bluuebunny/crossref_metadata_2025_split huggingface dataset:
Onset of Drillstring Precession in a Directional Borehole
Authors: Dunayevsky V. A. , Judzis A. , Mills W. H. 
Published: December 2007

ABSTRACT
This paper presents a mathematical procedure for the determination of drillstring precession in a directional borehole and stability of drillstring rotation constrained by borehole geometry.
The conditions are found when the energy of axial vibrations is transformed into energy of transverse vibrations. Under these conditions the drillstring rotation around its axis becomes unstable and the transition to the rotation around borehole axis, i.e. pre-cessional motion, takes place. The conditions are formulated in terms of rotary speeds, amplitude of weight-on-bit vibrations, damping and geometry. A finite element procedure reduces the partial differential equation describing drillstring dynamics to a set of Mathew-Hill ordinary differential equations. The boundaries of parametric resonances for these equations determines the onset of precessional motion of the drillstring.
The results can be used to predict stable performance of drillstrings during directional drilling operations.
Propagation of Polymer Slugs Through Porous Media
Authors: Lecourtier J. , Chauveteau G. 
Published: December 2007

ABSTRACT
This paper describes an experimental and theoretical study of the mechanisms governing polymer slug propagation through porous media. An analytical model taking into account the macro-molecule exclusion from pore walls is proposed to predict rodlike polymer velocity in porous media and thus the spreading out of polydispersed polymer slugs. Under conditions where this wall exclusion is maximum, i.e. at low shear rates and polymer concentrations, the experiments show that xanthan propagation is effectively predicted by this model. At higher flow rates and polymer concentrations, the effects of hydrodynamic dispersion and viscous fingering are analyzed; A new fractionation method for determining molecular weight distribution of polymers used in EOR is proposed.
A Simple Analytical Model for Simulating Heavy Oil Recovery by Cyclic Steam in Pressure-Depleted Reservoirs
Authors: Gontijo J. E. , Aziz K. 
Published: December 2007

ABSTRACTThe cyclic injection of steam to stimulate or produce wells in heavy oil reservoirs is extensively employed by the oil industry. The performance of such wells may be predicted from empirical correlations, simple analytical models or thermal reservoir simulators. Empirical correlations can be extremely useful for correlating data within a field and for predicting performance of new wells in that and similar fields. However, use of such correlations for situations much different from the ones that led to their development can be subject to large errors. On the other hand one can use a compositional thermal model to predict the performance of cyclic steam operations. While thermal models are based on the fundamental laws of conservations, the fluid flow is related to pressure gradient through the empirical concept of relative permeability. In addition, the inherent sophistication of a thermal model makes it sensitive to rock properties, fluid properties and geological features. Much of this information is often unknown and must be estimated from limited data and experience in similar situations. Furthermore, because of the complexity of the recovery process - which involves reversal of flow directions - the equations of a thermal simulator are difficult and expensive to solve. All of this means that the use of a sophisticated thermal model may not be appropriate for routine design of cyclic steam operations. Instead one must consider the development and use of simple analytical models which give due consideration to important mechanisms involved in the process.In this study existing analytical models for cyclic steam are reviewed and a new model is proposed. This model incorporates many of the features of existing models with some important refinements. The flow rate of oil in the model is influenced by oil viscosity, effective permeability of the heated zone, porosity, mobile oil saturation and thermal diffusivity of the reservoir. The change in reservoir temperature with time is also modelled, and it results in the expected decline in oil production rate during the cycle. The model accounts for the heat remaining in the reservoir from previous cycles. The model equations are kept as simple as possible and, wherever appropriate, correlations are incorporated to minimize data requirements.The results of the model compare well with available field data and another analytical model. The model results are also compared with a thermal simulator.
"Service and Supply"
Authors: Cruikshank T. H. 
Published: December 2007

