bluuebunny/crossref_metadata_2025_split huggingface dataset:
Waterflood-Induced Fractures: A Simulation Study Of Their Propagation And Effects On Waterflood Sweep Efficiency
Authors: Dikken B.J. , Niko H. 
Published: December 2007

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Abstract
Fracturing occurs quite often in water injection wells, with sometimes unforeseen consequences on waterflood sweep efficiency. One of the causes of fracturing is often the cooling of hot formations by cold injection water. A special version of a thermal reservoir simulator for prototype applications has thus been constructed that is capable of dealing with propagating waterflood-induced hydraulic fractures. With this simulator, fracture propagation and the effect of growing fractures on the sweep efficiency are studied. Infinite fracture conductivity is assumed. The limitation to very high leak-off fractures justifies disregarding the changes in fracture volume. Fracture growth is calculated using the concept of a critical stress intensity factor. Both poro- and thermo-elastic changes in the horizontal stresses are calculated umerically and their influence on the fracture initiation/propagation is continuously taken into account. In addition, a model of fracture wall impairment because of filter-cake build-up due to poor quality injection water is included.
Results are presented for both thermal and isothermal situations. It is observed in isothermal cases that the voidage replacement ratio (volume balance during injection) determines to a great extent the length to which the fracture eventually may grow. In isothermal situations with balancing pattern injection and production a stationary fracture is observed in the steady-state flow regime. The observed dependence of the stationary fracture half-length on parameters such as the initial horizontal stress and the critical stress intensity factor is in agreement with analytical expressions for single-phase flow situations. As an illustration of thermal fracturing, results pertaining to high-rate water injection in a sandstone reservoir with properties similar to North Sea conditions are discussed. To demonstrate the importance of injection/production balance more clearly, well spacings in the simulations presented were purposely taken to be smaller than in practice. Sweep efficiencies are presented for two voidage replacement ratios with the fracture growing towards a producer; in the worst situation a reduction of the efficiency by about 20% is observed.
Method for Determining the Feasibility of Dynamic Kill of Shallow Gas Flows
Authors: Koederitz W. L. , Beck F. E. , Langlinais J. P. , Bourgoyne A. T. 
Published: December 2007

ABSTRACT
Gas flows from shallow sands present difficult well control challenges when encountered. Contingency plans for handling shallow gas flows generally are based on a dynamic kill procedure. In a dynamic kill, the bottom-hole pressure is increased without the use of a surface choke. With this method, high circulating rates are used to increase annular frictional pressure losses. In this paper, a systematic procedure is presented for estimating the loads present on the well and diverter system during a dynamic kill operation. This is useful both in well design and in planning well control operations. The procedure is based on a steady-state systems analysis calculation applied to a diverted well and includes consideration of the effects of critical (sonic) exit pressure and pressure changes due to elevation, friction, and acceleration.
Example analyses are discussed for well conditions typical of (1) a bottom-supported marine rig or a land rig, and (2) a deep-water floating drilling unit. The floating unit example is presented both with and without the use of a marine riser. The example analyses illustrate the importance of using diverters larger than 6-in. diameter and supports the practice of drilling pilot holes to the depth of the next casing string. The examples also illustrate that a dynamic kill will be significantly more difficult if the length of conductor casing is insufficient to prevent broaching from the conductor casing shoe to the seafloor.
Improved Hydraulics for Rock Bits With Extended Slant Nozzles
Authors: Cholet H. J. , Abdullah H. F. , Chia W-K. 
Published: December 2007

