bluuebunny/crossref_metadata_2025 huggingface dataset:
A Systematic Approach to Well Surveying Calculations
Authors: Taylor Howard L. , Mason Mack C.
Published: December 2007

The information used in well surveying calculations is studied and formalized. A general, natural, mathematical approach to the problem is presented and four special cases are developed: presented and four special cases are developed: (1) triangular or trapezoidal, (2) secant, (3) quadratic, and (4) minimum curvature.

These methods are compared and their properties analyzed for reasonableness. Two of these methods are new and have appeared promising when applied to real and test data.

Introduction

Several new approaches have been proposed to the problem of performing well surveying calculations; and it has been pointed out that improvements in directional drilling tools and techniques justify a better treatment than the old tangential methods. However, a systematic analysis of the problem in a standard mathematical form has not been published. This paper will try to cover several of the more useful methods in a natural mathematical framework and to suggest several alternative approaches and directions for improvement.

Formulation of the Problem

In performing a directional survey of a well, a tool measures an inclination angle with respect to the vertical and a bearing angle with respect to North at a number of points, Pi, in the well. Thus, we know three things: (1) the location of the first point, Po, at the surface, (2) the distance between any two points, Pi - and Pi+1, along the arc length, and (3) the direction of the wellbore at each point, Pi (as given by the inclination and bearing).

Pi (as given by the inclination and bearing).If one considers using a smooth approximation to the wellbore rather than straight-line segments joined at angles, the question of what degree of smoothness is to be used arises. For example, cubic spline approximations could be used to insure second-order smoothness. There are two difficulties that arise. In the first place, the authors know of no reason why a wellbore should have second-order smoothness. Second, the calculations become very difficult, partly because more than two points must be dealt with at a time. In this paper we shall follow the common practice of only analyzing the wellbore from one point, say P0, to the next point, P1, and assume that the process is repeated until P1, and assume that the process is repeated until the final point, Pn, is located.

Referring to Fig. 1, we assume that the Z-axis is vertical and the X-axis is in the direction North. Thus the Y-axis will point East. The angle of inclination will be 0 and the angle from North, which is essentially the bearing, will be, where and . Hence, we can state our problem mathematically as follows.
The Effect of Phase Data on Liquids Recovery During Cycling of a Gas Condensate Reservoir
Authors: Fussell Del D.
Published: December 2007

A linear, one-dimensional compositional model was employed to study the effect of phase data on the recovery of the pentanes and heavier fraction during gas cycling of a sour gas condensate reservoir. The results show that the phase data used and the method of handling the effects of composition on phase data can affect the computed recovery performance.

Introduction

Introduction

The prediction of performance for reservoirs containing volatile fluids historically has been very difficult. The development of compositional reservoir simulators has given engineers a new tool to attack this problem. Several recent papers, have discussed the application papers, have discussed the application of this type of simulator to the prediction of reservoir performance.

Huang showed that the predicted reservoir performance for a three-component system (methane, performance for a three-component system (methane, n-butane and n-decane) was not sensitive to small errors in phase viscosity and density data, but was sensitive to the accuracy of the methane K-value data. He recommended developing phase data based on an experimental depletion curve for the original fluid system.

Experimental data for the original reservoir fluid system would be expected to be the minimum information required for reservoir simulation during gas cycling. Large composition changes occur in a reservoir during injection of a dry gas (usually plant residue gas) with a greatly different composition than the reservoir gas phase. The predicted performance, then, is expected to be sensitive to performance, then, is expected to be sensitive to the method selected for describing the phase equilibria of the volatile fluid, particularly for pressures just below the saturation pressure. pressures just below the saturation pressure. In this study, gas cycling calculations were performed on a gas-condensate reservoir where performed on a gas-condensate reservoir where experimental phase behavior data were only available for the original reservoir fluid.
Successful Pilot Predicts Bright Future for Loco Hills Water Flood, New Mexico
Authors: Darden Frank , Cook Robert J.
Published: December 2007

The Grayburg-San Andres reservoirs of the Artesia- Vacuum trend, Eddy County, N. M., have produced more than 2 million bbl of primary oil. The rock characteristics and production performance of these reservoirs indicate that many of them should yield substantial volumes of secondary oil. This paper describes the performance of one of the most successful waterflood pilot operations in the Artesia-Vacuum trend. The Newmont Oil Co. pilot in the Loco Hills field consisted of six injection wells in a modified five-spot pattern. Existing producing wells were converted to injection and a local water supply was used until response justified construction of a 26-mile pipeline to deliver sufficient water volumes for full development. Production rates in individual pilot wells increased from 400 to more than 18,000 bbl/month by June, 1960. Injectivity profiles indicate that this field must be flooded at high injection rates and pressures to effectively sweep all of the productive sand and that the reservoir appears to be quite sensitive to variations in injection rates. Additional development of Newmont leases surrounding the pilot area has continued, and the project had 15 injection wells and 47 producing wells on Feb. 1, 1962. These properties, which were producing 444 B/D in Aug., 1958, averaged 2,618 B/D in Jan., 1962. Unit volume recoveries in the pilot flood indicate that the Loco Hills field should be one of the more important secondary recovery projects in New Mexico.

