bluuebunny/crossref_metadata_2025 huggingface dataset:
Gas Prices and Gas Volumes The Current Posture
Authors: Jacobs John C.
Published: December 2007

By 1990, the U.S. demand for gas could fall short of the supply by as much as 8 trillion cubic feet. Given proper governmental regulation, this supply could be met by importing liquefied natural gas or by gasifying coal, lignite and oil shade.

Introduction

Natural gas has become the single most important fuel produced in the U.S., and the use of it in other parts produced in the U.S., and the use of it in other parts of the world is increasing rapidly. This form of energy is the subject of far-reaching decisions in business, financial and governmental circles, and the continuation of its importance among fuels rests upon the supply available. Supply, in turn, resolves into a physical availability component (how much is there?) and a market incentive component (how much will users be allowed to pay?).

It is the burden of this paper to show (1) that many people want - and will pay for - comfort in forms people want - and will pay for - comfort in forms that can be satisfied only by increasing quantities of gas; (2) that adequate supplies of gas can be made available to meet this demand from sources domestic and foreign, natural and synthetic; and, (3) that the major question as to satisfying these wants is whether the governmental authorities will break with those past practices that have produced today's impasse in past practices that have produced today's impasse in world affairs and foreign trade and, instead, follow policies that will permit the necessary formation of policies that will permit the necessary formation of capital and freedom of commerce.

Demand

All authorities agree that there is a substantially increasing demand for gas in the U. S. Estimates of future gas consumption are shown in Table 1, which shows gas use increasing at the compound rate of 2.8 to 4.2 percent/year between 1965 and 1985. The estimates are made by highly experienced people who have taken into account oil reasonably measurable influences. With few exceptions each estimate assumes a continuation of past trends in birth rates, increasing efficiency of utilization, growth in GNP and relative prices of competitive fuels, with an adjustment for the prices of competitive fuels, with an adjustment for the inroads of nuclear power. But it is also assumed that communism will be contained without war, that the rich nations will continue to grow richer relative to the poor nations, that waste disposal (including that of nuclear power plants) will not become a limitation, and that air pollution control will not materially affect gas usage. One can only pause and remember the estimates of future whale oil use that undoubtedly were being made in 1859 as Colonel Drake spudded his well in Pennsylvania, or estimates of gas for lighting use that were being made in New Jersey when the local gas company threatened Thomas Alva Edison about his delinquent bill an action in part responsible for the electric light bulb.

JPT

P. 563
A Comprehensive Mechanistic Model for Upward Two-Phase Flow in Wellbores
Authors: Ansari A. M. , Sylvester N. D. , Sarica C. , Shoham O. , Brill J. P.
Published: December 2007

A comprehensive model is formulated to predict the flow behavior for upward two-phase flow. This model is composed of a model for flow-pattern prediction and a set of independent mechanistic models for predicting such flow characteristics as holdup and pressure drop in bubble, slug, and annular flow. The comprehensive model is evaluated by using a well data bank made up of 1,712 well cases covering a wide variety of field data. Model performance is also compared with six commonly used empirical correlations and the Hasan-Kabir mechanistic model. Overall model performance is in good agreement with the data. In comparison with other methods, the comprehensive model performed the best.
Completion Techniques for Horizontal Wells in the Pearsall Austin Chalk
Authors: Pope C. D. , Handren P. J.
Published: December 2007

Oryx Energy Co. used three basic completion techniques and various combinations of them to complete 20 horizontal wells in the Pearsall Austin Chalk. The completion method selected is based on a general set of guidelines. Additionally, equipment selection and various types of workover operations are reviewed.
New Perspective on Oil and Gas Separator Performance
Authors: Powers M. L.
Published: December 2007

This paper presents an improved method of predicting gas capacities of horizontal separators that properly accounts for the effects of the L/d ratio and the depth of the gas/oil interface. A theoretical basis for calculating oil capacities also is presented. Equations are developed for calculating optimum proportions with either gas or oil capacity governs equipment selection.
Fluid Mechanics of the Drilling String
Authors: Koch William M.
Published: December 2007

To help field men select the proper nozzle and pump liner size, a pocket calculator has been designed which will predict the performance of the hydraulic system.

