bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Seismic Data and Sequence Stratigraphy for Constraining a Stochastic Model of Calcite Cementation
Authors: Bakke N.E. , Ertresvag E.T. , Naess A. , MacDonald A.C. , Falt L.M.
Published: December 2007

Calcite cemented sandstone layers are common heterogeneities in shallow marine reservoirs where they cause significant flow barriers. Field analogue studies indicate that the most laterally persistent cemented layers are associated with sequence stratigraphic bounding surfaces where the cementation forms a complex network of beds concentrated around both maximum flooding surfaces and sequence boundaries.

Although individual calcite cemented beds are thin, they are associated with very high acoustic impedances and concentration of these thin, high impedance beds around bounding surfaces produces a significant seismic response which can be used to provide information on the spatial distribution of flow barriers. This information along with a sequence stratigraphic interpretation of the reservoir and geometrical data extracted from field analogues provides the input for an integrated reservoir description of calcite cemented barriers using a stochastic modelling approach.

The stochastic model is a non-stationary indicator field with an external trend in the indicator proportions. Variograms are used to control the geometry of individual cemented beds. Sequence stratigraphy and seismic data are used to define spatial trends in the proportion of cemented beds; sequence stratigraphy provides the vertical constraints, and seismic data provide lateral constraints.

The modelling approach has been tested using data from the TOGI area of the Troll gas field in the Norwegian North Sea. A controlled (verifiable) test has been carried out using synthetic seismic data based on a realistic, heterogeneous, 3D acoustic model of TOGI. These data have been inverted using a constrained sparse-spike seismic inversion technique. The test demonstrated that the prototype modelling procedure functioned satisfactorily. The integration of data from several sources contributed to the generation of realistic heterogeneity models constrained by a maximum amount of information.

A test using real seismic data from TOGI has been initiated. The results of the sparse-spike inversion are similar to those obtained in the synthetic test. These inverted data are presently being depth converted and prepared for use in stochastic heterogeneity modelling.
Upscaling Of Permeability: Implementation Of A Conditional Approach To Improve The Performance In Flow Simulation
Authors: Almeida J.A. , Soares A. , Pereira M.J. , Daltaban T.S.
Published: December 2007

In the present work it is proposed a conditional and iterative approach of upscaling of permeability based on the formulation of mass balance equations and Darcy's Law. In the classic approaches, the effective permeability in a particular set of blocks derives from the application of a pressure gradient between two opposite boundaries and imposing a no flow condition in the others. Based on the solver pressure techniques, the idea is to improve the quality of upscaling by including, in the calculation of the equivalent permeability of each large scale block (macroblock) the influence of the permeability values in the set of neighbouring small scale blocks (microblocks) as well as the interdependence between the scale up values of macroblocks previously transformed. These outlines have conduced to the proposed interactive method: in each iteration corresponding to the upscaling of one macroblock, the solutions are ranked according a criterion based on a flow test and expressed on one objective function. In a second step, the macroblock corresponding to the minimum value of the objective function is selected. The process continue until all blocks are scale up. This method guarantee that the solutions are successively conditioned both to initial permeability values and/or scale up values obtained in previous iterations.

The performance of this method is illustrated in opposition with the classic approach by comparing the amount of flow in a local grid (each local grid include the set of blocks to come up with one value) using the small scale blocks and the large scale blocks. A second test is the comparison of the waterflood shape in a flow test using two opposite wells located in the small scale blocks and the large scale blocks using the flow simulator ECLIPSE 100.
Ranking Geostatistical Models Using Tracer Production Data
Authors: Saad Naji , Maroongroge Vichai , Kalkomey C.T.
Published: December 2007

The stochastic modeling approach can result in a large number of realizations that must be ranked so that fewer numbers can be used in more detailed flow simulation to quantify the uncertainties in reservoir performance. The objective of this paper is to investigate the use of tracer production data for the purpose of ranking geostatistical realizations. Here we introduce ranking of geostatistical models based on the first moment of the tracer production data. In this study we have used single-phase tracer simulation to rank a large number of detailed geostatistical realizations. The results of the ranking based on single-phase tracer simulations are compared with rankings based on increasingly more accurate two-phase flow simulations of a waterflood recovery process. In addition to the analysis of the integrated tracer breakthrough curve for ranking, a new tracer test used for estimating reservoir heterogeneities, called Vertical Tracer Profiling (VTP), is used to rank the generated geostatistical models. This interwell tracer test is performed by injecting and/or collecting tracer samples at different locations along the wellbore Using the more detailed VTP ranking, we investigated the differences between the tracer ranking and waterflood simulation ranking.