ABSTRACT
A new concept of hydraulic design for rock bits has been developed and tested. The bit was equipped with two nozzle tubes extended downward. Each nozzle was outfitted with two fluid exits to direct the jets 60 degrees from the bit center line onto the hole bottom. In addition, a center nozzle was added to the bit to clean the dome and to increase the cone cleaning effects. In order to obtain the crossflow effect, the third nozzle was blanked off such that a high velocity and consequently a forced circulation over the hole bottom was obtained. The influx of kinetic energy strips off cuttings among the teeth and allows a very rapid removal of cuttings with reduced recycling.
The first part of the paper will describe the experimental studies. The efficiency of stripping the cuttings from the well bore bottom was measured in a cell with ball tracers injected into the flowing fluid. By means of ultra-high speed photography, the path of the tracers and hence the fluid movement was recorded. Furthermore, the bottom hole fluid flow pattern was simulated by a hydrodynamic computer code to quantify the cleaning effects as compared with conventional extended nozzle bits.
The remainder of the paper describes the results of field tests. The average drilling rate and footage increased about 20% with the use of the slant nozzle bits over that normally achieved with extended nozzle bits. The cost savings averaged about 15%, The nozzle is particularly effective in: –Soft formations,–Sticky shale formations,–Relatively high drilling rate formations.
Layer Pulse Testing Using a Wireline Formation Tester
Authors: Saeedi J. , Standen E. 
Published: December 2007

ABSTRACT
A Layer Pulse Test1 was designed, implemented and analyzed in a pinnacle reef in Alberta. Two Repeat Formation Tester (RFT)* surveys were performed in the observation well at a pre-designed interval. The second RFT survey was performed after the pulsed well was put back on production. The design was based on an older, history-matched model of the reef.
A geological and stratigraphic interpretation was performed to update the geological and the numerical model. Subsequently, a three-dimensional, three-phase, single equation numerical simulator2 was used to model the inter-well area and a history match was obtained to the pressure shift in the two RFT surveys.
The vertical pressure profiles from the RFT surveys identified barriers to vertical flow while the geological interpretation and the history match to the pressure shift provided a quantitative distribution of horizontal and vertical permeabilities in the inter-well area.
New Developments in the Analysis of Cores from Naturally Fractured Reservoirs
Authors: Bergosh J. L. , Lord G. D. 
Published: December 2007

ABSTRACT
New techniques have been developed to more accurately quantify porosity and permeability in naturally fractured core. Computerized tomographic scanning and fluorescent epoxy impregnation techniques have lead to improved measurement of fracture porosity. Directional permeability measurements at overburden stress better define permeability anisotropy and permeability reduction from ambient to reservoir conditions.
Working Smarter With Computers
Authors: Dodd D. L. 
Published: December 2007

ABSTRACT
Over the past few years, a wide variety of computer hardware and software has become available, ranging from personal computers to new mainframes, minicomputers, and engineering workstations. Continuing advances will result in even more computing power becoming available. The impact of this evolution will be major. In order to take full advantage of this hardware and software, the use of mainframes, workstations, and personal (or micro) computers must be well planned and integrated into the workplace.
Interactive systems and more "user friendly" software will be increasingly available. It will remain the engineer's responsibility to understand the limits of applicability of these systems and software and, for that purpose, good documentation and support for programs and systems is essential.
A key to effective computer usage is adequate training. Software and hardware vendors, employers, universities and the SPE must all participate in this effort. However, the individual is ultimately responsible for his or her personal development.
Status of Research and Development in the Oil Industry
Authors: Taylor B. G. 
Published: December 2007