Although the use of the drilling fluid to control and condition the hole is well known, the present use of high jet velocities has brought purely hydraulic problems to much wider attention. To help the field man, the design of a simple pocket calculator to solve some of these problems on the drilling rig was undertaken.

Calculation of the output of the slush pumps was straightforward; but experience has shown that a direct reading flowmeter would be much more satisfactory.

The energy losses in the down string were calculated by the Hazen-Williams equations with the Hazen-Williams roughness coefficient adjusted to allow for the restrictions in various types of tool joints.

Losses in the drill bit nozzle were found to vary as the 1.96 power of the flow and, inversely, as the 2.19 power of the exit area. A presently accepted production nozzle exhibited an efficiency of 70 per cent.

Losses in the return annulus are difficult to account for accurately; and, in this case, a rough estimate was used. This is practicable since these losses are a minor part of the total.

In view of these assumptions, the overall accuracy of the calculator is of interest. Based on a comparison of calculated values and actual mud pressure gauge readings, the average error was +4 per cent; and 70 per cent of the examples were in the ±15 per cent error bracket. This accuracy is sufficient to give useful answers to the field man.

Introduction

The importance of the drilling mud as a medium to control formation pressure and the stability of the walls of the hole is well appreciated. However, the present widespread use of high rates of flow has focused attention on the drilling mud as a conveyor of energy to the drilling bit. In an effort to use this energy efficiently, field men have been clamoring for information that would enable them to select a bit nozzle properly matched to their hydraulic systems. It became apparent that some quick method of estimating the performance of the hydraulic system was necessary.
Diverless Flowline Tie-In Techniques for the DISPS Project
Authors: Bruton D. A. S. , McKeehan D. S. , Metcalf Peter
Published: December 2007

This paper describes the Diverless Subsea Product System (DISPS) project design, development, and dry prototype testing of three diverless tie-in systems for application to 4- to 12-in.-diameter flowlines in water depths of 1, 200 to 2, 500 ft. Full-scale simulation of direct pull-in, lateral deflection, and vertical stab techniques with two tools for flowline pull-in and connection was undertaken and design limits were established.
History and Performance Prediction of Umm Farud Field, Libya
Authors: Allen W.W. , Herriot H.P. , Stiehler R.D.
Published: December 2007

Libya's Umm Farud field is unique in that it will have been discovered, developed, and depleted within 10 years. Computer simulation, used to select optimum injection and production rates, predicted a 21-percent recovery of original oil in place, and field data indicate that performance is reflecting the prediction.

Introduction

The purpose of this paper is to present a summary of the engineering data relating to the Umm Farud field. The production history of the reservoir is sufficient to allow at least a partial evaluation of the reservoir during the primary depletion and early injection phases. phases. In recent years, there has been an increasing interest in reservoir simulation techniques utilizing computers. In this study, the water injection distribution during secondary recovery operations has been predicted by computer simulation. The predictive predicted by computer simulation. The predictive portion of the simulation covers a relatively short portion of the simulation covers a relatively short period of 3 to 5 years. This short field fife lends itself period of 3 to 5 years. This short field fife lends itself to an economic re-evaluation of the reservoir mechanism and the simulation procedures.

Field Development

The Umm Farud field was discovered by Phillips Petroleum Co. in Nov., 1962. Fig. 1 shows the field's Petroleum Co. in Nov., 1962. Fig. 1 shows the field's location in North Central Libya on Concession 92. The discovery well, A-1, was drilled on a seismic closure about 17 miles from the nearest production. The well was completed in the Dahra "B" dolomite at 3,035 ft and the Mabruk "A" dolomite at 3,212 ft. Initial potential from both zones was 2,285 bbl oil.