The results indicate that there is no correlation between the ranking based on tracer breakthrough time or peak tracer concentration and ranking based on cumulative oil recovery. Ranking based on the tracer's mean swept pore volume, first moment of the tracer production data, shows the highest degree of correlation with ranking based on cumulative oil recovery from waterflood simulations.
Improved Technique for Off-Center Well Modelling in Multidimensional Reservoir Simulation
Authors: Agaev G.S.
Published: December 2007

At present one of effective tools of real reservoir systems simulation is the numerical solution of partial differential equations of multidimensional multiphase filtration theory with combination of well equations. Because of that the wells are a single source of information about reservoir systems, the realistic description of fluid flow around the wells is one of most challenging aspects of reservoir simulation.

In conventional reservoir simulation there is accepted that the boundary conditions for reservoirs must be to given in the production (injection) wells and in the external (internal) boundaries. Wells are assumed to be in the gridblock centers without taking into account their exact position. It leads to neglecting of closest neighbouring cells influences and the fluid flow around an off-center wells is described incorrectly. This problem is especially important in the full-field simulators development when the reservoir systems approximate with very coarse gridblocks and reservoir produces (injected) by numerous off-center wells.

In this paper the new well representation technique in the reservoir simulation is described. This technique allows to give exact off-center well position and take into account the influence from closest neighbouring gridblocks. The application of this technique is described in the explicitly and implicitly formulations.

The results of calculations by using of suggested technique was matched with results of reservoir simulation by fine-grid application and showed a good agreement. In this paper there is illustrated that the implementation of this technique allows to improve the accuracy of results and considerable decrease of computing time because of that suggested technique assumes the use of coarse grids.
Development and Testing of a Multi-Lateral System
Authors: Longbottom J.R.
Published: December 2007

This paper will discuss the progress that has been made in the development of multi-lateral completions that have a broader scope of application than those originally used in hard rock formations. Numerous multi-lateral wells have been drilled, particularly in the Austin Chalk where openhole completions are common. In other lithologies, a more sophisticated completion method is required to maintain borehole stability, flow control/well maintenance capabilities. For this purpose, a project was undertaken to develop a multi-lateral system that

- mechanically connects the lateral liner to the parent casing,

- allows through tubing re-entry access to selected laterals, and

- seals the junction between the lateral and parent bore to enable flow control capability.

In addition, the hole size of the lateral has been maximized in comparison to the parent wellbore casing. Bench tests of the components of the system were performed, and then, a full scale system test was conducted. An integrated development approach with a multi-disciplinary design team and direct producing company involvement was used. The system developed to fulfill the criteria described above was successfully tested and is currently undergoing field installations.
A Practical Model for the Effect of Salinity on Gas Hydrate Formation
Authors: Edmonds B. , Moorwood R. A. S. , Szczepanski R.
Published: December 2007

This paper is based on a previously developed thermodynamic model for gas hydrates and hydrate inhibition. The model uses a cubic equation of state for the fluid phases and parameters have already been determined for the following inhibitors: methanol, MEG, DEG and TEG.

The paper describes the extension of the model to include the effect of salinity in produced water or sea water on hydrate formation. To ensure the model would be of practical value, it was designed with the following characteristics: it should be simple to use requiring as input no more than a typical ion analysis table from a laboratory report. It should be based on a cubic equation of state suitable for engineering calculations and the model should operate reliably at temperatures and pressures normally encountered in oil and gas production.

The model represents the ionic components in water by a single salt pseudocomponent of the equation of state. The physical properties of the pseudocomponent were set by regressing them to experimental data for sodium chloride solutions. Results will be presented to show that the model can simultaneously represent the lowering of the hydrate dissociation temperatures, the depression of the freezing point of water and the reduction in the water vapour pressure (osmotic coefficient).

As sodium chloride is usually the dominant component in produced water or sea water, other salts are handled on a sodium chloride equivalent basis, so that only one salt pseudocomponent is needed for practical calculations. Data for the effect of natural waters supports the use of this approximation.

In practice, a hydrate inhibitor may be added to the water phase so it is important that the inhibition model can give accurate predictions in the presence of saline solutions. This has been confirmed by investigating the salting-out effect for methanol and results are shown for salt-water-methanol mixtures.

Practical ways of accessing and applying the model are summarised. These include using the model as a standalone computer program, accessing the model via a spreadsheet or using the model as an object code library or as a dynamic link library.
Environmental Self Audits for Upstream Petroleum Operators
Authors: Garvey C. A. , Gray W. A.
Published: December 2007

This paper presents the topic of environmental auditing so that upstream petroleum operators may be able to conduct an internal environmental audit of the properties under their care. The paper also discusses the role of environmental auditing in environmental management to assess the effectiveness of management controls in achieving compliance and in protecting the environment. Planning and implementation of the environmental audit process is covered in sufficient detail for practical use. A pre audit selection matrix to identify properties most likely to need auditing is presented and discussed. A check list prepared specifically for petroleum resource properties is also included By following this methodology the audit will document the degree of environmental compliance and how to achieve improved environmental performance. References and regulations mentioned apply to Western Canada and in particular to the province of Alberta.

