bluuebunny/crossref_metadata_2025_split huggingface dataset:
High-Permeability Fracturing at Prudhoe Bay, Alaska
Authors: Reimers D. R. , Clausen R. A. 
Published: December 2007

ABSTRACT
High permeability hydraulic fracturing at Prudhoe Bay? This paper documents the results of a very successful fracturing program at Prudhoe Bay in which ARCO Alaska Inc., Unit Operator for the Eastern Operating Area (EOA), has successfully fracture stimulated over 100 wells, with a total oil rate benefit that has exceeded 100,000 STB/D. The more prolific stimulations have resulted in individual well responses of greater than 5000 STB/D. BP Exploration (Alaska), Unit Operator for the Western Operating Area (WOA), has also instituted an aggressive fracturing program. The field wide program has significantly contributed to maintaining Prudhoe’s production rate at the onset of the field’s decline.
Relatively long, highly conductive fractures have proven quite effective at bypassing extensive formation damage and also accelerating oil production on the less damaged wells. This paper documents the development of the fracturing program which illuminates the potential for successfully fracture stimulating higher permeability reservoirs.
New, Delayed Borate-Crosslinked Fluid Provides Improved Fracture Conductivity in High-Temperature Applications
Authors: Brannon H. D. , Ault M. G. 
Published: December 2007

ABSTRACT
Moderate to high-temperature reservoirs frequently require hydraulic fracturing stimulation to be effectively produced. Temperature-stable viscosified fluids are needed to successfully execute treatments in these harsh downhole environments. The evolution of high-temperature fracturing fluids has led to the use of organometallic-crosslinked, aqueous-based guar or derivative guar gels. These fluids yield high viscosities for long periods of time at elevated temperatures and have received widespread application.
Unfortunately, several recent studies illustrated that organometallic-crosslinked fluids can cause significant damage to the permeability of the proppant pack. An industry consortium reported that the proppant pack permeability damage is often greater than 80% when these fluids are applied. Damage of this magnitude dramatically reduces the effectiveness of the stimulation treatment. Delayed breaker systems, recently introduced to reduce the permeability damage, have limited applicability at temperatures greater than 200°F and, where applicable, greatly increase treatment costs.
A guar-based fluid utilizing a new, organically-complexed borate crosslinking system has recently been developed. Laboratory evaluations of this new system demonstrate superior rheological properties at temperatures exceeding 300° F. More significantly, the new fluid has been observed to be much less damaging to the proppant pack permeability than conventional organometallic-crosslinked fluids. Retained permeabilities greater than 85% have been observed, without breaker, at 250°F.
The rheological, proppant transport, fluid loss and retained proppant pack permeability performance of the high-temperature borate-crosslinked fluid are described and compared to conventional fluids. Field case histories are provided to support the laboratory data.
Modeling of Formation Damage Due to Physical and Chemical Interactions between Fluids and Reservoir Rocks
Authors: Chang Frank F. , Civan Faruk 
Published: December 2007

ABSTRACT
A phenomenological model for formation damage in petroleum reservoirs is presented to describe the rock/fluid interaction processes including particle migration, physico-chemical interactions between invading fluid and reservoir rock, and geochemical reactions. Chemical reactions involving dissolution/precipitation and ion exchange are modeled. The precipitates are considered movable and mixed with other fine particles to contribute to the pore throat plugging. Size distribution of both precipitates and clay fines are accounted for by a bimodal distribution function. A probabilistic approach is used to calculate the fraction of the plugged pore throats. The model parameters are determined through an optimization method by fitting with experimental data.
The capability and validity of the model are demonstrated by comparing the predictions obtained from this model with previously published experimental data. The specific case considered addresses the effect of injection fluid composition. The predicted and the experimental data are shown to be in good agreement. This new model has a broader applicability in diagnosis, evaluation, and simulation of formation damage during drilling, production, and EOR processes. It can also be used to predict the performance of acidizing and other chemical flooding processes.
X-Ray Microtomography: A New Tool for the Characterization of Porous Media
Authors: Dunsmuir J. H. , Ferguson S. R. , D’Amico K. L. , Stokes J. P. 
Published: December 2007