Introduction

The Loco Hills field is located in the southwestern part of the Artesia-Vacuum trend of Eddy County, N. M., in a minor syncline on the flank of the Grayburg-Jackson monocline. Location of the field is presented in Fig. 1. The reservoir is a stratigraphic trap limited on three sides by permeability pinch-outs and on the east by a static water table. The principle producing formation his Zone 4 of the Grayburg formation of Permian age, locally known as the Loco Hills sand. This zone occurs at an average depth of 2,750 ft. It has good continuity throughout the area examined and, from the data at hand, appears to have uniform characteristics from well to well. The "typical" Loco Hills section consists of 10 to 30 ft of tight gray sand or sandy gray lime, underlain by 20 to 50 ft of soft brown sugar sand. Only the brown sand has a native permeability high enough to permit natural flow.

History of Development

The discovery well in the Loco Hills field Yates, et al, Federal No. 1 is located in the NW/4 of SW/4 Section 6, T-17-S, R-30-E. This well was completed in Jan., 1939, for a potential of 506 BOPD after being shot with 140 qt of nitroglycerine. Development on random spacing followed rapidly until the field ultimately contained 264 wells over a surface area of approximately 8,500 acres.

JPT

P. 1223^
Calculation of Stabilized Gas Well Performance Curves From Back Pressure Test Data
Authors: Cornell David
Published: December 2007

Back pressure test data on natural gas wells are short time test data of unsteady state nature. Performance curves from which unsteady state effects have been eliminated, called stabilized performance curves, are necessary for understanding the behavior of gas wells and for scheduling gas fields for periods up to 20 years. A calculation procedure has been developed whereby three day, seven day, 30 day, or other duration stabilized performance curves may be calculated from- back pressure test data. Such curves are essential for correct gas deliverability calculations and gas field scheduling.

Introduction

The manner in which a back pressure test is made will affect the slope of the back pressure curve because the radius of drainage changes with the length of time that the well is allowed to flow. The reciprocal of the slope of the back pressure curve is defined as n in Equation 1 and varies from 0.5 to 1.0.

(Equation 1)

If the flow is viscous and the radius of drainage constant, n will have a value of 1.0. Because of turbulence in the formation near the well bore, the pressure drop is usually greater than the viscous flow pressure drop and the exponent n is frequently less than 1.0. In addition, since the radius of drainage moves away from the wellbore during the test, the gas flows a greater and greater distance as the test proceeds, with a resulting increased pressure drop at the high flow rates, and, again, n for the test tends to be less than 1.0.

The effect of the changes in the radius of drainage may be calculated and the results used in preparing stabilized performance curves for fixed values of the radius of drainage. Such curves can be made for a definite time period, such as three day, seven day, or 30 day stabilized performance curves. These curves will show the effect of turbulence near the wellbore and can be used to predict the performance of the gas well at any flow rate or for any production period.
A Vessel for Offshore Construction In Heavy Seas
Authors: Goren Yoram , McMillan Bruce
Published: December 2007

A new generation of construction equipment an evolving for offshore work in heavy seas. The progenitor of the line is Choctaw, the world's first column-stabilized construction barge. She is capable of sustaining operations in seas up to 16 feet and of maintaining her station in unrestricted oceans.

Foreword

Increased worldwide demand for oil and oil products, together with political uncertainties in some of the major oil producing areas, is accelerating the search for oil offshore and extending its boundaries to deeper and rougher waters. Offshore oil production necessitates the construction of platforms and production facilities, as well as underwater storage and pipelines. A great many construction barges have been built to fill this need. Until June, 1969, all construction barges had conventional box-shaped hulls, a feature that limited their operations to seas not exceeding 5 ft. Because of the excessive motion in high seas, these barges had to be towed away to sheltered waters whenever a storm was forecast. In June, 1969, the construction barge Choctaw was christened. Choctaw represented an important turning point in the industry in that she is the first column-stabilized construction barge and is capable of sustaining operations in seas up to 16 ft and maintaining her station in unrestricted oceans.

