bluuebunny/crossref_metadata_2025 huggingface dataset:
Borehole stability in shales: A constitutive model for the mechanical and chemical effects of drilling fluid invasion
Authors: Wong S. W. , Heidug W. K.
Published: December 2007

The density of the drilling fluid and its chemical composition are the main operational parameters controlling the stability of wellbores drilled in shales. To quantify their impact on the stress evolution around wellbores in pervious shales, we have developed a model that accounts for the physico-chemical interaction between the invading drilling fluid and a shale formation. The model is based on the principles of non-equilibrium thermodynamics and provides generalisations of Biot's classical poro-elastic theory and Darcy's flow equation. We demonstrate that our model can reproduce the salient features of experimental work on the fluid/shale interaction and use a finite-element scheme to numerically calculate the stress and strain distribution around a wellbore when interactions occur. We show that these effects promote tensile failure of the wellbore wall.
Time Dependent Borehole Stability: Laboratory Studies and Numerical Simulation of Different Mechanisms in Shale
Authors: Horsrud Per , Holt Rune M. , Sonstebo Eyvind F. , Svano Geir , Bostrom Bard
Published: December 2007

Experimental work and numerical modelling have been applied to study mechanisms related to time dependent borehole stability during drilling in shales. Fully coupled numerical modelling showed that consolidation effects may act on a time scale of days, due to the low permeabilities of shale. Creep testing of a North Sea Tertiary shale showed that above 80% of the failure stress, the observed strain rates indicated that delayed borehole failure could occur within a period of 15 days. When exposing outcrop shale with close to zero swelling clay content to non-native fluids, substantial changes in mechanical properties were observed. Elevated temperature (80°C) also seemed to cause a weakening both in static and dynamic properties.
Sand Production in Vertical and Horizontal Wells in a Friable Sandstone Formation, North Sea
Authors: Ramos G. G. , Katahara K. W. , Gray J. D. , Knox D. J. W.
Published: December 2007

Sand production is detrimental in oil and gas production. Sand-control measures include gravel-packing, drawdown control, sand consolidation, slotted liners, pre-packed screens, and frac-and-pack. Vertical wells can use any of these methods. Extended-reach, highly inclined wells, and horizontal wells close to water tables have very few cost-effective choices like slotted liners and open-holes. To predict the potential for sand production, a perforated completion was analyzed as an elastic-plastic spherical cavity while an open-hole horizontal well was analyzed assuming cylindrical symmetry. This analytical procedure was applied to investigate the feasibility of sand-free oil production from a friable sandstone formation in the North Sea. The calculated sand-free drawdown pressure of the horizontal well is more than twice that of the vertical-perforated well, depending on the drainage radius. Subsequently, in the North Sea single-well production test, a horizontal well was drilled and supported with a slotted liner only. The field test produced oil at high rates with no measurable amounts of formation sand.
Observations of Sand Production and Perforation Cleanup in a Weak Sandstone
Authors: Tronvoll Johan , Halleck Phillip M.
Published: December 2007

Model experiments of sand production in a perforated sample of a weak outcrop sandstone are compared to tests on drilled cavities in the same rock. The perforation tunnel was filled with rock debris and a damaged zone occurred around it. Limited sand production resulted due to erosion of the rock debris, while instability of the perforation wall by formation of breakouts occurred at stress levels comparable to the failure stress of a drilled cavity. The failed material remained stable throughout the test, and most of the sand produced originated in the debris in the center of the perforation tunnel.
Wellbore Stability of a Superdeep Borehole in Crystalline Rock The KTB-Hauptbohrung, Germany
Authors: Hoffers Bernhard , Engeser Bernhard , Rischmüller Heinrich
Published: December 2007

The borehole stability of the KTB-Hauptbohrung in Windischeschenbach, Bavaria, Germany, with its target depth of 10 km is described down to the depth of 8,715 m. The well is drilled from surface in crystalline rock, mostly gneisses and amphibolites. The types of wellbore instabilities observed so far (breakouts, washout zones, undergauge sections) as well as their causes (lithology, tectonics, in situ-stresses, miid properties) are discussed. The operational impact of the instabilities (changes in mud system, increase in mud weight, vertical drilling strategy, sidetracks) and the countermeasures taken are elaborated.
Modeling of Gas-Driven Fracture Propagation for Oil and Gas Well Stimulation
Authors: Petitjean L. , Couët B.
Published: December 2007

We present a model that can describe the propagation of a fracture driven by either a liquid or a gas. This model can be applied to situations in which the wellbore pressure is significantly higher than the in-situ stress, resulting in high fracture propagation speed and turbulent fluid flow within the fracture. We present results of test problems, where analytical and/or numerical solutions are available. Finally, we have applied our model to simulate field operations where the formation is dynamically fractured, as in extreme overbalanced operations. We compare results of fractures that are gas-or liquid-driven.
Prediction of Fracture Density and Drainage Distance in Layered Rock Masses Using Borehole Data
Authors: Wu Haiqing , Willemse Emanuel J. M. , Pollard David D.
Published: December 2007