Abstract
In this paper we describe the application of a new high-resolution X-ray tomographic microscope to the study of porous media. The microscope was designed to exploit the properties of a synchrotron X-ray source to perform three dimensional tomography on millimeter sized objects with micron resolution and has been used in materials science studies with both synchrotron and conventional x-ray sources. An overview of the microscope design, operating modes, the reconstruction algorithm and the data display will be presented. The performance of the microscope using conventional and synchrotron sources will be compared. In this work we have applied the microscope to measure the three dimensional structure of fused bead packs and berea sandstones with micron resolution and have performed preliminary studies of flow in these media with the microscope operated in a digital subtraction radiography mode. Computer graphics techniques have been applied to the data to visually display the structure of the pore body system. Tomographic imaging after flow experiments should detect the structure of the oil-water interface in the pore network and this work is ongoing.
Reservoir Fluid Characterization Using Ultrasonic Velocity
Authors: Ye S. , Lagourette B. , Alliez J. , Saint-Guirons H. , Xans P. , Montel F. 
Published: December 2007

ABSTRACT
Reservoir fluids are usually characterized by phase equilibria measurements and volumetric properties. In this paper, we show that integrating ultrasonic velocity in the database increases the predictability of the model. Acoustic sensitivity to the fluid characteristics also permits direct detection of phase transitions.
Ultrasonic velocity is related in a simple way to isenthalpic and isentropic compressibility, hence the importance of its measurement and modelling in temperature and pressure ranges encountered in oil and gas processing where choke (mainly isenthalpic) and compressors (mainly isentropic) are widely used.
Ultrasonic velocity measurements have been performed on pure hydrocarbon compounds, binary mixtures and reservoir fluids at different temperatures and pressures up to 130°C and 70 Mpa. The measurements are much more accurate than for any other thermodynamical property, the accuracy of our determination is about +/− 0.5 m/s and the typical range is from 1000 to 1500 m/s.
Furthermore, phase transitions are determined easily by this method even in the case of liquid/liquid equilibria.
The experimental results are compared to the values calculated using different thermodynamic models and different mixing rules. A calculation procedure, applicable in the case of any model, is described.
It is shown that cubic Equations of State, poorly adapted to the description of pure compounds and binary mixtures, are very reliable to model the behaviour of complex mixtures such as reservoir fluids.
Characterization of Swirling Flow and its Effects on Orifice Metering
Authors: Shen J. J. S. 
Published: December 2007

ABSTRACT
The effects of swirling flow on the measurement accuracy of a 152 mm (6 inch) orifice meter are presented in this paper. The test was conducted in a low-pressure air flow calibration facility with swirls generated by an axial vane-type swirler. The flow fields inside the orifice meter were characterized by a multiport pitot-static probe traversing across the meter run. The orifice meter performance was compared with reference critical flow nozzles.
The salient features of the observed flow fields compared quite closely with swirling flows generated by two close, out-of-plane elbows reported in the literature. The axial velocity profile was shown to be generally flatter than the fully-developed one. The swirl angle measurements delineated a secondary flow pattern of solid-body rotation. Without a flow conditioner in the line, the orifice meter was found to under-measure the true flow rate in a swirling flow. The deviation in flow measurements increased with increasing swirl angle. The tube bundle flow conditioner was very effective in removing swirls in the flow but not rectifying the deficient axial velocity profile. Based on the collected swirling flow data, a method was proposed to estimate possible swirl-induced flow rate errors for orifice meters in field use.
Modeling of Wellbore Heat Losses in Directional Wells Under Changing Injection Conditions
Authors: Chiu K. , Thakur S. C. 
Published: December 2007

