bluuebunny/crossref_metadata_2025 huggingface dataset:
Fuzzy Logic Controls Pressure in Fracturing Fluid Characterization Facility
Authors: Rivera Vincent P. , Farabee L. Mark
Published: December 2007

A fuzzy logic pressure control system has been designed and implemented to deal with the demanding requirements of the Fracturing Fluid Characterization Facility (FFCF), a test bed that simulates downhole conditions for investigating fluid behavior during fracturing stimulation. Pressure control in the fracture simulator was difficult because of the wide range of fluid types and pumping conditions used and by the compliant structure of the simulator, which uses servo-controlled actuators to maintain a constant gap width under varying pressure conditions. The FFCF pressure control system must handle fluids that vary from water to high-viscosity gel slurries at flow rates ranging from 1/2 to 3 bbl/min. Conventional control approaches were successful only under very limited conditions. To solve this problem, a fuzzy logic controller (FLC) was developed to be a user function in the FFCF supervisory control and data acquisition system. Using several fuzzy logic rules, the FLC generates a position set point for a slurry throttling valve. An electro-hydraulic directional control valve uses the set point supplied by the FLC to position the active control element of the slurry throttling valve.
3-D Visualization as an Investigative Tool for Understanding Recovery Mechanisms
Authors: Dria M. A. , Sharpe H. N.
Published: December 2007

3D visualization can be an important investigative tool for understanding physical processes and recovery mechanisms in reservoir simulation. In this paper, we will demonstrate the utility of 3-D visualization in the context of compositional and thermal simulations, and how this new tool aids process understanding and facilitates project design.

The main uses of the reservoir simulator include history matching to understand past performance, gain credibility of the reservoir simulation model, and project design to optimize future recovery (in an economic sense) whether for continued primary recovery, waterflooding, or EOR. To achieve these goals, it is essential to understand the interaction of the fluid dynamical and physical and chemical mechanisms with the complex geology of the reservoir, and the operational parameters and constraints at the wells.

While the reservoir simulator is capable of answering these questions, one of the major problems in the past has been in the three dimensional representation of such key variables as oil, water, and gas saturations, pressure, temperature, and individual component concentrations. Maps of these quantities relative to local geology and wells are essential to understanding the complex interactions outlined above, before process optimization may be achieved. Even simple questions such as the location of bypassed pockets of oil, cannot be adequately addressed using these tools. With recent advances in complex reservoir characterization, it is even more essential to be able to visually understand the control that local geology exercises on the recovery mechanism.
Shifting From a Mainframe to a PC Environment
Authors: Benavides R. M. , Wilke J. G.
Published: December 2007

This case study of a PC-DOS®/Mainframe system highlights a unique method to reduce the dependence on the Mainframe Computer System by individuals preparing written engineering proposals for prospective customers. With the development and implementation of the Engineering Proposal System (EPS), data storage and remote communications are now the only two functions processed by the mainframe computer.

Two key areas for success were user involvement and proper training. While most of the individuals preparing the proposals had worked on the mainframe for some period of time, very few had worked on PC's. An EPS users' group was established to bring together the needs of the end user and the needs of the programmers. This group remains active in enhancing and troubleshooting the current system.

The problems involved with a totally dependent mainframe system, as well as communications problems experienced with remote locations, are discussed herein. Satellite and phone modem communications are also briefly discussed. Several hardware configurations were necessary to respond to various needs created by the engineers' location and working environment.

The existing PC system, its components and the method used to automatically combine all the components into a high quality end product are covered here. Since this is a case study, all aspects of the product experience are explored.
Document Imaging and Management: Implementation of a Geoscience Image Server With Corporate Scalability
Authors: Thrasher T. S. , Baughman S. A. , Grismore J. R. , Carnell D. A.
Published: December 2007

This paper presents an overview of the process that resulted in the implementation of a document imaging and management system in the Research & Services Division of Phillips Petroleum. The purpose of this system is to capture the various documents maintained by the Reservoir, Geology, Geophysics and Production Technology branches into a master electronic fileroom. The system will facilitate sharing of data and information between groups and help reduce time required to search for and maintain project files. Many of the issues that were addressed are outlined in a format that serves as a case history example. These issues include system integration and alignment to existing Information Technology Architecture and Corporate Record specifications, adherence to Common Look/Feel and Client/Server guidelines, local and wide-area network compatibility, budget limitations, security and corporate scalability.
Systematic Steps to Operational Control: The Multi-Functional Potentials of Safe Job Analysis in Internal Control Regimes Reconsidered
Authors: Sunde Gunnar , Andersen L. B.
Published: December 2007