Abstract
Ladies and gentlemen, I am honored to be here today. My topic is "Surplus and Shortages in the Service and Supply Industry" --and, in a broader sense, the outlook for the industry,
Let me say at the outset that the outlook is better now than it has been. But before anyone gets too excited, we must remember that from our industry's viewpoint it would be difficult for the situation to get cny worse than it was. Nor can we be certain that "better" will be enough to eliminate our problems in the short term. For the longer term, though, I believe there are brighter times ahead.
What is really brought home in analyzing where we were, where we are, and where we are going is the clear message that the old, predictable economic rules of supply and demand are functioning freely in our market place, And I don't believe we can escape them, Certainly, we in the service and supply industry enjoy it a lot more when demand is rising and our main problem is how to increase supply. However, it is also apparent that the pendulum sometimes swings too far before the corrective mechanism begins to work, Then the adjustment is painful and costly, That has been our experience in recent times.
Conclusions Based on Laboratory Tests of Tubing and Casing Connections
Authors: Biegler K. K. 
Published: December 2007

ABSTRACT
In the last two years, many of the available tubing and casing connections have been evaluated at the Exxon test facility. While we have not tested every available connection on the market, these tests have covered a range of connection types which incorporate the most commonly utilized connection design features. These features include various thread forms and configurations and also independent seal designs and seal combinations. In all cases, testing showed behavior that either differed from the manufacturer's published claims or varied from the behavior predicted by generally accepted mathematical models. The behaviors this paper will discuss include stress magnitudes and distributions, leak resistance under combined loads, and individual pressure and tension capabilities. Conclusions based on this test data will be presented for each design feature tested. Also included in the discussion are overviews of the new technology in connection designs which have evolved, in the most part, from attempts to solve the problems brought out in the existing test data. While most of these problems have not led to catastrophic failures in the field or laboratory, they have pointed out the need for better connection performance models and laboratory verification of these models.
Predicting Makeup Torque of Threaded Tapered Connections and Evaluation of Coefficients of Friction
Authors: Hawke Melvin C. 
Published: December 2007

ABSTRACT
This paper will show how it is possible to generate a general purpose formula to determine the amount of torque required to make up non-shouldering tapered threaded connections as are commonly used on tubing and casing connections. In addition, by manipulating this algorithm, values for the dynamic coefficient of friction of thread compounds may be derived. This algorithm allows any type of thread form to be analyzed and was verified through actual testing.
Threaded Connector Evaluation for Heavy-Wall Production Tubing in a Deep Well
Authors: Payne M. L. , Galate J. W. , Allen M. B. , Hurst D. M. 
Published: December 2007

ABSTRACT
In order to qualify a connector for a deep, critical service gas well, a connector evaluation program was executed which included both destructive laboratory testing and computer analysis. The advantage of using both tests and analysis to evaluate connector performance is emphasized. Both tests and analysis have strengths and limitations that must be understood and properly manipulated to construct an optimum evaluation program.
3D Thermal Simulation Using a Horizontal Wellbore for Steamflooding
Authors: Rial R. M. 
Published: December 2007

ABSTRACT
Steamflooding has been used for years in enhanced oil recovery. However, the use of a horizontal wellbore for injection is a relatively new application that could improve process efficiency. This paper explores the effect of a horizontal wellbore for steamflooding using a three-dimension thermal simulator. Using a Primos 1, and lately a Cray-1, a comparison was made between a conventional vertical wellbore and a horizontal wellbore model.
The data used were representative of the Kern River Field, Kern County, California. The results of the two models showed a 13% increase in oil recovery for a horizontal wellbore. The temperature and oil phase saturation distribution revealed an improved sweep efficiency with a horizontal wellbore. For a five year period the horizontal model had production of 214.14 MSTB (64% OOIP) compared to 163.61 MSTB (51% OOIP) for the vertical model. After 15 years the horizontal model produced 237.55 MSTB (71% OOIP) and the vertical model produced 194.01 MSTB (58% OOIP). The heat transmissibility was higher throughout the grid system using the horizontal model.
A horizontal wellbore proved to enhance oil recovery for steamflooding using the data and simulation developed. There are also possible applications to other enhance oil recovery processes.
Cased-Hole Evaluation with the Chlorine Log
Authors: Deimel J. M. , Andrus D. G. 
Published: December 2007