The design principles used in the vessel are discussed in detail in Ref. 2. To restate the basic design philosophy, the designers recognized that a construction barge is seldom called upon to use her maximum crane capacity. For this reason, Choctaw was designed to operate in two different drafts. In the low draft, the crane can handle up to 800 tons at 90-ft outreach, and in the high draft, the crane can handle 150 tons at 110 ft with full deck load and no ballast compensation.

On several occasions the vessel was called upon to perform lifts heavier than 150 tons while in the high-draft condition. These exercises were carried out by maintaining the list angle to a minimum through transfer of ballast. Lifts of this type necessitate that careful planning and exacting calculations be carried out by the barge engineers.

The crane was designed to sustain a dynamic load produced by roll motion of 5 degrees in 9 seconds double produced by roll motion of 5 degrees in 9 seconds double amplitude (for all but the 800-ton load condition). The force produced by a 50-knot wind was superimposed on the dynamic loading. The crane was designed to sustain a 3 degrees barge list when lifting 800 tons.

The vessel was designed to operate in adverse climates: in temperatures ranging from -35 degrees to + 120 degrees F. Both design and construction were closely monitored and approved by Lloyd's Register and the U.S. Coast Guard.
Wellbore Heat Losses and Pressure Drop In Steam Injection
Authors: Pacheco E.F. , Ali S.M. Farouq
Published: December 2007

This mathematical model of the mechanics of flow of wet and saturated steam down the wellbore during steam injection takes into account the variation of steam temperature and pressure due to friction, as well as heat losses by radiation, conduction, and convection. It consists of two coupled nonlinear equations that are solved iteratively.

Introduction

Chekalyuk et al., Moss and White, and Fokeev and Kepyrin, investigated wellbore heat losses during injection of a hot or cold fluid down the casing. Ramey made a comprehensive study of the injection of liquids and gases down casing or tubing. Squier et al. presented a complete analytical treatment of hot water injection down the wellbore. Satter extended Ramey's treatment to the case of steam injection. Huygen and Huitt, presented results of a theoretical and experimental treatment of wellbore heat losses during steam injection, and pointed out the importance of the radiation heat loss. Holst and Flock as well as Earlougher extended the above treatments by including, steam pressure calculations. Eickmeier et al. considered the early transient performance, using a finite-difference model. performance, using a finite-difference model. Apart from these studies, Leutwyler gave a comprehensive treatment of casing temperature behavior, and Willhite presented a complete calculation of the over-all heat presented a complete calculation of the over-all heat transfer coefficients.

The chief objective of our work was to formulate a comprehensive mathematical model of steam injection into a reservoir to include simultaneous calculation of steam pressure and quality. The model took into account the variation of steam temperature and pressure due to friction, as well as heat losses by pressure due to friction, as well as heat losses by radiation, conduction, and convection, and consisted of two coupled nonlinear differential equations that were solved iteratively. The model results were compared with those predicted by several of the above-mentioned approaches.

Formulation of the Model

Steam at a constant injection pressure, constant mass flow rate, and constant quality (at the surface) is injected through the tubing into the wellbore. The complete system consists of the fluid, the tubing, the annular space containing low-pressure air, the casing, the cement, and the formation. We propose to compute the pressure and the quality of steam as functions of depth and time.

An energy balance and a momentum balance can be written for the flowing fluid as follows:

Energy balance

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

Momentum balance

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

The term dQ is given by,...................(3)

where the rate of heat transfer to the formation is

(4) dq = ,

JPT

P. 139
Development of an Underground Heat Wave for Oil Recovery
Authors: Grant Bruce F. , Szasz Stefan E.
Published: December 2007

Introduction

During 1947, a Sinclair research team was assigned to investigate thermal methods of oil recovery. The assignment was recommended by a survey of possible research approaches to increase the amount of oil that ultimately can be recovered from oil producing reservoirs. The use of heat to stimulate, oil production rates by the melting of paraffin deposited in well bores can be traced back to within one or two decades of the drilling of the Drake well.

The application of heat on a larger scale has been discussed by generations of oil producers. Shortly after the turn of the century, one intrepid operator is reported to have injected steam into a Pennsylvania property. After a few weeks, he apparently became discouraged and terminated his experiment. Subsequently, the literature contains references to several well-developed techniques for supplying heat to a producing well bore to melt paraffin or to reduce the viscosity of oil contained in. the formation immediately around the well bore. Some early references discuss procedures to furnish heat to the reservoir, with the injection well as the heat source, thus obligating the process to maintain the entire rock mass at a temperature above that at which the desired improvement in oil recovery would occur.

