bluuebunny/crossref_metadata_2025 huggingface dataset:
Drill Stem Testing with Jet Pump
Authors: Dollar F. O.
Published: December 2007

While DST is not new to the oil industry, some of the methods of augmenting flow are changing. One of the more recent changes to be accepted is the use of the Jet Pump to improve producing capabilities and make DST more meaningful and more accurate.

The Jet Pump is a form of artificial lift being used when the well does not have sufficient bottomhole pressure to flow adequate volumes to the surface to evaluate the reservoir being tested.

By running a sliding sleeve above normal DST tools, the Jet can be inserted into the sleeve where it locates, seals, and is locked in place by wireline.

The use of mud pumps with water provides the power source to operate the downhole Jet Pump. The Jet Pump has the capability of producing volumes of less than 100 barrels per day (16 cubic meters) to several thousand barrels per day.

Since the equipment required (in conjunction with normal DST tools) is minimal, the use of the Jet Pump becomes very attractive, both operational and cost wise. The Jet Pump can handle GLR up to 1,000:1, abrasive fluids, corrosive fluids, low and high volumes.
Horizontal Well Workover Experience
Authors: González Orlando Rafael , Sequera Edgar Jesus , Acevedo Nerio Enrique , Arrue Gino Franco
Published: December 2007

In recent years, horizontal operations involving drilling and well completion techniques in the oil and gas industry have increased considerably, and the main reasons for this are economic feasibility and good production results. Focusing primarily on the drilling and completion techniques, very little attention has been placed on the workover aspects; therefore, this paper has been written in an attempt to describe the workover experience gained from well TJ-1095, drilled in Lake Maracaibo by Lagoven, S.A., a subsidiary of Petroleos de Venezuela (PDVSA).
3-RJS-298 - The First Lay-Away Guidelineless Completion Offshore Brazil
Authors: Moreira José Roberto Ferreira
Published: December 2007

A Brazilian made lay-away Wet Christmas Tree was installed guidelineless at 387m water depth, on the well 3-RJS-298 in Marimbá field, Campos Basin.

Although not specifically designed for guidelineless work, the tree was successfully installed by the dynamically positioned (DP) drill ship Pacnorse I.

The lay-vessel Flexservice I was used to accomplish this unprecedented lay-away operation, involving two DP units.

This completion proved the viability of the lay-away technique for very deep waters, where DP units will be extensively used in the development of the two giant Marlim and Albacora fields.
Reusable Permanent Guide Base for Guideline System and Bending Troubles in Wellhead System
Authors: Rebeschini Edson José , Ogura Jayme Hirotugu
Published: December 2007

This paper presents the technical and operational feature required by PETROBRAS for PGB used in guideline wellhead system. It emphasizes the following aspects:

– The PGB recovery and reusable system; – The guide post recovery and replacement system using running tools or ROV; – The PGB and guide post handling tools„

It's also presented the bending troubles that has occurred in PGB, guide posts and wellhead system since 1981 as well as the solutions adopted to solve these operational problems.
How to Calculate the Mechanical Characteristics of your Casing
Authors: Neto Alexandre Quadrado , Siqueira Luiz Gustavo Primo
Published: December 2007

This paper presents procedures for calculating collapse pressure, internal pressure resistance, and pipe body yield pressure resistance, and pipe body yield strength for casings, based on APE BUL 5C3, which is applicable to API pipes. Methods for calculating the non-API large diameter casings used by Petrobras are also presented.

Introduction

The main forces acting inside a casing are: collapse pressure, internal pressure, and axial stress. Understanding the resistance of pipes to such stresses is extremely important pipes to such stresses is extremely important and directly affects safety and cost factors in the case of casings designed for oil wells.

There are several ways to ascertain resistance, be it by direct reference to the tables found in most handbooks, be it by means of calculations based on theoretical and empirical formulas and equations. This paper shows how resistance can be calculated using API BUL 5C3. It also comments on the adaptations needed to calculate the resistance of the large-diameter casings used by Petrobras. Petrobras. The tables shown in Appendix B contain all information needed to calculate the mechanical characteristics of API casings. For more details on couplings and a better visualization of the variables, see API standard 5B - Specifications for Threading, Gaging and Thread Inspection of Casing, Tubing and Line Pipe Threads.

API CASINGS (AP BUL 5C3)

COLLAPSE PRESSURE

API BUL 5C3 defines four types of collapses that may occur in a casing and that vary as a function of the geometry of the pipe (nominal diameter/thickness, D/t and the grade of the steel used in its manufacture.

Tables 1.1.1.1, 1.1.2.1, 1.1.3.1, and 1.1.4.1 of API BUL 5C3 show the D/t ranges where each type of collapse occurs.

Collapse pressure is calculated using the values for D and t specified in the tables, rounding D/t to two decimal places and minimum collapse pressure to the nearest 10 psi.