We present a simple method to estimate fracture density and drainage distance from borehole data. The method is suitable for boreholes parallel to bedding and is based on the knowledge of fracture spacing observed in both outcrops and experimentally modeled fracture patterns. The method is relevant to long term well behavior as it identifies intervals of high fracture density that also have a long fracture drainage distance. To evaluate the method, the two-dimensional (2D) characteristics of known fracture patterns were compared with the ID data obtained from simulated wells bored through these fracture patterns.
Subsidence Induced Casing Deformation Mechanisms in the Ekofisk Field
Authors: Schwall G. H. , Denney C. A.
Published: December 2007

Casing deformation as a consequence of reservoir compaction and surface subsidence has occurred in the Ekofisk Field. Casing deformation database results show that reservoir deformations occur throughout the field, while overburden deformations occur primarily on the field flanks. Deformation geometry shows compressive loading of casings in the reservoir resulting in axial buckling. In the overburden, deformation geometry suggests formation movement along near horizontal features. Identification of the deformation mechanisms will be used to refine mitigative techniques which minimize casing loading, thus enhancing well life.
Improved Subsidence Monitoring Methods
Authors: Fourmaintraux D. M. , Flouzat M. , Bouteca M. J. , Kasser M.
Published: December 2007

The Differential Global Positioning System (DGPS) has been adapted to the oil industry by the CEA with EAP. It allows a continuous, accurate (+ or – 3 mm) and quasi-automatic monitoring of the subsidence above hydrocarbones field. The method is detailled and a simple case study explains how accurate subsidence data are able to precise the drainage pattern and help the production managment. The Airbom Laser System to measure subsidence developed with IGN is now at experimental stage. Monitoring a great number of points, it will be suited to onshore fields and allow to map the subsidence and the drainage pattern changes.
Computerised Prediction of Subsidence Over Oil and Gas Fields
Authors: Reddish D. J. , Yao X. L. , Waller M. D.
Published: December 2007

This paper presents the development of the theory and of a computer program to predict subsidence and horizontal displacement due to oil and gas withdrawal. Geertsma's nucleus of strain model has been modified and combined with an influence function program, developed for the prediction of mining subsidence, to form a new technique for the prediction of ground movements over oil and gas fields. The modifications and the influence function theory are described in detail, with particular emphasis being placed on the applicability of the developed theory to computer prediction. The influence function method allows complex reservoir geometry to be taken into account and both subsidence and associated horizontal ground movements may be calculated.
The Potential for Monitoring the Progress of Production Fronts Across Hydrocarbon Reservoirs
Authors: Crampin Stuart , Taylor David B.
Published: December 2007

Recovering more oil from a reservoir depends on obtaining a better understanding of the fluid/fluid and fluid/rock interactions over u wide range of scale lengths. Recent advances in understanding and modelling the behaviour of cracked and porous rock and developments in seismic instrumentation open the possibility of monitoring the movement of production and IOR fronts and interpreting the behaviour in terms of crack physics. Prototype strings of three-component broadband receivers and sources are designed to pass down production tubing into the reservoir, where seismic resolution is at least an order of magnitude better than in conventional techniques.
Numerical Simulation of Ekofisk Reservoir Compaction and Subsidence: Treating the Mechanical Behavior of the Overburden and Reservoir
Authors: Chin L. Y. , Boade R. R. , Nagel N. B. , Landa G. H.
Published: December 2007

Three aspects of reservoir compaction/subsidence simulation for Ekofisk are addressed: (i) stress paths in the reservoir during depletion, (ii) impact of porosity heterogeneities in reservoir chalk on scaling laboratory compaction data to field behavior, and (iii) methods for treating the behavior of the overburden in a finite element simulator. Specially created finite element models were used for the first two issues. Results indicate that geometry has a major impact on stress path. Results of the scaling analysis indicate that porosity heterogeneities cause a block of chalk comprised of numerous cells with different porosities to appear strong when internal shear failure is not allowed, but to appear weak when it is allowed. The discussion of the overburden behavior concentrates on field observations, interpretations of these observations, and methods used to represent them in a simulator.
Mechanical Testing and Permeability Measurements of Reservoir Chalk Under True Triaxial Stress Conditions
Authors: Christensen Helle F. , Foged Niels
Published: December 2007