The causes of environmental degradation and their prevention or minimization is the focus of this paper.
Predicting the Long-term Recovery From Naturally Fractured Reservoirs Utilizing Production Test Data and a Conventional Reservoir Simulator
Authors: Grant J. R.
Published: December 2007

Recently Imperial Oil Limited has been pursuing gas plays in North-Eastern British Columbia where single wells have the potential to recover gas in the 30-300 Bcf range. The tie-in costs for these wells are very high due to acid gas content, mountainous terrain and long distances to tie-in points. A reliable prediction of the recoverable reserves helps determine if a tie-in is economic and manage the business over the long-term. The intent is to demonstrate how the long-term recovery from naturally fractured gas wells can be accurately evaluated with buildup tests and a conventional finite difference reservoir simulator.

The decision to tie in a well is strongly based upon its initial deliverability. However, this is not generally appropriate since the initial deliverability and the longterm recovery are controlled by different factors. The initial deliverability is a function of the fracture system around the wellbore while the long-term recovery is related to the fracture system's extent and the ability of the reservoir matrix to recharge the fracture system. Other evaluation techniques such as open hole logs and core can only evaluate the fracture system at the wellbore which again only relates to the initial deliverability. Properly planned and executed production tests, in conjunction with reservoir simulation, can provide accurate evaluations of long-term recovery potential. However, the current suite of dual permeability/porosity simulators are either too simplistic to be of any use or very complex and difficult to use. Considerable lime and money could be saved if a conventional finite difference reservoir simulator could be used.

Two example wells will first be presented to demonstrate how a conventional reservoir simulator can be used to model the long-term production from a naturally fractured reservoir. It will then be demonstrated how a properly conducted flow and buildup test used in conjunction with a conventional simulator can be used to predict the longterm deliverability.
A New Numerical Model for Two-Phase Flow in Liquid-Cut Gas Wells
Authors: Li Yingchuan , Du Zhimin
Published: December 2007

A new model is proposed for predicting the pressure drop in liquid-cut gas well tubing. The liquid holdup is modeled as a function of dimensionless gas and liquid velocity numbers, as well as liquid viscosity number. It involves five parameters that are related to flow regimes and can be optimized using the field data. The friction loss is based on Mukherjee and Brill correlation. In this model, the pressure gradient equation is treated as an initial value problem for an ordinary differential equation, and is directly solved by Runge-Kutta method.

Based on the field measured data from 159 gas wells covering a wide range of production conditions, the model was found to be able to predict the pressure drops with an improved overall accuracy compared to the modified single-phase model and five commonly used empirical correlations.

Sensitivity of the models to liquid/gas ratio is also presented.
Integrated Applications for Infield Reserve Growth in Midcontinent Gas Reservoirs, Boonsville Field, Fort Worth Basin, TX
Authors: Lancaster David E. , Hardage Bob A. , Carr David L. , Hamilton Douglas S. , Elphick Robert Y. , Fate Thomas H.
Published: December 2007

Reservoir compartments identified in the Boonsville (Bend Conglomerate Gas) field, Fort Worth Basin, TX occur as a result of subtle structural and stratigraphic controls. Structural compartmenting results from previously unrecognized low-displacement faulting associated with karst collapse in deeper carbonate rocks. Stratigraphic compartments may result from surface, facies, or diagenetic boundaries. Some sequences within the Bend Conglomerate were imaged quite well using 3-D seismic, while others proved difficult to distinguish, especially when those units were associated with subtle impedance contrast or were extremely thin. Multiple stacked completion opportunities will typically be needed for economic success in new wells as well spacing is reduced, but analysis of the 3-D data suggests that stacked trapping geometries commonly exist. In addition, the influence of the vertical karst collapse features on Bend Conglomerate stratigraphy also suggests the opportunity for finding multiple stacked, and at least partially isolated, reservoirs.
A New Method for Predicting the Law of Unsteady Flow Through Porous Medium on Gas Condensate Well
Authors: Yu Xiong , Lei Sun , Liangtian Sun , Shilun Li
Published: December 2007

In order to consider the influence of variation of retrograde condensate saturation on well performance during production process in low permeability condensate reservoirs, this paper presents a new method to describe two-phase unsteady flow in formation around condensate well by using phase equilibrium and theories of unsteady flow through porous medium. The method takes into account the effect of retrograde saturation caused by phase behavior change on gas phase permeability and a new productivity prediction method by combining the variation has been offered. The method can be used to predict the distribution law of condensate saturation, pressure and relative permeability along radius direction as well as dynamic IPR curve and dynamic skin created by liquid saturation near wellbore in different production period. The method can also be used to predict effect of the dynamic skin on production. The application indicates that the method can reasonably describe the dynamic extension of retrograde condensate radius, the resistance effect of liquid dropping out on gas flow, and more rationally predict saturation variation near wellbore