ABSTRACT
R & D subjects in petroleum industry are numerous and diverse. We look at formations with Scanning Electron Microscopes and satellites. In order to trace hydrocarbons, we measure almost every physical and mechanical property of the rock; from its radioactivity and electrical resistivity, to magnetic properties. We measure fluid pressure to an accuracy of 0.01 psi. We can do well testing based on moon tides. We draw three-dimensional picture of underground strata based on seismic data. We launch and install offshore platforms which cost millions of dollars, weigh thousands of tons. We drill holes miles deep into very hot formations, and produce from them. We can transport fluid hundreds of miles on sea floors, thousands of miles on giant tankers across oceans, and then refine it to a final product usable by the public. And yet, we cannot answer some very basic questions: Where in a reservoir should we drill, how to anticipate the mechanical condition of the formation we will drill into, what are the relative permeabilities of the formation to its fluids, how to determine when we have a good cement bond, how to determine the size and direction of hydraulic fractures, how to prevent water coning, how to prevent damage caused by formation fluid itself, etc. While we have made giant strides in modeling and processing data through computers, we often do not have the very basic properties needed to fully take advantage of them.
There are many technical disciplines involved in oil and gas exploration and production. We employ almost all engineering disciplines, as well as draw on achievements of other industries. In such an environment, it is difficult to identify why R & D is vital to the petroleum industry.
Any strategy of R & D has to recognize an important element; people. Although people are the most valuable asset of every part of an organization, R & D accomplishments and value is substantially dependent upon the qualifications of those performing the work. Most R & D functions require people with high level of education and specialized training, disciplined in a methodical and logical approach to problems. Yet breakthroughs are often results of unorthodox thinking, the creative ingredient of a human brain which goes beyond what is normal and expected.
Perceptions the Key to Oil Prices
Authors: Powers L. W. , Stevenson W. M. 
Published: December 2007

ABSTRACT
Future crude oil supply and demand was explored in the late summer of 1986 under various pricing scenarios. Key findings include the importance of price perceptions on behavior, the significance of Middle East producers, the correlation between oil price and working rigs and the prediction that oil prices are not likely to fall below $18 to $20/Bbl with real growth in crude prices of about 4 percent a year, from 1990 until the year 2000, assuming a stable Middle East.
Equipment Selection Procedure for Subsea Trees
Authors: Otten J. D. , Brammer N. 
Published: December 2007

ABSTRACT
Subsea trees have typically been field-specific with different designs required for each project. Current industry trends to improve efficiency and cost effectiveness, however, indicate that increased standardization and versatility are required. This paper presents a new procedure to categorize proven equipment and simplify selection of tree components. Using the flowchart principle, the decision process is indicated for each major equipment decision or option, considering the range of equipment available in light of product features, technical specifications, rated capacities, operational histories, and costs.
Fracturing Treatment Design Improved by Conductivity Measurements Under In-Situ Conditions
Authors: Parker M. A. , McDaniel B. W. 
Published: December 2007

ABSTRACT
Gelled fluids are often used in hydraulic fracturing treatments. During these treatments a filter cake of gel solids is usually deposited on the walls of the fracture as the result of fluid leak-off into the formation porosity. The presence of this filter cake may have an adverse effect on the conductivity of the proppant bed used to prop open the hydraulic fracture. Laboratory testing methods that simulate these in situ fracture conditions have been developed. Multiple proppant concentrations and fluid systems have been used in this testing. The resultant data are incorporated into the design of a fracturing treatment to minimize the effect of the gel filter cake. This allows more effective stimulation of oil and gas wells and more realistic predictions of post-frac production improvements. The data presented in this work emphasizes the importance of achieving high concentrations of proppant to minimize the effects of gel filter cakes.
Flow Response of Propped Fracture to Repeated Production Cycles
Authors: Kim C. M. , Willingham J. R. 
Published: December 2007

ABSTRACT
Once a reservoir is hydraulically fractured, the fracture may experience several repeated production/shut-in cycles. Evidence of reduced rate of recovery as wells are placed back on production, has been noted in gas wells that have been exposed to this type of cycling. As the cycling process is repeated, the propped fracture undergoes the ups and downs of closure stress, resulting in a gradual reduction in fracture conductivity.
To observe the phenomenon, a propped fracture using formation rock, was subjected to cyclic loading in the laboratory. Change in fracture conductivity with time and the number of cycles was measured. Interaction between proppant and formation rock was examined. One sand size and two synthetic proppant sizes were evaluated. Two formation rock types of different hardnesses were used in simulating the fracture.
At the same closure stress level, fracture conductivity continuously decreased as the loading cycle is repeated. The amount of reduction in conductivity depended upon the rock hardness and proppant size. For the same hardness rock, the magnitude of closure stress dictated the suitable proppant size to minimize the cyclic effect. Thus, the combination of information obtained through this study is a tool to select a proppant to minimize the cyclic effect.
Suggestions and optimum design criteria to circumvent or minimize the repeated shut-in effect are presented along with the test results.
New High-Performance Field-Installed Sucker Rod Guides
Authors: Murtha T. P. , Pirtle J. , Beaulieu W. B. , Waldrop J. R. , Wood H. V. 
Published: December 2007