Appendix A shows the derivation of the formulas used in calculating collapse pressure. pressure. YIELD STRENGTH COLLAPSE: Refers to the external pressure capable of generating yield stress on the inside wall of the pipe that corresponds to the minimum yield strength of the steel (Yp). This type of collapse occurs at lower values of D/t and can be calculated using formula 1.

The value (D/t)Yp, calculated using formula 2, represents the upper limit of D/t values to which the yield strength collapse formula is applicable (see fig. 1)

.....(1)

.....(2)
The Evolution of Deepwater Drilling in Brazil
Authors: Oddone da Costa Décio Fabrício , Rodrigues Renato Sanches , Negrão Álvaro Felippe
Published: December 2007

In the beginning of the last decade PETROBRÁS identified, in the Campos Basin, some promising prospects under deepwater.

At that time, deepwater drilling was a new activity and there were few drilling units capable of operating in great water depths. The daily rates were expensive and no deepwater drilling program had been developed anywhere around the world.

Basically, the techniques and equipments employed were adaptations of the routinely used in shallow waters, in totally different conditions.

With the redution in deepwater vessel's daily rates and better analyses of the deepwater prospects, PETROBRÁS started its deepwater exploratory drilling program contracting the drillship PELERIN in 1984.

Since then, after confirming that the know-how at disposal was not adequate to deepwater application, the Company has started a process to develop its own technology.

This process, besides providing techniques and equipments which permitted efficient, economical and safe deepwater drilling operations, resulted in the spread of a new culture all over the Company.

Inovative equipments, as the template-manifold OCTOS-1000, the Guidelineless Christmas Tree, the 30" remote conector for jack-up rigs and the BUP-Single Guide Base were developed and procedures employed in all the drilling and completion activities have been modified.
Critical Flow Properties of Steam
Authors: Chien Sze-Foo
Published: December 2007

Understanding the thermodynamic properties of steam at critical flow conditions is important to the design, operation and management of steam distribution network and hence the cost of production in steam-enhanced recovery projects. Using the homogeneous equilibrium model, the properties of steam at critical flow conditions are presented. These properties include critical velocity, critical pressure, critical temperature, critical steam quality, critical specific volume, critical steam flux and Napier's parameter. The critical velocity, Napier's parameter and the dimensionless form of other properties are shown to be functions of the stagnation steam quality. The steam pressure is shown to have a slight effect on some of the properties. Empirical correlations for these properties are established for selected operating ranges and experimental results are presented to verify the model's predictions.
A Nine-Point Differencing Scheme Based on High-Order Stream Tube Modelling
Authors: Sammon Peter H.
Published: December 2007

Grid orientation artifacts and smeared fluid fronts can often be seen in the predictions generated by numerical simulations of EOR processes, or even in the simulations of adverse mobility waterfloods. Nine-point techniques exist that can attack these problems but various complications result when these methods are extended to non-square blocks and reservoirs with permeability contrasts.

A new method that avoids these complications is presented and discussed in this paper. The method calculates interblock fluid flows on a staggered grid using an interpolation between pressures taken at the usual finite difference nodes. The computation takes strong reservoir permeability contrasts into account, including those induced by differing fluid saturations at a sharp front. A stream tube decomposition is used to track the actual fluid movements in the reservoir.

Also, a new higher order modification for the calculation of (Darcy) velocities is described. This technique calculates the average effect on mobility of the saturation distribution created during the invasion of a shock into a grid cell and adjusts the velocity accordingly.

The combination of stream tubes and careful convective differencing provides the strong geometric component and accuracy required for accurate modelling.
Three-Dimensional Stochastic Flow and Displacement in a Five-Spot Pattern
Authors: Schafer-Perini A. L. , Wilson J. L.
Published: December 2007

Flow and miscible displacement through a three-dimensional, single five-spot well field is numerically simulated for heterogeneous reservoirs where the permeability is treated as a spatial stochastic process. Permeability fields are generated geostatistically using a Fast Fourier Transform method and are described in terms of the log of permeability by a mean, variance and covariance. The flow fields are simulated by finite differences, and displacement is simulated using a new front tracking technique.

Results of the simulations for the stochastic reservoir show that flow fields, displacement fronts, and breakthrough curves are highly non-uniform. Heterogeneity has a significant effect on reservoir behavior even for small spatial correlation and variance of the log permeability. As permeability correlation length decreases and variance increases recovery curves at pumping wells typically breakthrough earlier and take longer times to reach ultimate recovery. The fronts demonstrate significant three-dimensional fingering, even in the absence of any instabilities. Vertically distributed breakthrough curves and well flow rates provide a good indicator of vertical correlation length and vertical flow behavior. Vertically integrated breakthrough curves and flow rates, the type of information typically available, disguise this behavior. This disguise is related both to parameter sensitivity and the non-linearity of the equations in terms of the parameters.
Practical Aspects of Horizontal Well Technology: A Perspective
Authors: Ahmed U. , Jacobsen S.
Published: December 2007

Horizontal well completions to enhance hydrocarbon recovery have increased considerably in the past several years. The success of horizontal wells appears to be related to the development and application of special technology. Documentation of new technology exists in the literature; application to date has been limited and has not always met with measurable success. A critical evaluation of the technology and its associated applications allows one to choose the most practical options and methods.

