bluuebunny/crossref_metadata_2025 huggingface dataset:
Operator Imposed Quality Requirements on Rig Owner's Risk Management Systems
Authors: Andersen L. B. , Schumacher R. , Frøysland S. , Aune S.
Published: December 2007

Operators in the North Sea have developed quality requirements for Rig Owners’ risk management documentation and safety cases. Furthermore, methods to ensure that these requirements are being met have been developed.

In the past, conflicts often arose when a Rig was contracted and the Operator was required to demonstrate the acceptability of the risks involved with the Rig's operation. Unfortunately, contracts have often been vague on the issue of documentation needs, allowing for various interpretations and inefficient disputes. In addition, the Operator often failed to evaluate the documentation appropriately and incorporate the results of such evaluations into its own management system.

The quality requirements and evaluation methods that were developed and presented in this paper are unique and will provide for increased contract efficiency and improved management of risks. This paper will describe several of these requirements. It is anticipated that both Rig Owners and other Operators will be able to benefit immediately from the work that has been done. Moreover, it is expected that further discussion on this topic can lead to subsequent improvements and wider acceptance.
Cost-Effective Management of Petroleum Hydrocarbon Remediation Projects
Authors: Ratliff M. D. , Clodfelter C. L.
Published: December 2007

Remediation projects are well known for their high capital cost and long treatment times. However, proper management and foresight can significantly reduce costs in a number of areas.

Laboratory analytical cost is often a large portion of the budget for a remediation project. Unnecessary analytical work can cause great cost increases without increasing knowledge of the contamination. Controlling analytical costs is critical to proper management of any remediation project.

This paper discusses various options available for cost-efficient management of petroleum hydrocarbon contamination remediation projects, including techniques to maximize sampling in a cost-efficient manner. The paper outlines cost saving measures for both in-situ and ex-situ soil contamination projects, as well as groundwater contamination projects.

This paper identifies multiple techniques that can be applied to all projects and can be used to control costs and maximize efficiency before, during, and after the work begins. Topics include

options available for groundwater remediation soil contamination evaluation, sampling, and treatment/disposal options groundwater remediation negotiations with regulatory personnel dealing with common, but sometimes unnecessary requests from regulatory agencies
Mercury in the Gulf of Thailand: A Risk Communication Success Story
Authors: McDaniel M. F. , Kulachol K. , Siripatrachai T. , Lambert C. E. , Leuschner K. J.
Published: December 2007

The increasing globalization of industry has brought new challenges and new opportunities to risk communication practitioners, especially those working in Southeast Asia. Unocal's operations in Thailand—including a network of nearly 80 platforms in the central Gulf of Thailand—provide a valuable example of cross cultural risk communication. Unocal Thailand has been producing natural gas in the Gulf of Thailand for the last 17 years. A by-product of this gas production is metallic mercury, a small amount of which has been released around the production platforms in the Gulf. In recent years, concern has increased over the potential health and ecological impacts of the mercury levels. Unocal has been conducting fishing surveys as well as health and ecological assessments to provide the technical answers to these questions. The risk communication effort which has accompanied the Thai studies sheds some light on what is needed for an effective global risk communication strategy. In our paper, we focus on four areas of particular importance to Unocal's risk communication efforts in Thailand: 1) an approach to environmental issues through an understanding of the "outrage factors" which make people upset; 2) the importance of working within—rather than against—the cultural and legal expectations of different lands; 3) the process of identifying and involving stakeholders and credible sources of information; and 4) the implications for industry conducting business overseas.
Community Health Assistance Programme During Seismic Exploration - a Powerful Communication Tool
Authors: Ajoku C. O.
Published: December 2007

Good occupational health standards benefit the industry, its employees and the community at large. The seismic exploration which takes place in virtually every type of community setting around the world, including some that are extremely sensitive to the intrusion of humans, need some special health services scheme that will create a friendly and a supportive atmosphere with the community. This could also help to avert most social unrest and clashes that are becoming more rampant in some communities in the oil exploration and producing area.

Most of this unrest attributed by the communities to gross neglect by the oil companies and the Government for failure to provide the basic amenities and social support to them. This could be as a result of communication break down at grassroots level. A special health services scheme such as Community Health Assistance Program (CHAP) could be used not only as a social supports program to the community but as a powerful communication tool to bridge the gap between the Oil Companies and the communities at the grassroots level.

