bluuebunny/crossref_metadata_2025_split huggingface dataset:
How Bit Profile and Gauges Affect Well Trajectory
Authors: Menand S. , Sellami H. , Simon C. , Besson A. , Da Silva N. 
Published: December 2007

SummaryThe importance of wellbore deviation is well recognized by the drilling industry. An analysis of a drilling system's directional behavior must include the directional characteristics of the drill bit. This paper presents a comprehensive analysis of the directional behavior of polycrystalline diamond compact (PDC) bits, including the effect of bit profile, gauge cutters, and gauge length. Numerical simulations as well as laboratory tests have been carried out to better understand the mechanisms of PDC bit deviation and to evaluate the most important parameters affecting the directional behavior of PDC bits.The analysis presented in this paper shows that each part of the PDC bit (profile and active and passive gauges) plays a major role in its walking tendency and steerability. A quantitative evaluation of how these factors contribute to well trajectory (inclination and azimuth) is given.For the first time, a full-scale directional-drilling bench was built to measure the walking tendency and steerability of PDC bits. The results obtained demonstrate that the bit profile, gauge cutters, and gauge length have a significant effect. A 3D theoretical rockbit interaction model was developed to reproduce the drilling test results.
History Matching in Two-Phase Petroleum Reservoirs
Authors: Watson A. T. , Seinfeld J. H. , Gavalas G. R. , Woo P. T. 
Published: December 2007

Abstract
An automatic history-matching algorithm based on an optimal control approach has been formulated for joint estimation of spatially varying permeability and porosity and coefficients of relative permeability functions in two-phase reservoirs. The algorithm uses pressure and production rate data simultaneously. The performance of the algorithm for the water-flooding of one- and two-dimensional hypothetical reservoirs is examined, and properties associated with the parameter estimation problem are discussed.
Comparison of Sensitivity Coefficient Calculation Methods in Automatic History Matching
Authors: Dogru Ali H. , Seinfeld John H. 
Published: December 2007

Abstract
The efficiency of automatic history matching algorithms depends on two factors: the computation time needed per iteration and the number of iterations needed for convergence. In most history matching algorithms, the most time-consuming aspect is the calculation of the sensitivity coefficients – the derivatives of the reservoir variables (pressure and saturation) with respect to the reservoir properties (permeabilities and porosity). This paper presents an analysis of two methods – the direct and the variational – for calculating sensitivity coefficients, with particular emphasis on the computational requirements of the methods.
If the simulator consists of a set of N ordinary differential equations for the grid-block variables (e.g., pressures) and there are M parameters for which the sensitivity coefficients are desired, the ratio of the computational efforts of the direct to the variational method is
R = N ( M + 1 ) N ( N + 1 ) + M .
Thus, for M&lt;N the direct method is more economical, whereas as M increases, a point is reached at which the variational method is preferred.
Investigation of Three-Phase Regions Formed by Petroleum Sulfonate Systems
Authors: Blevins Creed E. , Willhite G. Paul , Michnick Michael J. 
Published: December 2007

Abstract
The three-phase region of the Witco TRS 10–80 sulfonate/nonane/isopropanol (IPA)/2.7% brine system was investigated in detail. A method is described to locate phase boundaries on pseudoternary diagrams, which are slices of the tetrahedron used to display phase boundaries of the four-component system.
The three-phase region is wedge-like in shape extending from near the hydrocarbon apex to a point near 20% alcohol on the brine/alcohol edge of the tetrahedron. It was found to be triangular in cross section on pseudoternary diagrams of constant brine content, with its base toward the nonane/brine/IPA face. The apex of the three-phase region is a curved line where the M, H + M, and M + W regions meet. On this line, the microemulsion (M*) is saturated with hydrocarbon, brine, and alcohol for a particular sulfonate content. A H + M region exists above the three-phase region, and an M + W region exists below it.
Relationships were found between the alcohol concentration of the middle phase and the sulfonate/alcohol and sulfonate/hydrocarbon ratios in the middle phase. These correlations define the curve that represents the locus of saturated microemulsions in the quaternary phase diagram. Alcohol contents of excess oil and brine phases also were correlated with alcohol in the middle phase.
Pseudoternary diagrams for sulfonates are presented to provide insight into the evolution of the three-phase region with salinity. Surfactants include Mahogany AA, Phillips 51918, Suntech V, and Stepan Petrostep™ 500. Differences between phase diagrams follow trends inferred from comparisons of equivalent weights, mono-/disulfonate content, optimal salinity, and EPACNUS values.
Effect of Temperature on Surfactant Adsorption in Porous Media
Authors: Ziegler Victor M. , Handy Lyman L. 
Published: December 2007