This paper discusses seven specific categories of horizontal well technology: reservoir and well location selection, well planning, drilling, formation evaluation, completion and testing, stimulation and production and reservoir monitoring. In each category the practical options and techniques are presented in conjunction with specific applications. The associated discussions will allow the reader to use the information as a reference. Generic tool and technique names have been used; however, when discussing specific applications of the technology, references to Schlumberger services have been made.
Development of Composite Reservoir Model for Heterogeneous Reservoir Studies
Authors: Yu J. P. , Yang Jian-ru
Published: December 2007

Oil and gas production across a producing reservoir may vary in a complex manner that is unrelated to any one physical property. Such variations relate to properties which together can be called reservoir heterogeneity. Some forms of heterogeneity can sometimes be resolved by classical geologic and engineering methods, but often the variability is not resolvable because of incomplete data, poor reservoir pressure analysis, or simply because the reservoir heterogeneity is beyond resolution as dictated by well spacing or well distribution. Thus, a new composite reservoir well testing model is a necessary tool to obtain more pertinent data for future studies. This composite reservoir model has the variation of fluid viscosities in two different zones. Hence, the fluids distribution information can be obtained with the pressure testing analysis. The composite reservoir can model reservoirs with a fluid bank, reservoirs with a water flooding front, and reservoirs with steam or a miscible flooding front.

When the reservoir heterogeneity of different formations can be more accurately defined, then fracture stimulation and well specing can be planned in a more manageable fashion. The production manager and engineer will be able to optimize production and infill drilling. The above objectives will definitely help West Virginia's current and future energy challenges.
Estimating Gas Desorption Parameters from Devonian Shale Well Test Data
Authors: Lane H. S. , Lancaster D. E. , Watson A. T.
Published: December 2007

The feasibility of detecting and accurately estimating gas desorption parameters from a history match of Devonian shale well-test pressure data is examined. Both drawdown and buildup tests are analyzed, and based on the results of these analyses a desorption-specific well-test design is proposed. The results from a simulated desorption-specific test suggest that it is possible to characterize gas desorption from a well test with reasonable accuracy, even when the effects of desorption are partially masked by wellbore storage and skin effects.
Using Measured Flow Rate and Bottomhole Pressure Data to Analyze a Fracture Treatment in a Devonian Shale Well
Authors: Murtha J. A. , Lancaster D. E.
Published: December 2007

Extensive data were gathered during the pumping and flowback of a nitrogen foam stimulation treatment on a Devonian Shale gas well in eastern Kentucky. Subsequent analysis of these data revealed that 1) duplicate monitorinc equipment, properly calibrated, yielded nearly identical data, 2) the job execution, largely because of extensive quality control, closely followed job design. 3) friction loss in the pumping annulus could be calculated at all stages of the treatment, and 4) both perforation friction loss and the number of holes open could be estimated throughout the job.

As part of the Comprehensive Study Well program sponsored by the Gas Research Institute (GRI). this fracture treatment design, planning, execution, and analysis involved cooperation.among several GRI contractors, the service company, and the operator. On-site monitoring equipment included densiometers. pressure gauges and transducers, and various types of flowmeters. Two control vans monitored real-time data and permitted adjustment to one of three tentative pumpinc schedules based on downhole treating pressures during the prepad stage. Direct measurements led to real-time calculations of foam quality, foam rate, and downhole proppant concentration.

When the data were analyzed, the wealth of data coupled with the redundancy allowed various calculations to be made with confidence. Direct comparisons between the two sets of monitoring equipment showed near-perfect agreement. Similarly, the actual data matched the desien estimates. Recently published results dealing with discharge coefficient change and hole enlargement formed the basis of our analysis of perforation friction.

This analysis has been performed on one other set of data from an offset well and led to similar conclusions. Comparable data is being acquired from other wells and may eventually provide a valuable database for fracture design in the Devonian Shales.
Analysis of Air Drilling Hydraulics
Authors: Adewumi M. A. , Tian Shifeng
Published: December 2007

Analysis of wellbore hydraulics is motivated by the need for improved understanding of this system so as to enhance air drilling operation. A viable wellbore hydraulics model is utilized as the basis for this study. Several important parameters that influence air drilling operations are analyzed, such as drill cutting size and size distribution, hole size changes, attrition, and particle shape. This work defines several areas that need special investigation and sheds light on several previously unanswered questions. The most salient findings are that hole size changes, cuttings size and size distribution and particle shape affect the wellbore hydraulics very significantly. The analysis led to the evolution of a clear explanation for choking in air drilling.
Experimental Observations of Hydraulic Fracture Propagation through Coal Blocks
Authors: Abass H. H. , van Domelen M. L. , El Rabaa W. M.
Published: December 2007

Hydraulic fracturing experiments were conducted on coal blocks in the laboratory to investigate the effect of stress variation on hydraulic fracture propagation through a coal formation.