ABSTRACT
Typical problems faced by operators in the Gulf of Mexico are the evaluation of low resistive potentially productive zones and depleted zones behind pipe. Tenneco Oil Company has used the chlorine logging system to solve these problems in numerous wells and several case studies are presented.
The chlorine logging system is a neutron-capture spectral measurement and analysis technique which provides a quantitative, 1ithology-independent water saturation (Sw) interpretation. Water saturation is derived from the measured spectral response, formation porosity, formation water salinity, and well bore geometry. No corrections for borehole fluid or shale volume are necessary. This logging system demonstrates its usefulness in evaluating low resistivity pay zones and evaluating water movement within producing and/or produced zones.
A Fast Coupling for a Deepwater Drilling Riser
Authors: Le Peuvedic J. P. , Guesnon J. , Soleille L. M. 
Published: December 2007

ABSTRACT
ELF AQUITAINE and TOTAL have operated the D.P. drill ship Discoverer Seven Seas in the Mediterranean Sea, temporarily establishing a new world water depth record on GLP1 well located south of Marseilles in 5 624 ft of water.
The success of this well and the following well GLP2 in the same area can be partially attributed to the careful engineering devoted to the riser system in cooperation with Institut Francais du Pétrole (I.F.P.). This riser built by CREUSOT-LOIRE uses a new connector allowing fast make-up and disassembly resulting in considerable time saving and increased safety for deep water operations.
Unlike all the other riser couplings, the CREUSOT-LOIRE/I.F.P. connector has no prestressed members. The load is entirely carried through compressive stresses at the interface. This eliminates the requirement to preload by tightening six or more bolts. Therefore the connector closing time is drastically reduced and the assembly of the riser is speeded up and nearly three times faster than conventional preloaded types.
Modified McKinley Early-Time Well-Test Analysis for Very Large Reservoirs: An Application to Prudhoe Bay
Authors: Petersen E. J. , McNaughton D. A. , Economides M. J. 
Published: December 2007

ABSTRACT
Pressure buildup tests from wells of a very large reservoir are analyzed using McKinley Early Time Analysis as extended by Streltsova-Adams and McKinley (1982) to account for partial completion. Other recent papers which address the issue of partial completion are briefly summarized also. Because the wells are directionally-drilled and partially-completed, a configuration pseudo-skin equivalent is determined for each well using correlations developed by Cinco-Ley, Ramey and Miller (1975). This quantity, which is a function of completion ratio and location, hole angle, and dimensionless formation thickness, corresponds to a Streltsova-Adams and McKinley (1932) partial completion factor. The configuration pseudo-skin equivalent varies from zero to one and is used for type curve selection in the same manner as the partial completion factor.
This work presents a procedure for the determination and application of the configuration pseudo-skin equivalent and demonstrates its use in early time analysis. Data from twelve pressure buildup tests on five Prudhoe Bay wells are analyzed and the results are presented with a discussion. It is shown that by accounting for all pseudo-skin effects due to well configuration, McKinley Early Time Analysis can be generally applied to yield consistent and reliable results, allowing valuable information to be obtained from conventionally uninterpretable pressure buildup tests.
MWD: Formation Evaluation Case Histories in the Gulf of Mexico
Authors: Hendricks W. E. , Coope D. F. , Yearsley E. N. 
Published: December 2007

