bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two Errors in Pressure Measurement Using Subsurface Gauges
Authors: Ainsworth W.J. , Hawkins Murray F. 
Published: December 2007

Introduction
In all types of subsurface pressure gauges the extension which occurs in the pressure-sensitive element is a function of the difference between the external (well or calibration) pressure and the internal pressure within the gauge, rather than a function of the external pressure only. The internal pressure is near atmospheric and depends uponthe quantity of air sealed within the gauge at the time of calibration or measurement,the quantity of moisture (liquid water), if any, sealed within the gauge, andthe temperature at which the calibration or well measurement is made.
Part of this correction for the change of internal pressure with temperature is taken care of by the customary temperature coefficient of the gauge. However, part of it is not, and while this portion may be only a few psi, it is nevertheless predictable or preventaple, and should be considered in precision measurements.

Summary
In precision measurements the error introduced by sealing the gauge during a well test at a different temperature and pressure from that of calibration may be corrected for by using the equation presented, or it may be prevented by taking care always to seal the gauge at near calibration conditions. The error introduced by sealing moisture in the gauge may be prevented by taking care to keep moisture out of the gauge, or by removing the moisture by either warming or evacuating the gauge. Both of these errors are independent of the range of pressure measurement and the type of gauge, and are in addition to the usual temperature correction.
Using Parameter Estimation Techniques To Convert Centrifuge Data Into a Capillary-Pressure Curve
Authors: Bentsen R.G. , Anli J. 
Published: December 2007

Abstract
Previously reported techniques for converting basic centrifuge data into a capillary-pressure curve have one serious drawback: they all involve the graphical or numerical differentiation of experimental data. The problems associated with the differentiation of experimental data can be avoided by using the parameter estimation techniques proposed here. The parameter estimation techniques proposed here. The purpose of this paper is to demonstrate The advantages purpose of this paper is to demonstrate The advantages of using parameter estimation techniques for obtaining a capillary-pressure curve from centrifuge data.
Two parameter estimation methods for handling centrifuge data were investigated and compared with a modified form of Hassler's technique for interpreting such data. This investigation indicates that, while Hassler's method and the parameter estimation techniques were equally able parameter estimation techniques were equally able to generate the capillary-pressure curve from centrifuge data, the latter procedures are preferable since they use various integration preferable since they use various integration schemes and, hence, avoid the differentiation problems associated with previously reported problems associated with previously reported methods of data interpretation. Moreover, if the parameter estimation techniques are used, the data can be smoothed and the irreducible water saturation, displacement pressure, and capillary-pressure normalizing parameter can be estimated.

Introduction
The theory for converting experimental data obtained with a centrifuge into a capillary-pressure curve was developed by Hassler and Brunner. The basic equation used in the conversion is
P2 a ci Sn(x) dxP S = cos ---- .....(1)ci n 2 × 21 - ----- sin aPci
wherep 2P = ----- w (re2 − ri2), ci 2
p 2x = ------ w (re2 − r2), 2
and
ricos a = ----- .re
Hassler and Branner were unable to find an analytical solution to Eq. 1, but they demonstrated bow it could be solved by the method of successive approximations. Since this method is very tedious in application, Hassler and Brunner preferred using a simplifying assumption that amounts to setting ri equal to re. This assumption, which the authors considered to be reasonable provided the ratio ri/re was greater than 0.7, resulted in the equation
P ciPci Sn = Sn(x)dx,
0
from which it follows that
d Sn (Pci) = ------ (Pci Sn)................(2)dP
Setting ri equal to re assumes that the length of the core is negligible compared with the radius of rotation of the core. Hoffman has shown that this assumption is unnecessary, and that Eq. 3 should be used to solve for the saturation at each speed level.
2 cos adSnS (P) = -------- (S + P ------)....(3)n ci 1+cos a n ci dPci
Eqs. 2 and 3 can be solved by taking slopes of graphs of Sn and Pci Sn vs Pci.
SPEJ
P. 57
Consistency Check and Reconciliation of PVT Data From Samples Obtained With Formation Testers Using EOS Models
Authors: Kikani Jitendra , Ratulowski John 
Published: December 2007