A newly developed specialized true triaxial cell for rock mechanical testing is described. The cell allows testing of 46 X 46 x 110 mm box shaped specimens under in-situ reservoir stress conditions. The operating effective stress is up to 100 MPa [14500 psi] in the vertical direction and 50 MPa (7250 psi) in the horizontal direction. The applied stresses may be varied independently in 3 orthogonal directions (true triaxial stress condition) and both the vertical and the 2 horizontal absolute permeabilities are measured. The application of the true triaxial cell is illustrated by 3 selected tests.
Open Hole Stress Tests in Shales
Authors: Thiercelin M. , Desroches J. , Kurkjian A.
Published: December 2007

This paper presents a series of stress tests which have been performed in shales using a wireline stress tool which includes a downhole pump. It is shown that the best technique to carry out stress tests in these weak rocks is to use a combination of sleeve fracturing and hydraulic fracturing. An inversion of the pressure response during propagation and closure of the fractures is presented leading to the estimation of the in-situ minimum stress and various rock properties.
Hydraulic Fracturing and Microseismicity: Background and Recent Developments
Authors: Deflandre J. -P. , Sarda J. -P.
Published: December 2007

Hydraulic fracturing generates acoustic emissions. Laboratory works, field experiments and theoretical analysis progressively improved the understanding of the source mechanisms. The direction of the source, its distance from the recording station and even its size can be derived from advanced analyses of the acoustic signals: polarization analysis and analysis of the signal spectrum. New types of sondes and softwares help improving such analyses and lead to envisage their use as reservoir monitoring tools.
Logistical and Drilling Considerations Associated with Sulphur Exploration in High Arctic
Authors: Marshall D.J.B. , Crain E.R.
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.

During 1969, a stratigraphic test hole program was conducted on Melville Island in program was conducted on Melville Island in the Canadian Arctic. The purpose of the program was to explore for sulphur bearing program was to explore for sulphur bearing limestone caprock associated with salt domes. Two track-mounted seismic style drilling rigs were used to drill thirty-six holes to a maximum depth of 1000 feet.

In such a remote location and difficult environment, many transportation and support services were necessary that would not normally be required. Hercules type freighter aircraft were found to be the most efficient means of transporting exploration equipment into the Islands. Conventional tracked vehicles were quite suitable for surface transportation of the drilling equipment. Both a helicopter and a mixed wing aircraft were needed for personnel movements on and between the Islands.

Drilling in a permafrost environment presented unique problems which have not been presented unique problems which have not been extensively covered in the literature. The selection of the proper drilling fluid appears to be the most important consideration in planning a drilling program in permafrost areas. planning a drilling program in permafrost areas. Contrary to many widely publicized opinions, it does not appear that human or industrial activity has a serious or lasting effect on the ecology of the area.

Introduction

In July of 1968, King Resources Company secured sulphur exploration permits covering approximately 880,000 acres in the Arctic Islands from the Canadian Federal Government. These permits were obtained after geological studies indicated an abundance of salt domes in the Sverdrup Basin which is centered in the Canadian Arctic. This basin bears a marked resemblance to the Gulf Coast Basin in that both contain large thicknesses of Mesozoic sediments and both have intrusive salt domes. The target in this venture was to find sulphur in limestone caprock associated with these domes. Preliminary economic studies were conducted which indicated that if sulphur reserves of the order of 20 million tons could be discovered at depths suitable for normal Frasch mining, the sulphur would be competitive on the world market.

Early in 1969, planning began for an exploration program.
A New Wellsite Information System To Aid the Drilling Process
Authors: Grenadier J. A. , McCann Dominic , Koch Steve
Published: December 2007

The IDEAL1 Wellsite Information System acquires data to monitor the drilling process. It interprets the realtime data flow from both surface and downhole and displays useful information on high resolution color screens to the key decision makers on and off the wellsite.

The IDEAL Wellsite Information System can support four classes of users simultaneously: The driller, the directional driller on the rig floor, logging specialists in the unit and the company representative in the customer's office. Color displays have been customized to the specialized needs of each class of user. In particular, the IDEAL Driller's Display is a pressurized unit located on the rig floor. The driller can select from a number of screens with a minimum number of keystrokes.

This information network improves drilling efficiency, geological evaluation and subsequent production through enhanced geological steering.

Data is continually stored in both the time and depth domains. These databases can be exported into a variety of formats. Data can also be transmitted in realtime to the customer's office offsite.

Backup system components allow for redundancy so that system downtime is virtually eliminated.

