bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interpretation of Falloff Tests on Fractured Wells of the Barsukov Oil Field in Western Siberia
Authors: Dros A.N.P. , Kuznetsov A.M. , Hagoort J. 
Published: December 2007

Abstract
The Barsukov field is a large oil field in Western Siberia that is being developed by waterflooding. The field has some 700 production wells and over 100 injection wells. In most of the injection wells water is being injected above the formation parting pressure, and as a consequence waterflood hydraulic fractures extend from the wells into the reservoir.
The injectors are regularly tested by means of fall-off tests. We have interpreted about 250 falloff tests in 80 different wells using the conventional graphical analysis methods for transient pressure tests, i.e. pressure-derivative analysis for flow regime identification, analysis of early-time fracture storage flow, and analysis of the linear and radial flow regimes.
A large number of the tests show pronounced storage effects, which can be attributed to fracture closing. Fracture size estimated from the storage period correlates well with the fracture size derived from the linear and radial flow regimes. Falloff tests are excellent tools for estimating the size of waterflood induced fractures.
P. 363
Industrial Application of Vortex Tube Separation Technology Utilizing the Ranque-Hilsch Effect
Authors: Lorey Manfred , Steinle Jurgen , Thomas Keith 
Published: December 2007

Abstract
A major processing step when treating gas is the removal of components such as heavy hydrocarbons or water. This is done either to recover saleable liquids or prevent hindsance during gas transportation (e.g. hydrate formation or two-phase flow). The Vortex tube device provides a novel and useful addition to the range of equipment available for this application. Vortex tube equipment has been used for improved separation in comparison with a Joule-Thomson system, without entering into the cost and complexity of a true is entropic system such as a turbo-expander unit. The relative advantage of the vortex tube is dependent upon the inlet conditions of the gas and available pressure drop. An optimum pressure drop of 25 - 35 % of the inlet gas pressure has been confirmed in practice. It is expected that future applications of vortex tube units will be concentrated where performance improvements over Joule-Thomson units, at low capital cost, are required.
P. 471
An Assessment Of The Cost Of Geothermal Power
Authors: Sapre Ashok R. , Schoeppel Roger J. 
Published: December 2007

Abstract
A technoeconomic model has been developed to assess the economic feasibility of generating electric power from the lower temperature gradient geothermal reservoirs. The cost evaluation in the numerical model is based primarily on three factors:the choice of the conversion system,the design of the production and transportation system, andthe natural surroundings in the area.The model is shown to be capable of evaluating the cost of geothermal power under varying technoeconomic and environmental conditions.

Introduction
The availability of domestic energy resources to meet future energy demands appears to be in doubt, especially if attention is restricted to only the conventional sources of energy such as natural gas, liquid petroleums coal, and uranium. Natural gas and petroleum may be resource petroleums coal, and uranium. Natural gas and petroleum may be resource limited while coal and uranium face many technological, environmental, and socioeconomic problems.
The energy supply situation is especially critical for the electric power industry. Whereas the demand for all energy resources has been power industry. Whereas the demand for all energy resources has been doubling every 15 years, electric power requirements are doubling in less than 10 years. The growth of the power industry is expected to be even faster than it has been, since electricity is perhaps the most versatile and cleanest form of end use energy.
In these circumstances, it appears prudent to consider supplemental domestic sources of energy especially for use in power generation.
Quantitative Interpretation of Temperature Logs
Authors: Keller H.H. 
Published: December 2007

Abstract
A mathematical model has been developed that can be used to determine fluid injection profiles by matching measured temperature logs. profiles by matching measured temperature logs. The method consists of assuming a fluid injection profile and calculating a temperature profile for the time of the measured log. The profile for the time of the measured log. The assumed injection profile is adjusted by the user until a suitable match of the calculated and measured temperature profiles is obtained.

Introduction
Temperature logs have been used to determine qualitatively the distribution of injected fluids in a formation. There has been recent interest in the theory of temperature logging, seeking meaningful quantitative interpretations.
A mathematical model has been developed that describes the thermal behavior of an injection well, the surrounding earth, and the formation receiving the fluids. A description of this model and an example of its use are presented in this paper. Although written presented in this paper. Although written specifically for the injection of acid into a formation, the model can also be used to interpret logs run after injection of any nonreactive, noncondensing fluid. It is also useful for predicting formation temperature distributions during fluid injection.