Introduction

When we compare the general gas reservoirs with gas condensate reservoirs, there are many special factors which affect performance of gas condensate reservoir in exploitation process. For instance, the prediction on performance of gas condensate well is related to the law of gas condensate flow through the porous medium. In formation, the liquid will drop out from gas with pressure decline. It greatly affect the flowing feature through exploitation process. The condensate oil saturation around wellbore will be greater than that in the place far away from the wellbore due to the effect of the pressure distribution, the oil absorbed by rock, capillary forces and flowing feature. All of these will affect gas flow characteristics and change the property of well inflow performance. In these cases, not only the volume of dropping out liquid but also the flowing feature of it will play a part. Therefore, the existence of condensate oil will affect the gas condensate mixture flow to borehole, and its effect varies with time. We can more rationally and economically exploitate the oil-gas resources if these phenomena can be adequately described.

O'Dell and Miller presented a simple method based on steady-state flow concepts that can be used to estimate quickly the deliverability from the well. Results obtained using this method indicate that prediction of producing well rates will be presimistic if the average reservoirs pressure is below the saturation pressure of the in place fluid.

D.D. Fussell described the use of modified version of one-dimensional radial model developed by Rocbuck etc. to study the long term single-well performance.

P. 665
Application of Pulsed Neutron Logs for Through-Casing Evaluation of Gas, Oil, and Lithology
Authors: Jacobson L.A. , Wyatt D.F.
Published: December 2007

Modern pulsed neutron capture (PNC) and pulsed neutron spectrometry (PNS) tools provide new information about lithology that can be important in gas and oil reservoir evaluation. New PNC tools, besides the usual capture cross section measurement, also provide useful lithology information and can pass through-tubing. The PNS tools provide highly accurate complex lithology information in addition to the primary oil saturation (carbon-oxygen) measurement. Discrimination between tight limestone and gas-saturated sandstone is enhanced through application of either of these two logging tools.

The newest PNC tools also provide several neutron count-rate ratios sensitive to formation gas. A near-far capture ratio, a near-far inelastic ratio, and an inelastic-to-capture ratio provide an array of measurements that have slightly different responses to gas usually allowing for definitive identification of gas saturated reservoirs. Production problems in reservoirs caused by water movement in the casing or cement annulus between zones can often be detected by oxygen activation logging using either tool. Furthermore, flow can often be determined as inside or outside the casing.

Field examples illustrate the benefits of using pulsed neutron logging tools for oil or water saturation determination and lithology evaluation in mixed limestone/dolomite carbonates. Additional field examples will demonstrate techniques for gas detection using the numerous PNC measurements. Finally, log examples will illustrate the use of oxygen activation for detecting undesirable water flow both inside and outside the casing.

Introduction

An early PNC service introduced in 1982 (TMD*) provided a formation capture cross section measurement (FM), the near/far countrate ratio (RTMD) which is sensitive to porosity. and the total near and far detector countrates (NTMD and FMD) which when used together provide a gas indication. Modifications to the original TMD tools have added the total inelastic countrate from the far detector which provides another measurement with gas sensitivity. In 1994 Halliburton introduced the TMD-L,* which provided all the earlier measures plus spectral measurements obtained from the far-spaced detector. In a 1-11/16" (43 mm) diameter tool the detectors are necessarily small, so the total count in the spectrum above 1 MeV is low. Usable results require slow logging speeds and/or merging multiple passes to improve the statistical precision of the answers. Where spectral information is needed, slowing down from the standard logging speed of 20 ft/min. (6.1m/min.) to 10 ft/min. (3.1 m/min.) is required. Best results are obtained if three passes recorded at 10 ft/min. (3.1 m/min.) are merged. These spectral measurements can be used for lithologic identification. Spectral measurements obtained during the background measurement period provide a determination of the oxygen activation. This is a useful measure of upward water flow during normal logging operations.

P. 685
Development Drilling in a Gas-Affected Reservoir: Kuparuk River Unit, Drill Site 1B
Authors: Foster G.W. , Pearson C.M. , Moothart S.R.
Published: December 2007

SPE Members

Oil production in the early 1990's from Drill Site 1B (DS-1B) in the Kuparuk River Unit was languishing. To the east, lean gas injection in a gas storage area was migrating onto the drill site. The waterflood portion of the drill site was rapidly maturing, while high gas oil ratio (GOR) wells in the gas affected portion of the drill site could only be operated for relatively short periods of time due to gas handling facility limitations.