This paper presents a new system of integrated and multi-functional elements and strategies of Safe Job Analysis (SJA) developed by Rogaland Research for the Norwegian oil company Statoil. The scope of the system is integrated operational control of complex and risk exposed field operations in multi-team contexts. The new SJA system is especially designed to satisfy rules, regulations and documentation principles in internal control regimes like those of the North Sea countries. With small adjustments of the supplementary text, the system has also proved to be directly adaptable to onshore internal control regimes. Recent research as well as field experiences indicate that safety and quality aspects related to e.g. lost rigtime, stuck pipe, injury rates and equipment failures can be traced back to the actual level of operational control. Key words to lack of operational control are poor communication and information procedures due to insufficient pre-job repertoirs, generally causing poor experience transfer and a lack of mutual task understanding between individuals and team, and insufficient co-ordination during operations. New and promising multi-disciplinary approaches now indicate that such human error related aspects can be fruitfully attacked and controlled if systematically mapped and undertaken within a tailored internal control system in combination with the multifunctional potentiality of the proposed SJA model.
Management of a Declining Field
Authors: Fattahi B. , Okita P. J.
Published: December 2007

The growing cost to produce our maturing oil and gas reserve base has placed the U. S. domestic oil industry in an unfavorable position with worldwide competition. In striving to survive, we must direct our efforts at reducing the operating cost of our hydrocarbon production by optimally managing our reservoirs.

The operating cost structure of a large producing field can be complicated. So-called "fixed" and "variable" costs are often difficult to identify from historical cost data. In the case of declining production, the complication further amplifies due to the varying nature of the cost components. Shrinking revenues decrease per barrel profitability (and the remaining field economic life) if fixed costs are allowed to remain constant. Thus, there is a need to develop more rigorous operating cost models to better understand, monitor and control parameters which impact the bottom line profit. This approach will facilitate the use of proactive surveillance techniques and result in overall field optimization.

This paper examines key elements of the operating cost structure and proposes simple cost component models for consistent surveillance and economical production of declining fields. Application of such models to the Mt. Poso Field, California is discussed.

Mt. Poso, a thermally driven oil field, is one of the first large scale heavy oil producing operations that is declining towards its economic limit. An approach on understanding cost component behavior, modeling, devising a surveillance strategy, and finally the impact on maximizing the operating income are presented.
Reservoir Geology and Production Performance of Turbidite Sands at South Timbalier 295 Field: Some Encouraging Results
Authors: Mason E. P. , Scheibal J. R. , Purdy G. E.
Published: December 2007

Better than expected recoveries, generally strong pressure support and high production rates characterize the main pay sands ("K8", "K16" and "K40" sands) at South Timbalier 295 field. We interpret these sands to be turbidite mid-fan sheets ("K8" and "K40") and amalgamated channel sands ("K16") deposited within a closed basin.

All three intervals are geopressured, highly compressible, and subarkosic sandstones, with reservoir temperatures of about 210°F, and porosities and permeabilities of approximately 31% and 500 MD, respectively.
A New Interference Test Method for High-Precision Diffusivity Distribution Measurements
Authors: Najurieta H. L.
Published: December 2007

Classical interference testing techniques are based on the superposition of the line source solution. The use of this method is limited by the precision and time resolution that is normally obtained when measuring the production rate in active wells. In the new technique proposed, the pressure signal is measured at the active well and it is used to accurately calculate its diffusion in the reservoir. The higher precision in pressure calculation at the observing well gives more resolution to the analyst and provides more confidence when evaluating local reservoir heterogeneities.

The new method and related equations are presented and applied to a field example where a five-spot injection pattern is evaluated for a future CO2 injection pilot project. The diffusivity distribution estimated from the interference tests agrees with the description of the advance of the injected water obtained from radioactive tracer techniques.
Multilayer/Rate Testing in the Cusiana Field, Colombia
Authors: App J. F.
Published: December 2007

Multi-layer tests are performed to identify layer properties, such as permeability and skin, in commingled layer completions. This permits improved reservoir management and completion optimization. Multi-rate tests are required to evaluate rate sensitive skin. This paper presents the results of multi-layer/rate tests performed on the two active wells in the Cusiana Field, Colombia. The two wells were the Buenos Aires #1, an oil producer, and the Cusiana #2A-ST, a gas injector. The tests were performed by monitoring rate and pressure with a spinner and pressure gauge placed above the lower layer in a two layer system. These measurements were made at multiple rates to evaluate rate sensitive skin. Skin determined from these measurements was used to estimate the upper layer skin and permeability through simulations of the buildup and falloff responses. Knowledge of the permeability of the lower layers from previous pressure transient tests aided the analyses. All pressure transient analysis was performed with conventional well test analysis software.
High-Resolution Density Logging Using a Three Detector Device
Authors: Eyl K. A. , Chapellat Herve , Chevalier Philippe , Flaum Charles , Whittaker S. J. , Jammes Laurent , Becker A. J. , Groves Joel
Published: December 2007

Significant improvements in both the resolution and the precision of formation density logging tools are possible through the integration of a new "backscatter" gamma-ray detector into the traditional dual-spacing device. The spacing and the geometry of the new measurement permit intrinsic high resolution logging while much higher count rates provide increased precision.