ABSTRACT
A field installed sucker rod guide with high resistance to movement from axial loads during well operation has been a target of the petroleum industry for a number of years. Research by J. M. Huber and Phillips 66 Company has led to the development of a new field installed guide which will not only handle the high axial loads but can be used in severe well environments. laboratory and field tests have shown the axial loading resistance of a RytonR PPS composite guide to be ten times greater than nylon guides at temperatures up to 400°F. In addition, these composite guides have excellent chemical resistance, impact strength and wear resistance. laboratory data is correlated with that found in actual dσwnhole service. These results have been translated to successful applications in production wells. General material properties and techniques for guide installation are also presented.
Reserve Predictions From Production Testing in Geopressured Gas Reservoirs
Authors: Ireland M. M. , Robinson J. B. 
Published: December 2007

ABSTRACT
Pressure transient analysis, material balance, and numerical reservoir simulation were evaluated for analyzing production tests in geopressured gas reservoirs. Data requirements, problems obtaining it, and practical limitations are presented for each method. After analyzing two Gulf Coast example cases, guidelines are given to improve the accuracy of volumetric and reserve predictions.
The Application of the Method of Characteristics to the Flow of Miscible Gases in a Reservoir
Authors: Modine A. D. , Bashbush J. L. , Kothari K. 
Published: December 2007

ABSTRACT
A reservoir simulator has been developed to solve gas-water reservoir problems where the gas may be treated as a two component miscible mixture. It is specifically designed to study gas-storage problems where an inert gas such as nitrogen, may be used as a displacing fluid during cycling operations. The model includes both the convective transport of components within the gas phase plus the diffusion or dispersion of components. The solution to the multicomponent gas problem is accomplished using the method of characteristics, so that numerical dispersion is eliminated or minimized.
A description of the model is included along with several example problems. The example problems include comparisons of calculated results with analytical solutions and experimental laboratory data in one and two dimensional models. The experimental data were measured on both liquid-liquid and gas-gas miscible systems.
Formation Damage Due to Synthetic Oil Mud Filtrates at Elevated Temperatures and Pressures
Authors: McKinney L. K. , Azar J. J. 
Published: December 2007

ABSTRACT
An experimental apparatus and a statistically-based test matrix have been designed for use in an on-going test program to determine the extent of formation damage which may be caused by oil-base 'drilling fluids on sandstone cores at elevated temperatures and pressures. Tests with a mineral oil-base synthetic filtrate on Berea sandstone cores have shown that of the three independent variables tested (temperature, flowrate and confining pressure), temperature has the most significant effect on the degree of reduction of relative mobility over the range tested.1 The synthetic filtrate, containing the maximum amount of surfactants expected in a comparable 12 ppg mud, caused severe damage (97-100%) in all cases. The mineral oil, also used as a test fluid to show the minimum damage effect corresponding to the same mud, resulted in little change in relative mobility.
Viscoelastic Gravel-Pack Carrier Fluid
Authors: Nehmer W. L. 
Published: December 2007

