bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analytical and Experimental Investigation of Flow in a Hydraulic Jar
Authors: McGill Howard L. , Dalton Charles 
Published: December 2007

Abstract
The purpose of this study was to develop a method for predicting the time delay created by metering a fluid through an annular restriction with translational motion of the boundaries. This time delay is utilized to control the opening of valves in various down-hole oilfield tools and forms the basis for the "hydraulic jar". The hydraulic jar is used to give upward impact forces to tubing or other tools that become lodged down-hole. The design of these jars has primarily been by trial and error varying the primarily been by trial and error varying the clearances, fluid viscosities and dimensions of the jar until a satisfactory time delay was achieved. Obviously, a better understanding of the fluid flow characteristics is required to produce designs that are satisfactory and to eliminate the trial-and-error approach. Previous studies of flow in annular spaces were based on constant length of the annular restriction. Any motion of the boundaries of the annular space was confined to a rotational motion, like that encountered in journal bearing design. Consideration of the effect of translational motion of one boundary with respect to the other was necessary in applying this previous work to a time delay device. A prediction method was developed that takes into prediction method was developed that takes into account this relative translational motion. Equations were developed to predict the relative velocity, the flow rate, and the time delay in a concentric annular space. The effect of eccentricity also was included. Experimental data were obtained and closely correlated with the prediction method. This correlation is presented graphically in terms of predicted and actual relative velocities for various annular clearances and pressure drops. This extension provides design equations which predict the performance of the hydraulic jar, thereby predict the performance of the hydraulic jar, thereby eliminating trial-and-error solutions and reducing the development time required for satisfactory designs.
High-Performance Black Oil Computations
Authors: Young L. C. , Hemanth-Kumar K. 
Published: December 2007

Summary
This paper presents the formulation of a black-oil reservoir simulator based on a generalized compositional solution algorithm. To achieve high performance on a wide range of computers, the formulation minimizes the number of calculations while maximizing the calculation rate. The simulator is well-suited for high-resolution and for full-field modeling, where large numbers of gridblocks are needed. The capabilities of the simulator are demonstrated by the solution of a series of realistic test problems, with the largest problem containing more than 1 million gridblocks.
Mixed Five-Point/Nine-Point Finite-Difference Formulation of Multiphase Flow in Petroleum Reservoirs
Authors: Bjorn Ostebo , Hossein Kazemi 
Published: December 2007

Summary
Nine-point finite-difference formulation of multiphase flow in the x-y plane is well-known to reduce grid-orientation effects. This paper proposes a new implicit pressure, explicit saturation (IMPES) formulation that uses implicit pressures for the customary five points of the x-y grid system, explicit pressures for the four points on the diagonals, and explicit saturations for all nine points. This proposed split-operator scheme produces virtually identical results as the standard nine-point formulation of Yanosik and McCracken, but can be easily implemented in existing five-point simulators without requiring any changes in the commonly used solution algorithms, such as the D-4 Gauss. The use of this new technique should enhance the accuracy of existing large-scale IMPES simulators with little increase in storage requirement or computing time. The method can be used with any set of nine-point coefficients and can be extended to fully implicit simulators.
Response Transforms From Comparative Study of Commercial Pulsed-Neutron-Capture Logging Systems
Authors: Saialta G. N. 
Published: December 2007

Summary
Three generations of Schlumberger's Thermal Decay Time (TDTSM) logging devices—viz., TDT-K, TDT-M, and TDT-P—along with an Atlas Wireline PDK-100SM system were run in a Saudi Aramco well. The wellbore (8½ in. with 7-in. casing) penetrated a sequence of clean sand, shaly sand, and shale streaks as exhibited by the openhole natural gamma ray log. The initial wellbore fluid was diesel. The fluid was then changed to brines of 42, 000 and 176, 000 ppm NaCl, respectively. Three repeat passes at a logging speed of 900 ft/hr were obtained by each device for each borehole liquid. As a result of this extensive comparative study, a set of departure curves and mathematical transforms was developed primarily for standardizing the various Schlumberger tools to a common reference logging system and/or borehole environment. The transforms were used beneficially to determine residual oil saturation (ROS) from time-lapse logs in a Saudi Aramco reservoir.
Multiphase Hydrodynamic Model Predicts Important Phenomena in Air-Drilling Hydraulics
Authors: Tian Shifeng , Adewumi M. A. 
Published: December 2007