Backscattering or single Compton Scattering in the formation complements standard attenuation logging by exhibiting a positive correlation between count rates and density. Statistical variations at higher densities are thus reduced. The reactions occur at short distances from the source dictating very short source-detector spacings and very high count rates. Such count rates have required adoption of a new crystal with attendant shielding and new count-rate electronics capable of digital treatment of the pulses. The backscatter detector is integrated into a skid that also carries more conventional short- and long-spacing detectors.

The energy spectra from the three detectors are binned into energy windows for data analysis. A nonlinear response model is established for each window count rate and the set of equations formed is solved for five unknowns—the formation density and photoelectric factor together with the mudcake density, thickness and photoelectric factor. This approach permits the optimal treatment of measurement errors and provides the best possible estimation of formation density and photoelectric factor available from the acquired measurements. The processing algorithms provide outputs at both standard and high resolution.

Field log examples show significant improvements in density precision and vertical resolution, and a dramatic improvement in the quality of the photoelectric factor (Pef) log.
Application and Interpretation of Continuous Oxygen Activation Logs for Measuring Complex Water Flow Profiles in Injection Wells
Authors: Chace D. M. , Trcka D. E. , Dawe B. A.
Published: December 2007

A continuous oxygen activation method of measuring water injection flow profiles in complex single and dual completion injection wells has been developed. The method allows deconvolution of superimposed activation signals originating from simultaneous, co-directional water flow in the tubing and tubing-casing annulus for a continuous log of annular water velocity. The theoretical basis of the measurement is reviewed and field examples are analyzed and interpreted. The examples of single and dual string completions demonstrate the measurement of continuous annular injection profiles in the presence of co-directional tubing flow and diagnosis of mechanical problems such as plug leaks and tubing-tubing communication.
Integrated Cement Evaluation Saves Time and Money
Authors: Wydrinski Ray , Jones R. R.
Published: December 2007

Cement bond logs (CBL's) are typically used to approve or condemn cement jobs. This "report card" has caused disputes between the cementing and logging companies for years because typically the CBL is interpreted independently from the cementing operation. Thus, a bad "report card" is usually translated into a bad cement job, which is often not the case. This paper illustrates the value of integrating cementing with bond logging to give a clearer picture of the actual quality of the cement downhole. Logs should be used as a tool to understand the cement quality and determine what improvements need to be made to enhance cementing job success.

Four examples are presented which show that factors such as 1) borehole conditions, 2) cement job design, 3) displacement practices and 4) tool selection and calibration all have an effect on the bond log interpretation. However, in all cases, integrating the log response with a thorough cement evaluation results in a more accurate analysis of the cement quality, and a better educated decision on the necessity for remedial work.
Integration of High-Resolution CT-Scan and Minipermeameter Measurements With Wireline Logs To Correlate Thin, High Permeable Zones
Authors: Sharma Bijon , Tomutsa Liviu , Martinez Guillermo , Kerr D. R.
Published: December 2007

The characteristic vertical variation in petrophysical properties across thin (0.6-1.5m) reservoir units was determined at 5 cm intervals from CT-scan and minipermeameter measurements of core samples from the Upper Cretaceous UA-5B sandstone at Patrick Draw Field, Wyoming and the Pennsylvanian Bartlesville sandstone of Oklahoma. This information was used to determine their expected responses on wireline logs. The correlation with this data of a highly permeable interval at the base of the producing shoreline sandstone (UA-5B) indicated that the distribution of this interval significantly affected waterflood production from the field.
The International Synthetic Fuels Picture
Authors: Cameron R.J. , Dailey J.L.
Published: December 2007

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussions may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

Although world oil supplies appear fully capable of providing the petroleum appetite of this planet for petroleum appetite of this planet for many years to come, national interests and geographic remoteness from prolific oil fields have promoted the establishment of synthetic fuel industries. An examination of existing and prospective synthetic fuels industries outside the United States reveals only two which may be considered to have the potential of future growth. These are potential of future growth. These are the tar sands of Canada and oil shale in Brazil. A comparison of the processing techniques now employed along with the reserves supporting these processes with a simple set of criteria for success points up the short-comings of the oil shale operations in Estonia and Manchuria and the coal facilities in South Africa. A lack of improved technology may be cited as the single most important criteria not met by these industries. Although attempts are being made to create an emerging technology from an antiquated base in these instances, the research may well have begun too late to permit the existence of these international synthetic fuel plants in a future competitive world oil market.

