bluuebunny/crossref_metadata_2025 huggingface dataset:
Statistical Method for Detection of Poor Hole Cleaning and Stuck Pipe
Authors: Gulsrud Thor O. , Nybø Roar , Bjørkevoll Knut S.
Published: December 2009

During drilling operations poor hole cleaning may result in low drilling efficiency, stuck pipe, problems with well control or even a loss of the wellbore. In this paper a method for warning of poor hole cleaning and stuck pipe is proposed. The method is based on correlating statistical features calculated from bottom hole or stand pipe pressure and torque signals. Especially, the correlation is performed by multiplying the third order moment of bottom hole or stand pipe pressure time series and normalized standard deviation of torque time series. The correlated signal is used as input to a warning generation scheme. This scheme is based on detecting the sign of the correlated signal samples within a moving time window. If the number of positive samples exceeds a predefined threshold a warning is raised. Results of an experimental study on data from three different wells indicate that the proposed statistical method can provide early detection of poor hole cleaning and stuck pipe.
Improvement of Safety Instrumented System (SIS) Performance through Detection Diversity
Authors: Naranjo Edward , Choo Edwin , Kornbech Mads
Published: December 2009

Detection coverage plays an essential role in defining the capacity of a fire and gas system to perform properly when required (ISA-dTR84.00.07 2008). The concept seems clear: As the probability of a sensor detecting a hazard increases, so does the likelihood that fire and gas systems (FGS) are able to mitigate more severe consequences.

Several reports document the importance of detection coverage. Statistical studies of hydrocarbon gas releases by the Health and Safety Executive (HSE) calculate the detection rate of gas detectors at 60% (HSE 2000) and 76% (HSE 2003a). Another report by the same agency on gas turbine incidents between 1991 and 2004 puts gas detection coverage at about 78% (HSE 2008). The collected historical record suggests that, even if an FGS design complies with a high safety integrity level (SIL) target, a reduction in risk is not achieved unless detector coverage is high. An independent calculation of risk reduction under different scenarios of detection coverage supports the empirical findings (Choo 2008).

An important, but often neglected element of detection coverage is the contribution of applying two or more sensing technologies toward risk reduction. Detection diversity improves the odds that a hazard is detected early on, independent of the number of detectors installed, their reliability, and geographic coverage. Diversity is often effective, because detection methods share few common failures. By drawing on the advantages of each, several different types of detectors can be more effective at mitigating the spread of an accident sequence than any one type alone.

In this report we examine how fire and gas detector coverage can be improved by means of detection diversity. The study applies Markov models to illustrate the potential risk reduction as a function of detection diversity. Monte Carlo simulations are also used to estimate the contribution of detection diversity on attaining a specific SIL. The results confirm that field devices have a substantial effect on SIS performance. The paper concludes with recommendations on the application of several detection technologies to protect offshore facilities. Note: This paper is not about whether or not FGS can be considered part of a SIS. The authors understand the arguments for and against this.
Making Friends with Your Computer—A Participatory Approach of the Workstation Ergonomics Program
Authors: As Safira Elsye , Syamsu Mariena , Darmawan Eric
Published: December 2009

Employees working in the office tend to underestimate the potential safety and health hazards in their immediate environment, including their computer workstation. Although most workers spend a large amount of time working with computers, they still possess a poor understanding of ergonomics and human-computer interaction. Health risks, such as MSD (Musculoskeletal Disorders), visual fatigue and mental stress can lead to severe health impairments i.e. Carpal Tunnel Disorder (CTD). These health problems do not appear overnight but only over a considerable period of time.

The participatory approach is one of the methods used for the ergonomic workstation program. This approach involves each department Champions conducting Display Screen Equipment (DSE) coaching sessions, which are followed by the completion of a self-assessment form by each DSE user in their departments. This self-assessment is important to ascertain the frequency of health symptoms related to MSD as well as the percentage of factors that contribute to health risks experienced by the DSE users.