Abstract
The effect of temperature on the adsorption of a sulfonate surfactant and a nonionic surfactant onto crushed Berea sandstone was studied by both static and dynamic techniques.
Static experiments were conducted over a temperature range from 25 to 95 °C to define temperature-sensitive rock/surfactant systems and to establish the shape of the equilibrium isotherm. Dynamic experiments served to reinforce the findings of the static tests and extended the temperature range for sorption to 80°C. This is a typical steamflood temperature. A mathematical model that incorporates the mass transport, thermal degradation, and rate-dependent adsorption of the surfactant represented these dynamic results. The model was used to determine the effect of temperature on the sorption rate constants.
Mineral dissolution at elevated temperatures has been found to cause precipitation of the sulfonate. Adsorption of the nonionic surfactant decreased with an increase in temperature at low concentrations, whereas the opposite was true at high concentrations. This has favorable implications for a low-concentration injection scheme. When performing static adsorption experiments, care had to be taken because of the poor thermal stability of the nonionic surfactant.
Combined Analysis of Postfracturing Performance and Pressure Buildup Data for Evaluating an MHF Gas Well
Authors: Bostic James N. , Agarwal Ram G. , Carter Robert D. 
Published: December 2007

This paper presents a method of combining postfracturing performance datawith postfracturing buildup data for analysis on the same constant-ratetype curve. This combination of buildup and production data isaccomplished through the use of the superposition principle. The method allows the use of production data that contain occasional shut-in periods of long duration.

Introduction
Low-permeability (less than 0.1 md) gas wells mustbe stimulated with massive hydraulic fracture (MHF)treatments to be commercial. Once a well has beenstimulated, it is important to determine the lengthand conductivity of the resulting fracture asaccurately as possible to predict rates and reserves andevaluate the effectiveness of the stimulation.
Two types of data normally are available toperform the required analysis. The first type isroutinely collected data such as gas flow rates and flowing wellhead pressures. The second type of datais that from specially designed tests such as pressurebuildup tests. There are various methods availablefor analyzing both kinds of data, but all of themethods have certain limitations.
Current analysis techniques are satisfactory forfinite-flow-capacity fractures when formation flowcapacity kh is known and sufficient production datawithout shut-in periods is available to perform atype-curve match as shown by Cinco et al. andAgarwal et al. However, one disadvantage of MHFtreatments is that they often cause the stimulatedwells to produce large volumes of load water(returning fracture fluids) for several weeks ormonths. Production data obtained during thiscleanup period usually are not applicable fortype-curve matching purposes with the currently available type curves. Since type curves normally are plottedon a log-log scale and exhibit the most character atsmall dimensionless times, the loss of the early-timeproduction data disproportionately reduces thelength of the available data band and is critical to theproblem of obtaining a satisfactory match.
The purpose of this paper is to present a method ofcombining the production and buildup test data sothat their concurrent analysis overcomes some of thelimitations of either individual data set. Thesuperposition principle is used in this combination, and the analysis of the resulting data set shouldprovide a more accurate result than previouslypossible. This combination has the potential togenerate field data curves of sufficient length that theshape of the data curve may be sufficiently definitive to determine formation flow capacity by type-curveanalysis. Additionally, this method makes it possibleto use production data that contain occasional shut-in periods of long duration.
JPT
P. 1711＾
Analysis of Pressure Data From Vertically Fractured Injection Wells
Authors: Bennett Curtis O. , Reynolds Albert C. , Raghavan Rajagopal 
Published: December 2007