Another approach to reservoir heating was reported by a group of Russian technologists in 1935. They definitely demonstrated that combustion can occur within the porous structure of an oil-bearing sandstone. Their field experiments, however, relied less on combustion within the rock than on heat furnished by combustion of oil supplied to the injection well bore. Ignition of the air-oil mixtures in the well bore was found very difficult, and the field tests were carried on for only short periods of time. Publication of the Russian work spurred at least one independent operator in this country to try firing an air-gas injection well. on for only short periods of time.

Publication of the Russian work spurred at least one independent operator in this country to try firing an air-gas injection well. The Brundred Oil Corp. reportedly obtained combustion in the sand immediately around the injection well bore, but the experiment was abandoned because of interference with normal production schedules. Injection capacity of the experimental well was greatly reduced by firing. The well was reshot and pieces of sand showing partial fusing of the quartz matrix were recovered.
The Bay Marchand Fire
Authors: Nelson R.F.
Published: December 2007

Introduction

Platform "B" was launched July 16, 1969, in the Platform "B" was launched July 16, 1969, in the Bay Marchand Block 2 field. The 12-pile structure was located in 55 ft of water, 7 miles offshore and 65 miles south of New Orleans. It was designed for 36 wells, which were to be drilled by two independently operated, full-sized drilling rigs.

The first well on the platform was started Sept. 15, 1969. By Dec. 1, 1970, the two rigs, Stormdrill 20 and Stormdrill 21, had drilled and completed 22 wells. Of those wells, 21 were dual completions and one was a single completion. Daily production was 17,500 bbl of oil and 40 MMcf of gas. Two additional wells were in the process of being drilled. (Fig. 1 is an aerial view of Platform "B" before the fire broke out.)

Platform "B" was equipped with the latest safety devices and was being operated in full compliance with Government regulations.

What caused the Bay Marchand fire? Several investigations have disclosed the following facts. The plastic coating on the tubing in Well B-21 sloughed off and plugged the well. In the course of wireline operations to clean out the well a serious human error was made: during a period when the well was unattended, the well control valves were left incompletely closed. The well blew out and the fire ignited. A subsurface safety valve waiver, granted for completion purposes, was in effect at the time.

JPT

P. 225
Shear Viscosities of Ionic Polyacrylamide Solutions
Authors: Mungan Necmettin
Published: December 2007

Solutions of ionic polyacrylamide polymers behave pseudoplastic in purely viscometric flow. Flow rate, polymer molecular weight and electrolytes affect solution viscosities to a large extent. Equations are given for the viscosity-shear rate relations in a form that can be used conveniently to account for the effect of viscosity on mobility.

Introduction

Polymers are being used increasingly in oil recovery operations, and therefore, an understanding of their flow behavior is gaining pragmatic importance. Past studies have shown that in the flow of polymeric fluids through porous media, the increase in solution viscosity, decrease in permeability, and viscoelastic deformations cause permeability, and viscoelastic deformations cause the fluid mobility to be greatly reduced. In general, viscoelasticity, i.e., extensional flow, is not so important because, for the largest part of a reservoir, polymer solution moves at very low and fairly steady polymer solution moves at very low and fairly steady velocities. Jennings et al. have concluded this for the specific polymers that they studied. Permeability reduction plays an important role in Permeability reduction plays an important role in the mobility control, particularly in porous media having low permeabilities initially. Reductions ranging from 25 to 70 times have been reported. However, the alterations that take place in a porous medium during polymer flow, the coupling between the geometry of the porous medium and the properties of the flowing fluid, and the influence of the flow regime on permeability have not been looked into in sufficient detail. A separate study, directed to the understanding of these important phenomena is required.

In the present work, the purely viscous behavior of solutions of three partially hydrolized polyacrylamide polymers was obtained under experimental conditions far polymers was obtained under experimental conditions far more extensive than any reported in the literature. Some data have been available in the past for two of the polymers, but the third is a new polymer for which no data have been reported before. Using a Weissenberg rheogoniometer, Cannon-Fenske viscometers, and various capillary cubes, viscosities were measured over 8 decades of shear rate, ranging from 10 to to 10 (5) sec-1. These are the limits of measurable rates of shear and cover those that may apply to flow in reservoirs. Distilled water and various NaCl solutions were used as solvents to afford comparison of the rheological properties between fresh and saline solutions. Measurements were also made with solutions containing calcium' and magnesium to study the effect of divalent cations.
Inaccessible Pore Volume in Polymer Flooding
Authors: Dawson Rapier , Lantz Ronald B.
Published: December 2007

We have found that solutions of typical waterflooding polymers do not occupy all of the connected pore volume in porous media. The remainder of the pore volume is inaccessible to polymer. This inaccessible pore volume is occupied polymer. This inaccessible pore volume is occupied by water that contains no polymer, but is otherwise in equilibrium with the polymer solution. This allows changes in polymer concentration to be propagated through porous media more rapidly than propagated through porous media more rapidly than similar changes in salt concentration. At the front edge of a polymer bank the effect of inaccessible pore volume opposes the effect of adsorption and pore volume opposes the effect of adsorption and may completely remove it in some cases.