Abstract
Measurement-While-Drilling (MWD) logs are being used in the Gulf of Mexico for formation evaluation as well as for drilling applications in both exploratory and development operations. This study presents six case histories involving MWD data. They have been selected to illustrate various applications and some special features of MWD logs. Excellent well-to-well correlations with offset wireline logs as well as reservoir fluid movements in producing fields have been observed. Troublesome wells that could not be logged with conventional wireline techniques have been successfully logged with MWD tools. MWD resistivity data have been used to infer formation pore pressures. The quantitative accuracy of MWD logs is demonstrated by comparison with wireline induction logs recorded in the same wells.
The Effect of Bit Hydraulics on Bit Performance in Relation to the Rock Destruction Mechanism at Depth
Authors: Feenstra R. , Zijsling D. H. 
Published: December 2007

ABSTRACT
Bit hydraulics can contribute to a bit's performance by one or more of the following actions: *reduction of chip holddown*jet cutting*reduction of bottom balling*reduction of bit balling*transport of cuttings towards the annulus.
How and to what extent bit hydraulics can help to improve bit performance is mainly determined by the bit's cutters (teeth, inserts, diamonds, PDCs, jets), the drilling fluid and the formation drilled under downhole conditions. The introduction of a self-cleaning bit strainer and self-cleaning bit cutters widens the scope of bit hydraulics, particularly for PDC-type bits.
Planning and Practical Problem Solving Using an Engineering Simulator for Drilling
Authors: Brett J. F. , Summers M. A. 
Published: December 2007

ABSTRACT
This paper contains examples and case studies showing how a detailed drilling simulator can be used as a tool to help make decisions concerning bit selection, proper hydraulics, solids control, mud system selection, and the development of a comprehensive well plan. These studies demonstrate the value of the simulation process and how it can be used to weigh the options facing an operator and determine their effect on the final well cost.
The example results indicate not only that the simulator is capable of modeling the drilling process accurately and in great detail, but that each alternative that is simulated can have a cost calculated for it so it can be compared against the other options. This ability to evaluate different options is shown to be an integral part of the well planning procedure. The use of the simulator can help develop and improve comprehensive drilling plans more quickly than the use of conventional analysis. This allows faster learning and cost savings in actual field operations.
An Unusual Case of Salt Plugging in a High-Pressure Sour Gas Well
Authors: Place M. C. , Smith J. T. 
Published: December 2007

Abstract
During the course of development of the deep Mississippi Smackover trend Shell encountered a particularly troublesome production problem in one well, the Shell Ridgway 1-R well in the Southwest Pineywoods Field. This well plugs after producing approximately 1 BCF of gas and must be treated on a regular basis by injecting fresh water to restore the productivity of the well. Eight other Shell wells in three fields in the deep Mississippi Smackover trend have produced without encountering this problem. We have concluded that the plugging observed in the Shell Ridgway 1-R well is caused by the deposition of NaCl in the well bore. We believe that a trace of brine (±0.05 bbl/MMCF) is produced from an anomalously high water saturation interval in this well. This high water saturation interval is located ±300 ft. above the gas water contact in the field. Other zones having low water saturations were penetrated at greater depths in the well. We believe that this unexpected production of a small amount of brine from an isolated interval within the pay section possibly combined with the nature of the well completion created the plugging problem.
Initially we did not consider that brine flow could occur in a well completed ±300 ft. above the gas water contact. Instead we thought that transport of NaCl in the high pressure sour gas might be responsible for the plugging. To evaluate this possibility we supported a program conducted by Dr. James B. Hyne of the University of Calgary to measure the solubility of salt at reservoir conditions in the sour gas. His measurements show that trace amounts of NaCl are carried in the high pressure sour gas. However, we were not able to use Hyne's results to explain the difference between the production characteristics of the Shell Ridgway #1-R well and the other wells in the trend. Hyne's results do raise a warning that under certain conditions plugging due to NaCl deposition in the reservoir may occur in high pressure sour gas wells. Tn this paper we shall develop our understanding of this plugging problem by presenting material on two wells: the Shell Ridgway 1-R well in the Southwest Pineywoods Field, and the Shell Burch #1 well in the Thomasville Field. These two wells have pay zones of similar quality and are located in similar positions relative to the gas water contacts in their respective fields. The following items will be discussed:
Characteristics of the pay intervals, reservoir conditions and structural settings for the two wells. Completion and production histories for the two wells. The solubility of NaCl in sour gas based on the work of Dr. Hyne and the implications of these data for the plugging problems. Chemical evidence to support the hypothesis that NaCl deposition occurs from brine flowing into the Shell Ridgway 1-R well. A suggested prognosis of the sequence of events during a plugging and treatment cycle of the Shell Ridgway 1-R well.
Rod Pumping Optimization Program Reduces Equipment Failures and Operating Costs
Authors: Allen L. F. , Svinos J. G. 
Published: December 2007