Abstract
Although many analytical wellbore heat loss models have been presented, none has addressed the problems associated with (i) directional wells and (ii) changing injection conditions. Today, more and more wells are drilled directionally. Moreover, the injection rate, pressure, temperature and steam quality seldom remain constant throughout the injection period. This paper presents a semi-analytical model which can determine heat losses from directional wells (deviated or horizontal wells) under changing injection conditions.
To model directional wells, the well is divided into a number of segments whose inclination angle can be varied with depth. The energy and pressure equations are coupled and solved iteratively for each segment. The changes in injection variables (rate, pressure, temperature and steam quality) are approximated by step functions and the method of superposition is used. A new empirical expression is used to determine the transient heat loss to the formation. This simple expression is valid for all times and gives results closer to the exact solution than the more commonly used long time asymptotic solution.
The sample calculations in this paper illustrate the differences in heat losses between vertical and directional wells and demonstrate that the assumption of constant wellhead conditions may give unsatisfactory results in cases where the injection conditions vary.
An Experimental and Fundamental Interpretation of Fracturing Filter-Cake Fluid Loss
Authors: Mayerhofer M. J. , Economides M. J. , Nolte K. G. 
Published: December 2007

ABSTRACT
Interpretation and modeling of filtercake leakoff experiments are presented. Crosslinked polymer fracturing fluids were used under static conditions. Relationships between ratios of leakoff coefficients and polymer loadings were determined. These can lead to the calculation of any value if one is obtained experimentally. It was determined that the filtercake behavior deviated from the square-root of pressure dependence for an incompressible cake. Experiments, using a constant pressure differential across the cake, indicate relationships between leakoff coefficient and pressure raised to powers approximately 0.25 or less depending on the pressure value, whereas previous work reported a single proportionality for all pressures. Since pressure varies continuously throughout the pumping and closing of a fracture treatment it was imitated experimentally resulting in different pressure differentials at different times. The observed behavior is explained introducing the concept or filtercake resistance. Data interpretation for changing pressures indicates an apparent fluid-loss hysteresis, characterized by the behavior of polymer cakes subjected to changing pressures and by additional cake build-up. A more fundamental interpretation is provided from the theory of viscoelasticity. The hydraulic filtercake resistance, proportional to a rate-normalized pressure difference, leads to a stress-sensitive skin-effect, exactly analogous to similar situations in pressure transient analysis.
A Method for Gas Well Decline Analysis Under Constant Pressure Conditions and High-Velocity Flow
Authors: Vega P. J. , Samaniego V. F. , Berumen C. S. 
Published: December 2007

ABSTRACT
The correlation most widely used for predicting the rate decline of gas wells is that of Lee, Logan and Tek, which was derived from results of different constant rate production conditions. This paper presents the results of a study aimed at obtaining a correlation of the turbulent term coefficient D(μ) for constant pressure bottomhole conditions. Results were acquired through a radial real gas flow simulator, carefully tested for pseudosteady state conditions. The skin effect considered varies from 0 to 10. Two different gases are considered and other variables are the constant pressure, the reservoir size re/rw and formation permeability. The correlation is presented by means of log-log straight line fits of D(μ)qsc/Fμ (1-rw/rd) in the vertical axis and for the horizontal axis two options are considered: a) D(μi,s)qsc where D(μi,s)=D(μi)f (k/ks),f(k/ks)=β(ks)/β(k) (1–rw/rs)+rw/rs–rw/re, for the case of available estimates for ks and rs and b) sD(μi)qsc if the above mentioned estimates are not available; the correlation coefficient was 0.99968 for option a) and 0.99920 for option b) An easy method for predicting rate decline under transient and pseudosteady state conditions is presented.
Analytic and Numerical Model Studies of Cyclic CO2 Injection Projects
Authors: Emanuel A. S. , Tang R. W. , Fong W. S. , Langston M. V. 
Published: December 2007

Summary
This paper describes two methods for modeling cyclic CO2 injection projects: (1) analytic, based on decline curve analysis, and (2) numeric, based on 2D and 3D compositional radial models derived from detailed geostatistical analysis of near wellbore properties. The application of the decline curve analysis is shown for several published and unpublished CO2 Huff-Puff projects. The numeric models are described for successful and unsuccessful field trials.
An Approach to Screening Development Concepts for Static Resources
Authors: Dubose L. W. , Hordern M. J. , Hoh C. F. 
Published: December 2007