This paper is a documentation of a 4-year experience on introducing Community Health Assistance program in seismic exploration activities with Halliburton Geophysical Services (HGS), operating for Nigerian National Petroleum Corporation (NNPC) joint venture with Shell and Chevron. Set out as follows: - 1) the selection and functions of a medical team in carrying out integrated role of good occupational health standards including community health assistance program. 2) The coverage of the community health assistance program and the type of illness treated within the period including its cost-benefit, drawback and how it could be handled.
Sustainable Development - How to Assess Your Contribution?
Authors: Bradley A. S. , Hartog J. J.
Published: December 2007

The Royal Dutch/Shell Group has committed in its key policy documents to contribute to sustainable development (SD). Shell accepts the Brundtland Commission definition of SD "meeting the needs of the present without compromising the ability of future generations to meet their own needs" as adopted at the 1992 UNCED or ‘Rio’ Conference, and recognises that it comprises three components - economic, environmental and social aspects - which are interdependant. For the E&P business, the key challenge is to satisfy the growth for energy demand, whilst safeguarding the environment and acting in a socially and economically responsible manner. Particular issues facing E&P companies include emissions contributing to global climate change; local environmental, social and health impacts; conservation of biodiversity in sensitive areas; social and economic development in concession areas; transparency and openness in communication and assurance of performance.

This paper provides a background to SD and the issues that it raises for the E&P Business. It demonstrates how the commitment may be integrated into day-to-day activities and describes two tools which have been developed to allow for assessment and monitoring of progress towards a defined SD goal for new projects and for E&P companies respectively.
In-Situ Stress Assessment of Intra-Salt Stringers
Authors: van den Bogert P.A.J. , Strating E.H. Hoogerduijn , Eelman M.C. , van Eijs R.M.H.E. , Richard P.D.
Published: December 2007

A predictive in-situ stress model has been built using finite- element techniques for salt enclosed stringers located in the South Oman Salt Basin. The stringers comprise silicilyte reservoir and shale formation layers, in a semi-thrustlike configuration. The model provides input and support to the fracture distribution and the compaction assessment of the silicilyte reservoirs. The model has been build based on seismic, gravity and well data.

Before building the in-situ stress model, two series of sensitivity analyses have been carried out concerning the geometrical parameters that influence the stress distribution and stability of in salt enclosed stringers. In the first analysis, the dominating parameters in an environment with an active rising salt dome (halokinesis) have been investigated. This analysis improved the motivation for the kinematic and geological development of the structures. In a second analysis, the stability of a single dipping stringer in a stationary salt body was investigated. The latter configuration is concordant with the current situation in the South Oman Sat Basin. The outcome of this analysis provided insight into the stress distribution of sinking stringers encased in salt. The insights obtained from these analyses were incorporated into the in-situ stress model.

P. 43
Depletion-induced Compaction of an Overpressured Reservoir Sandstone: An Experimental Approach
Authors: Schutjens P.M.T.M. , Blanton T.L. , Martin J.W. , Lehr B.C. , Baaijens M.N.
Published: December 2007

P.M.T.M. Schutjens, SPE (1, T.L. Blanton, SPE (2, J.W. Martin (3, B.C. Lehr (1 and M.N. Baaijens (4

Laboratory experiments were done to investigate compaction of core taken from a 5 km deep, highly overpressured sandstone reservoir as a function of depletion, stress path, and time. Guided by a numerical analysis of the reservoir compaction and associated total stress change, a best-estimate and an unfavourable reservoir stress path were applied. Most samples showed a linear relationship between axial strain and total axial stress up to 65 MPa, which reflects the target depletion level. However, high-porosity samples compacted following the unfavourable reservoir stress path showed linear compaction up to only 52 MPa increase in total axial stress (i.e. up to 80% of target depletion). Non-linear (accelerating) compaction occurred in nearly all high-porosity samples with increasing total axial stress; total strains reached 4 to 23 ms after 65 MPa increase in total axial stress, typically followed by 20 to 50 axial ms creep at time periods of 11 to 3 weeks. Microstructural analysis revealed that the non-linear compaction is due to an increasing activity of grain-scale brittle deformation with increasing stress, which gradually leads to pervasive microfracturing including numerous intraand transgranular microcracks, collapse of weak minerals and grain size reduction. No strain localisation occurred. Analysis of the experimental data suggest that high-porosity layers loaded following the unfavourable stress path could show vertical compactions in the range 50 ms to 100 ms should they be depleted by more than 52 MPa. Monitoring of reservoir compaction and field stress path evolution is therefore advised.

P. 53
Integrating Rock Mechanics with Drilling Strategies in a Tectonic Belt, Offshore Bali, Indonesia
Authors: Ramos G.G. , Mouton D.E. , Wilton B.S. , Leksmono _
Published: December 2007

Early efforts to drill wells in a gas field north of Bali Island, a tectonicregion in Indonesia, were hampered by high costs associated with wellbore instabilities. In the recently completed late-phase development program, drilling efficiencies and costs were improved with a strategy that included a rock mechanics program, mud optimization, and batch drilling. Wellbore instabilities occurred in the Ngimbang Shale, a hard, brittle, anisotropic formation, that is highly stressed. Field measurements of stresses, coupled with laboratory measurements of strength, demonstrated the presence of elevated horizontal stresses. The computed safe mud densities for wellbore elastic stability ranged from 10 to 15 ppg, depending on location, well azimuth, and deviation. High mud densities did not necessarily alleviate instability, as indicated by stability-days, a method of tracking the stable- time periods of each well. Drilling-time and costs were also improved with the adoption of asynthetic mud system, a batch drilling schedule, and sound field engineering. Cost savings were substantial, and the wells are now in production.

