bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concentric Completions of Oil and Gas Wells
Authors: Harper G.M. 
Published: December 2007

Introduction
This paper discusses the use of 1 ¼-in. tubing placed concentrically inside the normal flow string in both oil and gas wells. The use of this extra string provides an annular space which can be employed to perform a number of functions.
The Union Oil Co. of California is probably one of the few companies still completing dual oil and gas wells concentrically, where feasible, rather than using parallel strings of tubing; i.e., Union uses the annulus between tubing and casing to flow the upper zones and the tubing annulus to flow the lower zones.
In view of the economics, further consideration should be given to concentrically completing dual oil wells before deciding to incur the extra expense of larger hole, larger casing sizes and two strings of tubing required for parallel duals. Particularly this is true where past history of the two zones is available.

Application to Oil Wells
Numerous oil wells have been completed in this manner and have produced over a million bbl of oil on the lower zone and three-quarters of a million bbl on the upper zone over the past 17 years. In view of this history, it is hard to justify to management the extra cost of parallel string, dual completions. Of course, it is fully realized that concentric duals have a number of disadvantages. They are impractical where the wells are completed in open water and are subject to marine damage or where there is a need for artificial lifting of both zones. Also, operational problems arise in controlling items such as paraffin accumulation and sand production. However, with the development of new tools, techniques and materials over the past few years, some of the problems which made this type of dual completion so unattractive can now be alleviated.
In one of the old fields, numerous wells were completed dually with 2-in. tubing inside of 5 ½-in. casing, producing from depths of approximately 6,000 ft. Natural water encroachment and declining reservoir pressure began to affect the upper zones in these wells, resulting in a need for artificial lift and higher gross rates in order to maintain the oil allowables. Experience on other wells in this zone also showed that at gross rates above 300 B/D, sand production became a problem. The lower-zone performance history showed that bottom-hole pressure was not declining because of a strong water drive and would not require any artificial lift for a number of years.
A Dedicated Production Support Vessel For Offshore Operations
Authors: Chong Yong Yin , Ibrahim Mohammad Isa bin 
Published: December 2007

Abstract
A dedicated support vessel for production providing facilities for stimulation, nitrogen service, endless coiled tubing and production testing, was used successfully by Brunei Shell to service offshore wells.
Four years of experience showed the tremendous flexibility and versatility of the vessel in an area where wells and fields are scattered. The vessel has shown to be a profitable resource for repairing problem wells to restore production. Indirectly, much rig time has been saved as a result.

Introduction
Brunei Shell has six oil/gas producing fields offshore. Offshore production started in the mid sixties and has been the main activity of production started in the mid sixties and has been the main activity of Brunei Shell's production. The development of offshore fields is very active and has grown into a complex network of structures and pipelines linking the wells to the oil terminal and the Brunei Liquified Natural Gas plant. The Headquarters of Brunei Shell are located in Seria, which is plant. The Headquarters of Brunei Shell are located in Seria, which is also the location of the onshore oil field (Figure 1).
The reservoirs development are all sandstone layers in complexly faulted anticlines. Offshore production at the end of 1982 was about 144,000 b/d of oil and 900 MMscf of gas.
At present, there are 5 tenders, 1 jack-up and 1 semi-sub operating offshore Brunei waters. On average, about 40 new wells per year were completed offshore for the past 3 years and about 15 wells were worked over per year. A production support vessel complements the offshore drilling per year. A production support vessel complements the offshore drilling resources.