Subsequent drilling established additional production from two zones in the Bu Charma "B" limestone production from two zones in the Bu Charma "B" limestone at 2,700 ft and 2,744 ft. All zones are commingled down hole. The field development was completed with the drilling of seven oil producers, six injection wells, and three water supply wells.

All wells are completed with casing set through the producing intervals. The producing wells are equipped producing intervals. The producing wells are equipped with submersible pumps capable of lifting 2,500 BFPD.

JPT

P. 570
Production Logging as an Integral Part of Horizontal-Well Transient-Pressure Test
Authors: Ahmed Usman , Badry Robert A.
Published: December 2007

This paper discusses a horizontal-well transient-pressure-test analysis method with emphasis on the use of production-interval and -profile data. The technique significantly enhances interpretation quality and answer uniqueness. The technique can be applied to specialized plots and to type-curve history-matching methods.
High Volume Pumping with Sucker Rods
Authors: Byrd J.P.
Published: December 2007

Recent studies have shown that often large fluid volumes can be lifted by sucker rods with great effectiveness from shallow to medium-depth wells. Wherever feasible, significant redaction in cost of elevating a barrel of fluid may be realized by the operator. The advent of longer stroke units with improved geometry, larger speed reducers and bottom-hole pumps, as well as the new high-strength sucker rods, make high volume rod pumping a practical and economical achievement. Past applications of this type generally have been considered only for bottom-hole centrifugal pumps. This paper reviews some field studies and emphasizes the practicality of high volume production with sucker rods.

Introduction

A century ago the almost universal mechanism for artificially lifting fluid in an oil well was the standard rig-front. A wooden walking beam drove a string of hickory sucker rods, often called "well poles", as many as ten 15-in.- strokes/minute with the maximum tensile stress of the rods about 12,800 psi. The bottom-hole pump was cast iron or brass with the barrel approximately 1 1/4-in. in diameter, and the well depth ranged from 500 to 1,000 ft. The torque capacity of the band wheel and flat-belt speed reducer ran only a few thousand inch-pounds, and the unit's structural capacity was from 1,000 to 1,500 lb.

Today, the structure of a modern pumping unit with its 240-in. maximum stroke reaches higher than the wooden drilling and servicing derricks of those early days. Its structural capacity exceeds 47,000 lb, with a torque rating greater than 2.5 million in. lb. The plunger diameter of some bottom-hole pumps (casing-type) runs as high as 5 3/4 -in. Perhaps the greatest improvement is in the sucker rod, which now has a tensile stress of some 140,000 psi. Today practice sucker rod pumping approaches 13,000 ft, and capacities of 5,000 and 6,000 B/D from shallow to medium depths are handled with ease. Volumes as high as 9,500 B/D are entirely practical with modern sucker rod pumping equipment.

Comparing the modern sucker-rod system with its counterpart of 100 years ago produces some startling figures. The structural capacity of the modern unit has increased nearly fifty-fold, the torque capacity perhaps a thousand-fold, the area of the bottom-hole pump over 20 times; the stroke length nearly twenty-fold; and maximum rod tensile stress nearly 12 times. With the increased stroke length, even the maximum rate of polished rod travel per minute has increased five or six times. Since all of these are compounding increases, the sucker-rod pumping unit of today has the capacity for producing massive fluid volumes from relatively great depths.
A Note on Pressure Buildup Curves
Authors: Ramey H.J.
Published: December 2007