This paper presents three experimental polymer floods showing the effect of inaccessible pore volume in the presence of varying amounts of adsorption. Results of these floods clearly show that about 30 percent of the connected pore volume in the rock samples used was not accessible to The polymer solutions. The changes required to include polymer solutions. The changes required to include inaccessible pore volume in mathematical models of polymer flow and in held prediction methods are discussed.

Introduction

One way of improving the mobility ratio during waterflooding operations is by addition of a water-soluble polymer to the flood water. Several different polymers have been proposed and a number of investigators have presented results on the behavior of these polymer solutions in porous media. In addition, mathematical models have been developed for predicting the field behavior of polymer flooding. In all these studies movement polymer flooding. In all these studies movement of the polymer bank through the reservoir rock is of great importance.

One phenomenon that has been repeatedly observed in polymer flooding is the removal of polymer from solution by adsorption on the reservoir rock. As a polymer bank propagates through porous media, the polymer bank propagates through porous media, the front edge is gradually denuded of polymer. The amount of polymer lost from a bank may be large or small, depending on the nature of the polymer and rock surface. This loss of polymer must be measured and included in any realistic mathematical model of polymer behavior. It has been widely assumed that polymer behavior. It has been widely assumed that adsorption is the most significant factor causing polymer to propagate through porous media at a polymer to propagate through porous media at a velocity different from that of water.

In this paper we present data that demonstrate that all of the pores may not be accessible to polymer molecules and that this "inaccessible polymer molecules and that this "inaccessible pore volume" can affect polymer propagation pore volume" can affect polymer propagation significantly. In addition to the experimental results, we discuss the changes in interpretation and in mathematical models that are required to include this phenomenon.
A Method for Creating 2-D Orthogonal Grids Which Conform to Irregular Shapes
Authors: Hales Hugh B.
Published: December 2007

Reservoir simulations in the past have usually been made using Cartesian grid systems. However, the Industry's current integration of reservoir simulation and reservoir characterization has demonstrated the need for more flexible gridding methods. Flexible grids allow the incorporation of more accurate reservoir descriptions into reservoir studies, but generally result in more complex simulation mathematics and decreased simulation speed. Only curvilinear orthogonal grids offer increased flexibility without such complications. This paper describes a simple method for generating grids of this type. It provides several examples of curvilinear orthogonal grids and compares their simulation results with those of Cartesian grids using a real reservoir.
Correlation and Prediction of Residual Oil Saturation for Gas-Injection-Enhanced Oil-Recovery Processes
Authors: Lange E. A.
Published: December 2007

A promising correlation has been developed that can be used to predict miscible or near-miscible residual oil saturation, Sorm, for a wide range of injected gases, crude oils, temperature, and pressure conditions. The correlation is based on the representation of the chemical and physical properties of the crude oil and the injected gas through Hildebrand solubility parameters. This approach has the advantage that characteristics of both the injected gas and crude oil are included in the correlation, in contrast to correlations based solely on properties of the injected gas.

The correlation was developed using available experimental data for tertiary recovery of eight crude oils in carbonate and sandstone cores with common enhanced oil recovery (EOR) gases [CO2, N2, CH4, CH4 + liquefied petroleum gas (LPG)]. Results for 45 coreflood tests at reservoir conditions collapsed along a band when Sorm was plotted as a function of the difference in solubility parameters between the injected gas and the crude oil. Results for a pure oil, decane, with CO2 lay along the same band. The success of this correlation scheme may be the result of the basic characterization of the fluids and of a relationship between solubility parameters and interfacial tension (IFT). Use of the correlation requires knowledge only of injected gas composition, injected gas density, oil average molecular weight, and temperature.