Summary
Wellbore hydraulics poses difficult problems for the drilling engineer designing a drilling program. Intricate interactions between the drill cuttings, the transport fluid (mud or air), the wellbore, and the drilistring cause the difficulties. Lack of understanding of the physics involved and the lack of a fundamental descriptive capability inhibit the development of an appropriate predictive model. This problem is more apparent in air drilling because only limited data are available on which empirical correlations can be based. This paper addresses wellbore hydraulics with a fundamental hydrodynamic multiphase-flow model. The model incorporates the fundamental physics involved in the pneumatic transportation of solids cuttings in the drillstring/wellbore annulus. This model forms the basis for a predictive tool for the optimal lifting velocity, an essential ingredient in the optimal design of an air-drilling program. Available correlations are, at best, gross approximations; more important, they fail to account for the physical phenomena observed in the pneumatic transport involved in air drilling (e.g., choking and clumping). The model accommodates nonuniformity in particle sizes. Extensive parametric analysis of the system explores the predictability of some of the phenomena associated with air drilling. The model is capable of predicting the pressure-drop profile in the annulus under various simulated drilling conditions. Also, results demonstrate that the model can predict many phenomena associated with lifting cuttings out of the hole during air drilling. Model prediction shows very good agreement with experimental data. Finally, the model possesses good scale-up capability.
Applying the Basic Performance Concepts of Single-Element, Unbalanced Gas-Lift Valves for Installation Design
Authors: Winkler H. W. , Eads P. T. 
Published: December 2007

Summary
This paper outlines a continuous-flow installation design procedure that uses the performance characteristics of singleelement, nitrogen-charged, injection-pressure-operated (IPO) gas-lift valves (GLV's). The Appendix gives a mathematical performance valve model for calculating the gas rate through GLV's as a function of the change in the injection-gas pressure at depth, pioD. Although several simplifying assumptions are made for the model, the calculated performance illustrates realistically the backpressure regulation of a typical unbalanced IPO GLV compared with a fixed orifice. The GLV depth spacing procedure requires matching the injection-gas-rate throughput of the IPO GLV with the total gas required to establish the unloading flowing-production-transfer pressure, pptD, at each valve depth to uncover the next-deeper valve. The GLV performance curve defines the injection-gas rate through an IPO GLV, and the tubing performance curve defines the total gas rate to establish the pptD at each valve depth. This paper gives a detailed installation design example. The GLV and tubing performance curves for spacing the valves are plotted for each valve depth.
A Coupled Rod and Fluid Dynamic Model for Predicting the Behavior of Sucker-Rod Pumping Systems—Part 1: Model Theory and Solution Methodology
Authors: Lekia S. D. L. , Evans R. D. 
Published: December 2007

Summary
Equations are derived from first principles for predicting the behavior of sucker-rod pumping systems including the effects of rod and fluid dynamics, and kinematics of the surface pumping unit. Equations are also developed for both incompressible and slightly compressible fluid flow scenarios. The resulting composite rod and fluid dynamic model is solved using the MacCormack Explicit Numerical Scheme. Example problems used to validate this model are presented in a companion paper.
Solution of Complex Management Problems by Total System Analysis
Authors: Finley Howard F. 
Published: December 2007

Because petroleum industry complexity is increasing exponentially with time, many management problems cannot be solved by traditional methods. An objective, total system analysis may help management make the best decision.