In 1954 Matthews, Brons and Hazebroek presented a method for correcting extrapolated buildup pressures on a Theis or Horner-type plot to static pressure. Matthews, Brons and Hazebroek considered buildup in a large number of geometric reservoir shapes with wells at various locations within a particular shape. In 1961 Brons and Miller pointed out that the presence of pseudo-steady state was indicated for the various shapes at long producing times, and that simple flow equations involving a producing times, and that simple flow equations involving a shape factor could be written for this condition. In 1965 Dietz extended this idea to show that static pressure could be found on the extension of the buildup straight line at a dimensionless time of

where A = drainage shape area, CA = shape factor and other symbols are SPE standard. Dietz work generalized the older Miller-Dyes-Hutchinson buildup method to geometric shapes other than circular. As stressed by Dietz, the method assumed that the well had been produced to pseudo-steady state prior to shut in. Neither pseudo-steady state prior to shut in. Neither Matthews-Brons-Hazebroek nor Dietz cataloged the actual buildup curves involved in the various shapes, although a few cases were shown as examples.

The purpose of this article is to present the Miller-Dyes-Hutchinson type of pressure buildup curves for most of the Matthews-Brons-Hazebroek shapes. As would be expected, assymetric location of a well in a particular drainage shape may lead to unusual bends in the pressure buildup curves. Because it is currently becoming practice to infer reservoir heterogeneities from the shape of the buildup curve, it appears useful to be aware of anomalies which may be a result of well location and drainage shape.

Figs. 1 through 4 present Miller-Dyes-Hutchinson pressure buildup curves for the rectangular shapes considered. pressure buildup curves for the rectangular shapes considered. Symbols used are SPE standard; It refers to elapsed time after shut-in. Fig. 1 shows buildup curves for a square reservoir shape with three different well locations. The heavy lines are the buildup curves. Curves 1 and 2 are similar; it would be impossible to detect the effect of movement of the well from an actual buildup curve. Curve 3, however, has a peculiar bend at a dimensionless buildup time of about 0.02. This bend could be misinterpreted as the result of a general fracturing in the reservoir as studied by Warren and Root.

Another interesting result is indicated by the dashed lines on Fig. 1. These lines represent the extrapolation of the initial straight line, and have the usual slope of 1.151. The intersection of the dashed lines with the ordinate at zero occurs at a dimensionless buildup time equal to the reciprocal of the shape factor Ca, for each shape. Note that the shape factors shown are the modified ones reported by Earlougher et al.

P. 119
Considering Wellbore Friction in Planning Horizontal Wells (includes associated papers 28646 and 29095 )
Authors: Seines Knut , Aavatsmark Ivak , Lien Svein Christian , Rushworth Philip
Published: December 2007

The importance of friction pressure loss within the completed section of horizontal wells, under some reservoir conditions, has been analyzed. The phenomena were studied both analytically and experimentally with sub sequent implementation in a commercially available 3-D,3-phase reservoir simulation model. Based on simulation studies, criteria for the selection of appropriated imensions for horizontal wells under different reservoir conditions are outlined. A field example from the Troll Field offshore Norway where these results were applied during the planning of a horizontal test well, is presented.

Introduction

The Troll field, located in 300m water depth offshore Norway (Fig. 1), contains 0–26 m thick oil rims sandwiched between a large gas cap and active aquifers. In the westernmost fault block of the field, the Troll WestOil Province, the oil zone is at its thickest; 22–26 m. The oil in place of this province is estimated at 121x10 6 Sm3.The reservoir contains several highly permeable, unconsolidated sands separated by low permeability micaceous sands. Impermeable calcite cemented horizons with imperfectly known spatial disposition and extensions occur within the high permeability sands. The oil production from Troll may be limited by gas coning, resulting in a limited available drawdown for the well. Since the oil rim is only 22–326 m thick, the drawdown can only be in the range of 1.5 to 2 bar in order to avoid the production of free gas-cap gas. The recoverable oil in the Troll West Oil Province is located in high-quality sands with permeabilities ranging from3000 to 10 000 md, so high liquid rates were expected(Fig. 2). With the combination of limited drawdown and high rates, wellbore friction pressure loss was considered to be of importance [1].The subject has been studied analytically by Dikken [1]. However, implementation of the effect of horizontal well friction in simulators with subsequent application for well planning and design purposes has previously not been reported. Horizontal well friction was given due attention during the planning of a 500 m horizontal well in the Troll field. The well was drilled and completed in late1989, and has been on production since January 10th 1990. The cumulative oil production as of early June1990 was 500 000 Sm [2].

