bluuebunny/crossref_metadata_2025_split huggingface dataset:
Review of Air and Gas Drilling
Authors: Cannon George E. , Watson Ralph A. 
Published: December 2007

Abstract
Experimental work with compressed air or gas as drilling fluid has been carried on by Humble in West Texas, South Texas, North Texas, and New Mexico with beneficial results in nearly all instances. During the past three years, gas has been used at certain stages in drilling seven wells and air in nine wells. Penetration of lost returns sections has been facilitated by this method of drilling and, in addition, drilling rates have been greatly increased.
Air or gas may be used to advantage with rotary drilling in areas where formation water is limited, the formation does not slough, and where pressures of fluids which may be encountered are sufficiently low to snake safe operation possible. An injection pressure as low as 65 psi is sufficient when the hole is dry, much higher pressure being required for handling formation water influx, however. Although its application is limited, as mentioned, progress is being made in developing techniques for handling formation water encountered in conjunction with air or gas drilling.

Introduction
The drilling industry in the United States during the past five years has effected a remarkable improvement in footage drilled with no basic or revolutionary changes in method of operation; average footage per rig year has risen from 35,369 ft to 45,200 ft. The average well cost and average footage cost have not been reduced, however, because of increased costs of materials and services. A possibility for reducing over-all costs lies in the further development of new techniques. It is the purpose of this paper to set forth benefits which have been possible through the use of air or gas as a circulating medium in rotary drilling, a technique which is creating considerable interest throughout the industry.
Rotary drilling with air or gas can greatly facilitate operations in wells penetrating sections in which drilling mud would be lost, by effecting reductions in rig time, mud, and casing costs, in many cases being more effective than cable tools. Damage to producing formations can be averted by eliminating contact with drilling mud. Great benefit is also derived, however, from markedly increased penetration rates and bit life as compared to drilling with mud. The following discussion is limited to Humble's experience with air and gas drilling.
Pseudosteady-State Flow Equation and Productivity Index for a Well With Noncircular Drainage Area
Authors: Odeh A.S. 
Published: December 2007

Most reservoir engineering flow-equations and calculations assume radialgeometry. Radial geometry implies that the drainage area of a well is circularand the well is located at the center. In many cases, the drainage area of awell is rectangular, triangular, or some other noncircular shape. Applicationsof equations based on radial geometry to noncircular drainage area could leadto appreciable error. In many wells, pseudosteady-state flow occurs during mostof their productive life. The productivity index (PI) concept is used in apseudosteady-state, depletion-type reservoir to predict the oil wellsperformance as a function of the difference between the average reservoirpressure and expected flowing bottom-hole pressure of the pressure and expectedflowing bottom-hole pressure of the well. The PI concept is not used for gaswells. The most common equations used by the reservoir engineer to describepseudosteady-state flow and productivity index are
.....(1)
.....(2)
and
.......(3)
where
qo = oil production rate STB/D qg = gas production rate, Mscf/D k =effective permeability, md h= thickness, ft
Handil Field: Three Years of Lean-Gas Injection Into Waterflooded Reservoirs
Authors: Gunawan Sugianto , Caié Didier 
Published: December 2007

Summary
The giant Handil field comprises more than 500 hydrocarbon accumulations in structurally stacked and compartmentalized fluvio-deltaic sands. Most of the accumulations consist of a large column of saturated oil underlying a gas cap, trapped in reservoirs with good rock properties, and produced by water injection or strong natural waterdrive.
In 1995 five reservoirs representing nearly one-fifth of the field's total original oil in place (OOIP)—and which had reached their final stage of waterflood development (58% of the total oil in place had already been produced)—were submitted to further development with lean-gas injection to increase the ultimate oil recovery. To date, after 3 years of gas injection, the recovery factor for these five reservoirs has increased by 1.2% of the oil initially in place, and the project is considered both a technical and an economic success.
The predominant drive mechanism with lean-gas injection has been confirmed by field data. The previous decline of oil production has been stopped, and the oil rate is now stabilizing. The main monitoring challenge has been the control of gas cycling for most of the producers, particularly during periods of higher injection rates, to compensate for low injection periods imposed by gas availability.
The very close monitoring of well and reservoir performance, the numerical simulation, and material-balance studies have helped provide a better understanding of the mechanisms involved and have led to a revised and more efficient policy to maximize oil production.
The experience gained and the analysis of this 3-year-old project gives us the confidence to pursue the extension of the lean-gas injection development to other Handil field reservoirs.
Details of In-Situ Foam Propagation Exposed With Magnetic Resonance Imaging
Authors: Wassmuth F. R. , Green K. A. , Randall L. 
Published: December 2007

