bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling of the Compaction Behaviour of Fractured Chalk
Authors: Gutierrez Marte , Tunbridge Lloyd , Hansteen Harald , Makurat Axel , Barton Nick , Landa Geir Helge
Published: December 2007

Numerical modelling of the behaviour of the fractured chalk in the Ekofisk reservoir was performed using the distinct element code UDEC-BB. The non-linear fracture behaviour was modelled by the Barton-Bandis model, while the pore collapse of the rock matrix was modelled by NGI's cap plasticity formulation. The analyses were performed to investigate the effects of fractures, both natural and compaction induced on the compaction behaviour of the Ekofisk reservoir, and to determine the shear/normal displacement and permeability coupling of the fractures during pressure depletion and water injection. The results of the modelling could be used as basis for explaining the observed behaviour of the Ekofisk field, provide possible guidelines to future actions in the development of the Ekofisk field, and as input to large-scale models of the Ekofisk field.
Mechanical Effects of Water Injection on Chalk Reservoirs
Authors: Piau J.-M. , Maury V.
Published: December 2007

Water-injection is often implemented in oil reservoirs with mainly two goals. On one hand, it provides an efficient means of secondary production in water-wet fields by sweepage and pressure maintenance. On the other hand and precisely because of pressure maintenance it generally contributes to mitigate compaction and subsidence of highly compactable reservoirs. This last function is however severely put in question by the mechanical behaviour of North Sea chalk fields submitted to massive water-injection. From experimental results common to most labs we develop several models including a water-induced compaction, which allow to restore numerous field observations remained unexplained until now.
In-Situ Stress Modelling of the Snorre Field
Authors: Aadnoy Bernt S. , Bratli Rolf K. , Lindholm Conrad D.
Published: December 2007

The Snorre field is located in the Tampen area in the North Sea. This area is characterized by intense faulting, and is located in one of the most earthquake active areas in northern Europe. The paper summarize several activities to determine the stress state of the Snorre field. The regional in-situ stress state and direction is obtained from earthquake focal mechanism studies, while the local stress fields are modelled by borehole elongation and a new inversion technique that estimates both magnitude and direction of the principal stresses from leak-off data. A comparison between these analyses results in the proposed stress model. This local stress model provides a tool for field development and well planning.
The Estimation of Horizontal Stresses at Depth in Faulted Regions and their Relationship to Pore Pressure Variations
Authors: Addis M. A. , Last N. C. , Yassir N. A.
Published: December 2007

Relationships used for estimating the magnitudes of horizontal stress which can exist in faulted sedimentary basins are discussed. The relationships are based on simple assumptions and take into account the tectonic stress component associated with active normal and thrust faults. Predictions based on the equations indicate that the orientation of the far field minimum stress can change once a normal or thrust fault has formed. Stress-depletion measurements from normally faulted basins and stress measurements performed ‘at depth’ in compressive tectonic ‘thrust’ regions are presented and the predictions from passive basin and faulted basin based relationships are assessed.
Modelling the Damage Evolution in Rock Containing Pore Fluid by Acoustic Emission
Authors: Sammonds Peter R. , Meredith P. G. , Murrell S. A. F. , Main I. G.
Published: December 2007

We report results from laboratory triaxial deformation experiments on sandstone specimens containing pore fluid in which the evolution of microcrack damage was continuously monitored by acoustic emission (AE) output. We use the AE output to calculate the evolution of mean strain energy release rate, mean crack length and crack density. We then calculate the evolution of a damage parameter and relate microcracks to the constitutive stress-strain behaviour describing the deformation history. For "drained" experiments there is good quantitative agreement with experimental results.
Vertical Integration and Cooperation in the German Gas Industry
Authors: Kind H. D.
Published: December 2007

In Germany, production, transportation and trading of natural gas are dominated directly or indirectly by few vertically integrated oil and energy companies.

Structures, main players and trends towards liberalisation are described. The growing demand for gas calls for international co-operation to finance new large pipelines and the development of large gas fields in remote areas.
Sharing Risk and Reward: Floating Production Contractorship
Authors: Gisvold K. M.
Published: December 2007

Golar-Nor Offshore is a floating production contractor that has provided turnkey production services in the UK and Norwegian Sectors of the North Sea since 1986, with the production vessel PETROJARL I, and its dedicated shuttle tankers, PETROSKALD and PETROTROLL. They are currently engaged in early production for Amerada Hess (UK) in the Hudson Field, and shall be commencing a full field depletion contract for Arco (UK) in the Blenheim Field in early 1995, for a period of 35 years.

The paper will examine the applicability of contractor-based production services for extended well testing, early production and full field depletion, addressing the economic limitations and considerations, both of Company and Contractor, for these three market segments.