Introduction
The use of total system analysis to solve complex management problems is new. Because it is new it is not well defined and not well understood by many managers. Simply put, it is the analysis of a total system, but this means nothing unless we know what a total system is. There are many kinds of systems: natural, physical, abstract, man-made, military and industrial, to name a few. But for convenience we will limit this paper to business systems. All of our examples will be from the oil industry.
We use the following terms to define a total system.
Total System an on-going process composed of a set of entities with given relationships between the entities and their attributes and with the objective of producing a specific result, given a number of constraints.
Subsystem a component process of a total system. Subsystems may be further subdivided into more detailed subsystems.
Entity a class of objects described by a fixed collection of parameters called attributes. Entities "exist" and have numerical values that describe the state of the system.
Attribute property of an entity -the external manifestation of the way the entity is known. Attributes "describe".
Set a collection of individual entities.
Relationship bonds that link entities and attributes in the system process.
State the complete description of a system's entities, attributes, and relationships at a point in time. System dynamics are represented by changes of state.
Events a change of state that occurs instantaneously at a distinct point in time.
Environment the set of all entities that can influence the system. For practical reasons environments are arbitrarily limited by specified boundaries or otherwise they might be infinite.
Constraint a limitation on the operation of a system.
We can illustrate a total system by a refinery containing such subsystems as an atmospheric distillation unit, a vacuum distillation unit, and a catalytic cracking unit. Some entities of the subsystem "atmospheric distillation unit" are towers, a furnace, heat exchangers, pumps and motors. Attributes of the entity "pumps" are horsepower, rpm and up-time-ratio. A relationship between the furnace and tower T-1 might be, "When the fuel rate to the furnace is increased from 700 to 770 B/D, the inlet temperature of the tower feedstock is increased from 734 to 752F." A system constraint might be, "Throughput is limited to 49,000 B/D by the T-1 bottom pumps."

Business Systems
Business systems that hold interest have several common properties.
1. They are large and composed of many entities.
JPT
P. 275
Design, Installation, and Operation of a Remote Hazard-Warning System in West Texas: A Case Study
Authors: Seanard K. C. , McClurkin C. C. 
Published: December 2007

Summary
A major problem facing operators in the Permian Basin is the hydrogen sulfide (H2S) associated with oil and gas production in populated areas. Population growth in the area has led to the encroachment of the once-small towns into the producing fields. This situation is potentially hazardous in areas of west Texas where the concentration of H2S can range from 5 to 10 mol% of the produced gas. To protect the population living around these wells, it has become necessary, and in some circumstances mandatory, to install early warning systems to inform company personnel of problems on producing leases. This paper describes the process of designing, installing, and operating an early hazard-warning system to monitor the leases operated by Fina Oil & Chemical Co. in the Foster field in Ector County, TX.
Successful Cementing of Shallow Steamflood wells in California
Authors: Goodwin K. J. , Calvert D. G. , Root R. L. , Henderson V. S. 
Published: December 2007

Summary
Successful cementing of shallow casing strings (150 to 400 ft) for steamflood operations in Kern County, CA, has been difficult to achieve. Lost-circulation problems accompanied by cement fallback are common. Ultrasonic cement evaluation logs commonly show the cement sheath to be severely cut with gas (air) and show numerous cases of large gaps in the cement column. Extensive remedial work typically is required for effective completions. Numerous cement formulations, including foamed cement, have been pumped to solve these problems, without apparent or consistent success. A system now has been developed that provides operationally precise low-rate nitrogen metering from commercially available nitrogen cylinders to overcome previous metering problems. Several yard tests were conducted, and 26 wells were cemented with foamed cement with a low-rate nitrogen metering system. Surface-stable foamed-cement systems have been created with nitrogen rates as low as 6.4 scf/bbl and densities as low as 6.5 lbm/gal. Results illustrate that, with proper metering equipment, typical field crews can perform foamed-cementing treatments with minimum equipment. Posttreatment evaluations demonstrate that properly designed and executed foamed-cement treatments virtually have eliminated the lostcirculation problems and gaps in the cement sheath.
Horizontal Well Damage Characterization and Removal
Authors: Frick T. P. , Economides M. J. 
Published: December 2007