Summary
Accurate description of hydrocarbon fluids is critical to field development planning including facilities design, recovery efficiencies, secondary recovery processes, and remedial procedures for intervention. Despite this large impact of fluid characteristics on field development, generally a small number of downhole fluid samples are collected. Often they are not representative of the reservoir fluid for a variety of reasons. These include phase separation caused by drawdown during sampling and leakage during recovery and transport.
In this paper we show the utility of a routinely reported piece of data, namely, the tool opening pressure, in a quantitative manner to check the quality of the sampled fluid. The condition of the fluid is modeled by performing an isochoric flash experiment that mimics the actual conditions. A significant discrepancy in modeled and real opening pressure data often suggests leakage. When this method is used, the fluid samples may be approximately reconstructed, multiple fluid samples from the same reservoir may be reconciled, and a consistent phase behavior of the fluid may be determined.
Sulfide Removal and Prevention in Gas Wells
Authors: Hitzman D. O. , Dennis D. M. 
Published: December 2007

Summary
Major problems in oil and gas operations result from the biogenic formation of H2S in the reservoir. The presence of H2S results in increased corrosion, iron sulfide formation, higher operating costs, reduced revenue, and constitutes a serious environmental and health hazard. A new technology that removes and prevents the formation of biogenic H2S has been developed. The technology is based on the addition of low concentrations of a water-soluble nutrient solution, which selectively stimulates the growth of an indigenous microbial population, thereby inhibiting the detrimental sulfate-reducing bacteria (SRB) population, which causes the generation of H2S. This deliberate and controlled modification of the microflora and reservoir ecology has been termed biocompetitive exclusion. This directed alteration of the microbial ecology is achieved by the introduction of a nutrient formulation that favorably influences the dynamics of the reservoir microflora. The treatment system does not require the addition of microbial cultures. Periodic well treatments have been shown to dramatically reduce or completely eliminate sulfide levels and establish control of the system in diverse field demonstrations supported by the U.S. Dept. of Energy. Field data in a variety of reservoirs will be presented that demonstrate the effectiveness of this new approach to treating and remediating wells with high levels of H2S. The versatility and low cost of this novel technology offers the petroleum industry a practical and cost effective methodology for the control of H2S in oil and gas wells.
Analyzing a Multilateral-Well Failure in the East Wilmington Field of California
Authors: Brister A. R. 
Published: December 2007

Summary
As the industry pursues optimum cost drilling techniques, more focus is being applied to multilateral (ML) technology. The presently available literature invariably focuses on the cost and efficiency benefits of drilling ML wells. What is missing in the media, however, are the benefits associated with publication of the negative aspects or costly failures of higher-technology, multiple-lateral projects that require a mechanical tieback, cement, or a pressure seal at the junction of the laterals (i.e., Class 3-, 4-, or 5-type wells, respectively). This paper presents a case study of a Class 4 ML well attempted by THUMS Long Beach Co. in the East Wilmington field of California.
Effect of Pretest Pressures and Temperature on DST Interpretation
Authors: Johns R. T. , Ma Long 
Published: December 2007

Summary
Drillstem tests (DST's) in porous media typically consist of a sequence of production and shut-in periods. Interpretations of DST's are often based on application of the Horner method to the shut-in periods. Such an analysis assumes that the wellbore rate is constant during the production period and that the pressure response during the shut-in is affected only by that production period. For many DST's, however, these assumptions are no longer valid and other interpretation methods are required. For example, prior production and shut-in periods and/or pretest pressures can significantly affect the pressure response of subsequent periods and cause erroneous parameter estimates.
In this paper, we present a new DST semianalytical solution that can account for the effect of pretest pressures, prior test periods, wellbore temperature variations, and other factors such as wellbore storage and skin on the pressure response. The solution is an extension of the solution presented by Correa and Ramey1 who derived a DST solution by writing a single time-dependent wellbore boundary condition. Application of the new solution to example DST data shows that estimates of formation pressure from the Horner analysis can deviate from the true formation pressure by several hundred psia, whereas permeability estimates can differ by a factor of two or three.
Pressure-Volume-Temperature Correlations for Gulf of Mexico Crude Oils
Authors: Petrosky G. E. , Farshad F. 
Published: December 2007