Introduction

This review of the international synthetic fuels picture, although not intended to be exhaustive, will attempt to outline the current situation as we know it with some thoughts on the future. Since several recent reviews adequately treat the situation in this country, our primary aim will be to bring you up to primary aim will be to bring you up to date on synfuel activities outside the United States, especially where industries are in being or where prospects appear encouraging.

Before proceeding further let us establish a definition of "synthetic fuels" as we use the term. Synthetic fuels are hydrocarbons derived from coal, oil shale or tar sands, that are similar in quality and characteristics to petroleum liquids and gases.
An Integrated Technology Approach Yields 101 MMCFPD in the Eugene Island 295 "B" Horizontal Well Project
Authors: Schroeder Tom , Mathis D. E. , Howard Ron , Williams G. N. , Sun J. A.
Published: December 2007

In late November 1993, Pogo Producing Company successfully completed a five well horizontal drilling program on Eugene Island Block 295. These five wells encountered over 7000 ft (2133 M) of gas sand and tested at a combined rate of approximately 101 MMCFPD. This success was attributed to the integration of geologic control with MWD, direction drilling, drilling fluids, tubular programs, and completion techniques.

The program was designed to develop three shallow gas sands which occur at 1200, 1800, and 2500 ft (366, 549, and 762 M) TVD, and are referred to as the AA-5, AA-10, and AA-15 respectively. These sands are Pleistocene in age and are associated with a broad, low relief, anticlinal structure which was confirmed by subsurface control and seismic amplitude.

The "B" platform is set over the #6 vertical well. The resistivity and gamma ray from this well were used to model the MWD resistivity responses associated with each objective as the wellbores approached horizontal. These modeled resistivity logs, along with gamma ray, were correlated with the MWD real-time logs to pick casing points within the top of the targets. The actual BHA and mud system used to drill the horizontal sections resulted in difficult conditions for the MWD resistivity logging (eccentered tool, low resistivity mud). Despite these conditions, the MWD logs provided critical information for geosteering, helping the team to drill in proximity to the overlying shales without exiting the sands.
The Influence of Shear Rate History on the Thickening Time of Oilwell Cement
Authors: Purvis D. L. , Mueller D. T. , Matson R. P.
Published: December 2007

Current industry thickening time test methods adopted by the API simulate shear rates in excess of 725 sec-1. Yet, under many circumstances, a cement slurry encounters much lower shear rate during its pumping history. Thickening time testing was performed comparing standard API methods with lower shear rate conditions simulated with a helical screw rheometer. Results indicate that thickening times are directly influenced by the shear rate found during mixing and displacement.

Previous investigation of wellbore shear rate effects on cement thickening time has shown an unexpected reduction in API thickening time under the low shear rate conditions common to many field operations. Using the helical screw rheometer and mathematical modeling presented in SPE 265761, this paper expands upon the initial studies by investigating a variety of typical slurry formulations under low, intermediate and API shear rate environments at temperatures up to 308 °F.
Flowline Insulation Thermal Requirements for Deepwater Subsea Pipelines
Authors: Rubel M. T. , Broussard D. H.
Published: December 2007

Current technology limits the distance over which subsea produced well fluids may be transported to approximately 10–15 miles. Many offshore leases exist in water depths in the order of 4,000 feet that could require transportation distances of 50–60 miles. The prevention of hydrate formation in the flowline is of concern for this service. Injecting a chemical inhibitor has typically been considered as the primary method for preventing hydrate formation. The current knowledge of subsea insulation, particularly for deepwater applications, is very limited.

The purpose of this study is to develop data needed to evaluate the effectiveness of flowline insulating systems in maintaining the fluid temperature above the hydrate formation temperature for a typical Gulf of Mexico application.
Database Analysis of Thru-Tubing Inflatable Packer Systems
Authors: Coronado M. P.
Published: December 2007

Since early 1986, Thru-Tubing inflatable packer technology has allowed operators throughout the world to improve the efficiency of many of their workover operations, as a result of working through the existing production completion, and thus decrease the cost of these operations. As this technology has evolved, new applications are continuously being investigated and executed in the field. Thru-Tubing inflatable packer technology has proven to be a very versatile way of performing many workover operations, and the number of different applications being done today is ever increasing1.

This paper will detail the types of applications being done today using Thru-Tubing packer technology, utilizing information compiled in a database which dates back to the original packer runs made at Prudhoe Bay, Alaska, where this technology was pioneered. Many of these applications are a result of creative thinking on the part of operators who realize the flexibility of using an inflatable tool system.