P. 69
A Parametric Study of Compressional and Shear Wave Velocities in Ekofisk Reservoir Chalk
Authors: Pedersen Sean H. , Rhett Douglas W.
Published: December 2007

A parametric study of compressional and shear wave velocity was conducted on Ekofisk reservoir chalk to gain more insight in the acoustic response of the chalk to changes in temperature, stress state and fluid saturations. The information from the study is used to interpret seismic signature changes associated with a Repeated Seismic Monitoring Program. Three factors have been identified to have a possible impact on acoustic velocities as a result of a waterflooding process. These three factors are 1) changes in effective stress state, 2) changes in water saturation, and 3) changes in temperature. It would appear that these 3 effects act together to increase the compressional wave velocity. Laboratory measurements show that the largest effect on velocity is a reduction in porosity, which results from an increase in stress and/or an increase in water saturation. Changes in temperature and fluid saturation are secondary effects which also produce increases in acoustic velocities. Together, these two parameters can account for about 5% increase in compressional wave velocity. However, compaction alone accounts for approximately 3-4% increase in compressional wave velocity. Experimental data indicate that the low frequency Biot-Gassmann relation predicts compressional and shear wave velocities to within ±2% of the measured values when appropriate rock moduli are used. This relation has therefore been considered to be a suitable approach for modeling fluid substitution in Ekofisk chalk.
Monitoring and Management of Fractured Reservoirs Using Induced Microearthquake Activity
Authors: Jupe A. , Jones R. , Dyer B. , Wilson S.
Published: December 2007

The potential value of induced microearthquake (microseismic) imaging for the monitoring and management of fractured hydrocarbon reservoirs is illustrated using a high quality data set obtained during development of the European Hot Dry Rock (HDR) geothermal energy project, Soultz-sous Forets, Alsace, France. This development has involved massive hydraulic fracturing Operations (MHF), waterfloods and water extraction in a naturally fractured rock mass. The characteristics of the development, operation and hydraulic behaviour of this system are in many ways analogous to those of fracture dominated hydrocarbon reservoirs. The data set consists of 28,000 located microseismic events detected during two phases of reservoir development, comprising a total injected fluid volume of 1 50,000m3. The microseismic data has provided detailed images of the 500Mm3 reservoir volume, successfully identifying the hydro-mechanical controls on fracture dominated flow an isotropy, enabling the successful targeting of a production well and allowing delineation of the principal flow paths. The analysis of microseismic connectivity has recently been used to successfully construct a reservoir simulator grid for modelling the long term performance of the reservoir.

P. 493
A Conceptual Model for Correlating Ultrasonic Attenuation to Deformational Behavior
Authors: Couvreur J.F. , Thimus J.F. , Lousberg E. , Vervoort A. , King M.S.
Published: December 2007

A number of laboratory tests (uniaxial, triaxial and hydrostatic) were conducted on a dry porous limestone. A conceptual model is proposed to correlate deformation and damage fields with the variation of ultrasonic velocities and quality factors. This correlation is presented in a stress deviator versus confining pressure diagram. In this way, the successive steps occurring in the damage process of this rock are well described. In particular, the quality factor of the S wave distinguishes clearly the onset of the initially stable cracking, while velocity of the S wave and strain measurements are sensitive to dilatancy which appears later in the damage process of the studied limestone.

P.187
An Experimental Study of Elastic Wave Propagation an Isotropy and Permeability an Isotropy In an Illitic Shale.
Authors: Jones C. , Meredith P.
Published: December 2007

Shales are highly anisotropic and are generally characterized by very low permeabilities. In this paper we report results of an experimental study of the relationship between elastic wave propagation anisotropy and permeability anisotropy of an illitic shale.

Elastic wave velocity was measured as a function of angle relative to the bedding plane orientation. Radial compressional and shear wave velocities were measured around the circumference of a core taken parallel to the bedding of the shale. The shale was highly anisotropic.

Permeability measurements were then taken for cores oriented in the directions of the maximum and minimum velocities. The permeability was measured using a novel steady-state-flow permeameter capable of measuring extremely low flow rates of water, brine, or oil. At low effective pressure the shale was highly anisotropic, but the anisotropy reduced to zero at high effective pressure.

We compare the shale results with those from measurements on a sandstone and a tuff, where permeability anisotropy is maintained even up to the highest effective pressures used.

