63 percent over a three year period of time, thereby realizing insurance savings in the million dollar per year range. Included will be a detail of each individual vehicle used in this program and an analysis of their impact. A final result/conclusion will show both the positive impact on employee and customer relations and the profitable impact on the organization.
PDC Bits Using Positive Rake Cutters
Authors: Knowlton R. H. 
Published: December 2007

ABSTRACT
A radical new concept in bit technology has been developed for use in drilling the deep water shales of the Gulf of Mexico and the Mississippi Delta where both milltooth and conventional PDC bits have performed poorly. This new tool utilizes the following technical elements: Large diameter positive rake PDC cutters as the primary cutting elementCurved PDC cutters to stretch the formation to its elastic limits for easy shearingCritical spacing between the cutters to take advantage of rock harmonics and fail the formation in tension.
The applications qualification procedure for the use of this new technology is based upon standard electric logs.
Risk and Economics Evaluation in Drilling Operations
Authors: Willis J. B. , Johnson S. M. 
Published: December 2007

ABSTRACT
A drilling operations time and cost modeling program has been used to perform risk and economic evaluations of drilling plan alternatives. Three major benefits resulted from the use of the modeling program: Speed: major variations can be evaluated quickly allowing far more "what-if s" to be examined.Quality: the comprehensive analysis is superior to previously used methods.Acceptance: because of the quality, conclusions are more readily accepted.
The program uses only normally available well data and time and cost parameters.
Examples include evaluations of directional profile, Top Drive economics, and drilling fluids selection.
Successful Squeezing of Shallow and Low-Pressure Formations
Authors: Grant W. H. , White R. L. , Smith R. C. , Miller A. G. 
Published: December 2007

ABSTRACT
Squeeze cementing technology is available that allows first attempt success In almost any situation. Gone are the days when three, four, and five attempts were necessary. Even a second attempt is rare when this technology is properly applied.
This paper illustrates three areas of squeeze cementing that are generally misunderstood and misapplied: Injection rates are conducted at excessively high rates and pressures and either create or perpetuate damage. Valuable information that could be used to make the right decisions during the squeeze job is lost forever.Proper slurry design is often neglected. Slurries are almost always tested incorrectly if they are tested at all.The slurry is placed downhole at too high a rate because of the fear of cementing up a workstring. This causes excessive formation damage and places the bulk of the slurry so far from the wellbore that It Is of no value to a successful remedial job.
This paper is the result of field studies in which the injection rate, slurry design, and placement procedures were developed and monitored. Field examples are presented.
Innovative Application of Lift Barge to Mobilize MODU into Shallow Water
Authors: Wolford B. G. 
Published: December 2007

ABSTRACT
Transworld Drilling Company's utilization of auxiliary lift barges to buoy large submersible MODUs extends the shallow-water operating range of these units. These large submersible MODUs offer greater storage and hookload capability than MODUs typically used on shallow-water locations. Two case histories describe the technical and logistical details associated with this innovative application of existing equipment.
Fracture Toughness Criteria for High-Strength Drillpipe
Authors: Szklarz K. E. 
Published: December 2007

ABSTRACT
Higher fracture toughness materials are more resistant to fracture than lower toughness materials under the same loading conditions. This fact is particularly important when considering potential drill pipe failures because there exists no industry standard which specifies fracture toughness for drill pipe. How fracture tough should your pipe be? This question is discussed through a comparison of recent fracture toughness criteria for high strength drill pipe. A Chevron Corp. criterion based on field observations has suggested 40 ft-lbf (54 J) at room temperature from 3/4 size Charpy impacts. Shell Canada Limited has developed fracture toughness criteria based on a fracture mechanics, leak before break concept for a pipe body containing fatigue cracking and on field observations of parted pipe and washouts in pipe. This has allowed the application of a room temperature, 80 J (59 ft-lbf), 3/4 size Charpy criterion in Shell Canada drilling contracts. A single, impact-type criterion has ease of application but flexible, fracture mechanics criteria may allow for better operational use of drill pipe in specific situations. An empirical relationship between fracture and impact properties was determined which allows the use of required toughness curves and leak before break curves based on operating conditions and drill pipe impact properties. Examples are given with respect to tested properties of new, high quality drill pipe and used, failed drill pipe. These show it is possible to obtain drill pipe that will washout before parting but a criterion of 54 J will not guarantee it.