bluuebunny/crossref_metadata_2025_split huggingface dataset:
DST Flow Rates From Two Horner Slopes
Authors: Mackett R.A. 
Published: December 2007

Summary
The slopes of the initial and final shut-in periods of a drillstem test (DST) are used to calculate the corresponding flow rates knowing the recorded flow times and the total liquid recovery and assuming constant transmissibility. Examples of the calculation are included for a closed-chamber test and a conventional test from Earlougher.1
Calculations
" If the shut-in period is long enough, and if wellbore storage is not dominant, a Horner plot of buildup data should have a straight-line section with slope -m." 1 The value of the slope of the Horner plot may be used to calculate the transmissibility:Equation 1
The value of the constant 162.6 is 2121 for the corresponding SI units listed in the Nomenclature. The following derivation is based on the assumption of constant transmissibility and a flow regime in which the Horner analysis is valid (see Discussion):Equation 2, 3, and 4
Substituting Eqs. 3 and 4 into Eq. 2 and rearranging yieldsEquation 5
whereEquation 6
SubstitutingEquation 7
into Eq. 5 yieldsEquation
Rearranging results inEquation 8
Eqs. 7 and 8 used to allocate recovered liquid volumes between the initial and final flow periods.
Example 1: A Closed-Chamber DST
A northwest Alberta well, Well 6–4-65–20W5, had a straddle-packer DST run at a depth of 5,653 ft [1720 m] in 7 7/8-in. [200-mm] hole with 442 ft [134.7 m] of 2.875-in.- [73-mm]-ID drill collars. A 9.1-lbm/gal [1090-kg/m3] gel chemical mud resulted in an initial and final hydrostatic mud pressure of 2,736 psi [18 864 kPa]. The preflow was 10 minutes with corresponding final pressure of 161 psi [1110 kPa]. The initial shut-in time and pressure were 90 minutes and 2,153 psi [14 844 kPa]. The pressure at the beginning of the second flow was 106 psi [730 kPa], building to 561 psi [3868 kPa] over 90 minutes, and the final shut-in pressure was recorded as 2,121 psi [14 624 kPa]. The slopes of the Horner plot for the initial and final shut-in periods were 107.6 and 127.4 psi/cycle [741.9 and 878.4 kPa/cycle], respectively. The formation temperature was 119°F [48.3°C] and the net pay was 7 ft [2.1 m]. The operator (Mobil Oil Canada) calculated a total fluid recovery of 400 ft [122 m], composed of 340 ft [103.7 m] of 26°API [898.4-kg/m3] oil with a viscosity of 4.05 cp [4.05 mPa·s], and 60 ft [18.3 m] of oil-cut mud from closed-chamber calculations and a production rate of 46 B/D [7.4 m3/d].
The Viscosity of Natural Gases
Authors: Lee Anthony L. , Gonzalez Mario H. , Eakin Bertram E. 
Published: December 2007

Abstract
Experimental viscosity and density data of four natural gases are presented for temperatures from 100 to 340 F and pressures from 100 to 8,000 psia. A correlation is discussed and results reported.

Introduction
This investigation is one of several efforts by the authors to provide viscosity data for pure hydrocarbons and mixtures. Results of some pure hydrocarbons and their mixtures have been presented. Several predictive methods and correlations have also been reported. This paper presents the experimental viscosity and density data of four natural gases and confirms a correlation in a previous study.

APPARATUS
The viscometer was described previously. A bank of stainless steel pycnometers was included to determine density in conjunction with the viscosity measurements (Fig. 1).

DATA AND MATERIALS
The natural gases were furnished by the Atlantic Richfield Co. (Samples 1 and 2), the Continental Oil Co. (Sample 3) and the Pan American Petroleum Corp. (Sample 4). Table 1 shows the composition of these gases obtained by mass spectrometer analysis. The pure component viscosity data used in the correlation have been published. Experimental and calculated viscosity data for the natural gases are presented in Tables 2 through 5.