TECHNICAL ENVIRONMENT
Brunei Shell has about 500 connected wells offshore scattered in six fields at present. The majority of the wells are drilled from 12-slot platforms. There are a number of satellite wells which are supported by small jackets.
The wells are usually multi-zone completions with dual production tubing (Figure 2). All the oil bearing reservoirs are sandstone formation ranging in depth from 1000 feet to 12000 feet. Gravelpacks are extensively used for sand exclusion. Active wells have specific offtake requirements. In many a case, problems develop (impairment, sand, mechanical etc.) and in order to meet drainage objective, problem wells will have to be serviced.
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Low-Viscosity Base Fluid for Low-Toxicity Oil-Mud Systems
Authors: Boyd Phil A. , Whitfill Donald L. , Carter T. S. , Allamon J. P. 
Published: December 2007

Summary
The use of a new low-toxicity oil for drilling-fluid systems is presented. The low-viscosity, low-aromatic oil has undergone extensive laboratory and toxicity testing with favorable results. In addition, a number of field tests have been conducted to evaluate the use of this oil in oil-based muds, water-based muds, and spotting fluids. These tests were very successful and showed excellent performance of the oil for each application. Evidences of improved penetration rates (ROP's), reduced mud-treatment costs, and better borehole stability are all characteristic of this low-viscosity, low-aromatic oil in low-toxicity, oil-based mud systems.
Practical Use of Recent Research in Multiphase Vertical and Horizontal Flow
Authors: Brill J.P. , Doerr T.D. , Hagedorn A.R. , Brown K.E. 
Published: December 2007

ABSTRACT
A recent correlation for multiphase vertical flow by Hagedorn and Brown1has been used to examine the effect of numerous variables such as pipe size, gas-liquid ratio, liquid flow rate, liquid viscosity, liquid surface tension, oil API gravity, water cut, etc., on flowing pressure gradients.
Most previous correlations were derived by using a form of the generalenergy equation which assumed negligible changes in kinetic energy. Undercertain flow conditions this can lead to serious errors in predicting pressuretraverses. Examples of traverses calculated both with and without the kineticenergy term are included here.
The Chew and Connally correlation for calculating change, in viscositywith changing pressure and temperature has been extended so that the effect ofa changing viscosity with depth on pressure gradients can also bepredicted.
Examples illustrating the effect of tubing size show the importance ofthis correlation in determining pipe sizes for initial well completions. Limitations on production rates in small pipe sizes from excessive frictionlosses can be predicted with greater accuracy.
The combined use of a vertical-flow correlation with a horizontal-flowcorrelation provides a method for determining the maximum flow rate possiblefrom both flowing and gas-lift wells.
Examples are included to illustrate application of the combined use ofvertical and horizontal-flow correlations in optimizing production rates andminimizing excessive costs from over injection of gas in gas-liftwells.

INTRODUCTION
The problems of multiphase vertical and horizontal flow are immediatelyencountered in any producing well. Fig. 11 shows three stages ofproduction: flow in porous medium, vertical flow and horizontal flow. All threestages affect the production rate from a well.
If we are confronted with a particular well and consider only the variablesinvolved in the vertical and horizontal stages of Fig. 1, we should be capableof calculating the flowing bottom-hole pressure necessary to produce aparticular flow rate. A change in any of the variables results in a newsolution to the problem.
Recent approaches in developing horizontal and vertical-flow correlationshave improved to the extent that the solution can now be obtained with moreconfidence than previously.
A Note on the Application of the Theory of Coherence to Surfactant Flooding
Authors: Saneie S. , Yortsos Y. C. 
Published: December 2007

Summary
Previous studies have shown that in the absence of dispersion, a surfactant flooding process is amenable to a simplified solution by the method of coherence. The development of the solution requires the construction of composition paths that are obtained numerically by the integration of ordinary differential equations. In this paper, we show that in the particular case when all tie lines in the triangular phase diagram originate from a single point on the w,o axis, the construction of the composition paths can be considerably facilitated, because the tie lines obey the condition λ1 = constant (contact discontinuity). It is shown that this exceptional case corresponds to a phase equilibrium relationship of the form (CV32CV11- CV12CV31)/CV31-CV32)=K. This relationship was originally proposed to describe the thermodynamics of concentrated solutions. The connection of this relationship to a generalized Hand-plot model is also discussed.
Design of Chemically Balanced Polymer Drilling Fluid Leads to a Reduction in Clay Destabilization
Authors: Griffin J. M. , Hayatdavoudi A. , Ghalambor A. 
Published: December 2007