Also analyzed in this paper will be the success rates that have been demonstrated with these systems, including a discussion of the types of failures that have been seen in the field. Since inflatable packer performance is thought to be related to the expansion the element must withstand during the application, the database will also be utilized to study the success rates experienced as a function of element expansion. Advancements made in elastomer and design technology during the last few years has allowed for increased expansion capability, along with differential pressure capabilities and temperature resistance. Element success rates will also be given as a function of element outside diameter and bottom hole temperature in which the element is being used in.

Utilizing the various fields set up in the database system, a series of frequency analyses will also be presented which cover wcllbore deviations, setting depths and geographical information. A comparison of conveyance means will also be made which will describe the ratio between electric wireline (EWL) and tubing (including coiled tubing (CT)) tool conveyance by year.
The Effect of Viscosity on Near-Wellbore Tortuosity and Premature Screenouts
Authors: Aud W. W. , Wright T. B. , Cipolla C. L. , Harkrider J. D. , Hansen J. T.
Published: December 2007

The success of most fracture treatments is primarily dependent on the ability to evaluate the characteristics and critical mechanisms that control how a formation hydraulically fractures. By developing an understanding of the mechanisms, it is possible to make the necessary improvements to ensure optimum proppant placement and therefore maximize economic results. This discussion presents a simple, low cost method for improving the overall fracture geometry and reducing the risk of premature screenouts. Dramatic improvements in near-wellbore tortuosity and improvements in proppant placement can be achieved by maximizing the viscosity of fluid that is used to initiate the fracture and carry proppant through the near-wellbore region. Using the approaches presented, it has been possible to eliminate premature screenouts and improve the overall proppant placement in many different environments.
State-of-the-Art Survey on Hydrate Formation
Authors: Hight M. A.
Published: December 2007

The formation of hydrates in wells and pipelines can seriously hamper production operations since hydrates can completely block flowlines. The formation of hydrates is due to the presence of water along with certain low molecular weight gases. To avoid hydrate blockages it is imperative to first know under which temperature and pressure conditions hydrates will form. This can be predicted by computer models based on the fluid composition. This study predicts hydrate formation conditions for a range of live oils by computer simulation and determines the sensitivity of several physical properties.
Biotechnological Breakthrough Improves Performance of Moderate to High-Temperature Fracturing Applications
Authors: Brannon H. D. , Tjon-Joe-Pin R. M.
Published: December 2007

Historically, the application of breakers in fracturing fluids at elevated temperatures has been a compromise between maintaining proppant transport and achieving the desired fracture conductivity. Conventional oxidative breakers react rapidly at elevated temperatures, potentially leading to catastrophic loss of proppant transport. Encapsulated oxidative breakers have experienced limited utility at elevated temperatures due to a tendency to release prematurely or to have been rendered ineffective through payload self-degradation prior to release.

Enzymes, from a theoretical perspective, are known to provide superior performance relative to oxidative breakers. This is due to the inherent specificity and the "infinite" polymer-degrading activity of enzymes. However, the application of enzymes has historically been limited to low-temperature fracturing treatments due to the perceived pH and temperature constraints. Recent developments in biotechnology have resulted in the isolation of hyper-thermophilic organisms, which led to the separation and purification of extreme temperature-stable, polymer-specific enzymes. Laboratory evaluations utilizing these enzymes as gel breakers have demonstrated exceptional performance capabilities over a pH range of 3-11 and temperatures exceeding 300°F.

Performance properties of systems incorporating the new breakers are provided, including rheology, proppant transport, and retained permeability. Case histories of fractured wells in several moderate to high-temperature reservoirs are provided to validate the utility of this technological breakthrough. The data illustrate that the enzyme breakers can be successfully incorporated without compromising proppant transport capabilities, yielding improved productivity relative to observations in offset cases treated with conventional breakers.
On the Threshold: Subsea Multiphase Pumping
Authors: Beran W. T.
Published: December 2007

Subsea multiphase pumping offers an economic alternative for developing offshore reserves otherwise thought to be unreachable or uneconomical. Primarily for satellite subsea field development scenarios, subsea multiphase pumps can provide pressure boosting and increased production flowrates without the need for satellite surface pumping facilities and riser systems. Such surface facilities can be prohibitively expensive, particularly in deepwater fields.

This paper presents an update on the state of technology of subsea multiphase pumping systems. The potential production benefits of subsea pressure-boosting systems and the advantages of seafloor multiphase pumps relative to other pressure-boosting alternatives are also briefly discussed; field conditions that are especially appropriate for such pumping systems are also outlined.