Summary
New empirical pressure-volume-temperature (PVT) correlations for estimating bubblepoint pressure, solution gas-oil ratio (GOR), bubblepoint oil formation volume factor (FVF), and undersaturated isothermal oil compressibility have been developed as a function of commonly available field data.
Results show that these PVT properties can be predicted with average absolute errors ranging from 0.64% for bubblepoint oil FVF to 6.66% for undersaturated isothermal oil compressibility.
Waterflooding Performance Using Dykstra-Parsons as Compared With Numerical Model Performance (includes associated papers 6403 and 6404 and 6407 and 6411 and 6416 )
Authors: Mobarak Salem 
Published: December 2007

Introduction
Multilayered models have been used by a number ofinvestigators to represent heterogeneous reservoirs.Standing et al. calculated coverage and defined thepermeability variation factor in their theoretical study permeability variation factor in their theoretical study of variable-permeability, retrograde-condensatereservoirs undergoing gas cycling. Dykstra and Parsonsadopted the fundamental ideas presented by Standinget al. and developed a method for estimatingwaterdrive coverage factors. Based on experimental datafrom a linear-layered model, Dykstra and Parsonsdeveloped correlation charts relating coverage tomobility ratio and permeability variation for differentwater-oil ratios (WOR). Another chart, based solelyon laboratory data, showed recovery modulus as afunction of coverage. The recovery modulus is givenby
(1)
where
R = fractional recovery of the original oil inplaceSwi = initial water saturationWOR = producing water-oil ratio
The steps used in the Dykstra-Parsons predictionsare outlined in their original paper. Johnsonproposed a simplified method for making proposed a simplified method for making Dykstra-Parsons predictions. He plotted permeabilityvariation against mobility ratio for lines of constantrecovery modulus as given in Eq. 1. Four charts wereconstructed for WOR's of 1, 5, 25, and 100, respectively. Both the Dykstra-Parsons and Johnson chartsshould give the same results. Another modified formof the Dykstra-Parsons method eliminated the needfor graphical correlation to calculate oil recovery.In this modified form, one proceeds with Steps 1through 4 of the standard Dykstra-Parsons methodto calculate coverage. Oil recovery is then computedas follows:
(NP/N) percent pore volume = C(1 - Sor - Swi)............................(2)
(NP/N) percent original oil in place =C(1 - Sor - Swi)/Soi,...................(3)
where
C = coverageSoi = initial oil saturationSor = residual oil saturationSwi = initial water saturationNP/N = fractional oil recovered
The purpose of this note is to present waterfloodperformance for multilayered systems using the performance for multilayered systems using the standard Dykstra-Parsons method as compared with thatpredicted by the modified form using Eqs. 2 and 3 predicted by the modified form using Eqs. 2 and 3 and those obtained by using a numerical model.
JPT
P. 113
Alaska -- Oil and Forget-Me-Nots
Authors: Chatterton C.V. 
Published: December 2007

CHATTERTON, C.V., STANDARD OIL CO. OF CALIFORNIA, ANCHORAGE, ALASKA MEMBER AIME

Abstract
The oil industry singularly provided major justification for Alaskan statehood and continues to play a responsible role in the State's very existence. One out of every three dollars of current State revenue is a direct oil dollar.Alaska offers a safe haven for oil investment, and leasing regulations provide incentive for exploration. The combination of Alaska's climate, terrain and remoteness presents a unique challenge to operators and makes the cost of doing business high. Air and water transportation plays an important role. Alaska's potential has barely been scratched. Offshore drilling offers new hope. Scheduled early completion of a refinery insures that Alaska will be a fully integrated oil state. Also, the State's natural-gas potential is great.