Summary
Many water-sensitive shale formations destabilize when contacted by a drilling fluid. This can lead to hole sloughing, stuck pipe, and balled downhole assemblies. If the chemical activity and chemical compounds of the shale are analyzed, then a drilling fluid can be formulated with at least an equivalent chemical activity so that fewer shale cations are removed from the shale by the drilling fluid. Activity of the designed fluid was calculated on the basis of the Debeye-Huckel activity theory. Comparison of the formulated fluid with oil-based muds was conducted with the roller oven and one-dimensional (ID) swelling tests. The formulated fluid produced a combination of electrolytes that yielded more favorable results than did additions of potassium chloride alone.
The procedure for designing a fluid to inhibit swelling for a particular shale is the central focus of this research. The laboratory investigation for developing a stabilizing polymer electrolyte is applied to the Wasatch shale. The technique requires formation samples beforehand and, therefore, has application for both developmental drilling and completion-fluid design.
An Investigation Into Stratified Co- and Countercurrent Two-Phase Flows
Authors: Johnston A. J. 
Published: December 2007

Summary
This paper investigates theoretically and experimentally certain stratified co- and countercurrent two-phase flows in circular pipes that have not been studied adequately. The theoretical analysis produced semiempirical relationships based on the momentum-balance concept. These relationships were then experimentally evaluated with two fluid systems of significantly different density ratios. It is suggested that the equations that correlated these results can be accepted for general use. An example is presented for a certain natural-gas/condensate application.
Accuracy of JBN Estimates of Relative Permeability: Part 2—Algorithms
Authors: Tao T. M. , Watson A. T. 
Published: December 2007

Abstract
We develop algorithms that can be used for computer implementation of the Johnson, Bossier, and Naumann (JBN) method for estimating relative permeabilities from displacement experiments. The developed algorithms differ in the method used to calculate derivatives of measured data. The Monte Carlo error analysis developed in Part 1 of this paper (Pages 209–14) is used to evaluate the performance of the computer algorithms.
Evaluation of Waterflood Prospects
Authors: Callaway F.H. 
Published: December 2007

Introduction
The historical background of water flooding is well known to most engineers associated with the petroleum industry. The earliest water floods were accidental in nature resulting from improperly plugged wells or casing leaks. The obvious benefits of these accidental floods soon encouraged the operators to inject water intentionally. The early waterflooding techniques were thoroughly developed and standardized long before even the most elementary concepts of reservoir mechanics were understood. Under these circumstances, the evaluation of waterflood prospects was strictly a matter of analogy and application of "rules of thumb." If a successful water flood had been conducted in a certain sand in a certain area, operators would presume that a nearby field producing from the same zone could be flooded with similar results.
Use of analogy and rules of thumb had obvious limitations, as is apparent from the rather frequent unsuccessful waterflood attempts. Reliance upon such methods is still surprisingly heavy even today. Modern reservoir engineering enables us to determine the range of reservoir conditions which will result in favorable response to waterflood efforts, and also to delineate the range of conditions under which water flooding will be of doubtful success. By means of relating the various reservoir parameters involved to the results obtained from water floods, a more reliable set of experience factors can be obtained and the uncertainties involved in water flooding greatly reduced.
As is illustrated herein, there are a number of reservoir factors which have a profound influence upon the success of a waterflood project and unfavorable values for any one or two of these factors can result in complete failure of a flood, even though other factors may be quite favorable. It is hoped that this discussion of the effect of various reservoir parameters upon waterflood results will, if nothing else, point out the severe limitations of the rules of thumb by which so many decisions to water flood have been made.
In order to illustrate the manner in which the various reservoir factors operate and their relative importance, it has been necessary to assume a certain set of hypothetical reservoir conditions and investigate the effect of varying one or two of the factors independently. It must be emphasized that the values for waterflood recovery efficiency derived herein are of no real significance except for those specific conditions assumed and must not be used directly for the purpose of evaluating any given waterflood prospect. The term "waterflood recovery" as used herein refers to the increase in recovery over and above that which would be obtained by producing a field to its economic limit by primary means. In the case of a flood initiated before all of the primary oil has been produced, the recovery from the date of inception of a flood is the sum of the remaining primary recovery plus the "waterflood recovery" as defined herein.
A Test for Detecting Rock Property Nonuniformities in Core Samples
Authors: Watson A. T. , Kerig P. D. , Otter R. W. 
Published: December 2007