P. 307
Reservoir-Scale Fracture Permeability in the Dixie Valley, Nevada, Geothermal Field
Authors: Barton C.A. , Hickman S.H. , Morin R. , Zoback M.D. , Benoit D.
Published: December 2007

Borehole televiewer, temperature, and flowmeter data recorded in six wells penetrating a geothermal reservoir associated with the Stillwater fault zone in Dixie Valley, Nevada, were used to investigate the relationship between reservoir permeability and the contemporary in situ stress field. Data from wells drilled into productive and nonproductive segments of the Stillwater fault zone indicate that permeability in all wells is dominated by a relatively small number of fractures striking parallel to the local trend of the fault. However, Coulomb failure analysis using our fracture orientations in conjunction with stress orientations and magnitudes determined by Ref. 1 suggests that fault zone permeability is high only when individual fractures as well as the overall Stillwater fault zone are optimally oriented and critically stressed for frictional failure. Fracture geometry may also play a significant role in determining reservoir productivity. The well-developed populations of low-angle fractures present in wells drilled into the producing segment of the fault are not present within the relatively impermeable segment of the Stillwater fault zone.

P. 315
Cracking and Compaction Behavior of Sandstone
Authors: Braun Roland , Jahns Eberhard
Published: December 2007

Compression and extension tests with measurement of permeability and elastic wave velocity were made on two different sandstones. Distinctly different cracking and compaction behavior were observed in the two types of test. Conclusions are drawn for the choice of wellbore orientation and allowable pressures. The results also enable the stress conditions and fracturing in the area around a wellbore to be characterized on the basis of measurements in the same direction of shear and compression wave velocities.

P. 339
Prediction of In-Situ Formation Compressibility from Production Data
Authors: Yildiz Turhan
Published: December 2007

This study presents simple graphical methods (0 predict itt-situ formation compressibility from production data. The graphical methods are based on the conventional material balance equation for oil reservoirs. The material balance equation is recasted into several straightline formats such that either the intercept or the slope of the straightline yields an estimate of formation compressibility. Also, floe information from the straightline plots can be used to predict oil-in-place.

The new predictive methods were applied to field data from a depletion/compaction drive reservoir. The formation compressibility and oil-in-place values predicted by the proposed methods were compared with those from other sources and methods, resulting in excellent agreement.

The proposed graphical techniques are limited to depletion/compaction drive reservoirs and cannot be applied to reservoirs subject to strong water-drive.

P. 357
Water/chalk (or Collapsible Soil) Interaction: Part I. Comprehensive Evaluation of Strain and Stress Jumps at the Waterfront
Authors: Piau J.-M. , Bois A.-P. , Atahan C. , Maury V. , Halle G.
Published: December 2007

Ekofisk, Valhall and other North Sea reservoirs are made of water sensitive rocks such as pure high porosity chalk (Andersen 1). Production of these fields may imply water- flooding which has two important consequences. On one hand water-flooding seems to fracture the reservoirs, hence increasing their gross permeability, while compaction drive becomes one of the main mechanism for production. On the other hand, compaction may endanger well completions and subsidence surface facilities.

In order to perform reliable predictions of compaction and subsidence when water-flooding such reservoirs, it is necessary to take into account not only the deformations that come from the compressibility of the reservoir rocks but also to include additional deformations induced by water-flooding.

This paper presents two constitutive models that predict such additional deformations. The first model is an elastoplastic model which depends continuously on the water saturation (WS) while the second is a particular case of the first model where the water-flow is assumed to be piston-like and water saturation jumps from Swi (not water-flooded) to Swf (water-flooded), at the waterfront. These constitutive models have not been developed taking into account any specific microscopic mechanism at waterfront. They can be used even if more than one mechanism is responsible for the water effect.

P. 419
A Two-Domain, 3D, Fully Coupled Fluid-Flow/Geomechanical Simulation Model for Reservoirs With Stress-Sensitive Mechanical and Fluid-Flow Properties
Authors: Osorio Jose G. , Chen Her-Yuan , Teufel Lawrence W. , Schaffer Steve
Published: December 2007

A 3D finite-difference, fully implicit model has been developed to represent the physical phenomena occurring during the production from reservoirs with stress-sensitive mechanical and fluid-flow properties. The model considers two different physical domains:

an inner domain representing the reservoir, where fluid-flow and rock deformation occur, and an outer (surrounding) domain representing the extended stress-disturbed region caused by reservoir depletion.

The inclusion of the surrounding domain leads to realistic modeling of the actual geomechanical boundary conditions taking place in the subsurface. The reservoir is treated as a multiphase poroelastic system consisting of a deforming solid skeleton and a moving compressible pore fluid. Non-linear elastic deformation ts assumed for both domains. The governing equations describing the deformation of the surrounding domain, the deformation of the reservoir solid skeleton and the motion of the pore fluid are fully coupled.

