bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multi-Phase Flow Properties for Coalbed Methane Wells: A Laboratory and Field Study
Authors: Conway M. W. , Mavor M. J. , Saulsberry J. , Barree R. B. , Schraufnagel R. A. 
Published: December 2007

ABSTRACT
The traditional concept of coalbed methane production is one where the coal natural fracture system is initially 100% saturated with water and that this water must be produced to initiate gas production. This paper summarizes an investigation designed to reconcile measured relative permeability data with well test analysis results obtained during single-phase and multi-phase tests, and with reservoir simulation projections of gas and water deliverability as a function of bottom-hole pressure. Improved well test and relative permeability measurement procedures are summarized so that projections of future fluid deliverability made during the dewatering and early multi-phase production stages are more accurate.
A variety of well tests were performed that included water slug tests, water injection tests, gas injection tests, and multi-phase production and shut-in tests. Estimates of absolute permeability obtained from these data were variable depending upon the test procedures. In addition, multi-phase and gas injection test analyses were strongly influenced by the relative permeability data used during the analysis. Based upon newly measured relative permeability data and by history matching multi-phase production data, it was possible to reconcile some of the differences in estimates of absolute permeability that were obtained from each of the test types. Finally, a new field procedure is proposed and demonstrated to measure permeability in wells producing both water and gas.
Determining the Effectiveness of Multi-Zone Completions and Stimulations in Low Permeability Formations with Production Logs
Authors: Mullen Mike , Frisch Gary , Johnson Jeff 
Published: December 2007

Abstract
The current economic structure of the petroleum industry often requires multiple completions with production from each zone co-mingled to reduce completion costs. However, these multiple completions require a different approach to analyze the effectiveness of both the original completion and possible later stimulation treatments of low permeability formations. To reduce the financial impact of individual zone testing it is desirable to run production logs to detect the contribution from each zone to the total production rate.
Some wells encounter multiple low permeability pay zones that are uneconomical to complete and stimulate individually. If the well does not do as expected or has a problem producing, the problems may not be recognized by conventional testing. If multiple zones are stimulated simultaneously there may be a concern whether each zone was responding to the stimulation treatment. Radioactive isotopes are used as a tag during the stimulation process to measure completion and/or placement effectiveness. Other methods for evaluating stimulation treatments include well testing, using pressure drawdown, and/or buildup analysis. However conventional analysis’ techniques are complicated to interpret with multiple completion intervals and may not yield information on the flow capacity of each zone.
With production logs it is possible to detect the type and rate of the fluids being produced from each individual zone in a timely manner. By comparing the open hole log analysis to a production log after stimulation it is possible to determine the effectiveness of the stimulation. This information could serve as a knowledge base for future stimulation design and improved well performance. Further computer analysis of the openhole logs, production logging data, and stimulation information could provide additional insight to enhance the economics of the reservoir development and to help understand wells that are producing below their expectations.
This paper will suggest guidelines for running production logs and show the usefulness of using these tools when evaluating multi-zone completions in tight gas sands. A three well example from the Rocky Mountain area is used to highlight the use of production logs to analyze multi-zone completions.
A Semi-Empirical Model of the In-Situ Stress Distribution for a Strike-Slip Regime: the Long Beach Unit, California
Authors: Katahara K. W , Lynch K. W. , Keck R. G. 
Published: December 2007

ABSTRACT
The Long Beach Unit (East Wilmington Field, California) consists of nearly a thousand active wells and currently produces about 47,500 BOPD. Values of the in-situ stresses are needed for designing hydraulic fracture stimulation treatments. Estimation of the stresses is complicated by the fact that the field is in an active strike-slip tectonic regime where the vertical stress magnitude is intermediate between the minimum and maximum horizontal stresses. Stress magnitudes from casing-leakoff tests and density log calculations are consistent with this structural interpretation,
Stresses were directly measured in several casing-leakoff tests, micro-fracs, and mini-fracs performed in various sands and shales in the field. The minimum horizontal stress in the shales is roughly linear with depth, while in the sandstones it increases more rapidly, and is more variable than in the shales.
This paper presents a semi-empirical model for calculation of in-situ stresses from logs. It assumes that the stresses are determined by a mechanical stability criterion, and that the ratio of the mean horizontal effective stress to the vertical effective stress is constant from one formation to another. This ratio can be determined from casing-leakoff tests. The new model matches the observed stress contrasts better than conventional elastic models.
A Practical Approach For Predicting Casing Running Speed From Couette Flow Of Non-Newtonian Power-Law Fluids
Authors: Chukwu Godwin A. 
Published: December 2007

Godwin A. Chukwu*

Abstract
The displacement of drilling fluid by the movement of the drill string or casing pipes produces pressure variations in the borehole. The velocity of this displacement governs the magnitude of the pressure change which can add or subtract to the hydrostatic pressure of the mud to produce surge or swab pressure, respectively.
The surge or swab pressure computation techniques presented in this paper are based on sound, easy to follow, step-by-step analysis of steady laminar couette flow of non-Newtonian power-law fluids through a concentric annular wellbore. The annular geometry is made of a stationary outer pipe and a steady axial motion of an inner pipe.
By employing the computed surge pressures, in combination with family of curves, the maximum velocities at which the casing pipes can be run in the hole without the danger of fracturing the formation are obtained. The results obtained from these analysis will aid in proper design and optimization of drilling programs.