In addition to the statistics obtained, the other important part of the assessment is focusing on actions to be taken to minimize DSE health risks. These action items will be followed up through personal coaching sessions to fine-tune behavioral approaches and deploy appropriate equipment to ensure that the most optimal ergonomic workstation designs are implemented. The key to making this program a success is to encourage multiple departments to actively participate.
Multilayered Reservoir Stimulation: Case Study of Effective Acid Diversion Achieved Using the Associative Polymer Treatment Diverting Agent in Khuff Carbonate Reservoir Wells in Saudi Arabia's Ghawar Field
Authors: Núñez Walter , Leal Jairo , Malik Ataur , Solares J. Ricardo , Sierra Leopoldo , Izquierdo Guillermo
Published: December 2009

One of the key objectives of all acid stimulation treatments in multilayered reservoirs is to achieve effective diversion so that acid is equally displaced throughout all hydrocarbon bearing zones. The highly heterogeneous nature of the multilayered high-pressure/high temperature (HPHT) Khuff carbonate reservoir, the significant depth separation between layers, and the sour characteristics of the gas and condensate deposits in Saudi Arabia's Ghawar field present a complex technical challenge when attempting an effective stimulation and diversion.

The Associative Polymer Treatment (APT), which is a water base diverting agent formulated with a very low viscosity that allows effective fluid diversion during stimulation treatments, has been successfully field tested by Saudi Aramco. Three matrix acid stimulation treatments, comprising an organic blend, retarded acid, nitrogen and the APT diverting agent, were successfully implemented in wells completed in the Khuff carbonate reservoir with perforated intervals upwards of 260 ft. Clear diversion and acid reaction signatures have been observed in the surface and bottom-hole pressure (BHP) data recorded throughout the treatments. Data analysis of the post stimulation pressure buildup (PBU) test conducted in one of the treated wells showed a skin factor of −4.3. Additionally, production logging tool (PLT) surveys conducted in two of the treated wells showed flow contribution from all the perforated layers, which contrasts with offset producers previously treated without the diverting agent, showing the largest contribution coming from a single perforated layer. More than 40% poststimulation gas rate increase has been observed in the treated wells.

This paper discusses the rationale for selecting and field testing the APT diverting agent, and provides details about the acid treatment designs, highlights implemented treatment optimization steps, discusses treating pressure behavior and lessons learned throughout the treatments, and provides zonal contribution and post-stimulation test results evidence confirming the effectiveness of the APT diverting agent.
Practical Aspects of Integrity Management for Large Oil and Gas Production Infrastructures
Authors: Ciaraldi Stephen W.
Published: December 2009

Major accident prevention and production reliability are among the top priorities for upstream oil and gas operations. Effective Integrity Management (IM) is a fundamental requirement for achieving these objectives. For large and aged production infrastructures, substantial people and money resources are required for effective IM, in addition to practical implementation strategies and tactics. Observations on implementing IM for large infrastructures are described based on the author's experiences with offshore production operations in Egypt, Trinidad and Indonesia.

The observations start with development of IM strategies aligned to the business and the deployment of risk based evaluation tools to set priorities and implementation targets. Experiences defining execution tactics which fully consider people and money resource limitations, competing business objectives and activities, contracting requirements, materials limitations and logistics constraints are noted. Organizational aspects and interfaces are discussed, as are important aspects of safety management, planning, scheduling and implementation tracking using ever-evolving key performance indicators (KPIs). Finally, the role of regular status reviews and external audits are noted with respect to continuous improvement of IM programs.
Optimization of Hydraulic Fracture Geometry
Authors: Mahdiyar H. , Jamiolahmady M. , Sohrabi M.
Published: December 2009

An optimized design for hydraulic fracturing is of great importance especially with the growing demand for this method as a means of production enhancement from tight gas reservoirs. The first optimum fracture design (OFD) approach, which maximizes well productivity for a given fracture volume, was introduced by Prats in 1960 for single-phase Darcy flow systems. This method, which was later modified and presented in the form of Unified Fractured Design (UFD) charts by other investigators, is widely used in the petroleum industry, even for gas condensate systems. Recently some methodologies have been proposed to modify UFD considering the two-phase region around the fracture as a damage zone with reduced permeability. These methods are generally oversimplified as they neglect the phase change and variation of relative permeability with interfacial tension (IFT) and velocity for these low IFT systems. They also require data that are not readily available, in particular the pressure profile (the two-phase boundary) around the wellbore.