A thorough review of the geology and production history, in conjunction with recently available 3-D seismic information, revealed a more accurate method of predicting sand thickness and net pay trends. The sand trends were mapped using this new method, which aided in the placement of a water injection well which was used to mitigate gas encroachment from the gas storage area.

Producing GOR's in previously gas affected wells fell rapidly following water injection in the new well. Halting the gas migration allowed for the drilling of seven additional wells resulting in increased incremental oil production.

Introduction

Located in the Alaskan arctic, the Kuparuk River Field is one of the United State's largest producing oil fields (280,000 barrels oil per day), and covers an area of approximately 115,000 acres. The field was discovered in 1969, but was not deemed economic for development until 1977, after completion of the Trans Alaska Pipeline. Figure 1 shows the field location on the North Slope of Alaska. Field development was started using gravel pads as central drill sites from which deviated wells are drilled to drain a four section area (4 square miles). Initial development is on 160 acre well spacing with some 80 acre infill locations.

The Kuparuk reservoir is a sandstone at approximately 6000 feet subsea with solution gas drive as the primary production mechanism. The majority of the field is under secondary recovery receiving pressure support through a combination of waterflood and water alternating immiscible and miscible gas injection. Previous reports have documented both the geological description and the reservoir mechanisms of the field.

Production occurs from two horizons within the Kuparuk sandstone. An upper sandstone interval, referred to as the C Sand, is present over most of the southem half of the field and consists of very coarse to very fine grained siderite and sandstone. With average permeabilities of 130 md to 2600 md, and net pay ranges up to 80 ft, the C Sand typically produces at rates from 1000 to 5000 barrels per day (BPD).

The A Sand, the lower producing zone, is present throughout the field and contains 65% of recoverable oil in place. Six distinct subzones exist throughout the field with as many as three of these intervals present in a single well.
California Dreaming – Development Potential Assessment of a Major Offshore Field
Authors: Beckner B. L. , Fast R. E. , Hornafius J. S. , Myers G. A. , Timmer R. S.
Published: December 2007

Inspired by the economic necessity of compressing the technical and economic evaluation time cycle, Mobil's conventional project planning evaluation process was reengineered. This new approach was successfully applied to a novel development plan for a major California offshore field. With 155 MMSTB of remaining recoverable oil, the South Ellwood Field is one of the larger oil development opportunities remaining in the continental United States. While portions of this field have been under production from Platform Holly since 1967, at least 65 percent of the recoverable original oil in place (OOIP) remains. Mobil's "Clearview" Development Project would have used extended reach drilling from shore. The extended reach wells would have horizontal depth to true vertical depth ratios of up to 5:1. The development proposal included abandonment of Platform Holly. This paper focuses on the creation of a development plan for this major California offshore field.

A self-directed, multi-disciplinary team identified and resolved several technical issues that could have allowed the transformation of the existing 4500 STB/day field to one producing 20,000+ STB/day. Technical issues addressed for the heterogeneous Monterey Formation include; hydrodynamic tilt of the oil/water contact; identification and mapping of various lithologies using seismic, logs and regional geology; productivity variations between lithologies; recovery factor range, natural fracture orientation and effects upon horizontal well trajectories; horizontal well production forecasts using advanced decline curve analysis and reservoir simulation; and the use of a stochastically based methodology for quantifying production profiles at various confidence levels.

The re-engineering of the technical study methodology put a premium on team work, communication, and integration. As a result of this re-engineering, the previously planned three year technical/feasibility study was completed in 6 months. This paper reveals how a self-directed, multi-disciplinary, multi-worksite team integrated solutions into a unified reservoir description and a cohesive strategy for future development.
Increasing Hydrocarbon Production Through Liner Replacements in the Shallow Oil Zone, Elk Hills Field, California
Authors: Drown Michael G. , Chacon Juan , Stratton Michael S.
Published: December 2007

The Shallow Oil Zone (SOZ) reservoir within the Naval Petroleum Reserve #l, Elk Hills field occurs at depths ranging from 2500′ to 4500′ A significant portion of the SOZ reservoir was developed on 20 acre spacing in the mid 1940's to early 1950's. These wells were usually completed with 7″ combination casing strings (i.e., slotted 7″ pipe on bottom with cemented 7″ pipe above). Following Reserve open-up in 1975, 10 acre development and infill drilling was reinitiated throughout the SOZ. Wells were drilled to TD, logged, and 7″ casing was cemented to the top of the pay. The pay was opened to 13″ and the wells were completed with 5½″ gravel packed, slotted liners.