The general design and operational difficulties facing multiphase units are briefly recounted, and the various generic types of multiphase pumps proposed and tested over the years are listed. The types that are evolving into the leading contenders are briefly described along with a concise and current status of their development. Future development, prototype testing, and field application is also forecasted.
The Use of Metallic Films to Improve Gas-Lift Valve Operability
Authors: Patterson J. C. , Lagerlef D. L.
Published: December 2007

This paper provides a status report of ARCO’s use of thin metal films to improve the operability of gas lift valves. Thin metal films have been used to minimize the problems associated with performance degradation of the gas lift valves due to scale accumulation and sticking of the gas lift valve packing in the mandrel. A brief discussion of the problems, the theory behind the performance improvement with thin metallic films and field test results are provided.
Predictive Model and Verification for Sand Particulates Migration in Gravel Packs
Authors: Bouhroum Ahsene , Liu Xinghui , Civan Faruk
Published: December 2007

A phenomenological model is presented to optimize the performance and to minimize the costs of gravel-packs, which are subjected to severe flow and pressure conditions. The theoretical basis for the development of the model equations is discussed and the equations are derived to represent the mechanisms involved in gravel-pack damage. This model is an averaged representation of the experimentally observed step-like motion of particulates, which is characteristic for particulates transport in gravel-packs. An implicit finite difference solution of the gravel-pack damage model is utilized.

The identification of the model parameters is emphasized. The influence of error in the determination of parameters is estimated by performing a sensivity analysis. Of the three parameters, namely the amount of mobile particulates, the particle deposition rate constant, and particle mobilization rate constant, the last one is found to be less important because particle mobilization is sensitive to reduced transport capacity of the clogged gravel-pack

The model has been verified by data from a set of 35 experiments conducted via large scale non-Darcy flow tests with optically transparent filtration cell. The predictions of the model are found in reasonable agreement with the test results with respect to the particulates migration distance and the amount of mobile particulates.
A Three-Phase Separator for the Removal of Oil and Solids from Produced Water
Authors: Seureau J. J. , Aurelle Yves , Hoyack M. E.
Published: December 2007

A novel three-phase cyclonic separator has been developed to remove solids and oil from produced water in a single unit. This new cyclone configuration combines the functional characteristics found in both desanding and deoiling hydrocyclones. The result is a lighter and more compact system that performs as well as existing hydrocyclones and is particularly adapted to off-shore use.
Modeling of Fracture Propagation During Overbalanced Perforating
Authors: Petitjean L. , Couet B.
Published: December 2007

We present here a model that describes the propagation of a fracture created during extreme overbalanced perforating or overbalanced surge of existing perforations. Model predictions are compared with field results. This paper shows that the wellhead pressure (WHP) decay is well predicted by our model and that this type of operation exhibits new features compared to hydrofracturing operations (high propagation speed, turbulent fracturing fluid flow, noticeable friction losses in the tubing). Finally, a sensitivity analysis defines some of the key parameters affecting the success of such operations. Impact on the fracture extension of the in-situ stress, the WHP, the volume of gas, the formation permeability and the number of fractures is investigated.
The Application of Fluid Injection To Mitigate Coning
Authors: Patel R. S. , Batycky J. P. , Tang J. S. , Lai S. Y. , Tibold M. P.
Published: December 2007

As an oil zone thins during the mature stages of a vertical miscible or immiscible flood, oil production becomes dominated by coning of water, gas and / or miscible solvent. This results in lower revenues and increased operating costs which in turn accelerates well abandonment. In contrast to the early operations of a pool, the remaining oil volumes which are increasingly at risk have access to only limited capital. Coning therefore is controlled by conventional techniques such as re-completions, choking back oil production or intermittent operation. As the effectiveness of these techniques becomes reduced, other less conventional approaches are sought.

Such techniques as the placement of polymeric agents or the injection of oil or water to divert the coning fluids, are becoming attractive because of their low capital requirements. In support of the present work, scaled laboratory experiments and numerical simulation studies have demonstrated the recovery benefits using fluid injection as a way to maintain production from a thinning oil sandwich. Currently, Imperial Oil is developing oil re-injection technology to increase recoveries by 1.5 to 3 percent of the original oil-in-place (OOIP) by reducing solvent coning in a number of their vertical miscible flood pools located in the Pembina Nisku area. A pilot project evaluating this technology has been in operation for nearly a year. After overcoming a number of start-up and other operational problems, the pilot has demonstrated that oil re-injection can successfully control GOR. History matching the pilot performance has confirmed the design approach and performance expectations. Based on the encouraging results, four more projects have been planned for start-up in 1994.
An Integrated Model for Underground Coal Gasification
Authors: Biezen E. N. , Bruining Johannes , Molenaar Johannes
Published: December 2007

Underground coal gasification receives renewed interest in both Western and Eastern Europe because of the vast amounts of otherwise unminable coal deposits that occur on the European continent.