The first part of this study presents the measurements of mechanical properties of coal samples, which include Young's modulus, Poisson's ratio, tensile strength, compressive strength, shear strength, and fracture toughness. Mohr envelopes were determined to obtain the failure characteristics for the coal used in this study. A relationship between Young's modulus and confining pressure was derived. The physical explanation of this relationship is given.

The second part of this study presents the experimental results of hydraulic fracture propagation through coal blocks. Two groups of experiments are presented; unconfined and confined tests. This paper discusses observations and results which ranged from multiple parallel fracture systems when the blocks were unconfined, to single fractures created when a confining stress was applied. Laboratory conditions were designed to investigate the creation of T-shaped fractures in the coal, and to study the treating pressure response during the creation of these unconventional fracture shapes.

Treatment pressure response during these tests was significantly different from those observed when fracturing sandstone blocks in the laboratory. The factors which govern this different type of pressure response (roughness, fracture tortuosity, cleat system, spalling, etc.) will be described in detail. Also, a comparison is drawn which relates the observations made during this laboratory testing to actual field reports made during mineback experiments.

New fracture width, height, and initiation criteria related to coal seam fracturing, are presented in this paper. These criteria are based on close examination of the rock properties of coal under different stress-loading conditions.
Depth Control for Openhole Frac Procedure
Authors: Knowlton L. W.
Published: December 2007

This paper describes a method of measurement to be used in completing an open-hole frac procedure. Unlike cased hole work, a gamma ray – CCL log is used in correlation with a steel line measurement (SLM) to supply the completion rig crew with correct depths for placement of completion activities. This assures that the dollars spent for stimulation of the reservoir rock will be used to achieve the greatest results.
North Sea Application of Seismic Correlative and Seismic Velocity (ITT) Techniques to Predict Pore Pressure
Authors: Haas Michael A.
Published: December 2007

It has become extremely important in recent years to do a better job in well planning to ensure that well cost estimates and drilling programs are as complete and accurate as possible. Comprehensive well programs and realistic estimates are necessary to determine which drilling prospects are most attractive considering current upstream economics.

Pore pressure analysis is the initial, and in most cases, the most important step in developing an accurate, complete well program. Casing setting depths, hole sizes, number of casing strings, mud programs, and hydraulics are examples of items in a well program which are influenced by the pore pressure profile determined for a well. Pore pressure analysis is especially critical for exploratory and delineation wells but until recently our predictive techniques were somewhat inadequate.

This paper will present the application of seismic correlative and seismic velocity (ITT) techniques to predict pore pressures on a North Sea exploratory well prior to drilling. Actual mud weights used on the prospect are compared to the predicted pressures.

The steps used to predict pore pressures will be discussed including sonic log pore pressure analysis correlated to the prospect, development of a regional pore pressure overlay for interval transit times, and analysis of ITT information developed from seismic shot points at the prospect and an offset well. Results from this interpretation of seismic information will be compared to the actual pressures determined after drilling the well to emphasize the effectiveness in using these techniques for pore pressure prediction.
Steam Separating Solves Phase Splitting Problems in Wet Steam Distribution Systems
Authors: Rector Bradley P.
Published: December 2007

Texaco operates several large steamflood projects in the Southern San Joaquin Valley in which individual wellhead mass flow rates and steam quality measurements are difficult to obtain. Uneven and unpredictable phase splitting at lateral and dead end tees is the problem (Hong, 1978.) In one instance, Texaco has solved this problem by utilizing a horizontal separator to separate 10,500 BPD of 70% quality cogeneration steam.

The separator is able to deliver saturated water and 96.5% quality steam. These two single phase flows can be divided into any number of flow streams and then measured using simple orifice plate, differential pressure, technology.

The steam flood distribution piping consists of two single phase trunk lines running the length of the field to serve small headers located near the steam injectors. The purpose of these headers is to measure and control water and steam for each well, using orifice meters and adjustable chokes. Because each injector is controlled separately, the injector mass flow rates and steam qualities are independent of one another. Not only does this solve the phase splitting problem, this flexibility allows some injectors to receive higher or lower qualities than others. For instance, lower qualities may be warranted for patterns experiencing steam breakthrough, or for areas of the field in which the flood is more mature.

One of the problems associated with this type of operation is the chemical treatment of the dry steam line. A neutralizing amine needs to be added to combat the high pH caused by the formation of carbonic acid. The goal is to hold corrosion to 6.25 mpy (1/8 " over 20 years.)