CORRELATION
Starling and Ellington have reported several semi-empirical expressions based to a certain extent on the theory of viscosity advanced by Born and Green. The final expression presented by Starling and Ellington is:
(micropoise)= o exp[X(T) pY(T)]....... (1)
Eq.1 was modified by Lee et al. to represent mixture and pure component data simultaneously. This equation has the form:
..........(2)
where
K= ..........(3)
X= ..........(4)
Y= ..........(5)
Over the pressure and temperature range studied in this investigation, this equation represents the data on methane, ethane, propane, n-butane and four methane-n-butane mixtures with a standard deviation* of 1.89 per cent. Density data by Sage and Lacey were used to fit the equations. Eq. 2 gives reliable values of the viscosity of light hydrocarbons without prior knowledge of experimental viscosity values, but accurate density data must be available. Eq. 2 was used to predict viscosity values for the natural gases studied in this paper. The particular set of parameters contained in Eqs. 3 through 5 gave values that reproduced experimental data within 5 per cent. Needless to say, in using Eq. 2 better density values will give better viscosity results. However, those engineers who do not have accurate density values at hand or the time, or such facilities as a library. computer, etc. readily available, may feel uneasy in using Eq. 2. Therefore, the authors sought the easiest but by no means best density prediction method, which was reported by Kay 30 years ago. A set of density values, which were calculated based on Kay's method, and a generalized compressibility factor chart were used to fit Eq. 2.
JPT
P. 997ˆ
Air Drilling Operations Improved by Percussion-Bit/Hammer-Tool Tandem
Authors: Whiteley Maxwell C. , England William P. 
Published: December 2007

Summary
Contractors and operators air drill whenever possible to improve rate of penetration (ROP). This is done with pneumatic hammer tools (HT's) and various bit types used with standard rotary air rigs. The recent application of a "flat-bottomed" percussion bit (FPB) combined with a custom-designed HT originally developed for mining operations has significantly improved air drilling operations in the Arkoma basin. The improvements include a large increase in ROP, improved hole geometry, reduced drillstring stresses, and a substantial reduction in cost per foot. This paper provides (1) a discussion of the engineering design and operation of the FPB/HT tandem, (2) applications and limitations of the tools, (3) guidelines for optimization of performance, and (4) documentation of field performance on Arkoma basin wells to demonstrate the improvements in air drilling operations.
Triaxial-Load-Capacity Diagrams Provide a New Approach to Casing and Tubing Design Analysis
Authors: Johnson Rick , Jellison Michael J. , Klementich Erich F. 
Published: December 2007

Summary
A computer program has been developed that generates a two-dimensional (2D) graphic representation to display the effect of anticipated service conditions on specific casing and tubing. The triaxial-load-capacity diagram permits a visual determination of string design adequacy by both API and equivalent-triaxial-stress design factors. The program is useful in the design and analysis of any casing or tubing string.
Measurement of Drilling Properties
Authors: Gault Allen D. 
Published: December 2007

Summary
Rock-bit performance is related here to formation strength. Bingham mathematical models and steel-tooth rock bits are used in a procedure to optimize rates of penetration (ROP's) and to extend bit life.
The ability to distinguish elastic formations from plastic formations has been used to introduce polycrystalline-diamond-composite (PDC) bits in the Gulf of Mexico, where shale is the predominant formation. The validity of the mathematical models has been confirmed on long, homogeneous shale sections, and the models have also been expanded to include soft-formation insert rock bits.
Deepwater Drilling Riser System
Authors: Chastain T. , Stone D. 
Published: December 2007

Summary
The principal focus of this paper is to discuss and summarize, from the manufacturer's perspective, the primary milestones in the development of the marine riser system used to drill in record water depths off the U.S. east coast.
This riser system is unique in that it used advanced designs, material technology, and quality control to enable safe operation in water depths beyond the capability of conventional drilling riser systems. Experience and research have led to design improvements that are now being incorporated in new riser systems that have the potential of expanding the frontiers to increasingly deeper water.
Formation Productivity Evaluation From Temperature Logs
Authors: Bird J.M. , Frost N. 
Published: December 2007