DESCRIPTION OF THE MODEL
The physical system consists of a radially symmetrical cylinder surrounding a wellbore, as shown in Fig. 1. This region is initially at the undisturbed geothermal temperature distribution. Fluid injection at known rates for a specified period of time occurs. This fluid enters a permeable formation with some unknown distribution. The fluids flowing down the injection pipe exchange heat with the surroundings and enter the formation at an unknown and, likely, varying temperature. The fluid flow into the formation causes a disturbance in the initial temperature distribution, which is dependent on the volume of fluid injected. This disturbance is then recorded on a temperature log run soon after the termination of fluid injection. The distribution of fluids into the formation may then be inferred from this log. To describe this sequence of events, the following mathematical model was developed.
Assuming radial symmetry, an energy balance in the region exterior to the wellbore gives the equation:
......................(1)
Numerical and Analytical Well Test Analysis: A Case History
Authors: Lee W. John , Spivey John P. 
Published: December 2007

Abstract
In this paper, we present a case history of integrating numerical and analytical well test analysis methods to interpret the pressure and production history of a complex, multilayer, multiphase reservoir. Some engineers believe that recent improvements in analytical models have made numerical modeling for well test interpretation all but obsolete. Others believe just as strongly that numerical models should be used for routine well test interpretation. Still others believe that both tools are useful, and that a combination of the two approaches provides the best general strategy for reservoir characterization.
This field case focuses on the Gas Research Institute (GRI) Staged Field Experiment (SFE) No. 2. This well was hydraulically fractured. A variety of different analysis techniques were applied in order to evaluate the consistency between reservoir and fracture properties estimated by the different methods of analysis.
Analysis methods applied to the flow and buildup tests performed on this well include type curve matching using analytical solutions, numerical modeling with single-phase, multi-layer radial and Cartesian grids, and numerical modeling with multi-phase, multi-layer radial and Cartesian grids. The simpler models were able to match segments of the production and pressure history; only the full multiphase, multilayer model was able to satisfactorily match the complete production and pressure history.
We have found that an approach combining analytical and numerical models has been the most successful strategy in our work. As in this field case, analysis begins with the simple models and proceeds through more complex models as necessary to match the reservoir behavior in the desired detail.
Wellbore Liquid Blockage in Gas-Condensate Reservoirs
Authors: Ahmed Tarek , Evans John , Kwan Reggie , Vivian Tom 
Published: December 2007

Abstract
Gas condensate reservoirs have long presented production problems when the pressure around the well bore drops below the dewpoint pressure. The formation of the condensate around the well bore can be thought of as an additional "skin" that causes a reduction in the gas flow rates. Many processes have been used successfully to prevent or reduce the formation of liquids within the entire reservoir, such as pressure maintenance schemes and gas cycling processes. The pressure maintenance scheme is designed to keep the reservoir pressure at or above the dewpoint pressure while the gas cycling process is intended to reduce the liquid dropout by vaporization.
Often times the pressure in the near-wellbore region of the reservoir falls below the dewpoint pressure, while the pressure in the reservoir remains higher than the dewpoint pressure. As the near–wellbore pressure drops below the dewpoint pressure, retrograde condensation occurs leading to the formation and then the mobilization of the condensate phase towards the producing wells. The liquid phase accumulates in the near wellbore region, forming a ring, which progressively reduces the gas deliverability.
This study is designed to provide an insight into the mechanism of gas injection process in reducing gas-well productivity losses due to condensate blocking in the near wellbore region. The effectiveness of lean gas, N2, and CO2 Huff ‘n’ Puff injection technique in removing the liquid dropout accumulation in and around the wellbore is evaluated. Results of the study show the importance of selecting the optimum injection volume and pressure for the successful use of the Huff ‘n’ Puff process in gas condensate reservoirs.
Novel Application of Nondamaging Polymer Plugs with Coiled Tubing Improves Efficiency of Temporary Well Isolation Projects
Authors: Beall Brian B. , Suhy Thomas E. 
Published: December 2007

Abstract
Temporary well isolation projects have been successfully performed using a non-formation damaging polymer plug and coiled tubing. Previously used conventional kill muds can cause severe formation damage, reducing productivity once the well is put back into production. Other concerns while performing workover operations include the stability of casing in older wells to support inflatable plugs and the entry size to expansion diameter required to set the packer in each well. Use of a crosslinked polymer plug in conjunction with coiled tubing achieved accurate placement while avoiding the problem of overdisplacement. The crosslinked polymer plug protected the formation while supporting the kill fluid allowing for multiple casing string top joints to be cut and welded, along with wellhead replacement to be accomplished.
A second application of this non-damaging temporary isolation plug has been to control sloughing shales. These shale fragments tend to bridge off on ledges located above gauge hole sections causing problems running and setting production casing through the caving area. The crosslinked polymer plug has been used to suspend the shale fragments allowing the casing packer to be un-set and lowered through the problem area without any problems.
Real-Time Pressure Diagnostics Used To Improve Pre-Treatment Frac Design: Case Studies in the Antrim Shale
Authors: Dozier G. C. , Sutton T. 
Published: December 2007