We introduce an explicit formulation and a more general methodology for OFD that includes the important gas condensate flow parameters in both matrix and fracture. The optimum fracture dimensions are obtained by maximizing the effective wellbore radius, using the recently developed correlation by Mahdiyar et al. (2009). This formulation accounts for the mechanical and flow skins based on quite readily available information at wellbore conditions.

In this paper, the integrity of the introduced formulation has been verified for many different prevailing conditions, whilst highlighting the errors of using conventional approaches with some important practical guidelines. In this exercise, the maximum productivity calculated using the proposed formulation is compared with results of the literature or our in-house simulator. This program, using a fine grid approach, simulates gas condensate flow around a hydraulically fractured well for various fracture length-width ratios and identifies the optimum fracture dimensions, for a given fracture volume, providing maximum mass flow rate.
The International Association of Oil & Gas Producers (OGP) Naturally Occurring Radioactive Material (NORM) Management Guideline
Authors: Mously K. A. , Cowie M. I. , Campbell J. A.
Published: December 2009

It has been established that Naturally Occurring Radioactive Materials (NORM) may accumulate in the oil/gas production process. This can create a radiation hazard for workers, the general public and the environment if adequate controls are not established.

Regulations and guidelines on radiation protection in general, and NORM in particular, have been issued by various National and International entities, however, these are not specific to the oil and gas industry, and do not provide clear and concise guidlines to enable NORM to be managed effectively.

The International Association of Oil and Gas Producers (OGP) established a task force, headed by Saudi Aramco, to develop NORM Management Guidelines. This task was completed after research, review and thorough consideration of most available NORM regulations, and the industry's current best practices in NORM management. The OGP guidelines offer a simple and logical method of managing NORM impacted operations that are flexible enough to be implemented across the industry.

This paper outlines major aspects of OGP NORM management guidelines and elaborates on key issues related to the management of NORM in the oil and gas industry, in particular on NORM monitoring, control of NORM contaminated equipment, managing NORM waste handling and disposal, and worker protection, awareness and training.
The Design, Fabrication and Operation of a Mobile Naturally Occurring Radioactive Material (NORM) Decontamination Facility
Authors: Cowie Michael , Mously Khalid
Published: December 2009

The contamination of oil and gas processing equipment with Naturally Occurring Radioactive Material (NORM) bearing scales can present a radiological hazard in addition to restricted operability. NORM contaminated equipment cannot be released for sale or re-use as it has enhanced levels of radioactivity, which can lead to exposure of workers, the general public and the environment, if not managed appropriately1.

Part of a successful NORM management strategy is the ability to decontaminate equipment which has become contaminated with NORM. The removal of relatively insoluble NORM scale, which has become adhered to equipment surfaces, requires aggressive agitation of the surface to remove it. The control of NORM contamination removed from contaminated equipment and the protection of workers during the decontamination process are achieved primarily by engineering controls, however, these must be supported by administrative procedures and personal protective equipment (PPE).

This paper details the design, fabrication and operation of a mobile NORM decontamination facility and lessons learned in a demonstration trial where it was successfully used to remove NORM contamination.
Microbial Enhanced Oil Recovery: An Investigation of Bacteria Ability to Live and Alter Crude Oil Physical Characteristics in High Pressure Condition
Authors: Halim Amalia Yunita , Fauzi Umar Dani , Siregar Septoratno , Soewono Edy , Gunawan Agus Yodi , Astuti Dea Indriani , Juli Nuryati
Published: December 2009