Well surveillance and production monitoring in the early 1990's revealed that the 1970's gravel pack completions were, in general, producing at lower rates than offset non-gravel packed wells. Efforts to stimulate production from these wells utilizing conventional techniques such as acidizing, chemical soaks, jet washing, and knifing/scraping proved only marginally successful. As a result, a liner replacement program was developed whereby existing slotted liners and gravel packs were removed and replaced with non-gravel packed slotted liners

A five-well pilot program was initiated in August 1992 to assess the economic feasibility of liner replacements in the SOZ This program incorporated traditional recovery techniques utilizing a spear, bumper-sub, jars and accelerator. Four of the jobs required the liner to be mechanically cut and recovered in sections based on free point survey results.
E & P Forum Risk Assessment Data Directory
Authors: Waters L. B. , Blotto P. , Covil M. , Cracknell D. , Heimly T. , Hulbaekdal J. , Mjelde A. , Thomas I. , Tigg J. P. , Turner S. M. , Wendes M. , Whiskin K.
Published: December 2007

A directory of data for use in risk assessments has been developed by the Quantitative Risk Assessment (QRA) Subcommittee of The Oil Industry International Exploration and Production Forum (E&P Forum). The directory provides readily available benchmark data and references for common incidents analyzed in upstream production operations. The directory is intended for estimating screening level and order of magnitude incident frequencies. Its primary uses are for reviewing external risk assessments and evaluating risk in QRAs and qualitative assessments. The project was carried out as a QRA Subcommittee activity to take advantage of the pooling of knowledge and expertise between participants representing various major E&P companies and other E&P Forum members. Sources for the data include information available to the public and industry such as may be obtained from industry projects and the literature. Typical incidents analyzed in E&P risk assessments were identified and divided into four major categories: accident data, event data, safety systems and vulnerabilities. Twenty six individual datasheets were developed. Each datasheet contains incident frequency, population and causal data, along with a discussion of the data sources, ranee, availability and application.
Approaches to Management Competence: A UK Perspective
Authors: Slaven Georgina
Published: December 2007

Case studies have been conducted within two UK oil and gas companies to identify their approach to devising and implementing managerial standards of competence for personnel in safety-critical posts. Results suggest that company-specific standards ensure that training and assessment is targeted towards the organisation's strategic objectives. The findings are discussed in relation to the implications for staff in safety-critical posts such as installation managers.
NORSOK - Where are we Heading? A Standardised Approach Discussing Rigidity and Flexibility in Choice of Solutions
Authors: Nja Ove , Lode Torlaug , Sandve Kjell , Aven Terje
Published: December 2007

NORSOK is a Norwegian initiative to reduce the cost of offshore projects. It consists of a set of industrial standards, which are to replace current use of individual company specifications. The starting point for the views in this paper is NORSOK report no. 6\ covering Health, Environment and Safety, and the presented potentials for improvement therein; e.g. standardisation of risk models, fewer and more comprehensive databases and common understanding of taxonomies. A prompt question raised is; Does standardisation and other changes enhance rigidity in development and choice of solutions? The paper presents and discusses expected consequences for risk analysis performance based upon ideas and recommendations from NORSOK.

The major challenge within the NORSOK principles is to establish standardised models applicable to the specific problems under consideration. Today, such standardisation is nonexistent and a major criticism of risk analyses is concerned with uncertainties and arbitrariness in risk results causing lack of credibility. Is it then really possible to meet the NORSOK intentions, for instance, defining standard minimum acceptance criteria and does the standardised risk assessment models serve its purposes? In this paper we present an alternative approach dealing consistently with these questions with respect to risk acceptance criteria and uncertainties. The approach enables structured use of expat opinions and engineering judgements within risk assessments. We conclude that use of standardised models and hard data are rational only with an adaptive frame using Bayesian probability theory.
Environmental Accounting as a Communication and Management Tool
Authors: Molinari M. , Ratti S. , Sammarco G.
Published: December 2007

International organisations such as United Nations and Euro-pean Union are developing methodologies that should be the starting point tor company environmental halanee sheet to draw up national environmental accounts.Fondazione ENI Enrico Mattei is working with ISTAT (Italian national statis-tical office) on a scheme of accounts for physical and mone-tary environmental data, finalised to integrate them with na-tional economic accounts, gathering information about the flows of inputs, products, waste streams and monetary values related to environmental issues. This methodology has been applied to hydrocarbons exploration and production activities and a software has been implemented in order to organise quantitative environmental data and current and capital envi-ronmental expenditures. The degree of data disaggregation is such as to fulfil complete balance sheets for each drilling site and for each gas and oil gathering centre: data can be also consolidated at a corporate level and used for environmental performance indicators. This detail increases the effectiveness of the company environmental accounting especially for planning and goal selling, as well as for external communi-cation.
Malaria Prevention by Chloroquine for Seismic Workers in The Tropical Jungle of East Kalimantan, Indonesia
Authors: Waworuntu Jimmy
Published: December 2007