This paper addresses the system design, flow measurement, and automatic control apparatus, as well as the details, results, and sampling techniques of the chemical program.
Long Term Performance of Small Cogeneration Units in Oil Field and Gas Plant Operation
Authors: Livesay Joseph D.
Published: December 2007

Amoco Production Company installed two of its first onshore cogeneration units during late 1983 and mid-1984 in west-central Wyoming, USA. These 2.4 megawatt cogeneration units were placed in an oil field that uses steam and hot water injection in the recovery of a viscous crude oil and in the operation of a natural gas sweetening plant that uses steam for its heat-medium requirements. This paper examines the operating performance of both units over the past six years, improvements made in these systems to achieve high online operating factors and the economic justification for their installation.
Completion and Workover Well Control Needs Are Different
Authors: Rike Jim L. , Whitman David L. , Rike Erik R. , Hardin Lynn R.
Published: December 2007

Applying blowout prevention concepts that have been developed for drilling operations to a completion/workover situation is improper in many cases. In fact, application of all rules required by drilling well control courses and manuals will result in dangerous situations on many workovers. Furthermore, the majority of class time in a typical well control school is devoted to minimizing surface casing pressure during a kick, a principle that has almost no application in a completion/workover situation.

There are at least sixteen key differences between workover wells and drilling wells that demand a different set of requirements for safe well control. These important differences continue to be revealed in the form of surprises as workover crews struggle to comply with a multitude of very strict rules, all of which have evolved from situations encountered while drilling. This paper will emphasize these key differences and will introduce an idea for replacing current Completion and Workover Blowout Prevention Specifications with just a few easily understood specifications based on the Barrier Concept.
Combination of Selected Solvents and Mutual Solvents Successful in Removing Hydrocarbon Based Formation Damage
Authors: Hamberlin C. W. , Thomas D. C. , Trbovich M. G.
Published: December 2007

Solvents and mutual solvents have been used for numerous years as stimulation treatments or as components of stimulation treatment packages. This paper presents the results of field case histories of stimulation treatments using a unique combination of selected solvents and mutual solvents to remove hydrocarbon based formation damage. Treatment with this chemical has been effective in removal of multi-constituent hydrocarbon and hydrocarbon/water caused damage. The removal of this damage in producing wells provides increased production at rates and lifetimes exceeding those obtained by conventional solvent or solvent/acid treatments, and hot oiling treatments.
Dual Injection with Steam and Hot Water in the Kern River Field - A Case History
Authors: Messner G. L. , Stelling D. R.
Published: December 2007

In 1984, Texaco initiated a field test of multizone thermal recovery with dually-completed injection wells. With a single tubing string and packer, a concentric injection arrangement was implemented. Hot water was injected down the tubing into a previously-steamflooded sand, while high-quality steam was injected down the tubing-casing annulus into an overlying active steamflood zone. While both floods have demonstrated favorable production behavior, the heat transfer between the tubing and annulus has had a major impact on the planned injection strategy, with indications that the "hot waterflood" has actually been a low to mid-quality steamflood for most of its project life. Furthermore, regional gravity drainage has unexpectedly been a dominant recovery mechanism in the lower zone, creating regions of distinct production characteristics within the project area.

This paper analyzes the field results from the first 2-1/2 years of the dual injection project and discusses the identified recovery mechanisms in addition to the heat transfer consequences of dual steam/hot water injection.
Computer Simulation Improves Cement Squeeze Jobs
Authors: Bour Daniel L. , Creel P. , Kulakofsky D. S.
Published: December 2007

Squeeze cementing has been a common oil field operation for decades. During this time, technical improvements in squeeze job performance have been achieved through (1) a better understanding of hydraulic fracturing principles, and (2) utilization of fluid loss additives. In spite of these improvements, however, the common practice of interpreting downhole performance from surface pressure indications has remained arbitrary and imprecise. Typically, attainment of some specified final surface pressure is regarded as an indication that the well has been squeezed, with little or no regard for fracture gradient, frictional pressure, or hydrostatic pressure---all of which contribute to the actual downhole squeeze pressure.

Computerized simulation of squeeze cementing operations, which allows operators to take into account various well parameters, has recently been developed. Based on fluid densities and rheologies, fracture gradients, and well configuration, a prediction of nonsqueeze surface pressure is provided for the entire job. This allows operators to obtain an accurate determination of when they are actually getting a squeeze--without excessively exceeding the fracture gradient--by noting when actual surface pressure rises significantly above the predicted pressure.

The simulator has proven particularly useful in squeeze job applications utilizing foam cement. A description of operation of the simulator is provided, including case histories comparing actual and predicted wellhead pressures.
Segmented Bond Tool - A New Generation Cement Bond Logging Device
Authors: Tyndall J. H.
Published: December 2007

A new cement integrity tool has been developed, the Segmented Bond Tool (SBT), which affords a complete cement bond analysis in one logging pass. An array of transmitter-receivers, mounted on six pads, are utilized to extract quantitative measurements of the cement bond in six 60 degrees segments around the borehole. In addition, by effectively mounting the transmitters and receivers in contact with the casing wall through the use of pads, many of the problems common to the standard mandrel-type tools are effectively eliminated. Experimental laboratory tests indicate that angular resolution of the tool is 60 degrees as expected and that channels as small as 15 degrees can be detected.