Abstract
This study investigates the flowing and shut-in pressure behavior of a fractured well located in a square drainage region with the outer boundary at a constant pressure. The fracture plane lies on one of the diagonals of the square. The report shows how to analyze pressure data for a five-spot pattern when the fracture orientation is most favorable (from the viewpoint of sweep efficiency). Comparisons are made with studies in the literature that assume an unfavorable fracture orientation. Fracture orientation must be considered in the analysis of pressure data for the following conditions: (1) small fracture-penetration ratios, (2) large flowing times prior to shut-in, and (3) large values of fracture flow capacity.
Insights into the application of type-curve analysis to estimate drainage volumes are presented. Claims in the literature regarding the determination of the drainage volume by type-curve matching appear to be unrealistic.
An Equation of State Compositional Model
Authors: Coats Keith H. 
Published: December 2007

Abstract
This paper describes an implicit, three-dimensional formulation for simulating compositional-type reservoir problems. The model treats three-phase flow in Cartesian (x-y-z) or cylindrical (r-θ-z) geometries. Applicability ranges from depletion or cycling of volatile oil and gas condensate to miscible flooding operations involving either outright or multicontact-miscibility.
The formulation uses an equation of state for phase equilibrium and property calculations. The equation of state provides consistency and smoothness as gas- and oil-phase compositions and properties converge near a critical point. This avoids computational problems near a critical point associated with use of different correlations for K values as opposed to phase densities.
Computational testing with example multicontactmiscibility (MCM) problems indicates stable convergence of this formulation as phase properties converge at a critical point. Results for these MCM problems show significant numerical dispersion, primarily affecting the calculated velocity of the miscible-front advance. Our continuing effort is directed toward reduction of this numerical disperson and comparison of model results with laboratory experiments for both MCM and outright-miscibility cases.
We feel that the implicit nature of the model enhances efficiency as well as reliability for most compositional-type problems. However, while we report detailed problem results and associated computing times, we lack similar reported times to compare the overall efficiency of an implicit compositional formulation with that of a semi-implicit formulation.
Experimental Study of Severe Slugging in a Two-Phase-Flow Pipeline - Riser Pipe System
Authors: Schmidt Zelimir , Brill James P. , Beggs H. Dale 
Published: December 2007

Abstract
Slug flow was studied in a simulated, offshore, pipeline-riser pipe system. Two distinct slug flow patterns were identified: severe slugging and normal slug flow. Severe slugging, characterized by generation of slugs ranging in length from one to several riser pipe heights, occurs at low gas and liquid flow rates and for negative pipeline inclinations. A mathematical model was developed for severe slugging. Results agree well with experimental data. Choking was found to be an effective method of eliminating severe slugging.
Biological Oxidation of Dissolved Compounds in Oilfield Produced Water by a Field Pilot Biodisk
Authors: Palmer L.L. , Beyer A.H. , Stock J. 
Published: December 2007

Summary
Besides small amounts of suspended oil, oilfieldproduced water after conventional treatment cancontain dissolved organic and ammonium compounds that may preclude its discharge into the oceanbecause of environmental protection regulations.Two field pilot studies in southern California established the technical feasibility and cost ofremoving these dissolved compounds by biologicaloxidation in a biodisk. Effluent from the two pilot plants complied with all requirements of Californialaw.