Abstract
Over thousands of fracture treatments have been performed in the Antrim Shale of Northern Michigan. Very few have been altered significantly based on pressure data acquired from each preceding treatment. In essence, there has been very little evolution in how operators stimulate the Antrim. Primarily, this is due to the inability to accurately model (fracture) the effect of natural fractures in the Antrim Shale. Nevertheless, it is possible to use these models to analyze pre-treatment pressure responses to produce a more efficient frac design and improve the resulting frac conductivity. As the industry moves away from the "cookie cutter" frac design towards one specifically design, with minimal additional time and effort, for the well, a mere 10 mcf/d/well increase in production over a period of 10-15 yrs becomes very economical.
This paper will illustrate simple diagnostic tests that can be performed prior to each fracturing treatment to give good indication of fluid efficiency localized rock stress. Under real-time circumstances, a 10-15min injection test followed by a complete fall-off can yield an abundance of information regarding the viability of a particular fracturing treatment.
In the Antrim Shales on Northern Michigan, these diagnostic techniques have been used successfully to determine leak-off, closure, fracture extension and various other parameters essential in designing a fracturing treatment. In addition, pre-treatment results have been linked with the success or premature screen-out of particular wells in the Antrim. Through case studies, this paper will show a logical progression of data analysis based on diagnostic results.
Resultantly, a fracturing treatment can be designed or altered on location based on actual reservoir response and measured stresses. In turn, operators can regain a measure of predictability in controlling fractured behavior by tailoring a unique solution for each well without excessive time or added cost.
A New Approach to Predict Bit Life Based on Tooth or Bearing Failures
Authors: Bilgesu H. L. , Altmis U. , Ameri S. , Mohaghegh S. , Aminian K. 
Published: December 2007

Abstract
This paper presents a new methodology to predict the wear for three-cone bits under varying operating conditions. In this approach, six variables (weight on bit, rotary speed, pump rate, formation hardness, bit type, and torque) were studied over a range of values. A simulator was used to generate drlling data to eliminate arrors coherent to field measurements. The data generated was used to establish the relationship between complex patterns.
A three-layer artificial neural network was designed and trained with measured data. This method incorporates computational intelligence to define the relationship between the variables. Further, it can be used to estimate the rate of penetration and formation characteristics.
The new model was successful in predicting the condition of the bit. In this study, the value of 0.997 was obtained by the model as the correlation coefficient between the predicted and measured bearing wear and tooth wear values. The validity of the model was demonstrated with data from an existing field.
Prediction of Frictional Drag and Transmission of Slack-off Force in Horizontal Wells Using Neural Networks
Authors: Sadiq Tanvir , Gharbi Ridha 
Published: December 2007

Abstract
The use of mud motors and other tools to accomplish forward motion of the bit in extended reach and horizontal wells allows avoiding large amounts of torque caused by rotation of the whole drill string. The forward motion of the drill string, however, is resisted by excessive amount of friction. In the presence of large compressive axial loads, the drill pipe or coiled tubing tends to buckle into a helix in horizontal boreholes. This will cause additional frictional drag resisting the transmission of slack-off force to the bit. As the magnitude of the frictional drag increases, a buckled pipe can become "locked-up" making it almost impossible to drill further. In case of packers, the frictional drag may inhibit the transmission of set-up load to the packer. A prior knowledge of the magnitude of frictional drag for a given axial force and radial clearance can help avoid lock-up conditions and costly failure of the tubular.
In this study, we present a neural network model for the prediction of frictional drag and slack-off load transmission in horizontal wells. Several neural networks with different architecture were designed and tested to obtain the most accurate prediction of these parameters. After cross-validation of the neural network, a two-hidden layer model was chosen for simultaneous prediction of frictional drag and slack-off load transmission.
History and Potential Future of Improved Oil Recovery in the Appalachian Basin
Authors: Blomberg John R. 
Published: December 2007

Abstract
Although many concepts of Improved Oil Recovery (IOR) were first developed in the Appalachian Basin, early IOR methods were often inefficient and the quantity of oil in place in the various fields was small in comparison to many of the reservoirs found later in other states and countries. For these reasons, a lot of IOR investment money and expertise was not directed to the Appalachian Basin (Basin). This paper generally reviews the IOR methods used and crude oil recoveries in the five oil producing states in the Basin. A discussion is then presented of producing zones and IOR methods that might be successful in the future. Other aspects that could influence IOR development activity such as oil price and domestic demand are also discussed.
While 1998 oil prices do not encourage IOR development in comparatively low recovery oil fields as generally found in the Basin, this paper could serve as a starting point for operators looking for future IOR prospects. This interest could be stimulated by a world oil crisis that demanded an increased development of domestic crude oil production or by higher crude oil prices generated through any number of reasons.
Methods for Estimating Deliverability After Massive Fracture Completions in Tight Formations
Authors: Eilerts C. Kenneth 
Published: December 2007