By having system developers concentrate on making the workstation easy to operate, the users can focus on the drilling process and not on the computer system. Custom graphic displays were designed by drillers for drillers. "Smart Alarms" have been designed to alert the user of potential problems such as kicks, sticking pipe and drillpipe washout.
A Database Model for Drilling Data Storage
Authors: Opsahl Runar , Eide J-O. , Lorås D. H.
Published: December 2007

The main motivation for storing drilling data is to use them for post-analysis and efficient planning. Conventional drilling data storage systems often exhibit two major shortcomings that make such use difficult: In the first place, the data is often stored with depth as the primary key. Such a depth-based storage strategy may cause loss of valuable data if the depth is miscalculated at the time of recording, or when there is no steady depth progression. It also makes it difficult to analyse situations where the depth is set backwards due e.g. to sidetracking or to drilling of cement. Another problem is the amount of data collected during a drilling operation. This soon becomes unmanageable if there is no structured way of extracting information from such data.

This paper outlines a database model for drilling data storage, which aims at providing a high degree of data availability for efficient post-analysis. It also suggests an organisational model that should be adhered to in order to utilise the database efficiently.
Corrosion Control Cook Inlet Platforms
Authors: Hedborg C.E.
Published: December 2007

Introduction

In 1968 the average production of crude oil in California was about one million barrels per day, of which 227,000 b/d or 22% was produced offshore. By comparison the California crude oil offshore production was only 77,000 b/d in 1958. The California offshore oil industry has therefore seen a threefold increase during this ten-year period. For the year 1968 the average daily Alaska production was 181,000 b/d of which 143,000 b/d or 79% was produced offshore. From these figures it is obvious that oil produced on State and Federal OCS leases is becoming an increasingly produced on State and Federal OCS leases is becoming an increasingly important source of domestic crude oil.

To produce this oil, steel production platforms having room for up to 48 wells, living facilities for about 100 men and costing between $15,000,000 and $21,000,000 are being built. In many cases these platforms will be required to last twenty years. The only way that steel can survive for this length of time in a marine environment is to utilize all the technological knowledge that is available in the field of corrosion control.

In Cook Inlet, as in other offshore areas, cathodic protection is used to control corrosion. However, in Cook Inlet the corrosion engineer's job is made more difficult by unusually high tidal velocities and drifting ice. This paper will discuss problems encountered by Union Oil Company engineers in protecting the Monopod and Grayling platforms in Cook Inlet.
Development of a Petroleum Engineering Electronic Journal
Authors: Barnett A. A. , Russell J. E.
Published: December 2007

A new petroleum electronic journal with on-line submission, review, and distribution will provide an additional and needed outlet for technological developments. The primary objective of the journal will be to provide a medium for rapid exchange of up-to-date advances in petroleum engineering. The Electronic Journal of Petroleum Engineering (E-JPE) will take substantially less time to publish as it will decrease the time required by traditional reviewing, printing, and distributing processes and will allow for more widespread participation of international reviewers. E-JPE will be developed in phases that will allow "debugging" and incremental distribution and participation. Papers will lose many of the size constraints associated with hard copy publications and will not be limited to a fixed number of yearly volumes. Publication costs will be lower than for traditional hardcopy journals because the costs of printing and mailing will be eliminated. E-JPE will provide a more efficient avenue for the exchange of ideas among its authors, editors, and readers through electronic networking systems. Developing an electronic journal will put the industry at the forefront of technical publishing and pave the way into the next century.
Intelligent Interfaces for Fracturing Simulators: Part I—System Overview and Design
Authors: Xiong Hongjie , Sherry K. J. , Lancaster D. E.
Published: December 2007

There are several powerful 3-D (and pseudo 3-D) numerical simulators available in the industry for designing hydraulic fracture treatments. With each model, the accuracy of the simulation results depends heavily on the input data used. Thus, it is important to prepare a complete and accurate input data file for these simulators. This can be difficult to do, however, not only because a lot of data items are required, but also because many decisions have to be made.

Using artificial intelligence methods, we have developed a powerful and interactive software application that uses a series of friendly and intelligent interfaces to acquire the large amount of data needed by fracture simulators. In these interfaces, the user is guided through a series of screens specific to his problem. More importantly, the system helps the user make many decisions, such as selecting fracturing fluids and additives, selecting proppants, and selecting pumping schedules and pumping techniques. The system includes several databases from which a considerable amount of information can be accessed automatically, such as typical formation data, fluid rheology, and proppant conductivities. The system also provides a powerful expert help facility. In addition, based on the fracture simulation results, the system produces data sets that can be used to run reservoir performance simulators and economics software.

This paper is the first of two papers which will summarize our work – how to design and implement the intelligent interface system that we call STIMULATION EXPERT. This paper analyzes the requirements of different users, outlines the purpose and the system structure, and describes the system. The second1 of the two papers will describe the implementation and application of the system in detail.