Introduction
Despite the lack of documented adverse effects fromnormal petroleum operations, environmentalprotection regulations have been adopted that limitthe offshore discharge of produced water. The WaterQuality Control Plan for the Ocean Waters ofCalifornia (CWQCP), adopted in 1972 andamended in 1978, regulates all domestic andindustrial wastewaters discharged within California's3-mile (5.5-km) zone. The CWQCP includes effluentlimits on oil and grease, dissolved phenols, dissolvedammonium compounds, and toxicity to marine life.U.S. guidelines proposed in 1975 for the onshore petroleum industry by the Environmental ProtectionAgency would require"zero pollutant discharge"inside the 3-mile (5.5-km) zone by 1983.
Previous publications have reported thecompositions of oilfield produced waters. Workdone by Chevron shows that typical produced watersfrom the U.S. west coast and the Gulf of Mexico, after oil removal by gravity separation and/orflotation, have compositions ranging from 20 000 to135 000 g/m3 TDS, 45 to 130 g/m3 ammonia (as N), and 0.1 to 3.0 g/m3 phenols (as C6H5OH). Conventionaloilfield water-separation processes are notdesigned to remove these dissolved compounds, andother treatment processes are needed where disposalrestrictions on such compounds exist.
Biological oxidation uses harmless bacteria, algae, fungi, and protozoa to convert dissolved organic andammonium compounds into water plus CO2 andnitrates/nitrites, respectively. A field pilot studyof an aerated lagoon conducted at Carpinteria, CA, demonstrated the feasibility of biological oxidationfor removing dissolved compounds such as ammoniaand phenols from produced waters. This paperdescribes two field pilot studies conducted insouthern California that demonstrated, for the firsttime, the feasibility of another biological oxidationtreatment process - the rotating biological surface(biodisk).
JPT
P. 1136^
Calcite Control in In-Situ Uranium Leaching Process
Authors: Yan T.Y. 
Published: December 2007

A method has been developed to control the problem of calcite deposits inthe in-situ uranium leaching process using carbonates as the lixiviant. Achemical inhibitor is added to the calcium-supersaturated lixiviant (andother process streams) at critical locations in sufficient quantity to forma metastable solution of calcite so that the lixiviant can pass throughcritical areas without depositing calcite.

Introduction
Uranium values can be recovered from undergrounddeposits by open-pit or underground miningfollowed by milling or leaching in a surface mill. Recently, the efficient recovery of uranium fromsedimentary deposits also has been accomplished byin-situ leaching or solution mining. The in-situ leaching process integrates the standard mine/millcomplex by in-place leaching of uranium andprocessing the uranium-rich fluids at the surface. Useof an in-situ leaching process for sedimentaryuranium deposits has proved profitable andcompetitive with the conventional open-pit orunderground mine/mill systems. The advantages ofthe in-situ leaching process have been reviewed.
The nature of the lixiviant for successful in-situleaching depends on the nature of the ore bodies.Acid lixiviant, consisting of H2SO4 and NaClO3, has been tested successfully at Shirley basin inWyoming. Sulfuric acid and H2O2 lixiviant has beenused with success at Nine Mile Lake in Wyoming byRocky Mountain Energy Co. For ores with a highcontent of carbonate minerals, such as limestone anddolomite, the acidic lixiviants become uneconomical because of excess acid consumption. For such ores, carbonate lixiviant is preferred.
In the carbonate leaching process, the lixiviantsare made up of NaHCO3/Na2CO3 as the complexingagents and NaClO3 or H2O2 as the oxidant.However, in the field a permeability loss often isencountered when NaHCO3/Na2CO3 lixiviant isused. This permeability loss is thought to be due toswelling of clay minerals, such as smectite, in theformation by sodium ion. Use of ammonium ion inplace of sodium ion in the lixiviant can alleviatemuch of the problem of formation permeability loss.Intercontinental Energy Corp. has been successfullyusing (NH4)2CO3 and H2O2 as the lixiviant in southTexas for some time. Mobil Oil Corp. alsosuccessfully pilot tested the use of(NH4)2CO3 andNaClO3 in south Texas.
JPT
P. 2068＾
Planning the Directional Well - A Calculation Method
Authors: McMillian William H. 
Published: December 2007

Summary
This paper describes a radius-of-curvature calculation of the three-dimensional (3D) path of a directionally drilled well from kickoff point to target. Slant-well, S-shape, and maximum turn well paths can be computed. Equations are developed for calculating critical points along the well path in terms of cartesian coordinates and directional survey parameters. The effect of right-hand walk (drift) and a technique for calculating the appropriate lead to compensate for drift is presented.