Background

The Troll field covers an area of 700km2 . The estimated gas and oil in place is 1670x10 9 Sm3 and 615x10 6 Sm3respectively (Fig. 3). Two main north-south bound faults divide the field into three provinces: Troll West Oil Province, Troll West Gas Province and Troll East(Fig. 3).Concession Block 31/2 (Fig. 3), operated by A/SNorske Shell, was awarded in 1979. Blocks 31/3, 31/5, and 31/6 were awarded in 1983 with shared operatorship between Norsk Hydro a.s, Den norske stats oljeselskapa.s, and Saga Petroleum a.s.
The Use of Interpolation to Obtain Shape Factors for Pressure Buildup Calculations
Authors: Earlougher Robert C.
Published: December 2007

As pointed out by Brons and Miller, it is convenient to use a shape factor to calculate drainage region static pressures from pressure buildup tests. If the well is produced pressures from pressure buildup tests. If the well is produced at a constant rate long enough for pseudo steady-state conditions to be reached prior to shut-in, the drainage region average pressure may be calculated from

..........................................(1)

where:

p = drainage region average pressure,

p* = shut-in pressure linearly extrapolated toinfinite shut-in time on a plot of p vs log[ ], A = drainage area of the well, and

CA = shape factor.

Shape factors have another useful significance. Brons and Miller showed that

..........................................(2)

where the constant y is the exponential of Euler's constant and has the value 1.781. Eq. 2 is the general flow equation that describes the pseudo steady-state flow for any bounded (closed) shape.

Both Brons and Miller, and Dietz have tabulated values for the shape factor C, for various drainage region shapes and well locations. Nevertheless, a value of C, often is needed for a system that is not included in the tabulations. In this case the techniques of Ramey and of Earlougher et al. can be used to calculate the needed shape factor. However a simpler method may be used in many instances. This method consists of making a plot of C, against some shape-determining quantity (such as well location or length to-width ratio of a rectangular system) and graphically interpolating.

Fig 1 And 2 are examples of such plots. Fig. 1 shows the shape factor plotted against well location for three rectangular systems. To assume the accuracy of this plot, values of C4 have been calculated for a few points not given in the Dietz table. Actually, the figure could be constructed without calculating these Ca values if slightly inaccurate results were acceptable, or if only well locations for 0.25 less than x less than 0.5 were of interest.

P. 449
Analytical and Experimental Investigation of Flow in a Hydraulic Jar
Authors: McGill Howard L. , Dalton Charles
Published: December 2007

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

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

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

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.
A Two-Phase Flow-Splitting Device That Works
Authors: Jones Jeff , Williams R. L.
Published: December 2007

Laboratory and field tests of wellhead steam quality have shown that typical methods of regulating phase distribution are unsatisfactory. This paper describes a successful project to develop a distribution device that is economical to install and yields the desired phase split.
Multiphase Hydrodynamic Model Predicts Important Phenomena in Air-Drilling Hydraulics
Authors: Tian Shifeng , Adewumi M. A.
Published: December 2007

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

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

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

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

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

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

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

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

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

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.
Impact on Casing Design of Thermal Expansion of Fluids in Confined Annuli
Authors: Adams A. J. , MacEachran Angus
Published: December 2007

Existing 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.
Practical Evaluation of Rock-Bit Wear During Drilling
Authors: Faÿ Hubert
Published: December 2007