From conception of this new generation CBL to final product, several rigid parameters were demanded. Briefly these are: Ease of interpretation.Eliminate ambiguity of conventional bond logs by quantitatively depicting the bond condition around the casing (i.e. channelling).Complete data acquisition in one logging pass in all casing sizes 4-1/2" to 13-5/8" in both vertical and deviated wellbores.Be unaffected by gasified wellbore fluids, fast formation and slight tool decentralization.

The purpose of this paper is to determine the success of the SBT in fulfilling these goals. Presented here are four Canadian examples from widely varied areas having casing strings cemented with various slurries.
Horizontal Wellbore Stability in Low-Permeability Reservoirs
Authors: Polillo A. , Crafton J. W.
Published: December 2007

Among the many advantages provided by a horizontal well, it permits better knowledge of the reservoir, as well as implies an increase in productivity. The main objective is to drill reliably, safely and economically. To accomplish this, it is essential not to compromise the wellbore stability, which typically requires an increase in the mud weight. This workprovides a method to design the weight of the drilling mud to hold the fluid pressure, avoid collapse and breakdown of the formation. A knowledge of the formation breakdown pressure is also necessary in production operations such as hydraulic fracturing, secondary recovery, squeeze cementing or matrix acidizing.

This work reports the study of rockmass behavior resulting from underground excavation and injection of fluids by applying finite element simulation methods and rock mechanics, to simulate the wellbore stability and onset to hydraulic fracturing for horizontal wells. The stress redistribution analysis simulates three individual effects: the wellbore (hoop stress) effect, the internal pressure effect and the fluid flow effect. Nonlinear material behavior is described by the Mohr-Coulomb yield criterion. A number of examples are presented regarding the wellbore stability of a horizontal well considering fluid injection, the nature of the injected fluid, nature of the rock and orientation of the wellbore with respect to the least initial stress and impermeable barriers.
Determination of Limestone Performance Characteristics by Model Flow Tests
Authors: Stewart C.R. , Craig F.F. , Morse R.A.
Published: December 2007

Published in Petroleum Transactions, AIME, Volume 198, 1953, pages 93–102.

This paper presents the results of a series of model flow tests on a number of large limestone cores, having different pore configurations. For limestone cores having substantially sandstone type porosity, the production characteristics for solution and external gas drives are similar. For cores whose pore spaces were microscopically heterogeneous (i.e., consisted of combinations of solution cavities, matrix, and fissures), the production characteristics for solution and external gas drives vary widely. The degree of divergence between gas-oil relative permeability relationships calculated from solution or external gas drive tests is an indication of heterogeneity of rock pore structure. The results of water floods on cores depleted by solution gas drive for each of these two general types of limestone porosity are also shown. Generalizations are made on the, water flood recovery that could be expected from each of these two types of limestone porosity.

The similarity between solution drive field performance and model solution drive performance on cores from the same formation is shown for several cases. This indicates the feasibility of predetermining limestone field performance from such large core tests.

Photomicrographs of plastic-impregnated rock thin sections of the samples tested are presented as an aid in understanding the flow test performances.
The Practical Application of Risk Analysis in the E&P Oil Industry
Authors: Kent R. P. , Sanborn L. W.
Published: December 2007

The paper discusses some of the various types of risk analysis methods (PHA, HAZOP, FTA, What if? etc.) and from a practical viewpoint draws conclusions on their application to Onshore and Offshore exploration and producing oil and gas facilities. The advantages and disadvantages of each method are reviewed. The costs associated with each method in conducting the study are compared with the benefits of carrying out the study.
Lost Circulation Material Usage in Coiled Tubing Remedial Cementing at Prudhoe Bay
Authors: Krause R. E.
Published: December 2007

Lost circulation materials (LCM) have traditionally seen wide usage in drilling mud and drilling cementing operations. However, the use of LCM in remedial coiled tubing unit (CTU) cement work has been avoided in the past due to concerns that plugging could occur in the coiled tubing nozzle ports with the potential for cementing up an entire string of coiled tubing.

In certain types of problem wells at Prudhoe Bay, standard CTU squeeze cementing techniques have been unable to effect the desired zonal isolation. Despite multiple CTU squeeze attempts and large volumes of cement pumped in these wells, significant squeeze pressures could not be achieved.