Introduction
Couette flow phenomenon occurs when two co-axial cylinders are placed such that one of which is stationary and the other is moving at a specified velocity. This flow characteristic is representative of flow in the borehole annulus where the wall of the wellbore is represented by the stationary cylinder, and the drill string or casing is represented by the moving cylinder. The fluid local velocity is dependent on the velocity of the moving cylinder. The geometric representation of a concentric annulus is as shown in Figure 1.
In drilling operations, the displacement of fluid encountered when running or pulling the drill string or casing in the annulus produces momentary variations in fluid pressure. This pressure change is known as surge or swab pressure, the magnitude of which is governed by the movement of the inner pipe, the annular geometry, and the drilling fluid properties.
Surge or swab pressure evaluation is important in the general planning of drilling a well. Excessive surge or swab pressure can lead to formation fluid invading the well annulus, causing a threatened blowout. High surge pressure can lead to loss of mud, either suddenly by fracturing the formation or slowly by continuous efflux to permeable formation, The drilling fluid enters the fractures and this produces a drop in the fluid level, causing a reduction in mud hydrostatic pressure in the borehole. The reduction in mud hydrostatic pressure allows formation fluids to enter the wellbore, which may result to blowout.

PREVIOUS WORK
Several investigators have developed methods for predicting pressure surges in drilling wells.
P. 263
Design Of A Storage Field For A Variable Hourly Market
Authors: Farris Clifford B. 
Published: December 2007

Abstract
The design of a gas storage field and associated dehydration plant for transient hourly flow is more complex than for steady-state flow. The major difference is that a transient gas flow facility requires 30 to 100 percent more capacity than a steady flow for the same daily gas rate. Further, water in the gas withdrawn from storage is not a problem under steady-state conditions but causes many operating and processing problems under transients. Low ground temperatures cause the formation of gas hydrates and free liquids in the gathering systems and plant.
The effect of these liquids is minimized, but not eliminated, by removing the free water at the wellhead and heating the gas to 125 degrees F. Careful operation is still required on startup to avoid freeze-ups and to deliver pipeline quality gas into the transmission system. pipeline quality gas into the transmission system. The water problems are analyzed qualitatively for the effect on the final design.
Introduction
A. BACKGROUND:
Colorado Interstate Gas Company (CIG) operates a natural gas storage field near Denver, its major market. A map of CIG's main transmission system and storage field is shown in Figure 1. Gas supplies are located far from Denver in Kansas, Oklahoma, Texas, and Wyoming. The Fort Morgan storage reservoir, when it is filled during the summer, supplies gas to Denver on cold days throughout the winter.
Clean, dry gas is used to fill the reservoir. However, water in the reservoir is picked up and carried back out when the stored gas is withdrawn. A dehydration plant is required at the field site to remove the water before the gas reenters the transmission system for sale to Denver.
This same site also houses injection compressors to pump the gas into the ground during the summer.
Since the Fort Morgan storage field and plant are located only 60 miles from Denver, plant are located only 60 miles from Denver, they undergo quite variable gas flow rates and pressures. The unusual features of the design to handle the transient operations are the main topic of this paper.
A Method for Optimizing the Design of Gas Storage Systems
Authors: Van Horn H. Glen , Wienecke Donald R. 
Published: December 2007