Simulation results clearly show that the permeability of stress-sensitive reservoirs may significantly change through the reservoir producing life. Different reservoir conditions yield different degrees of permeability reduction. In general, permeability decreases as production time increases. Zero- displacement boundary conditions yield less permeability reduction than constant stress boundary conditions. The permeability reduction decreases as the rock elastic moduli of the outer domain increase. The "arch effect" has a strong influence on reservoir permeability behavior.

P. 455
Targeting a 'Step Change' in Offshore Safety Performance
Authors: Cosad C. , Donald M. , Davies T. , MacChesney R.
Published: December 2007

A North Sea industry-wide initiative has set out a framework to target a 'step change' in offshore safety performance, broadly defined as a 15% year-to-year improvement. To achieve this, one major operator and alliance partners have focused on behavioral and cultural issues, underpinned by an innovative training program. This step change is being pursued in an environment of strong industry growth and high personnel mobility and turnover, adding to the challenge.

Initial training goals are to: train individuals to stop any operation because of uncertainty or safety concerns; institute open, low-level incident reporting and communication; and instill personal ownership of individual and colleague safety.

A number of 'tools' have been put in place to promote these behavioral changes, with supervisors trained to provide better communication and counseling on safety matters.

There are four main elements to supervisor training. Safety Leadership comes first. This session is reinforced by three other courses: Risk Assessment, Auditing in Safety, and Accident/Incident Investigation. Supervisor training is conducted with a 'diagonal slice', from senior onshore to frontline rig management, with a side benefit of improved interpersonal understanding and communications.

One training innovation uses actors role-playing a scene offshore subsequent to an accident. Those being trained have the opportunity to demonstrate their skills, both interpersonal and investigative, to manage the situation and discover root causes. 'Freeze the action', 'living playback' and behavioral coaching of actors allow participants a learning experience not found in the real world: 'If only I had a chance to do that again.' This paper presents a summary of the strategy, tools, obstacles and results to date.
Towards a Learning Organization
Authors: Kaspersen Bjoerg
Published: December 2007

Ever since Phillips Petroleum Company Norway (PPCoN) started operating in Norway, the company has invested heavily in training. The majority of this training has been safety related courses and equipment courses, many of them internal and focusing on specific equipment, systems or procedures.

However, in the 90's the world changed. There were changes in the political as well as in the economical situation. The advances in IT technology facilitated a different way of working and cooperating, but also required a higher level of knowledge. As systems become more and more integrated, it was felt that a better understanding was critical in order to operate safely and efficiently.

All of this required a whole new look at competence development, focusing on learning rather than training, on responsibility rather than entitlement, on education rather than courses and on teams rather than on individuals.

The presentation will focus on how the company managed to change the culture and people's attitude with it, and what the results are so far.
Management of Wellbore Instability & Formation Damage by Improved Drilling Mud Design
Authors: Azizi T. , Chen H. , Rahman S.S.
Published: December 2007

Wellbore instability and formation damage are the two major problems encountered by the petroleum industry. It is commonly accepted that formation damage is mainly caused by fluid-rock interaction due to the change in pore fluid chemistry which is caused by invading mud filtrate. Invasion of mud filtrate can be reduced by forming a tight filter cake on the wellbore wall. A tight filter cake can also provide support to the wellbore wall and prevent wellbore collapse. Therefore, the most effective option for solving wellbore instability and formation damage problems is to design a drilling mud that is compatible with formations in relation to both fluid-rock interaction and mud caking characteristics. This paper considers a number of mud systems with novel features and investigates their potential use in drilling and completion of tight gas formations in Central Australia, which are highly susceptible to formation damage. Among the four (4) muds investigated, ester based mud has been found to be the most effective in reducing formation damage by producing a tight filter cake on the wellbore wall.

P. 113
Investigation of Blast Furnace Slag Addition to Water-Based Drilling Fluids for Reduction of Drilling Fluid Invasion into Permeable Formations
Authors: Tare Uday A. , Growcock Frederick B. , Takach Nicholas E. , Miska Stefan Z. , Davis Neal
Published: December 2007

Granulated quick-quenched blast furnace slag (BFS or slag) in water-based drilling mud systems has been studied before, mainly from the perspective of mud-to-cement (MTC) conversion. However, the concept of using slag in a drilling mud for an effective low permeability filter cake, which minimizes formation damage, has not been explored.

This work explores the potential of using slag to consolidate filter cakes, thereby achieving reduced filter cake permeability. Also investigated is the overall impact on the reduction in formation damage by selective activation of BFS in dynamically deposited filter cakes. Studies were conducted on lignosulfonate, partially hydrolysed polyacrylamide (PHPA) and CaCO3 Drill-In fluids with BFS as a mud additive. Various mud properties, such as rheology (ambient as well as high pressure/high temperature), pH, filtrate loss and initial spurt loss are reported for muds containing variable loadings of BFS, and a control containing no BFS.