This system can be used to help engineers design hydraulic fracture treatments. The methodology described in both papers can be used to develop other similar software for different types of simulators in the industry.
A PC-Windows-Based Program for Geostatistical Modeling Application
Authors: Wu G. G. , Yang An-Ping
Published: December 2007

This paper describes a technically advanced, user-friendly, PC-Windows™ based reservoir simulation tool (SIMTOOLS) that allows construction of realistic reservoir models using a geostatistical approach. This PC-Windows based product has three application tools: digitizing, mapping and geostatistics. It has been designed primarily to enable reservoir engineers to apply the geostatistical gridding technique in mapping and reservoir simulation practices.
Integrated Formation Evaluation With Regression Analysis
Authors: Hawkins J. M.
Published: December 2007

A comprehensive formation evaluation method is presented which integrates log, core and well test data on a reservoir using regression analysis. The method employs a capillary pressure curve model correlating four reservoir variables: porosity, water saturation, permeability and capillary pressure. Porosity and saturation are estimated by conventional log analysis, permeability is obtained from empirical correlations with logs (usually porosity) and capillary pressure is directly related to height above the water level.

Depth profiles of the four variables are adjusted by regression analysis constrained by the capillary pressure curve model. Results of the regression include: An estimate of the water level,Improved profiles of the four variables which are consistent with both log analysis and capillary pressure theory,Adjusted log analysis parameters,Complete synthetic capillary pressure curves for each depth level,Relative permeability curves (drainage) generated from the capillary pressure curves, andEstimated effective permeability to hydrocarbons and to water opposite the wellbore.

These results are then integrated with well test data by comparing effective permeabilities from 6. above with the test results. If there is a mismatch, it may be necessary to rerun the regression in order to honor all of the datasets.

The method is illustrated with log, core and test data from an offshore Gulf of Mexico well.
3D Scientific Visualization of Reservoir Simulation Post-Processing
Authors: Sousa M. C. , Miranda-Filho D. N.
Published: December 2007

This paper describes a 3D visualization software designed at PETROBRÁS and TecGraf/PUC-RJ in Brazil for the analysis of reservoir engineering postprocessing data. It offers an advanced functional environment on graphical workstations with intuitive and ergonomic interface. Applications to real reservoir models show the enriching features of the software.
New PC-Based Software for Multiphase Flow Calculations
Authors: Aziz Khalid , Petalas Nicholas
Published: December 2007

A new multiphase flow analysis and design system for DOS-based personal computers is described. Examples are also presented and analyzed using different multiphase flow techniques. These techniques are investigated using flow map and three-dimensional pressure surface comparisons and a new mechanistic model is discussed which attempts to overcome many of the problems associated with existing multiphase flow analysis methods.
Variance Simulation: A Practical Alternative to Monte-Carlo Simulation and Sensitivity Analysis
Authors: Tortike W. S. , Frimpong Samuel
Published: December 2007

The technique of variance simulation is introduced here as an adjunct or an alternative to Monte-Carlo simulation for the practical evaluation of outcome distributions in petroleum engineering as a consequence of uncertain inputs. Both methods allow one to establish the probability of a desired function falling within a range of extremes, by establishing the output distribution. However, not only is the method by which the output distribution is attained different in each of the two cases, but the variance simulation also supplies the component variance for each of the uncertain inputs. In other words, it provides a measure of simultaneous sensitivity of the output to the combined effect of all the uncertainties, and the rate at which the sensitivity changes with increasing uncertainty in the data. This extra information is a key to deteπnining the relative value gained per unit expenditure on data to improve the quality of the input variables. It can be applied equally to economic or technical evaluations.

As variance simulation requires the evaluation of second order system moments, the object function must be continuous so that numerical derivatives can be calculated. The method is demonstrated by illustrating the effect on payout and economic limit of decline data containing quantifiable uncertainty. The uncertain data affect the values of the well operating cost, the hyperbolic constant, the initial decline and oil rate in the case of a hyperbolic decline. The uncertainty is defined as a normal or log-normal distribution about a mean value with a defined coefficient of variance. The moment output distribution is compared to an equivalent Monte-Carlo analysis of the same data, and the component variance is tabulated. The results show that variance simulation can be used to examine mean estimates, the total variance and the probability of success or failure, and can be used as an alternative to Monte-Carlo simulation, while providing additional information for decision making in the form of component variance and bias.
Buy don’t Build – What does that Mean for a Software Developer?
Authors: Little Todd , Rahi M. Ahsan , Sinclair Craig
Published: December 2007

The buzz-phrase of the 90's in the petroleum industry has become "Buy, don’t Build". For an end user in an oil company, this generally means acquiring application software rather than developing it internally. For a software developer, either within an oil company or with a software vendor, the concept of "buy don’t build" can apply to software toolkit components and can expedite the development of an application as well as reduce future support requirements.