SummaryThis paper demonstrates the application of magnetic résonance imaging (MRI) to steady- and unsteady-state foam flow in porous media. Foam corefloods with and without surfactant preadsorption are discussed. The MRI instrument proved to be a useful tool in determining the in-situ saturation distributions during foam-flow experiments, with resolutions unmatched by other imaging techniques.
An Approach to Simulating the Effects of Water-Induced Compaction in a North Sea Reservoir
Authors: Cook C. C. , Andersen M. A. , Halle G. , Gislefoss E. , Bowen G. R. 
Published: December 2007

SummaryRock-compaction drive under waterflood re-pressurization has not been accounted for previously in our flow-model studies for a Valhall waterflood. However, field observations from pilot water-floods indicate an increase in permeability with the injection of cool seawater into the chalk formation. Platform subsidence measurements taken during the pilot waterflood also provide evidence of a chalk/water interaction. Laboratory experiments on reservoir core samples indicate an accelerated compaction effect as the flood front passes through the sample. To assess the value of a large-scale waterflood at Valhall, we have developed a new approach to simulate the possible effects of water-induced rock compaction in our black-oil flow models.
Interpretation of Three-Phase Relative-Permeability Measurements by Front Tracking
Authors: Haugse Vidar 
Published: December 2007

Summary
A new algorithm for analysis of laboratory experiments with flow of three phases through a porous medium is presented. The method is based on discrete measurements. Saturation and fractional-flow profiles that exactly match the measured recoveries are constructed from measured average fractional-flow values. The profiles are piecewise constant in the part of the solution that reaches the outlet during the experiment. The total mobility along the saturation path is estimated from the measured pressure drops. Application to synthetic examples and measured data show that the method is a powerful tool to estimate relative permeabilities along the saturation path of an experiment.
Using an Electrochemical Approach for Monitoring Kinetics of CaCO3 and BaSO4 Scale Formation and Inhibition on Metal Surfaces
Authors: Morizot A. P. , Neville A. 
Published: December 2007

Summary
To date, much emphasis on scale-inhibitor evaluation and the study of scale kinetics has been carried out using static beaker tests. This paper describes the use of an electrochemically based technique that allows the extent of scaling on a solid surface to be determined in the presence and in the absence of scale inhibitor. The ability of the technique to provide kinetic information on surface scaling will be demonstrated with two common varieties of scale. A comparison is made between surface- and bulk-scaling kinetics. Finally, the potential for this technique as a method for online monitoring of scale formation downhole will be discussed.
A Simplified Method for Calculating Temperature Changes in Deep Wells
Authors: Romero-Juarez A. 
Published: December 2007

Knowledge of temperature is important when estimating correctly the amount of additives to add to stimulation fluids and for calculating accurately tubing movements and thermal stresses in casing. This paper describes a fast method for determining temperature along the well using a pocket calculator. This simplified method can give the same temperature distributions as the more elaborate method.

Introduction
Temperature is an important parameter that determines the producing possibilities of a reservoir. Many papers with different objectives have been written regarding well and formation temperatures. Several papers focus on the determination of location and distribution of injected fluids in the formation. Other papers investigate the effect of injected fluids on formation temperature.Determination of temperature along the wellbore is important for several reasons. First, we need to know the temperature of the injection or stimulation fluids at the formation face, and second, we must evaluate the linear changes and stresses on tubing caused by the decrease in temperature when a well is converted from producer to injector, or when a well has to be stimulated. Many operating problems occur because of thermal effects: buckling of tubing, casing stress, and troubles when unseating packers. Particularly, after a deep well stimulation, accurate changes in tubing length must be known, since this may be decisive for a successful treatment. Moss and White, and Ramey, conducted important studies on temperature in injection wells. Ramey's paper has become a classic and many studies dealing paper has become a classic and many studies dealing with temperature effect on pipe movement refer to this paper.The effect of well temperature and pressure on stress and pipe movement is discussed by Matson et al., Lubinsky et at., and recently by Hammerlind . These and other papers where calculation of well temperature is necessary (as in Ref. 11) usually refer only to Ramey's study and do not give enough detail to apply the method easily. Even when information is complete, such as in Matson et al., it is heavily condensed and calculations are very difficult for most field engineers. A method for performing these calculations quickly would be helpful performing these calculations quickly would be helpful when evaluating well-temperature profiles for both injection and producing wells. Calculations using this method could be performed with a pocket calculator.This study relies a great deal on Ramey's paper and on data from Ref. 1.