Abstract
A brief review is presented of the methods of quantitative evaluation of borehole temperature logs as applied to gas flow measurements. A method for evaluation of the formation productivity is introduced, making use of a temperature log of the flowing gas well, the reservoir temperature and pressure and the Joule-Thomson expansion temperature of the gas. A method is discussed for applying a scale to the temperature log. Its use for obtaining a better understanding of both natural and man-made formation fractures is proposed
Introduction
In previous work on the quantitative evaluation of borehole parameters through the use of temperature logs, Bird and others made use of a function delta of the variation of the earth's and the borehole fluid temperatures with depth. Kunz and Tixier have referred to this function as the subtangentAfter a brief review of the use of temperature logs for measuring the volume of gas flow in a borehole, this paper deals with the application of temperature logs to evaluate the mechanism of gas production.
Determination of Gas Volume From a Temperature Log
Fig.1 illustrates a graphical method of determining the quantity delta. This figure shows the shape of a standard temperature log in a gas producing zone. Delta is defined as
where T, is for practical purposes the earth temperature, Tg, is the gas temperature and is the rate of change of gas temperature with depth. Fig. 2 is a plot of delta vs gas production rate. This figure was taken from Schonblom. The dots represent data taken in boreholes less than 5 1/2-in. diameter, the circles for boreholes between 5 1/2 to 7 1/2-in. and the squares for boreholes greater than 7 1/2-in. diameter. Schonblom, on a theoretical basis, concluded that the curve had to be discontinuous. The straight line on the left side represents the laminar portion and the curve on the right side represents the turbulent mode. Admittedly, the distribution of points in this figure looks distressing.
JPT
P. 301ˆ
Use of a Hybrid Grid in Reservoir Simulation
Authors: Pedrosa Oswaldo A. , Aziz Khalid 
Published: December 2007

Summary
A technique is presented to improve the treatment of wells in reservoir simulators by the use of an orthogonal curvilinear grid (cylindrical or elliptical) in well regions and a rectangular grid elsewhere in the reservoir. Special methods are developed to handle irregular blocks connecting the two types of regions. The nonlinear equations for the two Regions are solved with different levels of implicitness; the simultaneous solution (implicit) method is applied to the well regions, while an implicit pressure, explicit saturation (IMPES) technique is used for the reservoir region. An efficient approach, requiring no outer iterations, between well and reservoir regions is used to couple different regions. The scheme is validated by the simulation of the flow of a slightly compressible fluid in a square domain with one boundary open to flow. For this case, the numerical solution with the hybrid grid approach matches the analytical solution exactly. A computer model based on the approach was developed for simulating two-phase flow in multiwell horizontal reservoirs. We show that* the proposed technique provides much better prediction of the phase split in the producers than the conventional approach.
Local Mesh Refinement and Modeling of Faults and Pinchouts
Authors: Forsyth P. A. , Sammon P. H. 
Published: December 2007

Summary
Completely flexible gridblock connections are necessary for local mesh refinement and modeling of faults and pinchouts. For practical purposes, it is necessary to combine such arbitrary connectivity with an adaptive implicit technique. In this paper, the methods used to discretize the flow equations for unusual geometries is discussed, and a rigorous analysis is given. A completely general, sparse, incomplete LU iterative solver is described that can solve Jacobian matrices with arbitrary connectivity. Various test results are presented.
Block-Preconditioned Conjugate-Gradient-Like Methods for Numerical Reservoir Simulation
Authors: Eisenstat Stanley C. , Elman Howard C. , Schultz Martin H. 
Published: December 2007

Summary
We describe a collection of block preconditioners for use in solving large, sparse, linear systems of equations by iterative methods, and we compare their performance with several point preconditioners in solving some systems arising in numerical reservoir simulation. We consider block preconditioners that handle either lines or planes in an implicit manner and pointwise incomplete LU (ILU) factorizations combined with partial elimination preprocessors. We conclude that the best of the pointwise methods are both more robust and faster, but that the best of the block methods are competitive for certain orderings of unknowns and require less storage.
The Role of Bicarbonate Ion in Calcite Scale Formation
Authors: Przybylinski John L. 
Published: December 2007

Summary
In this paper, we study the influence of the seed surface area, supersaturation ratio, bicarbonate ion concentration, and pH on the calcite precipitation rate. All other things being constant, the rate is a nearly linear function of seed surface area and supersaturation ratio. The rate also, surprisingly, depends on the concentration of bicarbonate ion, which is not a thermodynamically relevant species. There is no discernable effect of pH on the rate after the effects of pH on the supersaturation ratio and bicarbonate ion concentration are accounted for.
A Buffer-Regulated HF Acid for Sandstone Acidizing to 550°F
Authors: Scheuerman R. F. 
Published: December 2007