Abstract
The design of underground gas storage systems requires the selection of optimal values for several interacting variables. Some of these variables are related by nonlinear functions so that frequently used optimization techniques, such as linear programming, are less than precise and cumbersome to apply. precise and cumbersome to apply. A method of optimizing the variables, subject to the operating and physical constraints, has been developed and programmed for solution by digital computer. A Fibonacci Search routine is used for efficient convergence on the optimal solution. The relationships between the variables are preserved in original form, nonlinear where this is the case.
The storage system includes the underground storage reservoir, the wells, the gathering system, the purification facilities, and the compressor station. purification facilities, and the compressor station. Because the gathering system is analyzed separately, only the average pressure loss from wellhead to compressor suction is entered into this system. The solution selects optimum horsepower for the withdrawal cycle. The reservoir is represented by the pressure-withdrawal relationship, and the producing ability of the wells by the back-pressure relationship.
The variables subject to optimization are the volume of in storage, the producing rate of the wells, the number of wells, the size of the casing, the size of the purification system, and the size of the compression equipment used for withdrawal. The optimal solution is the set of values for the variables that will minimize investment.
When the purification equipment is sized for the peak day volume, and the number and casing sizes of the peak day volume, and the number and casing sizes of the wells are temporarily considered fixed, the optimum-seeking computer program can be formulated as a two-variable, unimodal function that lends itself to efficient solution by the Fibonacci Search convergence technique. The program is designed to evaluate several casing sizes for any number of wells. By using the Fibonacci Search, the original range of uncertainty can be reduced to less than one percent in ten iterations. A tolerance of .001 percent can be achieved in 25 iterations.
Introduction
Variation in rates of gas consumption requires the use of some form of gas storage in conjunction with transmission and distribution facilities. Storage is used to supply additional volumes on peak demand days. it also permits the more efficient use of facilities during summer permits the more efficient use of facilities during summer months. Usually underground storage is the most practical means of gaining seasonal gas storage. An underground storage system contains several subsystems: the well casing, gathering, purification and compression facilities and the reservoir. The optimum design is the best combination of these subsystems.
Gas transmission facilities should be operated at a high load factor. Interruptible sales are one method of accomplishing higher load factors.
A New Model to Predict Steam Override and Viscous Fingering in Heterogeneous Oil Reservoirs
Authors: Godderij R. R. , Bruining Johannes 
Published: December 2007

Abstract
Early steam breakthrough, often observed in practice, is usually attributed to steam override. In the paper we address the question whether viscous fingering and/or channelling have an additional effect on the time of steam breakthrough. We have developed a pseudo 3-D mathematical model for steam drives that can handle steam override, viscous fingering and channelling in 3-D heterogeneous reservoirs.1
The model incorporates gravity and viscous forces as well as heat losses to the cap and base rock. Capillary forces are not included. We use an interface approach where we decouple heat and mass transfer. We simplify by the vertical equilibrium approximation and reduce the model equations to 2-D.
The ensuing model equations are solved by the probabilistic method proposed by King which is designed to model viscous fingering. The method allows 3-D evaluation of steam drive projects in heterogeneous reservoirs without the necessity for expensive fine grid three dimensional simulations,
Example calculations for a thin medium-viscosity oil field show that heat losses have a stabilizing effect on the displacement process. They completely suppress viscous fingering and reduce steam override. For the homogeneous cases, poor steam drive recoveries occur due to strong override and cusping towards the production well, as a result of the pattern geometry. For the heterogeneous cases, the additional effect of channelling through high permeable zones occurs.
Creating 3-D Reservoir Models Using Areal Geostatistical Techniques Combined with Vertical Well Data
Authors: Gorell Sheldon B. 
Published: December 2007

ABSTRACT
Advances in geostatistics, seismic processing and interpretation are now providing capabilities for improved reservoir characterization by allowing integration of seismic and well data. In certain situations where correlations can be established between seismic and well attributes, the seismic data can be used to bias the interpolation of well attributes away from the wells using techniques such as co-kriging (or variants thereof). Traditionally, this approach has been applied in situations where areal seismic attributes over a reservoir interval are correlated with zone-averaged petrophysical attributes. These techniques result in improved zone-averaged petrophysical maps. However, for certain applications, particularly dynamic reservoir simulation of fluid flow, zone-averaged properties may be inappropriate. In such situations, it is necessary to somehow "unaverage" the zone-averaged maps to produce vertically heterogeneous maps. Since the scales of seismic resolution are still generally much coarser than those needed for simulation models, seismic data often does not provide much, if any, information which can be used to infer details about internal reservoir heterogeneities. This paper discusses a technique for creating 3-D reservoir models based on underlying seismic maps and some measures of vertical heterogeneities at the wells. What results are 3-D reservoir models which honor both the vertical variations at the well locations and the geostatistically created zone-average petrophysical maps. Some examples are presented which demonstrate the applicability and limitations of this technique. In addition to visual inspection of the models, reservoir injection and production is simulated and used to illustrate the importance of various modeling assumptions.
An Experimental Study of Foam Flow Through Berea Sandstone With Applications to Foam Diversion in Matrix Acidizing
Authors: Parlar Mehmet , Parris M. D. , Jasinski R. J. , Robert J. A. 
Published: December 2007