This empirical correlation should have utility in screening studies as a simple means to forecast residual oil saturations as measured in coreflood tests. The correlation can be used to predict roughly the effects of changes in pressure, temperature, or injected gas composition on residual oil saturation. A new method to predict minimum miscibility pressure (MMP) based on the solubility parameter concept is also described.
Application of Horizontal Wells to a Tight-Gas Sandstone Reservoir: A Case History
Authors: Guyatt R. C. P. , Allen J. P.
Published: December 2007

The Anglia gas field is located in the southern sector of the U.K. Continental Shelf (UKCS) in Blocks 48/18b and 48/19b. The reservoir is contained within the Permian Rotliegendes sandstone and is of small to medium size by U.K. southern North Sea standards. The field is divided into an east and west area with the gas initially in place distributed equally. Appraisal-drilling results indicated that the eastern portion of the field exhibited good productivity, whereas wells drilled into the western area produced at subeconomic rates. Development studies showed that to make the field development economically viable, well rates would have to be increased in the poorer western region. Conventional stimulation techniques were explored, particularly hydraulic fracturing; however, these proved unsuccessful owing to the proximity of the water leg. Attention, consequently, focused on the then emerging technique of horizontal drilling as a means of increasing well productivity. Development of a geologic model identified that the reservoir could be zoned into six reservoir units and that to maximize productivity, placement of the well into the predominantly aeolian zones was necessary. Reservoir simulation studies showed that a minimum 70-ft stand-off from the gas/water contact (GWC) was required to maximize ultimate recovery. This paper describes the analysis methods used and the results of applying horizontal wells in the field development and shows how, at a small cost premium, the method enabled a marginal field to be developed successfully.
The Dual-Spacing Neutron Log-CNL
Authors: Alger R.P. , Locke S. , Nagel W.A. , Sherman H.
Published: December 2007

A new dual-spacing neutron tool developed for porosity determination and gas detection in open or cased boreholes is combinable with various other logging tools. Simultaneous recording saves rig time, and an overlay log presentation facilitates wellsite interpretation. presentation facilitates wellsite interpretation. Introduction

A two-detector neutron tool has been developed to determine porosity in open and cased boreholes. The response of the tool is determined by the rate at which the thermal neutron population decreases with distance from the source. This rate of decrease is principally determined by the porosity of the formation.

The quantity measured is the ratio of counting rate from the near-spaced detector to that from the far-spaced detector. The surface control panel converts this ratio to a porosity index, which is then displayed on a linear scale. Individual counting rates, count-rate ratio, and porosity index may also be recorded on magnetic tape for subsequent machine computation.

The dual-spacing measurement provides compensation for the effects of hole conditions - salinity, temperature, mud type, and mud cake. The residual effects are generally small. The log has therefore been named the compensated neutron log (CNL*).

The porosity uncertainty caused by statistical variations is diminished through the use of a high-yield chemical neutron source.

A unique feature of the tool is that it may be run in combination with other logging tools such as the formation density, thermal decay time. sonic, and induction-spherically focused logs. Such combinations make possible overlay presentations for wellsite interpretation, and offer the advantages of reduced rig time and positive depth matching.

Dual-Spacing Neutron Detection Principle - Fast neutrons from a point source radiate into an infinite homogeneous medium and are slowed down by repeated collisions until they are in thermal equilibrium with the atoms of the medium. The thermal neutrons continue to diffuse, but, on the average, suffer no further energy loss. Eventually they experience absorbing collisions (capture collisions) and disappear from the system.

In the process of slowing down, the neutron "cloud" spreads out spatially. The width of this spatial distribution is frequently characterized by a single property, called the slowing-down length. This is a measure of the size of the cloud of neutrons of a particular energy. It is proportional to the mean particular energy. It is proportional to the mean distance that neutrons travel from the source in slowing down to that energy.

An alternative theoretical model emphasizes the so-called group-diffusion theory. In this case, one treats all the neutrons in the medium (usually down to some preassigned energy) as if they had the average energy of the group. This approach, also, leads to the definition of a characteristic parameter, the diffusion length, which is a measure of the width of the spatial distribution of the neutrons in the group.

P. 1073
Computer Methods of Diplog Correlation
Authors: Schoonover L.G. , Holt O.R.
Published: December 2007

This paper presents an automatic Diplog processing system that incorporates several new processing system that incorporates several new techniques and allows alternative processing paths.

The rationale for selecting the product-moment method as the primary correlation technique is given, and the algorithm for variable window-length correlation and infinite-clip methods discussed. In the screening section, several approaches to grading and screening of picks to improve the appearance of the machine-correlated Diplogs are discussed. The derivation of flexible vector analysis equations for dip calculation is also presented.

Introduction

Modern logging technology appears to be on a definite trend toward the recording of well log data on magnetic tape. The use of digital tape for Diplog data processing has been increasing for several years and will continue to become more significant. The use of magnetic tape for processing theoretically makes the turn-around time faster and makes screening and filtering of large amounts of data feasible.