The paper will further examine the applicability of variable reimbursement schemes to such contracts, based on the risk-sharing scenario currently practiced by GNO, and discuss how such models can be further developed to optimize risk-sharing between Contractor and Company, in the context of development of smaller fields with uncertain reserves.
Long-Life Production and Corporate Survival
Authors: Markland J. T.
Published: December 2007

The difficulty of valuing long life production is commonly experienced in oil + gas economic evaluations. High project discount rates are observed to reduce the Net Present Value of late life-of-field production to a low level, thus lending doubts as to the credibility of the valuation tools employed in practice. This paper attempts to identify the fundamentals which control the value of long life production. In so doing it is, inter alia, necessary to consider issues of corporate finance and to employ concepts derived from modern asset pricing methodologies. Attitudes to Corporate Survival and the availability of reinvestment opportunities are cornerstones in the analysis. A by-product of this process are some important observations on the volatility of oil prices.

The complexity of ‘rear problems and the availability of suitable data upon which to base the valuations are seen as difficulties to be overcome in practical applications.
Risk Sharing in Exploration and Production Contracts
Authors: Kellas G. K. , Hodgshon Susan
Published: December 2007

The increasing number of countries providing exploration opportunities are having to compete for oil company exploration budgets which are inextricably linked to oil prices. In today's climate of sub-$15 oil this competition is fierce. Companies carefully evaluate the array of available opportunities and select those which provide the best balance between risk and reward.

Naturally, many of the inherent risks in E&P activities (such as the geological prospectivity) are very different from country to country and cannot be influenced by the host government. There are a number of mechanisms, however, which can be employed by governments in their contract and fiscal terms which can significantly affect the perceived risk/reward balance of the country.

This paper considers various contract and fiscal terms employed across the world and considers what impact these have on the investor's risk/reward balance. Simple examples are employed throughout to illustrate the effect that altering different terms can have on the balance-showing that often the strongest impact can be made by small concessions from the government.
Information Services From an Outsider's Viewpoint
Authors: Floyd B. A.
Published: December 2007

For three years I served as coordinator between Information Services and revenue accounting. From this vantage point I have formulated three concepts that may help to differentiate tomorrow's leaders. First, performance measures should be revised to measure customer satisfaction with Information Services. Second, Information Services should reevaluate their proprietary controls over systems and data. Third, joint information exploitation teams are needed by today's changing organizations.
IPDOS: An Integrated Pipeline Design and Operation System
Authors: Darwich T. D.
Published: December 2007

This paper presents the newly developed computer package IPDOS, an Integrated Pipeline Design and Operation System. The developed package provides a useful tool in assisting the pipeline engineers in compiling and processing the massive amounts of data needed for the various phases of pipeline design, construction, operation and maintenance.

IPDOS, which operates in a DOS environment, is made up of two main integrated modules: the database module and the processing module. The database module consists of a set of relational databases that are used to store the environmental, constructional, operational and maintenance parameters of the different pipeline systems within a company. These parameters can be entered, accessed, or reported via a number of easy-to-use interactive user menus. The processing module consists of a suit of programs that allow the user to perform a wide variety of data processing and analysis. These programs include wall thickness calculations, pipe size selection, stability analysis, pipeline lay-stress analysis and fluid flow analysis for gas, liquid, and multiphase pipelines.

The paper provides a summary description of the main features of the software. The application of IPDOS as an information channel and an analysis tool for field and office pipeline personnel to completely evaluate the available data in an expedient manner is also presented.
A PC/Workstation Cluster Computing Environment for Reservoir Engineering/Simulation Applications
Authors: Hermes C. E. , Koo John
Published: December 2007

Like the rest of the petroleum industry, Texaco has been migrating its applications and databases from mainframes to PC's and workstations. This transition has been very positive from the standpoint that it provides an environment for integrating applications, increases end user productivity, and in general reduces overall computing costs. On the downside, the transition typically results in a dramatic increase in workstation purchases and raises concerns with regards to the cost and effective management of computing resources in this new environment. The workstation transition also places the user in a UNIX computing environment which, to say the least, can be quite frustrating to learn and use.

This paper describes the approach, philosophy, architecture, and current status of the new reservoir engineering / reservoir simulation computing environment developed at Texaco's Exploration and Production Technology Department in Houston, Texas. The environment is representative of that under development at several other large oil companies and is based upon a cluster of IBM and Silicon Graphics workstations connected by a fiber optics communications network and engineering PC's connected to LAN's or Ethernets. Since computing resources and software licenses are shared among a group of users, the new environment enables us to get more out of our investments in workstation hardware and software.
Bit Wobble: A Kinetic Interpretation of PDC Bit Failure
Authors: Guo Boyun , Hareland Geir
Published: December 2007