Introduction
Oil men everywhere are interested in Alaska. The frontiersman spirit is kindled by Alaska's everyday challenges. Indeed this spirit is required to encourage the continuing search for oil so necessary to convert this infant state into a major producer of hydrocarbons.Alaska got off to a flying start in 1957 with a major discovery, the Swanson River field. Nearly six years later, private enterprise is still looking for Alaska's second major oil discovery. The success ratio since then has been low; nevertheless, enthusiasm for the oil potential of this great state has been far from diminished. To date, the surface has barely been scratched.This paper reviews the infant years of the industry in Alaska. This baby is continuing to be fed at ever-increasing rates with exploration and development dollars. New operators are continuing to accept the challenge of drilling in Alaska. To better understand the challenge this infant faces, the environment into which the babe was born must be understood. This state is the land of the forget-me-not, Alaska's floral emblem which is the hallmark of friendship and fidelity. Alaska is an enormous, beautiful and challenging country. This is a land of long summer days with its floor carpeted in wild flowers and forget-me-nots.Alaska is vast. In aerial extent, it is nearly one-fifth as large as the "South 48," and with more coastline than the entire Continental United States. It is more than twice the size of Texas with less than 2 1/2 per cent of the population of Texas. In fact, the population density is 0.4 of a person/ sq mile, compared with 36.2 people/sq mile in Texas. The 0.4 figure includes 35,000 Indians, Aleuts and Eskimos out of a total population of 226,000.This thinly populated country is unique. Alaska desperately wanted to become a state. The promise of oil aided in making Alaska eligible for statehood. Quoting Alaska's Governor William Egan, "The discovery of oil was instrumental in providing an economic atmosphere favorable for Statehood".

Understanding Alaska

Geography
Geographically speaking, Alaska consists of over 375 million acres.
JPT
P. 471^
Advanced Sandstone-Acidizing Designs With Improved Radial Models
Authors: Gdanski R. D. , Shuchart C. E. 
Published: December 2007

SummaryWith the intent of encouraging and helping the reader to design a radial model tailored to a particular use, this paper discusses and describes radial models that have proved useful in exploring and simplifying the application of the kinetics of sandstone acidizing. With the recent development of a comprehensive theory for the complete chemistry and kinetics of sandstone acidizing, it was appropriate to develop useful radial models for exploring and simplifying the application of the new technology. These radial models were designed to accommodate both the positive and negative aspects of the recent discoveries. These discoveries included ion-exchange transformation of brines, decomposition of clays in hydrochloric acid, precipitation of fluosilicates, removal of carbonate to prevent the precipitation of complex aluminum fluorides (AlFx's), silica-gel filming, colloidal silica-gel precipitation, precipitation of the various complex AlFx's, mixing between the various stages of the treatment, damage removal, permeability modeling, and skin evolution. Calculations were initially performed with a comprehensive workstation-based computer model so that the magnitude of the various effects could be measured. These calculations showed that many negative effects could be minimized or eliminated by special design considerations. A PC-based model was then written that could help design engineers avoid serious problems when acidizing sandstone formations and provide them with visual guidance to some of the other issues that were relevant. This avoiding problems approach for the PC-based radial model provided a powerful basis for introducing advanced designs for sandstone acidizing that have dramatically improved the success rates of field treatments. In addition to choosing the correct HF fluid to avoid secondary precipitations, considerations for choice of preflushes to condition the formation proved essential. Proper choice of preflush is based on acid stabilities of the clays, carbonate removal, and the avoidance of deep clay swelling. Appropriate acid-preflush volumes help ensure carbonate removal for at least 24 in. and provide sufficient fluid spacing between formation brine and the spent HF fluids at the end of the treatment.
Analysis of Low-Temperature Separation Plants
Authors: Stamm H.E. , McCarty D.G. , Allen D.B. , Moore C.S. 
Published: December 2007

Abstract
A method for calculating the performance of low-temperature separation plants is discussed, and comparisons of calculated recoveries with those observed during field testing of an installation are shown. The ability to calculate plant performance is of considerable value as a variety of possible operating programs can be investigated at little cost.
The close agreement between calculated and observed plant recoveries suggests that with reasonable diligence plant performance can be calculated within generally accepted engineering accuracy. However, as over-enthusiastic employment of calculations can lead to serious error, calculated results should be supplemented with sufficient field or laboratory test data to provide adequate experimental verification.