Abstract
This paper describes the approach taken by Esso Production Malaysia Inc. (EPMI) recently to review its portfolio of marginal oil resources (or "statics") associated with existing fields. This review was conducted in light of the latest technology to identify feasible development concepts and generate a seriatim of activities that could be undertaken, given an appropriate economic environment. A three man multi-discipline core team met with staff members to identify all current reserves additions ideas and address the concerns involved in their development. Preliminary development concepts were formulated and then refined using ideas and advice obtained from Exxon's international affiliates via the company's worldwide computer mail system. Applications of technologies ranging from extended reach drilling from existing platforms to use of mini-platforms and subsea wells were considered. Based on screening analysis, a seriatim of technically feasible projects was developed.
This paper also discusses EPMI and industry extended reach drilling experience, the evolution of EPMI'S approach to platform design concepts, and some affiliate experience in the areas of small offshore structures and subsea wells.
Gas Gathering: Toward a More Efficient Use of Western Australia's Energy Resources
Authors: Morhall J. P. , Parkhurst N. H. , Ryan D. P. , Yap D. C-L. 
Published: December 2007

Abstract
This paper briefly describes the history of gas development in Western Australia (WA) and overviews the Harriet Gas Gathering Scheme now under construction, which is the first project to collect associated gas in conjunction with non associated gas. The economics of gas gathering schemes are illustrated by reference to a case study and an approach to a gas flaring and gas gathering strategy for Western Australia is proposed. The implications of such a strategy for the petroleum industry and the development of WA are outlined.
The Role of Coiled Tubing in the Western Operating Area of the Prudhoe Bay Unit
Authors: Walker E. J. , Schmohr D. R. 
Published: December 2007

Abstract
Coiled Tubing is used in over 1000 operations a year in the western half of the Prudhoe Bay Unit. Fishing operations, well cleanouts, inflatable packers and bridge plugs, cement squeezes, logging, N2 lifts and jet pump operations are routinely performed year round. Special considerations taken into account include temperatures to −60° F, winds to 100 mph and the environmental sensitivity of the area.
Since 1980, when coiled tubing was first used at Prudhoe, it's use has expanded from simple corrosion inhibitor and acid pumping treatments to include the full range of operations listed above. In this time frame procedures have been worked out to ensure safe, trouble free operations. Accounting for the extreme environmental sensitivity of the area, for example, all rig ups employ flanged connections from the wellhead to the four ram BOP stack. Limits have been set on coil longevity and BHA's (Bottom Hole Assemblies) use safety equipment including hydraulic releases and check valves.
It is the purpose of this paper to discuss the evolution of coiled tubing operations in the WOA (Western Operating Area) of the Prudhoe Bay Unit. Upon completion of the paper one will have an excellent understanding of the wide range of uses for coiled tubing and the type of equipment / procedures necessary to do the job.
Rod Pumping Optimization in Duri Field
Authors: Nagy T. A. 
Published: December 2007

Abstract
This paper details a program that has improved the quality, quantity, and usage of dynamometer surveys in the Duri Field. The programs' evolution, from an evaluation of various dynamometer data gathering systems, to a comprehensive well surveying and lift system optimization program, is detailed. This comprehensive system includes routine well monitoring, problem evaluation, minicomputer database, and personnel training. This program has resulted in significant improvements in individual well profitability, optimum utilization of well servicing equipment, and superior engineering design data.
Workover Techniques in Bass Strait
Authors: Bisset S. J. 
Published: December 2007

Abstract
Over 200 workovers have been completed In Bass Strait since 1987. These workovers have been a major factor in arresting the decline of Bass Strait oil production. The work has been performed with a variety of equipment, including wireline, coiled tubing, hydraulic concentric and jack-up rigs. Individual costs have ranged from less than A$ 1k up to A$ 4M.
Bass Strait has 300 completions with an average age of 12 years, giving rise to numerous workover opportunities. Due to the isolation of Bass Strait, conventional workovers have proved expensive with long lead times. Hence effort has been placed on innovative wireline or concentric workover techniques, that have restored wells to production without resorting to conventional workovers.
Pressure Mapping as an Aid to Understanding Reservoir Drainage
Authors: Anderson J. S. 
Published: December 2007