Considering the configuration of bottom hole assembly (BHA), rock properties, effect of BHA rotation, and fluid damping, this paper presents a kinetic model for vibration analysis of drilling bits in vertical holes. Based on this model, it is demonstrated that drill bits undergo wobbling motion in drilling conditions. This model explains the lobed appearance of bottom hole patterns associated with PDC bit failure in hard rock drilling. Resonance is responsible for severe bit wobbling which may damage PDC bits rapidly in hard formation drilling. Sensitivity analysis with the model identifies possible solutions to the bit wobble problem: (1) using high-lateral-contact-area bits, (2) using full gauge near bit stabilizers and absorbers, (3) using high stiffness drill collars, (4) using heavy bits, (5) using low rotary speeds, (6) using high weights on bits, and (7) using viscous drilling fluids.
Innovative Approach to CO2 Project Development Holds Promise for Improving CO2 Flood Economics in Smaller Fields Nearing Abandonment
Authors: Hallenbeck L. D. , Harpole K. J. , Sistrunk G. T. , Wier D. R.
Published: December 2007

The South Cowden (San Andres) Unit is the site selected for one of three mid-term projects to be conducted under the DOE Class II oil Program for Shallow Shelf Carbonate Reservoirs. The proposed $21 million dollar project is designed to demonstrate the technical and economic viability of an innovative CO2 flood project development approach. The new approach employs cost-effective advanced reservoir characterization technology as an integral part of a focused development plan utilizing horizontal CO2 injection wells and centralization of production/injection facilities to optimize CO2 project economics. If proven successful, this new approach will help improve the economic viability of CO2 flooding for many older, smaller fields which are or soon will be facing abandonment.
A Comparative Analysis of Production-Sharing Contracts and Economic Risk Using a Weighted Criteria Decision Analysis Model
Authors: Hallermann D. R.
Published: December 2007

This paper is written for the smaller integrated producer, or the large independent producer in the planning stages of international exploration. The paper focuses on developing economic and geological criteria, and illustrates how to use a weighted decision model to compare multiple countries for exploration desirability. Then the paper will compare seven countries for exploration desirability using two weighting models.

It is important for the reader to understand that the criteria developed in this paper are only a few of several possible criteria. Additionally, when the reader applies a weighted decision model to determining where to explore, the reader should understand the reasoning behind using each set of criteria, and should adjust the weights used in accordance with the risk profile of the firm.
Engineering Salary Trends in the United States Petroleum Industry
Authors: Seanard K. C. , Leach T. A. , Frailey S. M.
Published: December 2007

A total of 6,194 SPE members responded to the 1993 SPE Salary Survey and reported an average salary increase of 2.6% when compared to the 1992 salary survey. The purpose of this paper is to highlight where significant differences in salaries exist within the membership. Due to problems with relatively small numbers of responses per country and changes in reserve exchange rates it was not possible to do data analysis for international members. In order to do an analysis of the international data properly it would have to be done on a country by country basis and the expertise is not currently available on the committee.
Trends in Reservoir Performance Prediction
Authors: MacKenzie A. S.
Published: December 2007

Stronger links between geoscience and petroleum engineering are being fostered by new tools and organisations. These linkages are improving the effectiveness of business decisions concerning reservoir performance, and are generating new challenges for the next generation of tools
Pressure Transient Behavior of a Finite Conductivity Fracture in Infinite-Acting and Bounded Reservoirs
Authors: Poe B. D. , Elbel J. L. , Blasingame T. A.
Published: December 2007

This paper presents analytic solutions of the pressure transient behavior of a well intersected by a finite-conductivity fracture in an infinite-acting, or in cylindrically or rectangularly bounded finite reservoirs. These solutions include the practical effects of reservoir permeability anisotropy and dual porosity behavior. These solutions are analytic, and thus do not require discretization in space.

The analytical solutions of the finite-conductivity fracture transient behavior presented in this paper eliminate the numerical difficulties associated with other mathematically rigorous finite-conductivity fracture solutions that have been reported in the literature. Both the pressure and rate transient responses can be accurately evaluated using the finite- conductivity fracture solutions presented in this paper. This is especially important for low-conductivity fractures, for which the pressure and rate transient behavior is often difficult to evaluate accurately using the solutions available in the literature.
Use of Supplemental Curves from Pulsed Spectral Gamma Logs to Enhance Log Interpretation
Authors: Wyatt D. F. , Jacobson L. A. , Fox Philip
Published: December 2007

Supplemental measurements from induced nuclear spectrometry tools are examined to demonstrate what additional information they provide about the well and reservoir conditions. Logs in shut-in wells from Indonesia provide examples of oxygen activation measurements showing cross-flow from one reservoir to another via open perforations. Leaking squeezed perforations were also observed. An example from Alaska shows radioactive scale build-up in the casing which spectral analysis identifies as a mixture of uranium and thorium salts. Another log, where the casing fluid was replaced with crude oil, demonstrates a technique for identifying cement channels. Logs from Nigeria comparing oil saturation estimates before and after a squeeze operation illustrate the effect of casing fluid flushing of the formation through open perforations. Understanding the diagnostic character of these curves leads to higher confidence in the overall log interpretation process.
New Solutions for Well-Test-Analysis Problems: Part III—Additional Algorithms
Authors: Özkan Erdal , Raghavan Rajagopal
Published: December 2007