Summary
This paper presents conceptual and mathematical descriptions of the damage along and normal to a horizontal well. Expressions for the skin effect that take permeability anisotropy into account are developed. Stimulation methodology, respecting the shape of damage, is presented. Treatment effectiveness, partial stimulation, and corresponding volume and time requirements are quantified.
Acid Refracturing Program Increases Reserves, Cottonwood Creek Unit, Washakie County, Wyoming
Authors: Aud W.W. , Sullivan R.B. , Coalson E.B. , Poulson T.D. , Warembourg P.A. 
Published: December 2007

Summary
This paper presents the results of coupling a reservoir simulator with an acid fracture design program. This model is used to identify program. This model is used to identify refracture candidates and to optimize acid refracturing treatments. Methods used to study treatment efficiency for specific reservoir properties are given for various acid systems.

Introduction
The Cottonwood Creek field in Washakie County, WY, was discovered in 1953 ad produces primarily from the Phosphoria produces primarily from the Phosphoria formation, a low-permeability, dolomite oil reservoir. This reservoir, covering about 60 sq miles, is one of the largest stratigraphic oil columns in Wyoming. Early development of the Cottonwood Creek Unit was concentrated in the updip portion of the field because of good production response obtained from high-permeability streaks. These streaks were originally interpreted as natural fractures. Reservoir modeling ad core data indicate that the reservoir is not naturally fractured. A waterflood was initiated in 1958 in the updip portion of the field, which maintained pressure support to the high permeability streaks. Productivity of these permeability streaks. Productivity of these wells was high ad stimulation was not believed to be necessary. The low-permeability portions of the reservoir, vertically adjacent portions of the reservoir, vertically adjacent to the high-permeability streaks were virtually unswept by the waterflood and contain a large amount of recoverable oil. As development continued in the Cottonwood Creek Unit, less prolific producers were drilled. Because of prolific producers were drilled. Because of the low permeability encountered, most of the wells required fracture stimulation to be commercial.
During 1987, a detailed reservoir and logical engineering study of the Phosphoria formation in the Cottonwood Creek Unit area was initiated to determine whether the producing rate ad ultimate oil recovery producing rate ad ultimate oil recovery could be improved. The study indicated that may wells in the area had short fracture half-lengths. Extensive reservoir simulation indicated that increasing the effective fracture half-length would increase the producing rate ad ultimate recovery. Because of producing rate ad ultimate recovery. Because of these results, a acquisition program was pursued in the area. The most significant pursued in the area. The most significant acquisition was the Cottonwood Creek Unit, acquired Jan. 1, 1989.

Geology
The Cottonwood Creek Unit is located in the Big Horn basin about 8 miles east of Worland. The field produces primarily from the Ervay member of the Permia, Park City formation (Phosphoria), covers about 33 sq miles, and includes 150 oil wells. The Phosphoria reservoir is a stratigraphic trap Phosphoria reservoir is a stratigraphic trap covering roughly 60 sq miles at depths varying between 4,500 and 11,000 ft. The downdip limit is controlled by a oil/water contact.
Well-Test Analysis With Changing Wellbore Storage
Authors: Hegeman Peter S. , Hallford Debora L. , Joseph Jeffrey A. 
Published: December 2007

Summary
This paper presents a model for analysis of changing wellbore storage during well testing. Our model is based on a modification and extension of a model for wellbore phase redistribution. The result is a general solution in Laplace space that can be used to add changing storage to a variety of weill reservoir models. Increasing and decreasing storage cases can be accounted for analytically. We present several field examples to show the application to well tests with changing wellbore storage.
Modeling of Acid-Fracturing Treatments
Authors: Settarl Antonin 
Published: December 2007