This study demonstrates the possibility of reducing invasion of mud into permeable formations through addition of small quantities of BFS to drilling mud. BFS appears to produce a more consolidated filter cake, which can be very useful for reducing wellbore stabilization problems in formation intervals that exhibit lost circulation and poor zonal isolation. In some cases BFS-containing drilling fluid appear to reduce formation damage in the near -wellbore environment.

P. 195
New Generation Wireline Logging Tools Enhance Rig Efficiency, Safety and Formation Evaluation
Authors: Davis R.J. , Benson R.H. , Boser D.J.
Published: December 2007

The traditional wireline formation evaluation tool has been redesigned to provide a driller friendly' tool providing standard log readings. Platform Express (PEx), the new design, integrates sensors used for formation evaluation into a short, highly reliable and efficient logging system. In addition, the new design allows for more robust measurements with higher resolution to be logged at a much higher speed than was possible in the past.

The new generation equipment is less than half the length and weight of the triple-combo equipment making setup and calibration of the tool much faster and safer. Through the use of integrated sensors, flex joints that improve pad contact, and other innovative technology, not only traditional triple-combo resistivity and porosity measurements can be collected, but also high-resolution micro-resistivity and imaging measurements, plus tool movement measurements for speed correction and depth matching. The hardware has been designed to meet LWD shock standards. This results in greatly improved reliability with as many as three times the number of jobs between failures as previously attained. Re-engineering of the sensors allows twice the logging speed while delivering better data than the previous generation tool.

This paper will present the results of operations and logs since the equipment's introduction in Indonesia. Setup and logging times are compared with those of the conventional tool string and several log examples are discussed to show the benefits of the new logging system both in terms of wellsite efficiency and more robust data acquisition.

P. 207
Density Behavior of Drilling Fluids During High Pressure High Temperature Drilling Operations
Authors: Kårstad Eirik , Aadnøy Bernt S.
Published: December 2007

In this study, we present an analytical model for the density-pressure-temperature dependence for drilling fluids. This generalized equation of state is valid for oil- and water based drilling fluids and also for completion fluids. The model is compared to other models already proposed, and is found to represent the measured data more accurately than the other models. In the application of the model we study the transient density behavior during drilling operations.
Innovative Perforating Techniques Show Promising Results in Problematic Deep Depleted Gas Sands
Authors: Dyer George , Gani Setiawan Rudy , Gauntt Gary
Published: December 2007

VICO's tighter gas sands in the 12000- to 13000-ft. depths have proven to be very difficult to produce efficiently. During the past two decades, hydraulic fracturing and acid stimulation of these zones has proven to be economically, mechanically, and logistically impractical. Recent evaluations of the damage mechanisms in these formations have indicated that crushed zone effects after perforating might be playing a larger role in some zones than previously thought. Thus, new techniques to increase production efficiency have been sought. Two perforating techniques are showing particular promise.

Extreme overbalance perforating, incorporating proppant with some of the highest pressures used to date (nearly 15,000 psi surface and 19,000 psi at depth), have been successfully executed and the results using this method have been encouraging.

The other new perforating method is the extreme underbalance technique, This method employs a specially designed modular gun system. and has been used in monobore completions. Underbalance as high as 4700 psi was achieved. The jobs have resulted in some of the most prolific wells in these reservoirs.

For the first time in the industry, new equipment technology that allows a true comparison between underbalance and extreme overbalance techniques has also been employed.
Multi-Lateral Case Histories in the Thailand, Malaysia and Brunei Area
Authors: Emerson A. Brent , Jones Rich C. , Lim S.B.
Published: December 2007

Multilateral well technology utilization continues to increase in the Asia Pacific Region. There is a significant variety to the level of complexity chosen in order to fulfill the requirements of a particular application. The key to a successful implementation of a multilateral well begins at the well selection phase based on the reservoir and ends with a team approach during operations and a thorough, post-job analysis. This paper will discuss the case histories of 5 Multilateral wells that have been completed in Thailand, Malaysia and Brunei. It will discuss lessons learned and thus the continuous improvement on multilateral technology.

P. 253
Why Not Use Aluminum in Drilling?
Authors: Akgun Ferda , Maidla Eric E. , Basovich Vladimir , Gelfgat Michail Y.
Published: December 2007

Using light weight drill and casing strings in drilling may cut down drilling costs by allowing the selection of smaller and/or cheaper equipment.

Drilling components are designed to meet or exceed certain load conditions and operational constraints (e.g. stress, strain, overall stretching limits, fatigue, corrosion, etc.). An important parameter that greatly impacts on the overall design is the material density of drilling tubulars, here limited to casing and drill string. Tubular density affects both stress (axial, bending and von Mises) and strength of the tubular itself and impacts on derrick compression and rotary torque that are determining factors for rig selection.