We extend the Laplace-space, source-function approach presented in Part I of this series to compute unsteady flows for some complex, well-reservoir configurations such as inclined wells, disc-shaped, horizontal and vertical fractures, and off-centered wells in cylindrical reservoirs. Asymptotic approximations for well responses at early and late times are provided. Computational issues are addressed and example applications are discussed.
Development of the Industry’s First MWD Slimhole Resistivity Tool
Authors: Maranuk C. A.
Published: December 2007

A new multiple depth of investigation resistivity device has been developed for use in slimhole drilling applications. The tool has a 4-3/4 inch nominal diameter and also contains gamma ray and vibration sensors.

The tool has been designed to work in medium radius horizontal wells. It can be run stand-alone or in conjunction with existing 4-3/4 inch MWD (Measurements-While-Drilling) directional tools. The data are stored in the tool’s downhole memory and are transmitted to the surface real-time.

This paper describes the requirements and design process used to develop this slimhole resistivity device and discusses its testing and field results.
Dipping Fluid Contacts in the Kraka Field, Danish North Sea
Authors: Thomasen J. B. , Jacobsen N. L.
Published: December 2007

The orientation of fluid contacts in chalk fields of the southern North Sea is influenced by a regional hydrodynamic gradient in the chalk aquifer.

This paper describes how dipping fluid contacts have been modelled in the Kraka field by integration of geophysical, geological, petrophysical and reservoir engineering data. The Kraka field is a thin oil accumulation developed with long horizontal wells. The main reservoir is fractured chalk of Palaeocene (Danian) age. The field is located in the southern part of the Danish North Sea.

The orientation of the fracture free water level (FWL) in Kraka was initially inferred from a lateral gradient in the virgin aquifer pressures between three wells. Subsequently, during the process of matching a theoretical saturation curve to the logged water saturations, a tilt of the matrix oil-water contact (OWC) was identified. In order to model this tilt it was necessary to assume a FWL with the same orientation as the fracture FWL interpreted from pressure data. Further support of the existence of dipping fluid levels was provided by a seismically mapped dipping planar anomaly interpreted as a fluid contact. The outline of this anomaly is in very good agreement with the OWC obtained from saturation modelling. Thus, three data sources (pressures, saturation modelling and seismic mapping) have independently provided evidence of tilted fluid contacts in the Kraka field. The validity of the model has subsequently been supported by data from new wells.
The Response of Dielectric Logging Tools to Dipping Thin Beds
Authors: Anderson B. I. , Lüling M. G. , Taherian Reza , Habashy T. M.
Published: December 2007

The response of 1.1-GHz dielectric logging tools to thin dipping beds, laminates and anisotropic formations is analyzed using a new modeling program. This program models the tool as an array of point magnetic dipoles. The formation is described as a sequence of dipping parallel layers with anisotropic conductivity, dielectric permittivity and magnetic permeability. The program is benchmarked against laboratory experimental results in dipping formations. The agreement between the modeled and experimental results is well within experimental uncertainties.

Additional modeling compares the tool response to laminates and to bulk anisotropy. In very thin laminates, the modeled tool response agrees with the response to an effectively anisotropic medium. The results show that vertically oriented tools in horizontal beds are mostly sensitive to the horizontal component of the conductivity and dielectric permittivity. With changing dip, the tools measure a weighted average of the horizontal and vertical components of the formation electrical parameters.

The program is also used to simulate 1.1-GHz, tool logs from an oil well in the Gulf of Mexico. The results of the simulations depend on the choice of electrical parameters input to the modeling code for individual beds. For thick beds with a negligible bed-boundary scattering, the input parameters are directly imported from the field log. For thinner beds, the electrical parameters are determined by iteratively varying the input parameters to minimize the difference between the simulated log and the field log.
Selection of Corrosion-Resistant Alloy (CRA) Pipeline Material for Pt. McIntyre Cross-Country Flowlines Via Life-Cycle Analysis
Authors: Schaeffer K. S.
Published: December 2007