One key factor in minimizing drilling costs is understanding rock-bit behavior, particularly the bit-tooth wear, at the well bottom. This paper describes a method that gives information about bit-tooth wear during drilling. The basic concept requires the following torque equation that is a function of weight on bit (WOB), W: TOB=uW + vW2. This equation is determined from measurement-while-drilling (MWD) data, and knowledge of v provides the bit-wear state, given the close correlation between these two parameters. Laboratory tests and field results have confirmed the validity of the concept quantitatively. In today's harsh economic environment, field applications of the method should lead to more-accurate decisions about when to pull out bits and, thus, should reduce drilling costs.
An Environmentally Safe Water-Based Alternative to Oil Muds
Authors: Enright Dorothy P. , Dye William M. , Smith Martin F.
Published: December 2007

A mechanism describing the onset of bit balling is given. On the basis of this mechanism, a new copolymer/polypropylene glycol (COP/PPG) water-based drilling fluid was developed. The properties of this fluid are described, and field test comparisons are made with water- and oil-based fluids
Cumulative Bioluminescence - A Potential Rapid Test of Drilling Fluid Toxicity: Development Study
Authors: Wojtanowicz A. K. , Shane B. S. , Greenlaw P. N. , Stiffey A. V.
Published: December 2007

A new rapid test of drilling fluid toxicity is based on the spontaneous bioluminescence of Pyrocystis lunula, an easy-to- culture alga that vigorously responds to shear stress (mixing) by emitting a sharp burst of light. In contrast to other bioluminescence methods, a cumulative flux of light is measured with a photomultiplier that eliminates the effect of exposure time on test results. Light quenching, caused by the presence of a toxicant, results in the dose/response relationship (DSR) typical for the enzymatic reaction kinetics. The Michaelis-Menten (dissociation) constant is used as a direct measure of toxicity. The evaluation study involved multiple experiments with 60 samples of drilling fluids from the U.S. gulf coast, as well as such typical toxicants as diesel oil, mineral oil, and chrome lignosulfonate (CLS). The results of the test error analysis and comparisons with the Microtox and Mysid shrimp assays are reported.
The Transition from Domestic to International Oil Operations
Authors: McLean John G.
Published: December 2007

The general strategies that Continental Oil Co. has pursued in developing its exploration, production, refining, pursued in developing its exploration, production, refining, and marketing positions overseas in the face of strong, deeply-entrenched competition are discussed. Attention is given to the contributions that the so-called "newcomers" can make to the oil economies of the producing and consuming countries in which they operate. A commentary on the political, economic, and competitive outlook for oil operations in the Eastern Hemisphere is also given.

Introduction

Continental Oil Co. is only one of many American companies that have made the transition from domestic to international oil operations during recent years. When the history books for the third quarter of the 20th century are written, they will mark an era for American business-an era in which we became for the first time a nation of international industrialists, merchants, traders, and financiers.

In the oil industry alone, some 200 or more companies have gone outside the U. S. during the past 10 or 15 years. Continental's experience has not necessarily been representative of the entire group, or any substantial segment thereof, and I certainly would not want to present it as such. My purpose is to discuss solely our own experience and our own viewpoints. I shall try to answer four questions:

- Why are we trying to develop a strong position overseas?

- What policies are we following? position overseas?

- What policies are we following?

- What has been the impact of the newcomers like us on the oil business abroad?

- What do we see ahead?
The Genesis of Torsional Drillstring Vibrations
Authors: Brett J. F.
Published: December 2007

Inherent drilling characteristics of polycrystalline diamond compact (PDC) bits alone can be sufficient to excite severe torsional drillstring vibrations. The work presented here augments previous findings that torsional vibrations can result from the drilling characteristics of the bit itself. Laboratory and field torsional measurements are compared with model results to show that the observed vibrations can be explained by a reduction in PDC bit torque as rotary speed increases. These torsional vibrations are important because they can cause drillpipe fatigue and may be severe enough to damage the bit. The model also is used to pinpoint possible solutions to the problem.