Abstract
This paper outlines an analytical technique for estimating well drainage areas in bounded or "semi-bounded", multiple well reservoirs. The technique is based on calculating reservoir pressure throughout the field in question and producing pressure maps over that field. From the pressure mapping, streamlines tracing the path of fluid towards the well can be plotted and drainage areas discerned. A method has been derived whereby the areal water cut development of a well and sweep efficiency can be estimated.
The technique is applied to a number of problems including the effect of flowrate variation on well drainage areas, infill drilling, well abandonment, water injection and horizontal well drainage in the vertical plane.
An Interpretative Method for Production Logs in Three-Phase Flows
Authors: Hai-Min Guo , Cheng-Dang Zhou , Zhen-Wu Jin 
Published: December 2007

Abstract
Most of oil fields in China have been in the mediate and later production stages during which flowing pressure is usually lower than bubble point pressure and hence the production zones produce usually in the form of oil, gas and water three-phase flows. In three phase flows, the difference among oil, gas and water properties such as density, viscosity and in-site velocity causes the complex response of production logging tool(spinner flowmeter, watercut meter). Consequently, how to determine the accurate oil, gas and water production rates of each perforated interval is a key problem in the comprehensive interpretation of production logs and well performance monitoring.
Based on experimental result from flow loop, theoretical analysis as well as practical data, the paper presents a new interpretive method for three phase flow with the inflatable diverter production logging instrument and the new response equations of water cut tool and spinner flowmeter in multiphase flow, and how to use production logging data for determining flow pattern is also given in this paper.
The field example from Chinese oil field has demonstrated the dependability of the developed method, and the interpretation results are considerably satisfied.
Revitalization of the Gidgealpa Oil Field (South Australia)
Authors: Chen K. L. , Lonergan T. P. 
Published: December 2007

Abstract
Appraisal drilling in the Gidgealpa Field which has a 20 year production history has confirmed the existence of a significant oil rim underlying the Permian Age Tirrawarra Sandstone gas reservoir and a large extension of the Jurassic Age Hutton Formation oil reservoir.
An oil leg to the Tirrawarra Sandstone reservoir gas pool in the South Dome could be inferred from the geophysical, geological, and production performance data obtained from Gidgealpa-7 and Gidgealpa −16. A PVT analysis of a gas sample collected more recently from Gidgealpa-34 was strong evidence to support this interpretation. Gidgealpa −41 drilled on the northeast flank of a four way dip closed anticline flowed oil at 600 BOPD from clastic Permian aged Tirrawarra Sandstone, consequently confirming an oil leg to a known gas cap.
The relatively low decline in production performance of the southern region of the Hutton Sandstone oil pool indicated a reservoir extension. Alternate seismic mapping techniques using isopachs and recognition of high velocity layers were successful in eliminating high velocity calcareous zones in the Jurassic Age Namur Sandstone Member which previously hampered mapping of the field. Appraisal drilling successfully extended the Hutton reservoir limit by 1.5 kilometres to the south.
Renewed focus has thus centred on these two (Hutton and Tirrawarra) oil pools which require separate development strategies.
The Angel Project: An Effective Gas Appraisal Campaign
Authors: Hann J. H. , Paterson G. A. D. 
Published: December 2007

Abstract
The technical approach to a successful gas appraisal campaign is presented in this paper. In 1990, appraisal of the Angel Field increased the technically proven reserves from 0.6 Tcf to 1.1 Tcf. The campaign was achieved on time and at a cost of A$9 million. A carefully planned program of seismic acquisition and an optimally positioned appraisal well was required to achieve the reserves target. These appraisal activities were optimised by use of a Monte Carlo program specifically written to model geological uncertainties.
A Design of Mono-Column-Type FPSO
Authors: Miyagawa M. , Isozaki Y. , Yokokura K. 
Published: December 2007

Abstract
A new concept of a hull form, composed of a disk-type lower hull with a circular well at its center and a cylindrical hollow column, with small motions in waves, a big displacement and a simple hull form, has been developed, which is most ideal for the FPSO.