A field test is currently being carried out in Spain. Other countries in Europe show interest in this method of utilizing coal resources. In this study we present a model that describes the development of an underground coal gasifier. Both permeable bed and channel surface gasification are combined with thermo-mechanical failure of both coal and overlying rock. By this combination the model predicts the channel development and thus the sweep efficiency of the gasification process.

The model consists of two modules: the first module solves the flow equations in the entire flow domain. The second module selects a block of coal for gasification and a block of coal and/or rock for thermo-mechanically induced spalling. Other features such as ash content and heterogeneity are included in the model as well.

Model calculations show that the ash content of the coal and the coal and rock spall rate determine largely the sweep efficiency of the gasification process.

The model is used for field test evaluation purposes and can be used for extrapolation of the test results to other situations, e.g. the deep lying thin coal layers that occur in Northwestern Europe.
A Comparison of Equation of State Tuning Methods
Authors: Merrill R. C. , Hartman K. J. , Creek J. L.
Published: December 2007

Equations of state find widespread use for their ability to describe a wide variety of reservoir fluid behaviour. However, this description is not usually obtained through a-priori predictions. The parameters of the equation of state (EoS) often need adjusting (tuning) before yielding usable reservoir predictions. During tuning, the parameters of the EoS are adjusted to make the predictions match a variety of experimental data.

As part of an industrial joint-venture, three Peng-Robinson equation of state models were developed to describe a single set of phase behaviour and PVT data. The EoS models were developed independently, and their variety illustrates the different techniques available for this purpose. This paper concentrates on: the differences in each of the development processes, the resulting match, and the effect this has on a-priori slim-tube predictions. The paper examines the rationale behind the choices made during development.

The three methods share many similarities in their execution, however, there are some pronounced differences. These differences are most obvious in the treatment given to the different classes of experimental data during EoS development. Despite these differences, the models were all suitable for reservoir development purposes, which leads to the conclusion that consistency in the application of a technique is more important than the technique itself.

The co-operative nature of this work serves as a successful illustration of the inherent strength of joint ventures. The participating companies have used this cross-fertilisation to ensure the technical integrity of their methods.
Combustion Performance in the Countess Project
Authors: Tzanco E. T. , Moore G. R. , Good W. K.
Published: December 2007

A combustion project in the Countess Β pool of Southeastern Alberta was performed between 1983 and 1992 in two phases: the first phase, the pilot, essentially a dry normal-air injection combustion, and the second phase, the expansion, a water alternating with air (WAA) injection. Both projects were concurrent with a waterflood. The objective of the project was to assess the technical and economic feasibility of combustion for commercial application in the Countess-Lathom trend, which is characterized by an 28°API oil and medium pressures (9.6 MPa). This paper describes a performance evaluation of the pilot and the expansion projects. Well-monitoring techniques and four methods that were utilized to estimate the incremental oil recovery from the fireflood wells are also discussed.

The Countess Β pilot project was a technical success, with an incremental oil recovery of 9% of the pilot original oil in place (OOIP), but the recovery from the expansion project was lower than had been expected, based on combustion tube laboratory experiments. Although the expansion was successfully ignited, the combustion shifted to a low temperature mode. An increase in barite scale, a problem already present in the area was detrimental to production. An incremental oil recovery of 3% of the expansion OOIP was obtained before the project was shut down. It was concluded that both combustion schemes were not robust enough to give confidence for future application in the Countess Lathom pools.
New Solutions for Wells With Finite-Conductivity Fractures Including Fracture-Face Skin: Constant Well Pressure Cases
Authors: Liao Yizhu , Lee W. J.
Published: December 2007

This paper presents new solutions for wells with finite- conductivity fractures including fracture-face skin damage under constant well pressure production. Fracture storage is also included. An infinite-conductivity fracture is included as a limiting case. The new solutions are obtained numerically by modeling a well with an elliptical finite-conductivity fracture in an infinite-acting reservoir. The new solutions are as accurate as other published solutions, which are available only for cases without fracture-face skin damage. The new solutions presented in this paper can be used to analyze, history match, and predict production data for wells with finite-conductivity fractures including fracture-face skin damage and fracture storage under constant well pressure production. Examples are provided.
Field Demonstration of the Electrofrac Heatflood Process
Authors: Vossoughi Shapour , Sarapuu Erich , Crowther R. H.
Published: December 2007

This paper will present the results of a field demonstration of a less known enhanced oil recovery process named Electrofrac Heatflood process. The process entails the use of down-hole electrodes mounted in the oil sand, a specially configured electric power unit, and facilities for injecting air and fuel into a controlled combustion zone within the area stimulated. One essential feature is creation of electrically conductive paths within the oil sand. This is accomplished in either, or both of two mutually supportive ways: (1) electrocarbonization of a small portion of the oil present between electrodes mounted in the oil sand and (2) injection of electrically conductive pellets with, or in place of the sand normally injected during hydrofracing as part of the original well completion. The process has been field tested successfully for the typical largely heterogeneous oil sands found in predominately fluvial deltaic formations. Field test was initially performed during 1979 and 1980 on a lease named Beachner-1 located in the east-central portion of Neosho County, Kansas and again in 1983 to 1985 expanded to Beachner-1 and Beachner-2. The oil reservoir at the location is shallow and generally unproductive with essentially no natural driving pressure, and natural flow is typically just 1 to 3 gallons per day per well from about twenty feet of pay sand.