Summary
This paper gives the theory and numerical implementation of a comprehensive acid-fracturing model that solves for fracture geometry (2D or 3D), leakoff, heat transfer, and acid transport simultaneously. The acid-transport model integrates a number of features not accounted for in earlier design models: multiple fluids (acids, gels, and foams); acidizing controlled both by mass transfer and rate of reaction; and leakoff, including the effects of matrix acidizing and wormholing. Examples of treatment design illustrate these features. Coupling with reservoir forecasting models gives the ability to optimize the job or compare it with a proppant treatment.
Joint Industry Qualification Test Program for High-Clearance Casing Connections
Authors: Payne M. L. , Asbill W. T. , Davis H. L. , Pattillo P. D. 
Published: December 2007

Summary
As a result of recurrent, costly failures in high-clearance casing connections, several major operators and connection manufacturers developed and executed a joint industry research project to verify connection performance experimentally. The program involved unique procedures for testing both makeup characteristics and structural performance of the connections, identified inadequate connection designs, and qualified a new generation of improved high-clearance connections.
Improved Concentric Workover Techniques
Authors: Frank Wallace J. 
Published: December 2007

The concentric tubing workover rig has alleviated considerably the high cost of offshore well servicing; and dual, triple and quadruple conventional completions in upper zones can be dealt with economically. But there are a lot of problems yet to be solved, and the inventive technologist still can have his field day.

The Concentric Tubing Concept Basic Technique
The offshore concentric tubing rig is a completely self-contained, highly transportable, skid-mounted workover unit that has been designed for offshore workover operations. The concentric technique calls for leaving the production string in place and running small concentric pipe inside the production tubing to perform a variety of workover operations (Fig. 1) perform a variety of workover operations (Fig. 1) requiring a circulating flow path. The primary reason for performing concentric tubing workovers is economic. Savings result from reduced workover time and reduced rig cost by avoiding the necessity to retrieve and re-run the installed well tubing and packers.

Rig Equipment
A typical rig (Fig. 2) consists of drawworks, mast, two triplex plunger pumps, manifolded measuring and mixing tanks, 1-in. nominal tool-jointed pipe, blowout-preventers, and the necessary handling tools, controls and accessory equipment required for workover operations. The hook-load capacity of these rigs varies from 50,000 to 100,000 lb. The rig is broken down into small packages for fast rig-up and for offloading and onloading with small "stiff-leg" platform cranes. A rig breaks down so that it can be handled in 12 to 17 lifts with an 8,000-lb capacity crane.

Evolution of Use
Concentric tubing techniques are a logical extension of wireline permanent-type completion methods, which used a tubing extension landed and retrieved by wireline. A concentric tubing set-up can be described as a tubing extension that reaches all the way to the surface. Continuous tube to the surface, and the rigs specifically designed to handle it, have resulted in the substitution of concentric tubing workovers for many potential, permanent-type well completion workovers.
The widespread application of tubingless completions where only small concentric pipe strings or wireline tools can be used gave additional impetus to concentric techniques. The experience and confidence gained with this technique in tubingless completions had a material influence on the expanding use of concentric tubing in conventional wells.
After these techniques had been proved on land and in straight holes, the economics made their use in offshore directional wells especially attractive. This discussion covers Humble's experience in Louisiana offshore operations where about four or more concentric rigs have operated continuously for over 5 years. In the past 2 years, the level of this work offshore for Humble has increased to as many as 14 rigs.

Offshore Experience

Tubingless Wells and Lower Zones of Conventional Wells
During this time, 287 jobs were completed offshore on tubingless wells and lower zone completions of conventional wells (see Table 1).
P. 401
Impact on Casing Design of Thermal Expansion of Fluids in Confined Annuli
Authors: Adams A. J. , MacEachran Angus 
Published: December 2007

SummaryExisting single-string analysis methods may be inadequate for more difficult casing design problems, such as annular fluid heat-up and platform wellhead thermal growth, which require a multistring (or global) analysis of the whole well system. This paper presents a method for such an analysis and describes a finite-element formulation developed to implement it. The formulation is fully general and is applicable to a wide range of casing-Aubing-design problems.