Abstract
Homogeneous core samples are needed for EOR experiments. We have devised a simple test for detecting the presence of nonuniformities in cores. The test consists of measuring the pressure drop across the core during a two-phase immiscible displacement experiment. We show that for a constant injection rate, the pressure drop will be linear with time provided that the core is homogeneous. In situations for which the initial section of the core is homogeneous, but the properties are not uniform in a latter section of the core, the location of the position where the rock properties first change may be approximately determined. The effect of heterogeneities on the pressure-drop profile is demonstrated with analytical solutions and laboratory experiments.
Heavy-Wall Production Tubing Design for Special-Alloy Steels
Authors: Payne M. L. , Hurst D. M. 
Published: December 2007

Summary
Critical wells require a comprehensive design philosophy for downhole tubulars. This paper describes novel design techniques used on four key tubing-design tasks on a 23,000-ft [7010-m], high-pressure, offshore gas well: material selection, tubing sizing, threaded-connector qualification, and field installation planning. The in-depth engineering approach combined stringent material and threaded-connector qualifications with new tubing-sizing methods and thorough installation planning. Standard tubing-sizing methods were unacceptable because of conservatism about erosional velocity and stress analysis inaccuracy. Proper stress analysis of the alloy required consideration of triaxial stress states, anisotropy of mechanical properties, and temperature weakening of yield stress.
Kinetic Study of the Decomposition of Surfactants for EOR
Authors: Angstedt H. P. , Tsao H. 
Published: December 2007

Summary
The effect of temperature, pH, surfactant purity, and air on the decomposition rate of two classes of surfactants typically used in steam EOR processes has been investigated. With synthetic alkylaryl sulfonates, isolation and characterization of the hydrocarbon reaction products established that the principal reaction is desulfonation of the surfactant. The kinetics of the decomposition of certain alkylaryl sulfonates under carefully controlled pH and temperature conditions are discussed and compared with the behavior observed for α-olefin sulfonates (AOS's) under the same conditions. The synthesis and decomposition of key pure isomeric alkylaromatic sulfonates of known structure led to a mechanistic description of the decomposition reaction. An explanation for the differing stability of alkylaromatic sulfonates and AOS's at high temperatures and at differing pH is suggested.
An Evaluation of Lignosulfonate as a Sacrificial Adsorbate in Surfactant Flooding
Authors: Hong S. A. , Bae J. H. , Lewis G. R. 
Published: December 2007