ABSTRACT
The ability of a fluid to flow adequately into the formation during gravel-pack treatments is critical to achieving a good pack. Recent studies have indicated "fish-eyes" and/or "microgels" present in many polymer gelled carrier fluids will plug pore throats, leading to impaired leakoff and causing formation damage. Intensive manipulation of the polymer gelled fluid using shear and filter devices will help remove the particles, but it adds to the cost of the treatment in terms of equipment and manpower. Excessive shear will degrade the polymer leading to poor gravel suspension, while too little shear will cause filtration problems.
A gelled carrier fluid using a viscoelastic surfactant system has been found to leak off very efficiently to the formation, and cause no formation damage, without the use of shear/filter devices. Viscoelastic surfactant-base gelled fluids develop viscosity because of the association of surfactant molecules into large rod-shaped aggregates. There is no hydration of polymer involved, so fish-eyes and microgels will not be formed in the viscoelastic fluid. A surfactant-base system having a yield point allows the gravel carrying properties to be much better than fluids gelled with conventional polymer systems (hydroxyethylcellulose [HEC]). For example, a gravel carrier fluid gelled with 80 lb HEC/1,000 gal has a viscosity of about 400 cp at 170 sec-1; a viscoelastic surfactant-base system having only one-half the viscosity still flows into cores about four times more efficiently than the HEC-base fluid. The rheology, leakoff, formation damage and mixing properties of a viscoelastic, surfactant-base, gravel-pack carrier fluid are discussed.
An Analysis of Bit Bearing Failures With Field and Laboratory Data
Authors: Lesage M. L. G. , Falconer I. G. , Wand P. A. , McCann D. P. 
Published: December 2007

Abstract
This paper discusses how to detect the onset of bit bearing failure before the failure results in a lost cone. It does not attempt to understand the physics of wear.
A history of failures was collected for both journal and roller bearing bits from wells where both surface and down-hole mechanical parameters were recorded. The data were then correlated with formation logs to differentiate lithology changes from bit effects.
A separate experimental program was conducted on full size bits to observe how a failing bearing affects a cone's speed, torque and temperature. A journal bearing bit was worn from new to failure under atmospheric conditions and data were acquired at regular intervals of wear. Comparisons are made between journal and roller bearing bits.
This work showed that journal bearings do not necessarily fail in a catastrophic manner as generally believed, but may degrade over several hours. The results suggest a likely technique for separating the onset of bearing failures from lithology effects. A field example is thoroughly examined.
Effects of Nozzle Configuration on Roller Cone Bit Performance
Authors: White D. B. , Curry D. A. , Gavignet A. G. 
Published: December 2007

Abstract
Laboratory experiments have been conducted to study the effects of nozzle size, extension and configuration on the flow patterns, pressures and shear stresses beneath a roller cone bit. The results are used to interpret laboratory drilling data, and to identify conditions when the use of extended nozzles, two nozzles or a centre jet will improve penetration rate.
Continuous Orientation Measurement Systems Minimize Drilling Risk During Coring Operations
Authors: Brindley C. P. 
Published: December 2007

Abstract
Complex new field developments and in-fill drilling programs have placed extra emphasis on the work conducted by an oil company's geological and petrophysical departments. Core samples retrieved from the wellbore are a key source of data to these groups. Secondary and tertiary recovery projects have placed an extra premium on these core samples being oriented to assist in fracture orientation and measurement of directional permeability and porosity.
The traditional survey instrument used to measure the in-situ orientation of a core as it is being cut has been the mechanical film recording system developed for borehole deviation measurement. The use of this system placed certain risks on the drilling operation, as it was necessary to stop drillstring rotation and fluid circulation to make the orientation measurements.
Solid state transducers developed for real time directional surveying formed the basis for the development of electronic survey tools as replacements for the mechanical film systems. The transducers used are stable enough to be used in a "continuous" mode within the coring operation, thus negating all risks previously associated with oriented coring. The impact on the coring operation of taking orientation measurements is now zero.
This paper seeks to outline the development and application of electronic survey tools for core orientation measurements. Advantages of the continuous method are highlighted, and operational experiences on more than 60 wells worldwide to date are discussed.