Corrosion Resistant Alloys (CRAs) provide for low maintenance expense and long service life, but require high up-front capital expenditures when compared to other materials. This paper examines the use of life-cycle cost analysis to select Corrosion Resistant Alloys for the Pt. Mclntyre Field’s crosscountry flowlines. Pt. Mclntyre, located two miles north of Prudhoe Bay, was discovered in 1988 by ARCO and Exxon. The field, developed by ARCO, Exxon and BP, began production on October 14, 1993. To a large extent, large project cost decisions are based on lowest initial capital cost. Life-cycle cost analysis takes into account the costs to operate the equipment in addition to the initial cost. Present worth analysis allows the selection of the most economic choice over the expected life of the project by allowing the input of expense costs into the analysis. For the Pt. Mclntyre cross-country flowlines, several competing material options were compared against Bare Carbon Steel (BCS) as a base case. Other materials analyzed were: internally coated carbon steel, Incoloy 825, 22% Cr duplex stainless steel, 25% Cr (super) duplex stainless steel, and carbon steel with internally clad Incoloy 825. In order to undertake life-cycle cost analysis, initial capital and operating expense costs were quantified. Effort went into understanding and making equivalent expected service life, operating costs, and repair costs. This analysis resulted in the selection of 22% Cr duplex stainless steel for the Pt. Mclntyre cross-country flowlines and the first large scale application of CRA flowlines on the North Slope of Alaska.
High-Rate Pre-Packing Using Non-Viscous Carrier Fluid Results in Higher Production Rates in South Pass Block 61 Field
Authors: Patel Y. K. , Troncoso J. C. , Saucier R. J. , Credeur D. J.
Published: December 2007

Production in South Pass Block 61 field is from Pliocene age sand reservoirs. Over the years different sand control techniques have been employed to maximize production rates and reserve recovery. In an effort to improve the productivity of our completions, we have employed High Rate Pre-Packing using non-viscous carrier fluids (High Rate Water Packing). The term "prepacking" is used to describe the process properly recognized as "outside casing packing". This paper will describe procedural aspects of the technique and present a possible explanation of the downhole process taking place using a pseudo 3D frac model. The post-job evaluation and comparative productivity data presented in the paper will clearly show the positive results of this economically attractive and simple procedure. We have used B-26 ST#1 (referred to subsequently as B-26) as an example well. Figure 1 shows the interval treated in B-26.
Combined Stochastic and Deterministic Reservoir Characterization Leads to Faster History Matching of a Horizontal Well in a Complex Fluvio-Lacustrine Environment
Authors: Calatayud P. M. , Petit F. M. , Tessier Philippe , Norris R. J. , Coffin Philippe , Alabert F. G.
Published: December 2007

An example of how to treat a complex fluvio-lacustrine reservoir, characterized by both continuous and discontinuous multi-scaled heterogeneities is presented. A detailed geological description was prepared, the heterogeneities were described and quantified, and discriminated in correctable or discontinuous levels. The discontinuous levels were geostatistically modelled and up-scaled, whilst the correctable ones were deterministically represented. The history matching process was very rapid, allowing greater time and confidence in sensitivity studies. The whole study is clearly a multi-disciplinary project, involving geology, geostatistics, up-scaling and simulation.
Moxa Arch Frontier Formation Development Success Through Increased Fracture Conductivity
Authors: Schubarth S. K. , Chabaud R. A. , Einhorn R. B.
Published: December 2007

Successful development of the Frontier formation in southwest Wyoming begins with the hydraulic fracture treatment design and implementation. Without a design to effectively stimulate the Frontier formation and a proper implementation of that design in the field, production rates will be limited. This paper will detail the efforts of the authors in the development by Bannon Energy Incorporated of a significant number of Frontier completions.

Information from over 100 fracture treatments and the production response from over 400 wells will be used to demonstrate the significant improvement in gas production resulting from the fracture treatment designs and implementation methods employed. A first year gas recovery improvement of over 50% was achieved when compared to offset production. The use of intermediate strength proppants along with other design and implementation methods have significantly improved production from this "tight" gas sand.
To Tender, Re-Negotiate or Partner: Strategies for Contracting Service Companies
Authors: Gouldie T. A.
Published: December 2007

The contracting of oilfield service companies by petroleum exploration and production operating companies is different than the contracting of civil engineering, construction or other project-oriented contractors. The relationship between operating companies and oilfield service companies has had a long and unique history which has evolved since the first oil wells were drilled over a century ago.

The process of contracting service companies by operating companies for petroleum exploration and production work can be split into three distinct stages: Decide what it is that should be contracted out and what should be kept "in house,"Determine the method to use to select the contractor(s) to perform the work, andAgree to the contractual structure to best reflect the relationship the operating company and the service company wish to initiate and maintain.

As there are ongoing changes to the business structures and corporate thinking of both operating and service companies, there are also evolving changes to what are considered "core businesses" and the methods of selecting and contracting service companies by operating companies.

Operating companies are recognizing the high costs of tendering for contractor services in terms of personnel time and administrative effort, and are relying more on negotiating and rolling-over existing contracts with their suitable, capable contractors. Partnering, in its many forms and levels, is increasingly being recognized as a useful method to get better work done at cheaper overall costs.
Bekasap Field Hybrid Streamtube Model Study
Authors: Rahardja Agus , Gerbacia W. E. , Pristiwanto H. P.
Published: December 2007

The Bekasap Field is located in the Riau Province of Central Sumatra, Indonesia. It produces mainly from three major formations, Bekasap, Bangko, and Menggala. The average field production in 1993 was 18,000 BOPD at a water cut of 86%.