This paper presents several software tools and the process by which they were evaluated for use in a commercial petroleum engineering application (DeskTop VIP). It highlights the tendency in the software development process to underestimate the complexity of the development process, as well as to underestimate the value of the services provided by a software tool. Ultimately, the decision of "buy don’t build" should be an economic decision. As a slogan, it reminds us that whenever one considers building or developing new software, one should also consider the possibility that buying off-the-shelf software could cost less in the long run and bring a product to completion quicker.
Software Licenses: Good Fences Make Good Neighbors
Authors: McCreary J. G. , Woodyard A. H.
Published: December 2007

Software licenses are the foundation for building win-win relationships between software vendors and clients. The basis for a good contract is that it is beneficial to both parties. A good foundation will cement the responsibilities and obligations of the parties after areas of agreement have been negotiated. Unfortunately, software licenses do not always reflect what is best for all. Some clauses are definitely for the benefit of the vendor while others are required by a prudent client. The resulting contract is then a matter of reasonable compromise to achieve a good business relationship.

Major issues of warranty, liability, training, support, and payment may be in conflict. Topics such as maintenance, testing, patents, extent of use, and return of software are often overlooked or addressed unevenly.
Operations and Accounting: Can’t Both Needs Be Satisfied With One Production Management System?
Authors: Schacht C. T.
Published: December 2007

Production Management Systems should have the ability to support operations as well as accounting, but many systems today, both internally developed and purchased, do not meet this requirement. This paper addresses issues and problems from the perspective of Production Operations and their associated needs and requirements. A major concern of production operations is the maximization of profit which involves the optimization of production and the minimization of the expenses involved. Timely and accurate information provides some of the basis on which management makes decisions related to daily operations and future planning and budgeting. Supporting systems are essential for data gathering and subsequent retrieval for meaningful analysis and decision making.
Cost Savings through Effective Use of Network Resources
Authors: Fife Leslie D. , Henry Stephen R. , Frost Kevin I.
Published: December 2007

The role of computers has become increasingly important for oil and gas field research and operations support. Today, the computer network is an integral part of the increasingly complex computing environment that exists in many companies. Computer networks allow users to efficiently share information, software, and hardware to support critical global communication needs. Because users are able to share software and hardware, the use of computer networks can also result in significant cost savings.

This paper describes typical network loading and demand levels for shared software applications on a computer network that has been used for several years.
On the Human Aspect of Cold Climate Operations
Authors: Lawrence N.A.
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.

The recent surge of activity above the Arctic Circle has attracted great attention to geology, topography, transportation, ice, and all manner of technical problems. In the rush to take advantage problems. In the rush to take advantage of the resources awaiting us, we tend to forget we are planning for a 25–50 year life of the facilities we build. Someone must stay and live on the site to operate and communicate. It's time to examine our Arctic areas as places to live on a permanent or semi-permanent basis. permanent or semi-permanent basis. This paper is intended to explore a few of the more obvious problems, note the state of the arts as at present, and to some degree, offer a glimpse of future developments.

In order to limit the area of reporting, the discussion herein will deal with only the Arctic Coastal Area.

Background

Referring to the Northland, Robert Service, the Poet Laureate of the Yukon, wrote the following:

"I am the land that listens, I am the land that broods; Steeped in eternal beauty, crystalline waters and woods. Long have I waited lonely, shunned as a thing accurst, Monstrous, moody, pathetic, the last of the lands and the first; Visioning camp-fires at twilight, sad with a longing forlorn, Feeling my womb o'er-pregnant with the seed of cities unborn.

This is the Law of the Yukon, that only the Strong shall thrive; That surely the Weak shall perish, and only the Fit survive. Dissolute, damned and despairful, crippled and palsied and slain, This is the Will of the Yukon,— Lo, how she makes it plain!"

In the preparation of this paper, the author was able to refer to his youth which was spent in the Turner Valley Oil Fields, and to a short-lived career as a roughneck. This career was cut short by a collision with a piece of drill stem which hospitalized him long enough to convince him that further education would be wonderful.
A Methodology Using Laboratory Experiments and Numerical Modeling To Optimize Roller Cone Bits Hydraulics
Authors: King Isabelle , Wells M. R. , Pessier R. C. , Besson Alain
Published: December 2007

Conventional roller cone bit hydraulics optimization techniques focus on minimizing circulation losses to deliver maximum power or impact force to the bit. Little emphasis has been placed on optimizing the bottom hole cleaning process by itself, even though it is highly influential in both penetration rate and bit life. Optimization of bit and bottom hole cleaning requires the elimination or minimization of flow stagnation in the open spaces between the rolling cones and the enhancement of shear flow and turbulent pressures across the hole bottom. Better understanding of this flow opens the door for improved bit design and better allocation of hydraulic energy to improve the efficiency with which the bit and hole bottom surfaces are kept free of cuttings and fines.