Cement slurries containing LCMs were field tested through coiled tubing in an attempt to squeeze these problem wells. This paper will: Examine the most common mechanisms for the failure of CTU remedial cement squeeze operations in problem wells at Prudhoe Bay.Look at recent experimentation with different types of LCM used in CTU squeezes in Prudhoe Bay wells.Present several case histories of squeezes performed on severe problem wells with one particular LCM, an expanded soil aggregate. So far, this particular LCM has been highly successful in achieving CTU squeezes in problem wells.
Alternatives for Closure of Solid Oily Waste Sites on the North Slope of Alaska
Authors: Kellems B. L. , Slocum R. W. , Kavanaugh M. C.
Published: December 2007

The purpose of this study was to evaluate available technologies for closure of solid oily waste sites located on the North Slope of Alaska. Most of these wastes are associated with petroleum sludges, drilling muds, and contaminated sand and gravel. In the arctic, below-ground lined pits are commonly used for waste storage. A wide variety of technologies were identified as being potentially applicable for containment, treatment and disposal of solid oily wastes. These technologies were screened according to technical feasibility (demonstrated performance, effectiveness and implementability) to determine those technologies most suitable for the arctic. Based on the results of screening, the alternatives determined to be most applicable are: Bioreactor/Soil WashingStabilization/SolidificationIncinerationIn-Place ContainmentOff-Site Disposal

This paper presents an overview of all potentially applicable closure technologies, as well as the results of the screening process. A later phase of the study will evaluate the five alternatives with respect to overall feasibility.
In-Service Corrosion Monitoring with Automated Ultrasonic Testing Systems
Authors: Galbraith J. M.
Published: December 2007

Advances in microcomputers in the last decade have resulted in the advent of computer-controlled field ultrasonic systems adapted to many requirements in modern industry. Integrated, automated scanner and ultrasonic systems are now available that gather wall thickness readings frequently enough to generate an accurate definition of the remaining thicknesses of corroded components. Not only does this automated ultrasonic system provide a method of on-line corrosion monitoring, but also it allows the analyst to determine the mechanical integrity of the corroded part. The capabilities of the system are discussed and a comparison of the data with the data generated by conventional, manual ultrasonic testing is made.
Permafrost and Thermal Interfaces from Norman Wells Pipeline Ditchwall Logs
Authors: Nixon J. F. , Saunders R. , Smith J.
Published: December 2007

During the construction of the Norman Wells pipeline by Interprovincial Pipeline Ltd in the early 1980s, a continuous ditchwall log was created during ditching for pipeline burial. The ditch was typically 1.2 m deep, and stretched continuously from Norman Wells in the Canadian Arctic to Zama Lake in Northern Alberta, a total distance of 869 km through the discontinuous permafrost zone. The ditch was logged by experienced geotechnical field personnel every 50-100 m, depending on changing conditions. Every transition from unfrozen to frozen soil was logged based on visual criteria such as color change, visual presence of ice or moisture in the ditchwall, etc. Recently, the authors have carefully studied the ditchwall records and compiled a data file containing all of the relevant data pertaining to permafrost distribution.

This provided a unique opportunity to study the amount and distribution of permafrost along a continuous transect through discontinuous and sporadic permafrost regions in Arctic Canada. The number of thermal interfaces per kilometer is an extremely important input parameter for studies relating to pipeline frost heave and thaw settlement in the Arctic. In addition, a knowledge of the percentage of frozen ground is important when deciding whether to operate a gas or oil pipeline above or below freezing. The number of frozen-unfrozen interfaces have been summarized in the paper by pipeline spread and geological terrain unit. The overall percentage of frozen ground decreases from up to 95% in the North to a low of around 16% at the South end of the study area, as might be expected. The number of interfaces typically varies between about one and three per kilometer, with the highest number occurring in some of the organic terrain units in the southern discontinuous zone.

Finally, comparisons are made with the amount of permafrost and number of interfaces as logged by electrical geophysical surveys carried out and published in advance of pipeline construction. There is reasonable agreement in terms of the overall amount of frozen ground, however the geophysical surveys appear to have significantly over-estimated the number of thermal interfaces.
The Team Approach to Application Development: A Case History
Authors: Seehafer J. A. , Glynn C. J. , Lee H. K. , Pipkin T. K.
Published: December 2007

Through the utilization of a new development methodology a major application has recently been completed and delivered in a timely and cost effective manner. The methodology employed, combining required skills into an interdepartmental team, allowed the varied talents of each of the participants to be put to optimum use. However, since each team member reported to different management and was thus influenced by different expectations and priorities, several issues had to be addressed and resolved early in the process. These issues included among others, exact definition of the team objective, definition and agreement on the specific roles and responsibilities of each member, and the establishment of a methodology for resolving team conflicts.
An Application of a 3D Geostatistical Imaging to Reservoir Fluid Flow Simulations
Authors: Morelon I. F. , Doligez B. , Guerillot D. R. , Rahon D. , Touffait Y.
Published: December 2007