Summary
Two earlier papers discussed the suitability of buffer-regulated HF acid (BRHFA) for high-temperature sandstone matrix stimulation treatments. Acetic-acid/acetate buffering (pH=4.5 to 5.0) limited corrosion to acceptable levels at temperatures up to about 350°F [177°C]. Subsequent development of reservoirs with terhperatures approaching 450°F [232°C] demonstrated a need for even higher-temperature acidizing systems.
This paper discusses a new, less corrosive BRHFA formulation that has clay-dissolving capacity comparable to 7½% HCl/1½% HF acid. The corrosion rate of carbon steel at 550°F [288°C] is only 330 mils/yr [8.4 mm/a]. The BRHFA systems are also compatible with a variety of coirosion-resistant alloys.
This paper presents clay slurry, core flow, arid corrosion data and discusses use guidelines.
Gravity Effects in the Displacement of Oil by Surfactant Solutions
Authors: Hornof V. , Morrow N. R. 
Published: December 2007

Summary
The displacement of isooctane by aqueous surfactant solutions was investigated in model porous media consisting of a thin layer of lightly sintered glass beads. Pre-equilibrated oil/surfactant pairs were prepared that exhibited interfacial tensions (IFT's) in the range 0.06 to 2.08 mN/m [0.06 to 2.08 dynes/cm]. Because aqueous solution viscosity was always higher than that of the isooctane, a stable displacement would normally be expected. While systems with IFT's greater than about 1 mN/m [1 dyne/cm] showed sharp interfaces and generally stable displacements, experiments conducted at lower IFT exhibited a considerable degree of instability. In particular, at lower tensions, the interfaces became fuzzy, and there was distinct evidence of gravity underride by the aqueous phase. The onset of gravity segregation with decreasing IFT was successfully related to capillary and viscpus forces operating within the systems. The degree of instability was found to increase with decreasing IFT, but oil recoveries did not necessarily decrease because of recovery mechanisms that involved mobilization and coalescence of zones of bypassed oil.
Dispersion of a Solvent Slug Injected Into a Communication Path
Authors: Schmidt Teddy , Heldrick Ted , Ridley Rod , Kissel Gerald 
Published: December 2007

Summary
Solvents may be injected into a formation once communication has been achieved between injection and production wells to increase the size of the communication path. However, the solvent disperses into the formation and bitumen flows into the communication path, increasing the viscosity of the flowing phase. As a result, no solvent may ever appear at the producing well.
In this paper, the problem is modeled for the one-dimensional (ID) case and an analytic solution is obtained from which breakthrough time, outlet concentration of solvent, and other significant parameters can be estimated.
Steamdrive Performance in a Layered Reservoir—A Simulation Sensitivity Study
Authors: Spivak Allan , Muscatello J. A. 
Published: December 2007

Summary
This paper describes the use of a thermal reservoir simulator to study steamdrive in a reservoir consisting of noncommunieating sand layers. The simulator was used to determine basic design parameters for steamdrive operations in the South Belridge field, Kern County, CA. Sensitivity runs were made to investigate the effect of various parameters—such as spacing, steam quality, and steam injection rate—on performance. Comparisons were made of the performance of a layered system with no communication between layers and that of an identical system with vertical communication.
Examination of the Confined-Pattern Concept in Steamflood Simulation
Authors: Chu Chieh 
Published: December 2007

Summary
The confined-pattern concept has been widely used in steamflood simulation for homogeneous reservoirs with negligible dipping. This work found that, for field projects with 9 to 100 repeated patterns, this concept underestimates the actual oil production by 3% at the end of 6 years. The usefulness of the concept has thus been ensured.
Analysis and Correlation of Nitrogen and Lean-Gas Miscibility Pressure
Authors: Firoozabadi Abbas , Aziz Khalid 
Published: December 2007

Summary
The vaporizing gas drive (VGD) process was modeled with the Peng-Robinson equation of state (PR-EOS) and a compositional simulator. The comparison of numerical results with available experimental data has shown that the PR-EOS overestimates the minimum miscibility pressure (MMP), but it correctly shows that the length required to achieve miscibility is different for N2 and methane. Experimental data and some simulation runs have been used to develop a simple and reliable correlation for the prediction of MMP.
Design of Surface Facilities for Khuff Gas
Authors: Sood L. K. , Jamsheer A. S. 
Published: December 2007