Summary
A study was conducted to investigate the feasibility of using lignosulfonate as a sacrificial agent in the surfactant flooding process. An analytical technique based on high-performance liquid chromatography (HPLC) analysis was used to determine the concentration of lignosulfonate and petroleum sulfonate. Lignosulfonate and petroleum sulfonate adsorption isotherms were established and used to assess the sacrificial effect of lignosulfonate. A simple model to describe the ion exchange in the presence of lignosulfonate was developed. This model includes the association of cations with lignosulfonate.
The main results of this study are as follows. First, surfactant loss can be reduced significantly (&gt;50% reduction) by pretreatment with a lignosulfonate preflush. However, no significant reduction is obtained when lignosulfonate is incorporated with the surfactant slug. Second, more cations are exchanged from the rock in the presence of lignosulfonate. This enhanced cation exchange is a result of the association of divalent cations with lignosulfonate. Third, lignosulfonate causes dissolution of soluble minerals to a much greater extent than brine or petroleum sulfonate, producing undesirable bivalent cations. Finally, the brine tolerance and optimal salinity of petroleum sulfonate are not greatly affected by lignosulfonate. From these laboratory results, we conclude that lignosulfonate has potential as a sacrificial adsorbate for surfactant flooding.
Interference Between Constant-Rate and Constant-Pressure Reservoirs Sharing a Common Aquifer
Authors: Sageev Abraham , Horne Roland N. 
Published: December 2007

Abstract
A practical pressure transient analysis method is presented for interpreting interference between two oil fields or an oil field and a gas field sharing a common aquifer. One oil field is approximated as a constant-rate line source. The other interfering field is represented by a finite-radius circular source producing at constant rate or constant pressure.
A rigorous application of the superposition principle is discussed, making use of a new model where a constant-rate line source produces exterior to a circular boundary. Both constant pressure and impermeable internal boundaries are considered.
Dimensionless pressure drop curves for both boundary conditions are presented. For the case of a line source producing near a constant-pressure internal boundary, dimensionless curves for the instantaneous rate and the cumulative injection from this internal boundary are given. These curves may be used to forecast the actual injection/production rate and the cumulative injection/production at the interfering reservoir as a function of time.
Computerized Analysis of Thermal Recovery Well Test Data
Authors: Barua Jawahar , Horne Roland N. 
Published: December 2007

Summary
The thermal recovery of oil requires large investments of time and money. Well tests are a relatively easy way to monitor this expensive process until breakthrough occurs at producers, and they can be used to find the volume (but not the shape) of the swept zone.
This paper discusses the application of automated type-curve match to such well tests. A comparison with the best of present methods, i.e., the pseudosteady-state method, shows that automated type-curve match proves to be better in the determination of swept zone radius when mobility ratio is not high or when multiple flow rates have occurred. The application of automated type-curve match to two field examples is demonstrated.
Comparison of K-Value Calculation Methods in Compositional Steamflood Simulation
Authors: Hong K. C. , Hsueh Liming 
Published: December 2007

Summary
The speed and accuracy of compositional steamflood simulation were compared for four K-value calculation methods: the Antoine equation, table look-up, the Peng-Robinson equation of state (PR-EOS), and the Hong-Makhlouf modification of Wilson's equation. These methods were used with a compositional steamflood simulator to model light-oil steamfloods in three- and one-dimensional (3D and 1D) reservoir models. The results indicate that the table look-up and the Hong-Makhlouf modification of Wilson's equation are the most preferred methods to use in terms of both speed and accuracy of computation. While the PR-EOS method is the most accurate, it fails to converge for certain problems and takes twice as much computing time to do the same simulation as the other methods. The Antoine equation method is not accurate for high-volatility oils and hence should not be used for those oils.
This paper describes how the four methods are used in compositional steamflood simulation and discusses the advantages and disadvantages of each method.
Solubility of Silica in Alkaline Solutions: Implications for Alkaline Flooding
Authors: Southwick J. G. 
Published: December 2007

Abstract
The expected loss of useful alkalinity caused by the slow dissolution of silica from pure quartz sand is shown for some typical alkaline flooding solutions (about 1 % NaOH or 1.25% sodium orthosilicate) to be only about 10 to 20%. This conclusion is based on the observation that alkaline solutions equilibrate with quartz and on the methodology proposed here for determining the useful alkalinity of a solution. Furthermore, the dissolution of quartz in alkaline flooding can be eliminated by the use of solutions saturated in silica with respect to quartz. Such formulations may be useful in controlling the erosion of the wellbore and gravel pack.