A good understanding of the internal geometry of a reservoir is necessary for making realistic oil recovery forecasts. In answer to this need, software has been developed to generate 3D lithological images of a reservoir by using a geostatistical approach. Based on previous images, a petrophysical description is then obtained on a geologic mesh scale. And to perform flow simulation, petrophysical parameters must then be scaled up to reservoir mesh scale. This paper shows an application of the complete procedure of processing from geostatistical imaging to fluid flow modeling.
ADIS: Advanced Drilling Information System Project
Authors: Schenato A. , Giacca D. , Pirocchi A. , Carli R.
Published: December 2007

Data acquisition and treatment to obtain intelligence for Oil Companies or Drilling Contractors are of primary importance but unfortunately they mostly look like disconnected words. The paper will describe the attempt of creating an integrated drilling information system (ADIS Project). The project has been conceived within some ENI Group Companies: AGIP (Oil Company), ENIDATA (Software and Computer Science), SAIPEM (Drilling Contractor) to provide better rig site support, improved drilling operations management, cost and risk reduction.
Improved Subsea Drilling System for Deep Development Wells in Deep Water: Auger Prospect
Authors: Gonzalez R. , Marsh G. L. , Ritter P. B. , Mendel P. E.
Published: December 2007

A study of exploratory well data revealed particular problems that faced the development drilling program for the Gulf of Mexico, GB 426, tension leg platform (TLP) in 2,862 feet [872 m] of water. Reservoir depths of up to 19,500 feet [5,944 m] TVD, and 7-inch [178 mm] production casing requirements, when coupled with limitations imposed by conventional subsea drilling technology, led to potentially troublesome and expensive well plans.

A Two Riser System (TRS) for drilling was developed and is being utilized to reduce drilling time and cost. This is accomplished by execution of well plans which circumvent conventional subsea drilling technology limitations. Development drilling is now being conducted prior to installation of the TLP and has shown the TRS method for drilling deep development wells in deep water for the Auger TLP to be safe and cost effective.
Development of Drilling Close Rules for Dubai Petroleum Co.
Authors: Burton R. C.
Published: December 2007

Dubai Petroleum Company operates two large fields and several smaller ones in the Arabian Gulf. In developing these fields more than 40 separate production platforms have been set and several hundred wells drilled. As drilling has progressed, the Company has developed a series of drilling close rules to help prevent well collisions in these congested offshore production areas. This paper summarizes the evolution of the Company's collision avoidance work from the introduction of drilling close rules in the early 1980's to the present. Over this period Dubai Petroleum has moved from qualitative drilling close guidelines through a series of empirical rules to the current rules which are based on well specific error modelling and associated survey uncertainty checks. Development of the current rules using well collision probability modelling, economic analysis and detailed survey uncertainty comparisons is highlighted.
An Extraordinary Drilling Challenge in the Anadarko Basin
Authors: Koenig R. L.
Published: December 2007

Exxon Company, U.S.A., is actively drilling deep Anadarko Basin wells in the development of its Northeast Mayfield Field in Beckham County, Oklahoma. Two wells have been drilled to date and a third and last one is drilling at the writing of this paper. The first well, Walne 1-34, drilled to a depth of 25,825′ and was plugged back and completed in a limestone reservoir at 24,500′. The second well, Hazel Howell 1-2, drilled to a depth of 25,565′ and was also completed in the same limestone reservoir.

This paper presents a combined case history of the two wells mentioned above. In general, it briefly discusses both the geologic and drilling history of Northeast Mayfield and Exxon's basic drilling plans. Emphasis of the paper though, is focused on actual drilling operations and results. Specific drilling practices developed for the area, including those related to safety and the environment, are outlined. In addition, detailed discussion is included on a number of unique occurrences and successful operations in the course of drilling both wells. These include: 1) large nitrogen foamed cement jobs, 2) extended nozzle insert bit usage, 3) setting of a 5,800′, 24 ppg pill at casing seat point, 4) casing wear mitigation, 5) deep underbalanced drilling and, 6) a high pressure well control problem at 25,825′. In conclusion, the paper notes the key factors contributing to the success of these deep Anadarko Basin wells.
Competition: An Industry Focus on Preparing To Maintain the Competitive Edge
Authors: Heneghan P. J.
Published: December 2007

The oil industry exists in an environment of changing oil price and exchange rate, legislation, province maturity and technology. This paper examines the current and forthcoming changes in the North Sea and the response of BP Exploration to those changes.

The shorter life cycle of smaller fields, the variety of operations and the pace of change have rendered once successful strategies and approaches obsolete. Maintaining competitive advantage requires an understanding of the changing environment and managing successfully in this environment. Preparing to maintain competitive advantage requires questioning and letting go of what has been successful in order to meet the changing environment rather than always playing catch up.

This paper presents a framework for understanding the business we are in, its future challenges and presents a number of examples of activities being undertaken by the operating arm of BP Exploration in the North Sea to respond to and prepare for changes in what it takes to be successful in the North Sea.