Sangatta Oil field area, operated by Pertamina is located in East Kalimantan. It ts surrounded by tropical jungle about 6.0 sq. Kms. There were two seismic survey to find out the earth basis for oil and gas in 1993-1995 In the first location there were I240seismic workers who were given chloroquine tablet for malaria prevention. Twelve cases (0,96%) were contracted malaria and had been hospitalised in Pertamina Sangatta Hospital. Four of them were worse cases and referred to Dalikpapan where the central referral hospital for Pertamina Kalimantan was located. In the second survey location, there were five malaria cases (0,29 %) out of 1.680 seismic workers had been hospitalized for 4 to 8 days in Pertamina Sangatta Hospital, and no worse ease was found..

In Conclusion, chloroquine for malaria prevention is still effective and should be recommended for seismic workers in Kalimantan tropical jungle.
Considerations in the Phase-Out of Halon Total Flooding Fire Extinguishment Agents
Authors: Ungerleider G. M. , Catchpole D. V. , Hamlin C. C.
Published: December 2007

Deciding on a fire protection strategy when replacing halon fixed-flood extinguishment or inerting systems in existing E&P facilities or for new designs can be challenging, since the technology and public policy (regulations) are changing so rapidly. To further complicate decision-making, performance data for alternative fire fighting technologies are sometimes reported selectively or do not completely reflect fire risks in E&P industry applications

To assist in this decision-making process, the Halon Issues Sub-Committee of the Oil Industry International Exploration and Production Forum (E&P Forum) has issued a series of technical guidance reports (Ref. 7, 8, 9, 10) on considerations for halon phase-out.

The considerations presented in this paper, from those E&P Forum guidance reports, are intended to assist in the process of halon phase-out and the selection of alternative and replacement fire fighting strategies. The considerations cover: regulatory trends which may influence agent selection; risk assessment, inherent fire safety design principles (Ref. 7); incipient fire condition detection and manual response; halon-like gases; water mist systems; inert gas flood systems; halon banking; and emerging fire fighting technology.

The paper concludes that environmentally benign fire extinguishing techniques can be used in many E&P industry applications. Anthropogenic (man-made) fire extinguishing gases that accumulate in the atmosphere should only be used where required by law or are the only cost effective and people-safe option.
How to Promote and Integrate Quality, Health, Safety and Environmental Concerns in Use of Different Drilling Fluid Systems
Authors: Clementsen Stig , Berntsen Morten
Published: December 2007

Over the past years articles have been published describing exposure conditions and possible health effects (potential health hazards) associated with the inhalation of aerosol/vapour and skin contact with different types of drilling fluids. Environmental aspects have also been highlighted in biological and ecotoxicological reports. However, reports describing the process used to avoid unnecessary exposure to workers and the environment in daily operations, and practical advice for implementing health, safety and environmental factors during drilling operations, are missing. This paper describes the process of promoting and integrating the Quality, Health, Safety and Environmental (QHSE) aspects in the use of different Drilling Fluid Systems.
Environmental Law for the E & P Industry: A Model for the Future
Authors: Armstrong K. E. , Fraizer W. K.
Published: December 2007

Countries are enacting more environmental regulations for the E&P industry. There is also increased recognition that environmental protection is linked to economic development. Prescriptive, "command and control" regulations have led to significant economic costs in nations like the USA. Developed countries are now pursuing more flexible, performance-based regulations. Any environmental law must balance the desires of government, industry and communities, with the socioeconomic needs of the country. The recommended regulatory approach redefines industry and government roles, encourages cooperation, and uses goal setting, cost/benefit analysis, risk management, impact assessment, and incentives. A model law would use environmental assessments, monitoring and management plans to define required performance and communicate with the public. The E&P industry should work with government to develop effective, efficient laws that achieve environmental protection at the least cost.
Internal Control (Self Regulatory System)-Weakness and Possibilities
Authors: Strømme Jan B.M.
Published: December 2007

In order to sort of setting the stage I find it necessary to give a short introduction to the Trade Union's choice of theme for this conference. I have been told, that the reason for our proposal beeing ranked as an Alternate, was that this subject is an old case that everybody knows enough about for a long time already. If this is the reason for an Alternate ranking this strenghten me in my opinion, which is that we, and we in this matter means all of us, have a long way to go. Our, and now I am refering to the Trade Union, our opinion is that Internal Control is a key to jointly deal with most of the challenges we seek a solution for today as for those we must prepare for to meet in the future.