Introduction
In contrast to the many references on methods for calculating directional surveys, there is a notable absence of articles discussing the related problem of well planning. Wilson derived the concept of compounded wellbore curvature in discussing the curvature method to calculate directional surveys. However, no 3D method has been published to handle the calculation of well paths that have both changes of azimuth and changes of inclination. This is a common type of well path, especially in sidetracked holes and for drilling around salt domes. The intent of this paper is to describe a procedure that will accommodate the 3D geometry of practical well trajectories.
The general solution assumes that all curvatures between two points are constant. The only other limitations imposed are a maximum curvature and a maximum inclination.

Radius-of-Curvature Equations
The radius-of-curvature method used in this procedure is a preferred approach to well-path calculation because of its relative simplicity and general use in the industry for interpreting directional surveys. It also appears to conform to the geometry of directional drilling since the objective of turning a well with, for example, a bent sub and downhole mud motor is to drill a well path with constant radius of curvature. Rivero has generalized the radius-of-curvature equations to the following form.
Cases 1 and 2.
(1)
Case 1. .
(2)
(3)
This case represents a constant curvature in azimuth as well as inclination.
JPT
P. 952^
The Application of the Buckley-Leverett Frontal Advance Theory to Petroleum Recovery
Authors: Dardaganian Stephen G. 
Published: December 2007

Introduction
Basically, the Buckley-Leverett theory involves two systems which are similar in nature but are differentiated by time. These systems may be described by the fractional flow and frontal advance equations which essentially characterize the mechanics of oil movement while being expelled from the reservoir.
The fractional flow equation originally developed by Leverett may be expressed in the more usable form
(Equation 1).
The development of this equation is based on Darcy's law describing fluid flow through porous media and applies to the flow at only one point (it is a point function). For simplification, the fractional flow equation is written in the above form because the capillary forces always increase the fractional flow of the displacing phase regardless of the direction of flow or the displacing phase.

Applications of the Frontal Advance Theory to Petroleum Recovery
Two general applications of the Buckley-Leverett frontal advance theory involve the system in which the oil is being displaced by an expanding gas cap overlying the oil zone and that in which the oil is being displaced by water.

Displacement by Gas in the Presence of an Immobile Water Saturation
A system in which gas is the displacing phase may be thought of as having two forces effecting the displacement process. These forces are the gravitational force and that force exerted by the displacing gas. The gravitational effects control the displacing efficiency of the gas. The gravitational effect will be less at higher rates of flow, thereby reducing the effectiveness of the displacement of the oil by the gas. The more efficient displacements occur at flow rates which are less than the gravity free fall rate. Capillary forces can be neglected without materially changing the magnitude of the gas saturation.
The Mile Six pool is used herein to illustrate the calculating procedures in evaluating gas drive-gravity drainage field performance. These calculations represent the determination of the gas-oil contact when the distribution of the hydrocarbon pore volume is considered.
Application of Reliability Analysis Techniques to Intelligent Wells
Authors: Drakeley Brian K. , Douglas Neil I. , Haugen Knut E. , Willmann Endre 
Published: December 2007

Summary
This paper describes the overall methodology and quantitative techniques applied during the development of an intelligent well control and communication system to ensure high system reliability and availability. In particular, the anticipated reliability impact of introducing high-temperature (HT) electronics technology together with redundancy for critical components is quantified.
One of the main challenges when analyzing the reliability performance of novel technology is to establish appropriate input data. Hence, a methodology applied to establish and validate reliability data is presented.
Harsh installation and operating conditions make a zero failure expectation for a 10-year life span appear unrealistic. The solution to this paradox is to assume that there will be some failures and to combat this by developing a highly fault-tolerant system.
The methodology described in this paper also has broader potential applications to other oil and gas system development projects. It brings to our industry practices that are frequently employed in the aerospace and nuclear industries.