ABSTRACT
The results of a series of dual (diversion) and single core foam experiments followed by liquid injection in unfired Berea sandstone cores are reported at high rates relevant to matrix acidizing. The sensitivity of the results to surfactant type and concentration, foam and post-foam liquid injection rates, permeability, temperature and presence of oil are discussed. Surfactant type, preflush and foam slug sizes are identified as critical parameters for subsequent liquid diversion into low-permeability regions. In contrast to EOR processes, surfactant adsorption is shown to be beneficial for diversion. At low liquid rates and high foam qualities relevant to EOR, foam at steady-state is found to behave as a Newtonian fluid with respect to liquid rate provided that the gas rate is above a critical rate. At high liquid rates and low qualities a shear-thinning behavior is observed. Pressure gradient during post-foam liquid injection is found to be independent of both foam and subsequent liquid rates, and to depend only on permeability for fixed surfactant chemistry. The entrance effects noted in foam literature are found to be more pronounced at high permeabilities and intermediate injection rates. Potential mechanisms as to why foam diversion in matrix acidizing works in the field are also discussed.
Technical Basis for Establishing Environmentally Acceptable Endpoints in Contaminated Soils
Authors: Nakles D. V. , Linz D. G. 
Published: December 2007

Abstract
There is a growing body of evidence that soils that contain residual concentrations of contaminants above background or pristine conditions may not pose unacceptable risk to the environment and human health. The initial results of a research program sponsored by the Gas Research Institute support this contention. The GRI research program has reviewed the existing soil literature: (1) to obtain a better understanding of the physical and chemical interactions that bind contaminants within the soil matrix and that govern their rate of release into the environment and to living organisms and (2) to examine and/or develop correlations between soil treatment and the resulting toxicity and mobility of contaminants in the soil matrix. This paper presents a sample of the supporting data which have been found regarding the persistence of contaminants in soil with time; the effects of aging of contaminants on their availability to microorganisms, the extractability of contaminants from the soil and the release of contaminants from the soil into the environment; the effects of the sorption of contaminants on soil on their effective toxicity; and the results of biological treatment on the concentration, toxicity, and mobility of PAHs in soil. The implications of these findings on the determination of environmentally acceptable endpoints in contaminated soils and the management of contaminated sites are also discussed.
Simultaneous Solution Of Oil-In-Place And Water-Influx Parameters For Partial Water Drive Reservoirs With Initial Gas Cap
Authors: Tehrani D.H. 
Published: December 2007

SIMULTANEOUS SOLUTION OF OIL-IN-PLACE AND WATER-INFLUX PARAMETERS FOR PARTIAL WATER DRIVE PARAMETERS FOR PARTIAL WATER DRIVE RESERVOIRS WITH INITIAL GAS CAP

Abstract
The application of Newton Optimization technique to volumetric balance equation is introduced. This is to determine, simultaneously, the original oil-in-place and water influx, using historical performance data of a petroleum reservoir. Equations are presented in a general manner so that the reader, familiar with matrix calculations, can easily apply them to any aquifer model. As a field example, an unsteady-state exponential form of water influx has been used to describe the aquifer performance of Haft Kel Field of Iran. performance of Haft Kel Field of Iran. The limitation of sum square deviations of oil-in-place as a basis for optimization has been described. Instead, the sum square deviations of cumulative reservoir withdrawals has been used for optimization which has accomplished satisfactory results.
The limitations of the method and the effect of its underlying assumptions have been discussed.
Seafloor Monitoring for Synthetic-Based Mud Discharged in the Western Gulf of Mexico
Authors: Candler John E. , Hoskin Sam , Churan Marc , Lai Cui Wei , Freeman Michael 
Published: December 2007

Abstract
Synthetic-based muds have been used to simultaneously improve drilling and environmental performance. The fate and effects of synthetic-based mud discharges in the marine environment have been issues of concern with the drilling industry and governmental agencies. Most of the environmental data on synthetic-based muds have been generated under laboratory conditions. This study uses field-collected data to investigate the fate and effects of a polyalphaolefin synthetic-based drilling fluid.
The first well drilled in the Gulf of Mexico using synthetic-based mud was completed in June 1992. Approximately 441 bbl of cuttings and 354 bbl of synthetic-based mud were discharged over a 9-day period. Three sampling trips have been made to the discharge location to collect sediment samples for chemical and biological analysis over a 2-year period. The sediment samples were analyzed for content of organic compounds and barium. On the third trip, infaunal samples were also taken.
Information collected from the chemical and biological analysis is documented and compared to similar field studies performed on oil-based and water-based muds. Sampling techniques and analytical protocols are described to facilitate future studies.
Two years after discharges of synthetic-based cuttings were completed, an area within 50 m of the discharge point continued to exhibit alterations in the benthic community not normally associated with water-based mud discharges. However, the study indicates that polyalphaolefin synthetic-based mud exhibits significant improvements over oil-based mud in terms of removal of organic contamination and minimization of adverse effects on the benthic community.