A waterflood project is being evaluated for this field. The top two formations, Bekasap and Bangko, are being targeted for this project, since reservoir pressure has declined due to a partial support from an edge waterdrive mechanism.

A reservoir model of the top two formations was done using a hybrid fmite-difference/streamtube method, to forecast field oil recovery under several producing strategies. This paper presents a discussion of the hybrid streamtube results, including history matching and forecasting of field performance.
Recovery of Condensable Liquids From Flare Gas
Authors: Jones J. A. , Grey P. C.
Published: December 2007

Esso Australia is currently installing a facility to recover hydrocarbon liquids and gas that are presently flared from the Esso/BHP Petroleum Longford Crude Stabilisation Plant and Gas Processing Plant #1.

The project recovers and sells LPG and condensate, reduces carbon dioxide emissions and conserves valuable energy resources.

After an extensive review of process options, a combination of compression and condensation of the recovered gaseous hydrocarbons was chosen as the optimum configuration to fulfill the project's economic and environmental objectives. The project is under construction at the Victoria plant.
Development Planning: A Systematic Approach
Authors: Cockcroft Peter J. , Grant John N. , Moore Kevin S. , Warnohardjo Gita N.
Published: December 2007

A primary goal of an oil or gas field development is to maximize the present value of the investment. A systematically-prepared Plan of Development (POD) can assist operators in achieving this goal by ensuring that all factors are considered in evaluating, planning, and carrying out the field development.

A POD should contain an evaluation of all major events that realistically may occur during the field development cycle. By considering these events in the planning stage their probability of occurrence, effect on operations, and risk-weighted financial impact can be analyzed before field development begins. Depending upon the financial impact of the event, the field development strategy can be planned to alter the probability of occurrence or to reduce the consequences of the event.

The contents of a systematic plan of development are presented and discussed: Design Basis, Exploitation, Operations & Maintenance, Engineering, and Economics. Two Southeast Asian Field examples are used to illustrate how field economics would have been enhanced had a development plan been prepared using a systematic approach.
Moomba Lower Daralingie Beds (LDB) Gas Storage Project: Reservoir Management Using a Novel Numerical Simulation Technique
Authors: Jamal F. G.
Published: December 2007

Engineers managing underground gas storage projects are often faced with challenges involving gas migration, inventory variance, gas quality and inventory-pressures. This paper discusses a unique underground gas storage project where sales gas and ethane are stored in two different but communicating regions of the same reservoir. A commercially available reservoir simulator was used to model the fluid flow behaviour in this reservoir, hence, providing a tool for better management and use of the existing gas storage facilities.
Reservoir Engineering Aspects of Fracturing High Permeability Formations
Authors: Hunt James L. , Soliman M. Y.
Published: December 2007

High permeability formations are not usually the realm of hydraulic fracturing. However, recently there has been a resurgence of interest in stimulating these reservoirs. Reasons for the interest include fracturing past damaged zones, controlling and preventing sand production, and generally providing better control over the wellbore.

In studying this problem, several factors need to be considered. One factor is the productivity improvement aspect of the fracturing treatment. Under certain conditions, fracturing can provide a significant production increase even in a very highly permeable formation. Therefore, production versus time is important. A second consideration is pressure as a function of distance. This factor is important in the sand production aspect. Fracturing can decrease the pressure drop and gradient within the formation and thus sand production can be controlled or even prevented.

This paper presents results of a study performed to investigate the effect of various parameters on well and fracture performance in a high permeability reservoir. These parameters include formation permeability, degree and depth of damage, fracture length, fracture conductivity, and fracture face damage. Conclusions from the study provide guidelines for candidate selection and fracture design as well as insight into the effect of stimulation of high permeability reservoirs.
A Unique Experience With Foamed Cement
Authors: Piot Bernard , Ferrière Rémi , Fraboulet Bernard
Published: December 2007

An extensive laboratory program showed that foamed cement was the only technically feasible solution to prepare a "floating" cement plug for solving severe lost circulation problems in big caverns. The technique had, however, to be adapted to fit well conditions that are relatively unusual in the oil field: the cement slurry should not become diluted and destabilized upon exiting the drill pipe and entering the 60-plus inches wellbore and the huge caves, several feet in radius, both filled with sea water. Moreover, the foam had to remain stable, even when surrounded by large volume of water, until cement setting.

Therefore a technique of using "protective" fluids was devised. In addition, logistics dictated the use of compressed air rather than nitrogen to prepare the foamed slurry. Therefore special gas metering and regulation devices were used for the first time in the oil field in order to automate the process and get a perfect control of the slurry density whatever the slurry mixing and pumping rates.