Summary
Although it was discovered in 1947, commercial exploitation of the Bahrain Khuff reservoir began in 1970. Current gas demand stands at 580 MMscf/D [16.4 × 106 std m3/d] and is growing rapidly. This paper briefly discusses the evolution of the design for surface facilities and field experience. The established design parameters could be used for the design of surface facilities for similar reservoirs.
Qatar NGL-2 Pipeline Problems
Authors: El-Jundi I. M. 
Published: December 2007

Summary
The Qatar NGL-2 plant, commissioned in Dec. 1979, was designed to process the associated gas from the offshore crude oil fields of Qatar. The dehydrated, sour, lean gas and wet, sour liquids are transported by two separate lines to the Umm Said NGL complex about 120 km [75 miles] from the central offshore station. The 300-mm [12-in.] -diameter liquids line has suffered general and severe pitting corrosion, and the 600-mm [24-in.] -diameter lean gas line has suffered corrosion and extensive hydrogen-induced cracking (HIC or HIPC). Neither line performed to its design parameters, and many problems in the downstream facilities have been experienced. All efforts to clean the solids (debris) from the liquids lines have failed. This in turn interfered with the planned corrosion control program, thus allowing corrosion to continue. Various specialists have investigated the lines in an attempt to find the origin of the solids and to recommend necessary remedial actions. Should the lines fail from pitting corrosion, the effect of a leak at a pressure of about 11 000 kPa [1,595 psi] will be very dangerous, especially if it occurs onshore. To protect the NGL-2 operations against possible risks—both in terms of safety and of losses in revenue—critical sections of the pipelines have been replaced, and all gas liquids pipelines will be replaced soon. Supplementary documents to the API standards were prepared for the replaced pipelines.
Regional Caprock-Destroying Dolomite on the Middle Jurassic to Early Cretaceous Arabian Shelf
Authors: Broomhall R. W. , Allan J. R. 
Published: December 2007

Summary
Massive, stratigraphically discordant dolomite occurs on the late Mesozoic Arabian Shelf in the northern portion of Aramco's main producing area. The dolomite is associated with solution-collapse of anhydrite seals and with enhancement of porosity and permeability in tight limestone seals within the region. By destroying regional caprocks, dolomitization has had an adverse effect on oil accumulation. The spatial distribution of this regional dolomite was mapped with wireline log and core data. Geochemical and fluid-inclusion analyses indicate that the dolomite formed from hot saline brines that were first expelled from halite-bearing evaporites, and then migrated into Arabian Shelf carbonates during burial.
Thermal Characteristics of Porous Rocks At Elevated Temperatures
Authors: Somerton W.H. , Boozer G.D. 
Published: December 2007

Abstract
Thermal diffusivities of some typical sedimentary rocks have been measured by a rapid unsteady-state technique. Thermal data including diffusivity and conductivity are presented for the temperature range of 200 to 1,800°F.
Diffusivities calculated from steady-state conductivity measurements compared favorably with unsteady-state data at the lower temperatures. Unsteady-state data are less reliable at higher temperatures; reported values may be as much as 20 per cent high at temperatures in excess of 1,500°F. This is caused partly by the simplified method used in calculating diffusivity from experimental data and partly by the many thermal reactions which occur at the higher temperatures.
The marked decrease in thermal diffusivity and conductivity at elevated temperatures indicates the importance of considering the temperature dependence of thermal properties in subsurface heat-transfer calculations. Knowledge of the effects of liquid saturation, overburden and pore pressures, and heats of reaction of reservoir materials will be required before complete subsurface thermal analyses may be made.

Introduction
Heat-transfer calculations are becoming increasingly important in the analysis of in situ combustion and underground nuclear explosions. Thermal data for natural rock materials at elevated temperatures are generally unavailable. Calculations at high temperatures may be grossly inaccurate if temperature-dependent thermal properties of rocks are not considered.
It is known that the heat capacities of rocks increase with temperature. Heat capacities may be calculated from chemical or mineralogical analyses of the rock system. Thermal bulk expansion of rocks is believed to be small, although few data are available. Thermal conductivities of most natural rock materials decrease with increased temperature. Thermal diffusivity, defined as the thermal conductivity divided by the product of the heat capacity and the bulk density of the material, is used in unsteady-state heat-transfer calculations. It is apparent that thermal diffusivity decreases markedly with increased temperature.