This paper presents the results of a numerical study of the highly turbulent, three-dimensional flow surrounding an 8 1/2″ IADC 517 class roller cone rock bit. The computations were performed using a three-dimensional finite element computer code (N3S). Numerical predictions were verified by full-scale laboratory experiments consisting of wet paint flow visualization tests on the exposed surfaces of the bit, high-speed photography of plastic particles to determine flow velocities and measurements of the mean and fluctuating pressures on the borehole bottom.

A similar approach has been used successfully to improve nozzle arrangements and bit geometry on easier-to-model PDC bits. This paper verifies that the same methodology is applicable to the more complex and highly disturbed flows around a roller cone rock bit and may bring about comparable improvements.
Field Measurements of Casing Tension Forces
Authors: Quigley M. S. , Lewis D. B. , Boswell R. S.
Published: December 2007

Tension forces acting on individual casing joints were accurately measured while installing 10,150 ft of 9–5/8 in × 47 ppf casing and 11,900 ft of 11–7/8 in × 71.8 ppf casing. A unique Casing Load Table (CLT) placed between the rotary table and the casing spider weighed the casing string as it hung from the spider slips. Strain gages attached inside the pin ends of selected casing joints directly measured tension force on those joints. A highspeed computer data acquisition system (DAS) automatically recorded data from all of the sensors. Several casing joints were intentionally subjected to extreme deceleration in order to determine upper limits for dynamic tension forces. The data clearly show effects of wellbore friction and casing handling conditions.

Over 250 megabytes of data were collected for 408 casing joints during the two casing jobs. In every case, tension forces in the casing during maximum deceleration were considerably less than expected. Peak tension forces caused by setting the casing slips were typically no more than 5 % greater than tension forces in the casing at rest. In some cases, the highest tension forces occurred when the casing lifted out of the slips.
A New Formula for Elasto-Plastic Collapse Strength of Thick-Walled Casing
Authors: Kuriyama Yukihisa , Mimaki Toshitaro
Published: December 2007

This paper describes the development of a theoretical formula for elasto-plastic collapse strength. The estimated collapse strength by this formula was compared with the Finite Element Analysis for bifurcation problems. This FEA had been tested its accuracy by many experiments.

Newly developed formula is based on the stress distribution of heavy wall cylinder and the evaluation of rigidity for clad pipe. This formula found to have enough accuracy for Diameter to Thickness ratio (D/t) from 24 to 12.

API 5C3 and 5C5 formulas were compared with this theoretical formula. As a result, the safety factor of API 5C3 in the "yield collapse" region is extremely small and the prescribed external pressure of API 5C5 using actual yield strength instead of SMYS may exceed the collapse strength of actual casing.
Designing Efficient Well Abandonment Procedures in the OCS-Gulf of Mexico To Include the Permanent Disposal of NORM Waste
Authors: Young D. R. , Scaife W. W. , Mueller S. G.
Published: December 2007

As Gulf of Mexico reservoirs are depleted, well abandonments are becoming a greater financial liability to operators in offshore waters. Some of the liability can be offset by developing more efficient abandonment procedures that can utilize wellbores for the disposal of NORM (Naturally Occurring Radioactive Material).

In the offshore area, well abandonments can be a significant expense due to the cost of workover rigs. Development of abandonment procedures which do not involve a workover rig can reduce the overall cost of the operation. With minor modifications, these cost effective procedures can be designed to include the downhole disposal of NORM.

In addition to controlling costs, an equally important issue for well abandonments and NORM disposal is the overall integrity of the operation. If the procedure is improperly designed and develops problems, an operator can be exposed to many long term safety and environmental risks. In many cases, the expense associated with these risks can far outweigh any short-term savings. With proper design, NORM disposal can be included in offshore well abandonments without compromising the integrity of either operation.
New Approaches to Safety on Alaska’s North Slope Successfully Reduce Accident Rates
Authors: Copoulos A. E. , Herndon Meyer , Manchester P. D. , Schmoyer Al , Welch J. L. , Stoehr Phil
Published: December 2007

New approaches to safety have been applied in the harsh operating conditions of Alaska’s North Slope. Dramatic reductions in accident rates have been achieved at higher activity levels and under busier, more difficult conditions by the service company that several of the authors represent (Fig. 1). Old approaches to safety no longer apply.

A number of actions were taken by both service and operating companies that contributed to the reduction in accident rates. In the service company, a series of management initiatives were implemented, including more direct management involvement, improved communications, more comprehensive safety training, direct organizational support, enhanced corporate support, investments in safety equipment and technology, and instilling the right attitude about safety in the employees. The operating company established a commitment to a long-term alliance, a monetary safety incentive program, and provided continued teamwork and assistance.