Before field implementation, the metering and regulation device was successfully yard tested, the gas phase being supplied by nitrogen bottles. The successful field implementation with air compressors, together with the "protective" fluid technique to combat lost circulation in loose coral reef and in highly fractured dolomitic formation, is described.*
Geologic Factors Which May Affect the Occurrence of Natural Gas in the Oklahoma Panhandle; with Notes on Gas Analyses in Uinta Basin, Utah
Authors: Moore Carl 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.

Introduction

The Oklahoma Panhandle has produced major amounts of gas for 50 years. Initial production came from shallow rocks of Permian production came from shallow rocks of Permian age the Herington, Krider and Winfield porous limestones located on the northwest flank of the Anadarko basin.

Beginning in the early 1950's, additional reserves of gas have been proved in the Panhandle from deeper horizons in Pennsylvanian Panhandle from deeper horizons in Pennsylvanian and Mississippian age rocks. Of these newer horizons, the Morrow sands are by far the most important, followed in importance by the Chester (Mississippian), then the Hoover, Tonkawa and Topeka in approximate equal proportions. This newer production has added significant reserves to the earlier reserves, making the Oklahoma Panhandle a major segment of the Panhandle a major segment of the Amarillo-Hugoton gas field.

REGIONAL GEOLOGY

The subsurface structure at the base of the Pennsylvanian system of rocks across the Oklahoma Panhandle is illustrated in Fig. 1. In Cimarron County, the western of the three Panhandle counties, depths to the Panhandle counties, depths to the pre-Pennsylvanian sequence of rocks average about pre-Pennsylvanian sequence of rocks average about 1,000 ft below sea level. Much of this county is not well recognized because of the lack of well control. Recent tests near Boise City are expected to provide additional information. Keyes Dome is situated within the closing contour in the northeastern corner of the county.

Across Texas County, the middle county, subsurface elevations range from 1,000 to 4,000 ft below sea level. Most of this difference in elevation is related to the prominent faults along the western county line. prominent faults along the western county line. East of these faults the shelf area of the Anadarko basin dips fairly uniformly backward.

Beaver County, the eastern county, lies on the hinge line between the shelf area of Texas County and the steep basin flank that drops southeastward into the Anadarko basin trough. In the basin, each formation is expected to be found in full or maximum thickness. Moving out of the basin, past the hinge line and onto the shelf, each individual formation becomes thinner either by onlap or by erosion. Along the hinge line, environmental conditions are in optimal development for the deposition of porous/Permeable beds. Thus, Beaver County contains a large number of multiple stratigraphic pinch-outs or traps, any of which are potential reservoir beds, and hence capable of becoming a producing field.
Drilling to the Limit / Long Reach Oil Strike Extended Reach Appraisal/Development Well Tern TA-05
Authors: Meertens Rob , Harst Taco van der , Kloss Peter
Published: December 2007

In February this year, Shell Expro drilled an extended reach platform well (21,082 ft AH) to a small hydrocarbon prospect. The well proved the expected oil accumulation and a long term production test is in progress to verify extent and productivity of the accumulation and thus scope for further development.

The project presents a milestone in low cost appraisal and up front oil production, key factors in the development of marginal accumulations in a mature oil province. The experience gained has increased confidence both in long reach drilling capabilities and in the viability of small accumulations around existing facilities.
Gannet C: Geological Risks in a Marginal Field Development
Authors: Oppermann R. H- J. , Grant C. J.
Published: December 2007

This paper reviews the means by which geological uncertainty has been addressed in a complex marginal field development. The Gannet C field development carries a significant element of risk resulting from a challenging drilling environment and large geological uncertainty due to poor structural definition on seismic. By creating extreme high- and low-case structure maps during a re-mapping exercise following completion of the first drilling round, a better grasp of the possible up- and down-sides to the development has been obtained. This case study shows that targeting horizontal wells using high- and low-case scenarios enables the geologist to optimise the well location within the confines of available data and to anticipate and react confidently to the unexpected drilling result.
Montrose: A case study of innovative, cost effective field rejuvenation
Authors: Andrews I. J. , Hennington E. R.
Published: December 2007

Since 1992, Montrose, a mature waterflood field, has been rejuvenated through a multi-disciplinary full field reevaluation and the innovative, cost effective application of completion technology. Workover opportunities and areas of potentially incomplete recovery, have been identified by the full integration of all field performance, reservoir and geological data. Then workovers incorporating innovative cost effective gaslift/velocity string completions, which addressed the concerns of weak and potentially non gas-tight casing, were carried out to rejuvenate the field.

This multi-disciplinary team approach to the rejuvenation of the Montrose field, has significantly increased field wide production rates, und dramatically reduced production costs per barrel, so allowing economic production in today's low oil price environment and the fulfillment of the fields long term potential.

In addition the study has identified many techniques/lessons that can be readily applied to other similar mature field studies.
Rob Roy Reservoir Management: Old Field, More Oil, Same Data!
Authors: Currie Susan , Lane R. L. , Woods J. S.
Published: December 2007

Between 1985 and mid-1993 estimates of STOUP in the Rob Roy Field varied from 89 mmbbls to 110 mmbbls. In 1993 three well workovers resulted in a significant increase in dry oil production from the field. This increased production could not be history­ matched to the existing simulation model of the field.