Processing of digital tapes can take any of several routes, some better than others for a particular set of conditions. In this paper, we particular set of conditions. In this paper, we present several of the possible approaches to present several of the possible approaches to processing the data and explain the rationale for processing the data and explain the rationale for choosing a particular one. In addition, several approaches that we feel are both new and useful are presented.
New Tool Permits Simultaneous Production of Two Reservoirs Through the Same Flow String
Authors: Hodges J.W.
Published: December 2007

HODGES, J.W., MEMBER AIME, SUN OIL CO., BEAUMONT, TEX.

The constant search for methods to increase the efficiency of production systems and to reduce operating costs has led to the development of a wireline tool which makes it possible to produce and control two separate reservoirs through a single string of tubing. This paper is a progress report of the experience one company has gained with this tool in eight of its dually complete wells in Louisiana and Texas. Field tests have clearly demonstrated that this device can be used to maintain separation of production from each and to change the rate of production as required. The advantages in simultaneous one-string multiple completions of the method are discussed.

Introduction

It is now almost standard operating procedure to complete wells in more than one zone wherever possible, with the great majority of these multiples being dual completions. This is a sign of the times. Saving must be accomplished wherever possible; however, there is no need to expand on this theme. All are painfully aware of the economic conditions within the industry. It is sufficient to say that the practice of multiple completions is here to stay and is becoming more popular every day. The only question is whether or not the practice has evolved into its most acceptable form. The earlier duals were the concentric type, with one zone producing through the tubing and the other through the tubing-casing annulus. This method is still practiced to a large degree. It is popular because it is relatively inexpensive. Unfortunately, it has some rather severe limitations, with which the reader undoubtedly is familiar. The twin-string dual is an improvement over the concentric in the sense that many of the problems associated with the concentric have been solved. The objectionable features of the twinstring dual are the high cost of equipping the well with an extra string of tubing, plus accessories, and the complications brought on by cramming all this tubing into one string of casing. Still another type of multiple is the tubingless completion, wherein two or more small casing strings are cemented in place and subsequent operations performed with miniaturized equipment. The purpose of this paper is to present a different concept in multiple completion-the simultaneous production of separate reservoirs in a single flow string. This method combines the simplicity and low cost of the concentric with the flexibility of the twinstring dual. In addition, it provides the unique advantage of prolonging natural flow from a low-pressure zone by combining its production with the fluids produced from a higher-pressure zone. The wireline tool which makes this method possible is the multiple-completion choke assembly.

Construction and Operation of the Multiple-Completion Choke Assembly

Fig. 1 shows a well properly equipped to receive a multiple-completion choke assembly. A conventional packer separates the two producing zones. The upper packer is optional.

JPT

P. 1079^
Knowledge Management in the E & P Sector: Concepts, Standards and a Vision for the Future
Authors: Donohue D. A. T. , Meyer H. S. , Johnson R. W. , Woelk Darrell , Ogle K. C.
Published: December 2007

New information technologies are poised to meet the E&P industry's growing need for a comprehensive technology transfer system that provides easy access to a wide range of information and training resources. Ongoing developments in electronic knowledge management offer a means of imparting structure, accessibility, and quality-control mechanisms to such a system. In this paper, we discuss new developments in technology transfer, report on results from a technology transfer survey of 92 companies, and suggest how knowledge management may be applied in the E&P sector.
Chemical Aspects of In-Situ Combustion - Heat of Combustion and Kinetics
Authors: Burger J.G.
Published: December 2007

General remarks on the oxidation reactions of hydrocarbons involved in in-situ combustion are followed by estimates of heat releases. A formula is derived for computing the heat of combustion in the high-temperature zone. Reaction kinetics in porous media applied to the in-situ combustion porous media applied to the in-situ combustion process is discussed. It is observed that there is process is discussed. It is observed that there is some similarity between the kinetics of reverse and partially quenched combustion processes. The influence of additives on crude oil oxidation in porous media is illustrated by effluent gas analysis experiments. Some information concerning the values of the kinetic parameters of the reaction controlling the velocity of a reverse combustion front is derived from the interpretation of laboratory experiments, using a numerical model.