Although a number of factors contributed to the reduction in accident rates, the main reason, as determined through an informal survey of field personnel, is the new attitude toward safety, fostered through the strategic alliance formed between the two companies represented by the authors. Within the alliance, service company field personnel are under less pressure to rush jobs and are treated as partners. As a result, the field personnel feel comfortable taking extra time where needed in order to work safely, and they always make safety the top priority. Successful accident reduction depends mainly on field personnel and their willingness to have the right attitude about safety.

The resulting benefits, measured in terms of social, economic, and loss control, are substantial.
Field Validation of the Offshore Operators Committee (OOC) Produced Water Discharge Model
Authors: Smith J. P. , Mairs H. L. , Brandsma M. G. , Meek R. P. , Ayers R. C.
Published: December 2007

This paper describes a field study demonstrating the ability of the Offshore Operators Committee (OOC) Mud and Produced Water Discharge Model to predict the dilution of offshore produced water discharges. The test involved: adding a fluorescent tracer to the produced water discharged from an offshore Gulf of Mexico platform; making measurements of the current and hydrographic conditions near the outfall; collecting water column samples with diver-held sample bottles (0-25 m from source) and through an array of sampling hoses (3 - 103 m from source; 103 m = 628 discharge pipe diameters); and comparing measured tracer concentrations with model predictions. Model predictions were in excellent agreement (R2 = 84%) with concentrations of samples collected by divers up to 25 m from the discharge point. Concentrations of samples collected through sampling hoses were highly variable, but model predictions for distances 58-103 m from the source agreed with average field measurements within a factor of two. These results demonstrate that the OOC Model can predict the dilution of produced water discharges and provide a documented set of field data useful for checking the performance of other dispersion models. The observed produced water discharges were rapidly diluted: a 6000 bbl/d discharge was diluted by a factor of 100 within 10 m and by a factor of 1000 within 103 m. Rapid dilution limits the potential for adverse environmental effects in the water column. Comparisons with previously published values of the 7-day "No Observable Effect Concentration" (NOEC) for Gulf of Mexico produced waters showed that the discharges sampled in this study were diluted below the average 7-day NOEC within 10 m of the source and in less than 2 minutes after leaving the pipe.
In Situ Bioventing for Environmental Remediation of a Natural Gas Dehydrator Site: A Field Demonstration
Authors: Lawrence Alonzo Wm. , Miller Daniel L. , Miller Jeffrey A. , Weightman Robin L. , Raetz Richard M. , Hayes Thomas D.
Published: December 2007

The Gas Research Institute (GRI) is conducting a comprehensive research program in Natural Gas Industry Exploration and Production (E & P) Site Remediation and Residuals Management to assist the industry in achieving cost effective compliance with evolving environmental protection regulations. Biological processes are considered to be a key component of the remedial strategy since most of the chemicals of interest in soils and groundwater at E & P sites have been reported to be biodegradable. Bioventing/biosparging is an in situ biological process which may have significant potential for remediating subsurface contamination caused by compounds such as benzene and natural gas liquid alkanes. Bioventing/biosparging is defined as the engineered movement of air through the subsurface to effect the removal of volatile and semi-volatile organics by both physical transport and microbially mediated mineralization.

This paper describes a bioventing/biosparging field demonstration which has been conducted over a ten month period at a former glycol dehydrator site, located near Traverse City, Michigan. The goal of the demonstration was to determine the feasibility of using this technology to remediate dehydrator sites and to develop engineering guidelines for other such sites.

The project was conducted at a former stand-alone glycol dehydrator site. Dehydrator reboiler condensate handling practice common at the time resulted in contamination of the saturated zone of the subsurface. The constituents-of-interest at the site are aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene (BTEX); and alkanes (C1 thought C10), particularly the compounds C4 through C10 (Butane through Decane). Sampling has indicated that the unsaturated zone is relatively free of the constituents-of-interest, with the primary impacted locations being the capillary fringe and saturated zones. A pump and treat system has been used since 1991 to reduce the size of the groundwater plume. The bioventing/biosparging system was installed to treat the impacted soils and groundwater in the source area. Five air sparging wells were screened in the saturated zone for air and nutrient injection. An additional well was screened in the capillary fringe for soil gas sampling and for soil vapor extraction, if needed to control subsurface air flow. A shallow soil vapor extraction well was used to collect the injected air as a means of measuring offgas constituent discharge.

This paper describes the results of the remediation in terms of soil permeability; air flow patterns, and sparge and vapor extraction well radius of influences; constituent stripping rates; and, constituent biodegradation rates. The experimental results are discussed in the context of a mass balance engineering model of the subsurface which can be used to guide the design of future bioventing/biosparging dehydrator site remediation projects.