This study investigates the stress and strength behavior of aluminum based drill and casing strings and compares with steel based conventional ones.
Drilling Performance Improvement Case Study - Lawit-A Development Drilling
Authors: Dong S.N. , Longwell H.J.
Published: December 2007

This paper will cover a drilling performance improvement case study of an Esso Production Malaysia Inc (EPMI) gas development drilling program in the South China Sea. A "fast-track" process to optimize drilling time and cost is discussed, which includes planning, critical path activity and time analysis, and implementation.

Rig time savings of 45 days were realized through implementation of the "fast-track" recommendations. The "fast-track" recommendations include performing activities outside critical path or simultaneously, enhancing operational efficiency, applying available technology and eliminating critical activities through risk management. These recommendations coupled with careful planning, close surveillance, effective supervision, and team work were implemented without compromising operational safety.

P. 319
Advances in Metering and Control Technology Improves Design and Execution of Foamed Cement Jobs
Authors: Judge Robert A. , Benge Glen
Published: December 2007

A renewed interest in utilizing foamed cement slurries in wells where conventional slurries pose difficulties has increased the need for equipment capable of accurately monitoring and reliably controlling the necessary additives. These additives typically include nitrogen and a foaming agent. The goal is to have a completely automated control technology for the liquid additives and nitrogen. A fully automated system will also incorporate a cement mixing unit with automatic density control, with the additives metered in proportion to the base slurry rate. Proper pumping equipment selection is essential, but it is the flow monitoring technology selected that ultimately determines the accuracy of the additives. While process control technology for liquid additives is well established, metering and control technologies for automating nitrogen addition are less mature, and are critical to the proper execution of a foamed cement job.

Prior knowledge of slurry designs for a particular drilling program allows suitable components to be selected for use in an automated system, ensuring properly generated foamed cement slurries. The corollary is also true - that knowledge of the limitations of the equipment used to generate the foamed cement can lead to optimization of slurry design. Software is generally used to generate the ideal rates for base cement slurry, nitrogen, and liquid additives to obtain an optimum foamed cement slurry for a particular well. It is important to know that a software-generated solution that combines equipment capabilities with slurry and well requirements is technically feasible.

This paper describes the equipment and methods used to monitor and control the nitrogen and liquid additives used in foamed cement slurries. Additionally, the limitations of the nitrogen pumping and metering equipment, and how these limitations affect foamed cement job design, are discussed. Techniques to modify job parameters based on equipment performance parameters are also discussed. Charts from field evaluations of the developed system are included.

P. 349
An Investigation into the Application of QRA in Casing Design
Authors: Adams A. J. , Glover S. B.
Published: December 2007

The paper describes a major joint industry project undertaken to develop risk-calibrated design criteria for well casings and tubings. Supported by eighteen oil companies and two regulatory bodies, it included assessment of target safety levels; collection of historical load data and tubular resistance data; gas kick modelling and comparison with field test results; software enhancement; and calculation of risk-calibrated design criteria for the gas kick and tubing leak load cases.
The Development of Risk-Based Burst Design for Well Casing and Tubing
Authors: Tallin A. G. , Paslay P. R. , Onyewuenyi O. A. , Burres C. V. , Cernocky E. P.
Published: December 2007

This paper reports on the development of a risk-based burst design method. A criterion is developed so that ductile materials can be identified. The results for an experimental and analytical burst pressure study are combined with a large body of data for tubular dimensions and material properties. Statistical measures were obtained for all the data and a reliability study was performed on the design equations developed. This reliability study investigated: The relationships between probability of failure the design factor used in the design.The relationship between material grade and the probability of failure.The effect of axial tension on the probability of failure.The effect of flaw frequency on the probability of failure of a well string.The effect of D/T ratio on failure probability.

The methods developed can be used to estimate the probability of failure for well casing and tubing under any given combination of pressure and axial loads.
Burst Pressure Prediction of Thin-Walled, Ductile Tubulars Subjected to Axial Load
Authors: Paslay P. R. , Cernocky E. P. , Wink R.
Published: December 2007

This study was undertaken to support the development of a Quantitative Risk Analysis (QRA) for tubulars. The QRA required a burst model that was relatively accurate compared to the normal burst models used in conventional design.

Conventional work-hardening plasticity theory was used to establish a computer program for the prediction of the burst pressure of a thin-walled tubular. The tubular material was assumed to be ductile and the burst phenomenon caused by plastic instability. Dimensions of the tubular, the constant, external, axial load, Poisson's ratio, and a stress–strain curve for the material are the required input data for the program.

In order to verify the predictions of the computer program, twenty-two full-scale bursts tests were performed. The test specimens had capped ends with five of the specimens having an external, axial load applied in addition to the pressure loading. A stress–strain curve was measured for each tubular used for the test specimens so that the computer program mentioned above could predict the burst pressure.