Introduction
Within the past few years the use of low-temperature separation and stabilization units to increase the recovery of condensate from gas streams has increased greatly. Although the principle of cold separation is simple, the processing that is required to separate the hydrocarbon stream into the gas and liquid fractions resulting in the greatest over-all economy of operation is sometimes complicated, and the equipment used for this purpose is often expensive. Frequently, several hydrocarbon streams of varying (and in many cases, unknown) composition are mixed prior to processing through a plant. As a result, the most desirable operating conditions have not always been selected, and unexpected operating difficulties have developed.
It seems plausible that a better understanding of lowtemperature processing and removal of much of the aforementioned uncertainty can be achieved by replacing rule-of-thumb analyses with convenient and usable calculation techniques. Therefore, the discussion which follows is designed to demonstrate that liquid hydrocarbon recovery resulting from processing light hydrocarbon mixtures through the type of low-temperature and stabilizer equipment commonly encountered in the Gulf Coast area may be calculated with sufficient accuracy for many engineering purposes.
Bundle-Flowline Thermal Analysis
Authors: Zabaras G. J. , Zhang J. J. 
Published: December 2007

Summary
The bundle flowline involves packaging multiple flowlines, control, and injection lines within a single carrier pipe. A bundle is claimed to provide an effective means of insulating flowlines by use of low-cost materials; however, no rigorous heat transfer analysis of bundled flowline systems has been offered by the literature or the vendors. For this reason, the thermal performance of bundle- insulated flowlines has been studied with a general-purpose, finite- element, partial-differential equation solver.
Steady-state and transient cooldown performance were analyzed for six different bundle configurations. Overall heat transfer coefficients for individual flowlines within a bundle have been determined in addition to cooldown performance for different insulation levels and pipe sizes. These results have been compared with results obtained for the simple bundle geometry of a pipe-in-pipe system, and found comparable.
To expedite the calculation of overall heat transfer coefficients for bundle flowlines, simplified heat transfer calculations were developed as an approximation to the finite-element solutions. These approximations are on the average within 5% of the finite- element solution.
Flexible Bit: A New Antivibration PDC-Bit Concept
Authors: Defourny P. M. , Abbassian Fereidoun 
Published: December 2007

Summary
This paper introduces the novel concept of a flexible polycrystalline diamond compact (PDC) bit and demonstrates its capability to reduce detrimental vibration often associated with drag bits. The tilt flexibility, introduced at the bit, decouples the dynamic motion of the bottomhole assembly (BHA) from that of the bit, thus providing a dynamically more stable bit. The paper describes the details of a prototype 8½-in. flexible bit design, laboratory experiments, and field tests, which verify the concept.
Cement Design Based on Cement Mechanical Response
Authors: Thiercelin M. J. , Dargaud Bernard , Baret J. F. , Rodriquez W. J. 
Published: December 2007

Summary
The disappearance of cement bond log response as a result of variations of downhole conditions has been observed in numerous wells. This observation has led to concern about the loss of proper zonal isolation. Stresses induced in the cement, through deformation of the cemented casing resulting from the variation of down-hole conditions, are the cause of this damage.
We present an analysis of the mechanical response of set cement in a cased wellbore to quantify this damage and determine the key controlling parameters. The results show that the thermo-elastic properties of the casing, cement, and formation play a significant role. The type of failure, either cement debonding or cement cracking, is a function of the nature of the downhole condition variations. This analysis allows us to propose appropriate cement mechanical properties to avoid cement failure and debonding. We show that the use of high compressive strength cement is not always the best solution and, in some cases, flexible cements are preferred.