The Simplified Method - Well Stimulation
In 1961, Ramey solved (with certain assumptions) the problem of distribution of transient temperature along a problem of distribution of transient temperature along a wellbore. For injection wells, the solution is expressed by the following equations, which may be adapted to the case of stimulating wells down tubing.
JPT
P. 763
Collecting Human-Factors Data From Accidents and Incidents
Authors: Gordon Rachael , Flin Rhona , Mearns Kathryn 
Published: December 2007

SummaryTo investigate human and organizational factors in offshore accidents, two human-factors incident reporting forms were developed and evaluated. The Open Reporting Form (ORF) contained 11 open questions and the Comprehensive Reporting Form (CRF) contained 166 questions/potential causal categories. Both forms were tested on five U.K. offshore installations where personnel involved in an incident were asked to complete one. Using statistical techniques, the form with more structured questions was found to provide 66% more information than the participating company's existing reporting form. Results of the research are described focusing on potential benefits for the offshore oil industry.
Candidate and Chemical Selection Guidelines for Relative Permeability Modification (RPM) Treatments
Authors: Mennella Aniello , Chiappa Luisa , Lockhart Thomas P. , Burrafato Giovanni 
Published: December 2007

Summary
Water shutoff treatments with polymers that selectively reduce the water permeability can be effective at reducing water production from hydrocarbon wells that cannot be treated with conventional approaches. This paper describes the elaboration of understanding-based rules for candidate and chemical selection to guide the application of this technology in the field. These rules are based on an analysis of the principal operative issues and on experimental and simulation studies that explore the physical and chemical mechanisms governing treatment efficacy.
A Dynamic Plunger Lift Model for Gas Wells
Authors: Gasbarri Sandro , Wiggins Michael L. 
Published: December 2007

Summary
Many low-volume gas wells produce at suboptimum rates because of liquid loading caused by an accumulation of liquids in the well-bore that creates additional backpressure on the reservoir and reduces production. Plunger lift is an artificial lift method which can use reservoir energy to remove these accumulated liquids from the wellbore and improve production. Lacking a thorough understanding of plunger lift systems leads to disappointing results in many applications. This study develops a plunger lift model that couples the dynamic nature of the mechanical plunger lift system with the reservoir performance. The model takes advantage of previous work and incorporates frictional effects of the liquid slug and the expanding gas above and below the plunger. The model considers separator and flowline effects and includes modeling of transient production behavior after the liquid slug has arrived at the surface. An improved understanding of plunger lift dynamics can lead to improved efficiency, increased production and recovery, and extended well life.
Oil-Based Muds for Reservoir Drilling: Their Performance and Cleanup Characteristics
Authors: Davison J. M. , Jones M. , Shuchart C. E. , Gerard C. 
Published: December 2007

Summary
This paper evaluates the performance of a standard oil-based mud (OBM) to drill horizontal wellbores, concentrating on its formationdamage characteristics and the flow-initiation pressures (FIP's) required for production to flow through the filter cake. For heterogeneous reservoirs, damage is relatively low in low-permeability rocks, but the FIP is high. Conversely, for high-permeability rocks, the FIP is low but formation damage is relatively high. If the drawdown pressure available from the reservoir is low, the scenario exists where inflow will occur predominantly from the higher-permeability formations, which could be damaged badly, but little inflow will occur from relatively undamaged lower-permeability rocks. In terms of maximizing production, this is obviously a less-than-optimal scenario.
Evaluations of cleanup fluids were conducted to gauge their effect on lowering the FIP of OBM filter cakes. Various fluids were screened for their mud-removal performance, which would indicate potentially good OBM "chemical breakers." Mud parameters such as oil:water (O:W) ratio, base-oil type, and emulsifier content all affected the efficiency of the cleanup fluids. The best cleanup fluids were used then in a series of core tests to evaluate their effectiveness in reducing the filter-cake FIP. Reductions between 25 and 40% were possible, although parameters such as soak time and overbalance pressure were critical to their success.
Performance Evaluation of a Mature Miscible Gasflood at Prudhoe Bay
Authors: McGuire P. L. , Spence A. P. , Redman R. S. 
Published: December 2007