Abstract
Three examples are provided for a desk calculation of the future deliverability of a gas well in a tight formation following massive hydraulic-fracture or nuclear-explosion stimulation. Methods of solution include a transient one that provides reservoir pressures at selected distances from the recovery well for a given recovery rate and well backpressure, and an arbitrary future stage of reservoir depletion. Steady-state equations have been devised to represent the effect of the improvement in permeability within the fractured area. permeability within the fractured area. A motive for developing the methods was to encourage the evaluation of fracturing prospects by persons who are not familiar with programmed computing.

Introduction
The practicability of extensive fracturing as a means of improving the deliverability of gas wells in low-permeability formations has been under investigation by the Bureau of Mines since 1963. A prediction was made of the benefits of nuclear stimulation for Project Gasbuggy in 1967. Following the stimulation, actual recovery data obtained by flowing the well in the chimney were analyzed by Lemon and Patel with results that substantiated much of Patel with results that substantiated much of the preshot estimate. Both investigations were made with the aid of programmed computing.
In view of the current widespread interest in methods for recovering natural. gas from the extensive low-permeability reservoirs of some western states, this present research was initiated to provide simple but dependable mathematical tools for appraising reservoir prospects. A progress report of the Natural Gas prospects. A progress report of the Natural Gas Technology Task Force provided background information for developing a set of equations to calculate deliverability of a well after massive fracturing. Most of the individual equations in this report have been used by engineers and scientists for many years, and it would be difficult to trace their origins.
In general, the treatment of problems has been to calculate the most deliverability that can be expected from a stimulated well. The result of a desk calculated analysis is intended to be as accurate as the approximations will permit, but is always an upper bound on the permit, but is always an upper bound on the deliverability to be expected. Approximations have been used to simplify procedures and to minimize the effort required for analysis. If a reservoir prospect is marginal or favorable, it should be reassessed by use of complete computing programs that give effect to variable properties and full consideration to all factors properties and full consideration to all factors that affect material balance. If a prospect is unfavorable, it can be rejected.
The equations required for calculating deliverability are described in the Appendix.
Neutron Decay Time in the Subsurface: Theory, Experiment, and an Application to Residual Oil Determination
Authors: Robinson J.D. 
Published: December 2007

Robinson, J.D., Member SPE-AIME, Shell Development Co.

Abstract
Theoretical solutions are given for the determination of thermal neutron decay time in the formation from measurements in the borehole with a capture gamma detector. Laboratory data from a sandstone formation of 17 percent porosity, saturated with water of various salinities, are in agreement with the principal theoretical predictions for the case principal theoretical predictions for the case of a capture gamma detector. The time derivative of the logarithm of the gamma activity is equal to the reciprocal of the neutron decay time in the formation plus a term that is, in general, time dependent. However, at source-detector spacings of 60 cm or larger, becomes independent of time at sufficiently long times following the neutron pulse. Also, is independent of the salinity of the aqueous phase.
The determination of residual oil saturation near the borehole of a nearly watered-out producing well in a sandstone reservoir in southern Louisiana is given as an application of this study. Stationary measurements with a specially constructed sonde and a time-of-flight analyzer were made. The FORTRAN programs used and an example of the input data programs used and an example of the input data are included.

Introduction
Two years ago we began a theoretical study of pulsed neutron logging, seeking to provide a quantitative understanding of how the measured apparent neutron decay time of a formation is related to the true neutron decay time, the decay time implied by the capture cross-section of the formation. A strong motivation for this study was the desire to determine the residual oil saturation in cased, watered-out wells by the use of log-inject-log techniques that require a measurement of true neutron decay time.
The Russian literature on pulsed neutron logging is more extensive than the American, and a model suggested by Polyachenko, Gavrina, Tseitlin, and Shaposhnikova was found most useful for the study of pulsed neutron logging with a gamma detector. Deductions from this model will be presented, and the data from experiments done at Schlumberger-Doll Research Center at Shell's request will be compared to those deductions. Finally, as an application of this study, we shall describe how measurements with a specially constructed sonde opposite a sandstone reservoir in a cased well in southern Louisiana were used to estimate the fraction of bulk volume of formation occupied by water. From this estimate and an independently known value of porosity, the residual oil saturation is immediately deducible.