Agreement between the predicted and measured burst pressures was excellent. The standard deviation of the ratio of predicted to measured burst pressure for the twenty-two tests was 0.04 with a mean value of 1.04. The program was then run extensively with all of the stress–strain curves to provide data for the development of an elementary equation which predicts burst pressure in the presence of an axial load. The resulting equation is surprisingly accurate so the program was modified using the same theoretical basis to allow different load paths to be investigated. By this means the burst load dependence on load path was established and shown to be rather small.

Finally, the elementary equation predictions were compared to the API Internal Yield Pressure Equation which is sometimes used for burst pressure predictions. The comparison of the API equation predictions to the elementary equation predictions shows that the discrepancies can be significant depending on (1) the ratio of the ultimate strength to the yield point and (2) the diameter to wall thickness ratio. The first discrepancy occurs because the API equation is based on yield point and the elementary equation is based on ultimate strength. The second discrepancy occurs because the API equation is based on outer diameter, while the elementary equation is based on mean diameter.
Accounting for Flaws in the Burst Strength of OCTG
Authors: Stewart G. , Klever F. J.
Published: December 2007

The quantification of risk using reliability based procedures offers significant safety-related and cost benefits. In order to progress this methodology for design of wells, accurate capacity prediction models for OCTG and associated statistical data for the model parameters are required. In this paper, we focus (a) on the development of a predictive model for burst failure of OCTG with naturally occurring crack-like flaws and (b) on constructing probability distributions of crack depth based on estimated mill rejection rates and inspection quality.

Limit load models and ductile fracture mechanics techniques are employed to identify the governing failure mechanism and a simple unified model is proposed for burst capacity. This model is supported by finite element (F.E.) J-integral analyses and burst tests on P110 and Q125 tubes with artificial axial part-through cracks.
Experience Transfer from Operational Environments to Installation Design: Why, How and What?
Authors: Pagenhart A. , Buset H. , Throndsen T. I.
Published: December 2007

Experience transfer of practical, technical information concerning working environment, work efficiency and equipment functionality from operations to development projects is a good investment. A variety of methods used for collecting relevant experience are discussed. Criteria for prioritizing the wealth of generated experience data include an evaluation of frequency and consequences. Experience transfer plays a major role in a systematic approach to achieving the zero mindset goal. Cooperation on an intercorporate, international level is vital to continual improvement of the experience transfer process.
Case History of Oil Well Performance Monitoring and Production Optimization in the Eldfisk and Ekofisk Fields, Norwegian North Sea
Authors: Wade J. M. , Hough E. V. , Harrington T. R. , Valdai J. , Pedersen S. H.
Published: December 2007

This case history reviews the systematic well performance monitoring procedures developed and implemented for the Eldfisk and Ekofisk Fields in the Norwegian North Sea. Examples of production optimization projects implemented as a result of the performance monitoring system are presented. Changes in well performance due to acid washes, acid fracture restimulations, perforation additions and tubing changeouts are illustrated in the examples presented.
Comparison of Plate Separator, Centrifuge and Hydrocyclone
Authors: van den Broek Wim M. G. T. , Plat Robert , van der Zande Mark J.
Published: December 2007

Frequently oil is produced while, simultaneously, large amounts of water are produced as well. Under these circumstances it is important to have compact and efficient deoiling equipment at one's disposal. After some remarks on other de-oiling methods, the attention in this paper is focused on three separation techniques: plate separation, centrifugation and the use of hydrocyclones. The working principles are described and subsequently typical data on separation efficiency, geometry of the separator section, separator volume and critical oil-droplet diameter are derived or given. Analysis of these data shows, that the ranking with respect to performance of the three separator types is: centrifuge, hydrocyclone, plate separator. In the last section of the paper attention is given to some recent developments concerning centrifugation and the use of hydrocyclones.
Modelling Porosity Distribution in the A'nan Oilfield: Use of Geological Quantification, Neural Networks and Geostatistics
Authors: Wang L. , Wong P. M. , Shibli S. A. R.
Published: December 2007

A'nan Oilfield is located in the northeast of the Erlian Basin in north China. The porosity distribution of the oil-bearing stratum is primarily controlled by complex distribution patterns of sedimentary lithofacies and diagenetic facies. This paper describes a methodology to provide a porosity model for the A'nan Oilfield using limited well porosity data, with the incorporation of the conceptual reservoir architecture. Neural network residual kriging or simulation (NNRK or NNRS) is employed to do tackle the problem. The integrated technique is developed based on a combined use of radial basis function (RBF) neural networks and geostatistics. It has the flexibility of neural networks in handling high-dimensional data, the exactitude property of kriging and the ability to perform stochastic simulation via the use of kriging variance. The results of this study show that the integrated technique provides a realistic description of porosity honouring both the well data and the conceptual framework of the geological interpretations. The technique is fast, straightforward and does not require any tedious cross-correlation modelling. It is of great benefit to reservoir geologists and engineers.