Summary
This paper summarizes the acquisition, conventional and compositional core analysis, and reservoir-simulation history match of a core taken roughly 300 ft from a production well in the most mature area of the Prudhoe Bay Miscible Gas Project (PBMGP). Compositional analysis of the core yielded a great deal of in-situ enhanced oil recovery (EOR) performance data and provided insights that could not be obtained from routine core analysis or production data. Fine-gridded reservoir simulations yielded a good match of the offset well-production rates and the observed compositional behavior of the core. The simulations and core data showed a complex layered displacement with alternating intervals of stripped and enriched oil. The data showed that roughly 70% of the cumulative EOR came from reducing the residual oil saturation near the injection well. The remaining 30% was caused by oil swelling.
The Magnetic-Resonance While-Drilling Tool: Theory and Operation
Authors: Prammer M. G. , Drack E. , Goodman G. , Masak P. , Menger S. , Morys M. , Zannoni S. , Suddarth B. , Dudley J. 
Published: December 2007

Summary
The first Magnetic-Resonance-Image Logging-While-Drilling (MRI-LWD*) tools have been built and field tested. The hardware was designed to provide data that are compatible with the Magnetic Resonance Imaging Log (MRIL®) wireline tool in terms of processing and interpretation. This paper discusses the theory of robust MRIL measurements in the drilling environment and reviews the theory of 7 relaxation time measurements. We report on the results of a field test in the Gulf of Mexico. The MRI-LWD device logged the entire total depth (TD) run from casing to TD and provided additional hydrocarbon-typing data in wiping mode over the target zones. Wireline MRIL data and conventional logs were used to verify the MRI-LWD measurements.
Evaluating Hydraulic Fracturing in Cased Holes With Cross-Dipole Acoustic Technology
Authors: Tang X. M. , Patterson D. , Hinds M. 
Published: December 2007

Summary
A cross-dipole technology was used to evaluate a carbonate formation in southeastern New Mexico to determine fracture trends in a waterflooded environment. The measurements were first made in open hole, then in cased hole before and after fracture stimulation. The cross-dipole data were processed to find the amount of shear-wave anisotropy and the associated azimuth. The results demonstrate that stimulated fractures create a substantial anisotropy and a well-defined azimuth behind casing. More important, by evaluating the anisotropy magnitude and azimuth from the cased-hole data, we can determine the fracture extent along the borehole and its azimuth in the formation. The fracture extent is also consistent with that from a radioactive tracer measurement. The results of this study suggest that cross-dipole acoustic logging is an effective technology for cased-hole fracture stimulation evaluation.
DDTW—A Method for Gas Reservoir Evaluation Using Dual Wait-Time NMR and Density Log Data
Authors: Thern Holger F. , Chen Songhua 
Published: December 2007

Summary
Accurate estimates of porosity, fluid saturations, and in-situ gas properties are critical for the evaluation of a gas reservoir. By combining data from a dual wait-time (DTW) nuclear magnetic resonance (NMR) log and a density log, these properties can be determined more reliably than by either of the data alone.
The density and NMR dual wait-time (DDTW) technique, introduced in this paper, is applicable to reservoirs where the pore-filling fluid consists of a liquid phase and a gas phase. The low proton density of the gas phase causes a reduction in the NMR signal strength resulting in underestimation of the apparent porosity. The polarization for different wait-times depends on the spin-lattice relaxation time of each fluid and may cause additional NMR porosity underestimation. The density log, on the other hand, delivers a porosity that is overestimated because of the presence of a gas phase. These data, together with known correlations for gas properties, yield a robust approach for the gas-zone porosity, ϕ, and the flushed zone gas saturation, Sg,xo. DDTW also derives gas properties including the in-situ gas density, ρg, as well as the two NMR-related properties, hydrogen index, IH,g, and spin-lattice relaxation time, T1g. Two field examples illustrate the method, and an error propagation study shows the reliability of the technique.
Relative Permeability Measurements for Post-Waterflood Depressurization of the Miller Field, North Sea
Authors: Naylor Peter , Fishlock Terence , Mogford David , Smith Robert 
Published: December 2007

SummaryThis paper describes a determination of critical gas saturations and relative permeabilities relevant to the depressurization of the Miller field. A series of reservoir-condition coreflood experiments and associated numerical simulations is described. Three experiments were conducted with aged Miller core and fluids at 120°C. Each was comprised of a waterflood at about 414 barg, followed by depressurization at different rates. The laboratory data included extensive three-phase in-situ saturation measurements that were used to derive gas relative permeabilities through the simulations.The rate-dependent critical gas saturations varied between 0.06 and 0.21, and gas relative permeabilities of the order of 0.0001 were deduced. These laboratory results are consistent with published data and suggest that conventional Corey-type gas relative permeabilities are an order of magnitude too large and do not represent the depressurization process.