Introduction

A great deal of laboratory and field work has been done on thermal recovery methods. The importance and limitations of these techniques have been extensively studied. However, some of the chemical and physical problems involved that needed to be elucidated were studied as part of a research program carried out by the Institut Francais du Petrole. Specific problems are created by in-situ combustion since both the possibility of combustion-front propagation and the air requirement are controlled by the extent of the exothermic oxidation reactions. Actually, the propagation velocity of a forward combustion front depends on the fuel formation and combustion, which are controlled by the kinetics of these processes; furthermore, the peak temperature is related to the heat released by oxidation and combustion reactions. Therefore, a quantitative estimation of the parameters related to the chemical aspects of the parameters related to the chemical aspects of the process is a necessary step in studying combustion process is a necessary step in studying combustion through a porous medium. General and theoretical considerations on heats of reaction and kinetics are presented and illustrated by experimental data and numerical interpretation of the results.
Web Sites Build a Network of Independent Resources
Authors: Rowell Deborah
Published: December 2007

Independent operators need access to new technologies that reduce the costs of finding, drilling, and producing oil and natural gas. Identifying new and existing cost-effective technologies, however, is often beyond the independent's reach because of limited resources. These E&P companies must gain electronic access to available technologies to survive today's changing industry conditions.

The Internet's petroleum-related Web sites contain records of reservoir management solutions, including case studies from applying new technologies. The design and content of these public and commercial Web sites rest solely on the skill of their creators. Few can predict the next turn in this information highway. Virtually everything is under construction, such as new programs, new ways of accessing and organizing data, and search engines.

The Petroleum Technology Transfer Council (PTTC), a national nonprofit organization, was formed in 1994 by the E&P industry to address the technology needs primarily of independent U.S. companies. PTTC offers an array of programs to help producers, such as an electronic information network on the Internet that allows access to a growing database of regionally maintained E&P information. The network links 10 regional Web sites to the national site (http://www.pttc.org/hq/).
Temperature Distribution in Circulating Mud Columns
Authors: Keller H.H. , Couch E.J. , Berry P.M.
Published: December 2007

A model describing the two-dimensional transient heat transfer in and around a wellbore is developed. The model considers the fluid flowing down a drill string and returning up the annulus. Calculated results show that the use of steady-state solutions previously published give good estimates of previously published give good estimates of circulating mud temperatures. The transient solution presented here is more suited for matching presented here is more suited for matching temperature logs. The viscous flow energy, rotational energy, and drill bit energy were found to be significant items in the energy balance and are included in the model.

Calculated vertical temperature distributions in the innermost casing string permit the determination of the average temperature increase in that pipe. This quantity may then be used to compute thermal stresses and to predict casing stability.

Introduction

In drilling deep wells (15,000 to 30,000 ft) the geothermal temperatures encountered can cause problems with drilling fluids, drill pipe, and casing. problems with drilling fluids, drill pipe, and casing. To evaluate the effects of these high temperatures on the drill pipe and casing, it is necessary to know the temperature distributions in these pipe strings.

Previous work includes the approximate model described by Edwardson et al. for estimating formation temperature disturbances resulting from mud circulation. This work formed the basis for the calculation method that Crawford et al. proposed for estimating mud temperatures. Ramey proposed a model for solution of the wellbore heat transmission problem. He assumed that heat transfer in the problem. He assumed that heat transfer in the wellbore is steady-state while heat transfer in the earth is due to transient radial heat conduction. Ramey's model gave results comparable to the more exact method of Squier et al. and formed the basis for the solution of other wellbore circulation problems. problems. Two recent treatments of the mud circulation problem are based on models that assume steady-state problem are based on models that assume steady-state conditions in both the wellbore and the surrounding earth. The treatment of this problem by Raymond is very good with the exception that he neglected the presence of the casing strings and the effects of presence of the casing strings and the effects of energy sources in the system.

The prediction of these temperature distributions can best be accomplished with a two-dimensional thermal model that accounts for the dynamic flow, of mud down the drill pipe and back up through the annulus around the drill pipe, with appropriate heat interchange by convection and conduction. Such a model is described in this paper.
Analysis of Short Transient Tests Affected by Changing Wellbore Storage
Authors: Vásquez-Cruz M. A. , Camacho-Velázquez R. A.
Published: December 2007

It is well known that wellbore storage and phase redistribution have a direct influence over well-testing data, mainly on those recorded at early times of the test. After this early time period, such influence disappears, and the pressure response is dominated by the reservoir and the skin zone properties. However, sometimes the effects of wellbore dynamics last long enough to completely disguise the reservoir response. This situation frequently constrains the use of such analysis procedures as type-curve matching, especially if the test did not last long enough to reach radial-flow conditions. Some tests are uninterpretable because of the duration of these wellbore effects.

By means of two classical models related to well test affected by changing wellbore storage, this work introduces a new method of analysis for those tests with insufficient duration to reach radial-flow conditions. The methodology proposed in this work is illustrated with synthetic examples and a field case. For some synthetic cases the type-curve-matching procedure may yield completely erroneous values for the parameters, whereas, with the suggested method, reasonable estimates are obtained.