During the initial field test, an enhancement ratio of 4.5 to 5.4 was achieved relative to natural production, even though the field was only partially stimulated Observed enhancement ratio during the second field test ranged from 4.6 to 10.7. And the enhancement ratio at the other more remote wells ranged from 1.8 to 3.1 giving overall enhancement ratios of 2.4 to 5.5 for all wells then on the lease at that time. Increased production was sustained for more than two years through partial stimulation of the field containing fifty wells. The neighboring leases to the south also benefitted indirectly from the stimulation on the Beachner-1 and Beachner-2 leases.

The Electrofrac Heatflood process facilities included a specially outfitted 500 KVA diesel electric generator, electrodes mounted down-hole in the oil sand, air and fuel injection facilities, and proprietary means for distributing electric energy deep into the oil sand to promote heat cycles through controlled combustion within patterns of injection and production wells.

The process has been proven to be an effective recovery technique for those reservoirs that because of nature of their heterogeneity the conventional recovery techniques fail.
WAG Flow Mechanisms in Presence of Residual Oil
Authors: Minssieux Louis , Duquerroix J-P.
Published: December 2007

Dry gas/water injections were performed under immiscible conditions in a water-wet 80 cm long sandstone, to analyse unidimensional aspects of water alternating gas (WAG) process in porous media.

Experiments were conducted under tertiary conditions at constant flow-rate, with a continuous pressure regulation in the gas injected cell, maintained at the pressure reached during each imbibition step, prior to any drainage period. Residual oil was a crude saturated or not with methane to determine the influence of swelling.

A modelling of several of these laboratory experiments is also presented, taking into account oil swelling and gas relative permeability hysteresis. The typical mechanisms of WAG flow in porous medium are highlighted and the simulations are shown to reproduce these features as well as extra oil production.
A Reservoir Model for Landfill Gas Projects
Authors: Fair A. R. , Maurer R. J. , Fair W. B.
Published: December 2007

In recent years there has been an increased interest in unconventional fuel sources, including the production of natural gas from organic decomposition of landfill waste material. This interest is not solely a result of the energy shortages which climaxed with the energy crisis of 1973. Capture and utilization of gas from biomass decomposition dates at least as far back as 18591. The unconventional fuel source addressed by this paper is methane gas from landfills.

Although petroleum engineers are usually not involved in landfill projects, the evaluation of gas reserves and production performance of these projects involves the use of reservoir engineering techniques, which must be modified to model the unique characteristics of these projects. This paper discusses the unique characteristics of landfill gas projects and shows how simple material balance and pressure transient models can be developed and applied to the evaluation of landfill gas projects.
Undersea Fiber Optic Technology for the Offshore Community
Authors: Mariano J. J.
Published: December 2007

The explosive growth in demand for global communications has been met by a rapid evolution in the undersea fiber-optic technology, which in just a few years has become the predominant method of communication across the world's oceans and seas. As the scope of applications has become broader, the technology has become more diverse, and now comprises a range of products capable of providing economical, reliable service in any subsea environment, from ocean depths to coastal lagoons.

In this paper, we discuss how undersea lightwave technology is being applied to meet the communication and production control needs of the offshore oil and gas industry. We discuss the trends and technology developments that are changing the economics of undersea fiber-optic communication networks, as well as synergies in the offshore industry. We consider various applications for the industry and means of enhancing the profitability of platform operations through reduced downtime, reduced operating cost, and enhanced safety. Finally, we discuss extensions to exploratory drilling and land-based operations.
Use of the Dual-Screen Thru-Tubing Sand Control Method
Authors: Freiman O. H. , Johnson K. J.
Published: December 2007

This paper will describe a new sand control method used in an area of Ecuador, South America where workover rigs are not readily available. Sand production had been significantly affecting maintenance costs on surface and downhole production equipment and had impacted performance of the downhole jet pump, subsequently causing a decrease in well production. By installing a small-diameter, sintered metal gravel-pack screen across the perforation interval and placing the gravel-pack sand with coiled tubing, the sand production was successfully controlled. The procedure and equipment used to perform this technique as well as post job data that provide results obtained will also be presented. Noteworthy advantages, such as recompletion without removal of the existing production completion string and without use of a workover rig, will also be discussed.