Without beeing boasting I just want to inform this conference that in our opinion there is no better legislation within international offshore oil and gas industry than the Norwegian Internal Control-based offshore legislation. According to our contact with the world-wide Trade Unions our view is supported by them. Therefore we feel that we are in a position where we can speak on behalf of more than just our Norwegian members.

The Norwegian legislation has come out from a process with good contact to the politicians as well as the Authorities has worked together with the industry partners, Employers and Employees, in order to find the balance where the authorities' objections are taken care of while the industry partners are given a framework for cooperation to fulfil the obligations set. Since the Norwegian offshore oil and gas industry is carried out in the the neighbourhood of the UK, the Nederlands and Denmark it is natural to draw a few paralells in this respect. These countries are all within the EU/EEA and covered by the legislation that prevails.
Risk Perception and Safety in Norwegian Offshore Workers
Authors: Rundmo Torbjörn
Published: December 2007

The relationships between perception of risk, behavior and involvement in accidents are receiving increased attention in the offshore oil industry. How employees perceive the risk they are exposed to during the conduct of their work may contribute to an understanding of risk management and thereby to the safety of their working conditions.

A self-completion questionnaire survey was carried out among employees on a representative sample of offshore oil installations in the Norwegian part of the North Sea in 1990. In I994 a follow-up study was carried out. A total of 915 respondents replied to our questionnaire in 1990 and 1138 in 1994 The studies were financed by the Norwegian Petroleum Directorate

There were significantly fewer of the personnel who felt at risk in 1994 compared to 1990 and a greater percentage of the personnel were satisfied with the safety and contingency measures and experienced job stress to a greater extent in 1990 than they did in 1994. Emotional reactions caused by potentially-hazardous risk sources were dependent on the respondents perceived controllability of the risk sources. The study also showed that there were significant positive correlations between organizational factors, safety status, perceived risk, and accidents. However, safety cannot be improved by changing risk perception. It is the factors that cause variations in risk perception as well as behavior and safety which should be the focus of safety promotion.
Halons: The Hidden Dangers of Accelerated Decommissioning
Authors: Dalzell Graham A.
Published: December 2007

Many operators have introduced a decommissioning programme for halon systems following the Montreal Protocol and the cessation of production of 1211 and 1301. Some have already decommissioned all their systems. This paper questions whether rapid decommissioning, particularly when faced with external pressure or a desire to be "seen to be green" does reduce the environmental impact. It examines the lifecycle of the halon in an existing system until it is finally destroyed, used, or lost to the atmosphere.

Halon is one of the most difficult gases to contain. It is more prone to leakage than almost any other gas. Fixed systems, which contain the majority of 1301 also have valve arrangements which are designed to open with the minimum of energy input. As a result they are also prone to accidental discharge. This paper examines these aspects and the potential for toss to the atmosphere when decommissioning, transporting, recycling and storing the halon. Controlling leakage and preventing accidental discharges within systems has been addressed in other work (1).
Environmental Quantitative Risk Assessment (EQRA)
Authors: Wiig Erik , Nesse Ellinor , Kittelsen Anita
Published: December 2007

Norske Shell E&P has developed a method for Environmental Quantitative Risk Assessment (EQRA), which has been applied to the Draugen oil platform, the Troll A platform, pipelines and onshore plant. The EQRAs have addressed planned and unplanned releases and ranked the risks according to acceptance criteria, which constitute a common denominator for the effect on the environment.
Reduction of Risk to the Marine Environment from Oilfield Chemicals - Balancing Environmental and Technical Needs
Authors: O'Neill J. E. , Hill D. G.
Published: December 2007

The study argues that the regulation of offshore use of hazardous chemicals for oilfield stimulation and completion applications is an important but not a total solution to reduce marine pollution from offshore sources. The aim of the study is to demonstrate that for a complete solution, chemical reformulation must be considered hand-in-hand with improved operational practices to provide a maximum effect on oveiall risk reduction.

The study is directed at one major service company's approach to the whole issue of chemical management in the 1990s, based mainly on North Sea experience in cementing, drilling fluid and stimulation activities. Oilfield chemicals arc incorporated into a fluid design to solve a specific technical problem in a well, such as well completion, stimulation and damage removal. While it is desirable to replace all the harmful chemicals, the practicalities of doing so are limited if the industry is to continue to produce efficiently. Other alternatives need consideration.

By their very chemistry, some chemicals have primary active ingredients which may be harmful if discharged into the environment. Improving the characteristics of chemicals to marine life requires the change of previously acceptable products, such as the elimination of banned materials as well as incorporating components with reduced toxicity and greater biodegradabilily. The idealistic goal is the immediate replacement of all chemicals by nontoxic, biodegradable alternatives-the practical solution is replacement and reformulation where possible and the improved isolation of the oilwell and marine environments through improvements in continuous-mix technology along with reduction of the use of chemicals by better job design.