This paper summarises the subsequent geoscience and engineering work which has led to a new STOIIP estimate of 143 mmbbls, a significant revision of the field reservoir simulation model, and a substantial increase in estimated oil reserves. These were achieved principally by a reinterpretation of the same geophysical dataset that was available at the time of the Annex B in 1985.
Oil Fields Waterflooding with the Help of Water-Gas Micronucleoud Solutions
Authors: Ametov I. M. , Bogopolsky A. O.
Published: December 2007

The paper presents mathematical models of one- and two-phase flow mass transfer of micronucleus water-gas solutions in non-uniform porous media and results of numerical simulation aimed at optimization of micronucleus flooding.
Offshore Refining: A Cost-Effective Approach for Treating Associated Gas
Authors: Antia D. D. J. , Seddon Duncan
Published: December 2007

A cost effective approach is outlined which can be used to remove the need to reinject associated gas (5 to 100 MMCF/D) on small, marginal, or remote North Sea oil fields by using a new application of a proven Fischer-Tropsch refining process to convert the gas into a high value synthetic crude oil which can be blended into the main crude oil stream. Additional offshore refining of the blended crude oil stream can be used to enhance its market value (by about $3/Bbl) for minimal additional cost (<$0.1/Bbl).
REGNAR - Development of a Marginal Field
Authors: Thalund K. M. , Brodersen F. P. , Roigaard-Petersen B.
Published: December 2007

Regnar is a small marginal field located some 13 km from the main Dan F complex and is the first subsea completion in Danish waters, operated by Maersk Olie og Gas AS. A short lifetime has been predicted for the field which therefore has been developed as a low cost project, using a combination of subsea technology and minimum topside facilities.

Regnar consists of a subsea x-mas tree producing through a 6" pipeline with a 2 1/2" chemical piggyback line to Dan F. The x-mas tree and the subsea choke valve are controlled from a buoy moored nearby the well. The buoy is radio linked to Dan F.

The Regnar field was brought on stream on September 26, 1993.
Minimising the Cost of Subsea Developments through Technological Innovation
Authors: Eyre Geoff , Loth Bil
Published: December 2007

The paper summarises the results of an extensive study carried out for the UK Government. This assessed the cost and economic impact of technological innovation on subsea and floating developments in the UKCS.

The study covered, innovations that could be applied to subsea developments to significantly reduce cost, including multiwell completions, composite pipelines, compartmented pipelines, pipeline specification breaking and autonomous control systems.

Cost and economic models were used to assess the economic impact of technological innovation on marginal field developments. The results of these assessments were drawn up as a series of ranking lists designed to assist manufacturers and suppliers in establishing priorities for research and development funding.

The study also explored the potential UKCS and World market for innovative subsea technologies and quantified the research and development required to bring key innovations into commercial use.
Not Normally Manned Compression Platforms for the North Sea
Authors: Kumaran K. S.
Published: December 2007

Gas turbine driven gas compressors havebeen widely used on manned offshore facilities. Similarly unmanned gas turbinedriven compressor stations have beeninoperation onshore with major gas transmission companies in Europe, North America and elsewhere. This paper summarises a recent joint industry study to investigate the technical and economic feasibility of Not Normally Manned (NNM) Offshore Compression Facilities in termsof reliability, availability and maintainability.

Classification of not normally manned (or unmanned) offshore facilities in the UK North Sea is in accordance with HSE Operations Notice 8. ON8 specifies criteria for offshore visits, visit hours and number of personnel on board for the operation of NNM platforms. This paper describes a typical Southern North Sea gas platform being considered for NNM compressor application.

The conclusions from the study was that NNM compression is technically feasible with the facilities being able to provide an availability in excess of 98%. Life cycle costs were of the order of 70% of manned facilities thus significantly improving field development economics.
Thru-Tubing Sand Control Circulating Technique
Authors: Pretto L. A. , Treglia Giuseppe , Di Iorlo Maurizio , Patel D. C. , Grigsby T. F.
Published: December 2007

The volatility of oilfield economics has always demanded operational efficiency and a need to put wells on production as quickly as possible. Conditions in today's oil and gas market have further increased these demands. To maintain profitability under current conditions, operators must carefully consider all factors that can impede well productivity, and sand production is one of the most critical of these factors. For this reason, effective sand control methods that can be performed at a reduced cost and do not have to be implemented until needed are becoming increasingly more important in today's operational strategies.

This paper will present one of these methods - a circulating thru-tubing sand control system that can be installed without pulling the production tubing or the downhole completion. This technique can be used for the repair of an original completion that has failed or in wells that are no longer economical to operate at flow rates restricted by sand production. An overview of the development, test, tool description, and installation will be presented.