ABSTRACT
In 1975, an intensive program was initiated by Gulf Oil E&P Central Area to reduce rod and tubing failure rates in the fields of the northwest corner of Crane County, Texas. Chronologically the program steps were: 1) The replacement of rod strings experiencing three failures in three months. 2) The replacement of tubing strings experiencing two failures in three months. 3) The use of inspected, classified and plastic coated new or used grade "C" rods. 4) The use of inspected, classified and internally plastic coated used or new tubing. 5) The exclusive use of high working stress rods. 6) The exclusive use of specially designed fiberglass sucker rod systems with improved sinker bar design.
This program reduced rod failure rates from 16% to 4% and tubing failures from 7% to 3% per month. The lighter rod design reduced lifting costs by $2 MM per year on 880 active wells. Of the 219 wells equipped with fiberglass sucker rods in the last two years, there have been no operational body breaks or tubing leaks.
Vertical Single-Well Pulse Testing of a Three-Layer Stratified Reservoir
Authors: Lee S. T. , Chien M. C. H. , Culham W. E. 
Published: December 2007

Abstract
A new mathematical model is developed for analyzing single-well pulse test data from a reservoir consisting of two permeable zones separated by a less permeable zone. The model considers well-bore storage and skin effects and allows the three zones to have different rock properties. The line-source assumption used in developing the analytic solution is validated via comparison of results with another model also developed in this work. This latter model assumes identical rock properties for the two permeable zones but allows the wellbore radius to be finite.
The numerical Laplace inversion methods available in the literature are evaluated with respect to some simple functions and the analytic Laplace space solution of the problem of interest. It is found that the Fourier-series and Zakian's methods can serve as alternatives to the well-known Stehfest algorithm.
The effects of wellbore storage and skin on single-well pulse testing of layered reservoirs are investigated. Consistent with the findings in the literature for multiwell pulse testing, it is shown that the influence of wellbore storage and skin is to reduce the response amplitude and to increase the time lag of the pulse response. Among the wellbore storage and skin factors involved in a single well pulse testing, the skin associated with the observation interval is least influential on the pressure response.
Using field data, it is shown that the mathematical model presented can be used, in conjunction with an optimization subroutine, to estimated the parameters of interests. It is further shown numerically that neglecting the effects of wellbore storage and skin could result in an underestimation of the formation permeabilities of interest. The problem of non-uniqueness of solution for parameter estimation using optimization techniques is also discussed for the subject problem.
Experimental and Numerical Investigations of the Primary Depletion of a Critical Fluid
Authors: Alonso M. E. , Nectoux A. C. 
Published: December 2007

ABSTRACT
The oil recovery expected from a fractured rich condensate gas reservoir is usually low. Most of the liquids remain trapped in the matrix porosity. However, when the amount of condensate is high, i.e. for a hyper-critical fluid, a simple natural depletion could lead to very high recovery levels, especially when the reservoir is heavily fractured. The object of this study was to understand physically and numerically the compositional flow mechanics which take place inside the fracture-matrix reservoir rocks. From the results it appears that high recovery levels could be also foreseen for natural depletion of volatile oil reservoirs.