Indonesia has officially declared its withdrawal from OPEC membership in September 2008 because of failing to meet its oil production quota as what is determined. For that reason, effective and environmentally friendly methods need to be applied in Indonesian reservoirs; one of them is Microbial Enhanced Oil Recovery (MEOR). This method involves the knowledge of biotechnology and petroleum engineering and is aimed to improve oil recovery in old and marginal wells. This paper presents laboratory investigation of bacteria ability to live and alter crude oil physical characteristics in high-pressure condition of 250 psi and 500 psi, provided with a mathematical model for further analysis. The experiment was conducted in a special apparatus called conditioning cells, which is made of stainless steel. Data obtained from the investigation are then used to make a mathematical model and simulation for analysis and prediction. After 3-days of treatment by bacteria in high pressure condition, oil viscosity decreases by 11,27 % in 250 psi and 11,88 % in 500 psi; further investigation after 7-days showed that oil viscosity decreases by 22,48% in 250 psi and 20,70% in 500 psi. The IFT after 3-days of treatment by bacteria in high pressure condition decreases by 18,84% in 250 psi and 6,09 % in 500 psi; further investigation after 7-days showed that IFT decreases by 27,54 % in 250 psi and 9,33 % in 500 psi. The mathematical model shows that the maximum production of bacteria increases with the increase of the initial input of bacteria, and the higher the pressure is, the faster the bacteria growth is. It can be concluded that the bacteria are able to live in high pressure (piezophile bacteria) and give positive impact to the crude oil by decreasing its viscosity and reducing the IFT hence improve oil mobility. It is predicted that by applying this method Indonesia crude oil production can be improved or at least the production decrease can be slowed down.
Applying LEAN Principles to Achieve Breakthrough Performance Gains from Existing Assets
Authors: van Zandvoord Walrick E.J.J. , Skilbrei Oddbjorn , Sim-Siong Wong , Wong Jeremy , Nones Nelson
Published: December 2009

One of the small assets in Shell Malaysia E&P has adopted a methodology earlier implemented by Aera in California, USA, hereafter referred to as "LEAN". The concept is to increase organization efficiency by applying Toyota manufacturing principles. This is achieved through continuous improvement of processes, while minimizing waste.

Before implementation, an assessment of the pilot asset revealed fragmented efforts and in-efficient collaboration between different disciplines supporting Well & Reservoir Management. In general cycle times between identification of problems and closing them out were long and below corporate standards.

The pilot project yielded almost immediate benefits. WRM cycle times were reduced by an average of 60% through co-location of key disciplines and work standardization. This enabled the existing well production to significantly exceed targeted production and a clear reduction in overall field decline has been observed. The key conclusion is that LEAN practice, originally directed towards manufacturing operations, is a highly effective way to overcome performance issues in existing assets, and can be replicated globally across diverse operating environments.

This paper will reveal new information from field operations, and demonstrates two technical contributions: detecting events from ongoing field surveillance activities such as well tests and real time meter monitoring, and dispatching a continuous flow of modeling, planning and remediation tasks to keep pace with events.
Safety activities for preventing human error
Authors: Hatakeyama Takashi , Saito Masaki , Ikeda Shoichi
Published: December 2009

In the industry of Japan, in order to prevent human error, the following three techniques are practiced widely.

YUBI SASHI KOSYO (Point and Call) This action prevents human error by lengthening an arm, by pointing firmly for an object and by calling in the voice which clarified. KIKEN YOCHI (Danger Prediction) Training This training aims at pointing out the risk of the work for a short time, and establishing the measure before work. HIYARI HATTO (Near Miss) report This report releases dangerous experience under work or drive, and aims to alert to other men.

Also in oil and gas industry of Japan, since these methods are generally practiced, it introduces.

Moreover, since the HIYARI HATTO map which utilized the HIYARI HATTO report is created and used uniquely in our company, it is introduced also.

The worker is able to show the dangerous factor and risk under work for every place and every work on a photograph, and to perform a forecast of danger before work by HIYARI HATTO map. The disaster in the recent years of our company is decreasing dramatically by using these techniques.
Marine Spatial Planning in Europe: Drawing the Lines on Access to Resources
Authors: Holthus P. F.
Published: December 2009

The European Commission (EC) has adopted a roadmap on marine spatial planning (MSP) to guide the sustainable growth of EU maritime sectors as a new approach to addressing the increase in competing uses of the sea. The growth of marine commercial activities such as offshore oil and gas development, maritime transport, port development, aquaculture, and tourism, combined with emerging uses such as offshore renewable energy, is increasing the pressure on already limited European marine space. The development of a common approach to MSP is an outgrowth of the European Union (EU) Integrated Maritime Policy, which aims to coordinate all EU policies with a maritime dimension in order to safeguard environmental sustainability. The EC considers a planned use of sea areas as the only way to provide a predictable framework for economic investments in offshore areas, creating the framework for balancing the vested interests of different maritime activities and the need to protect the marine environment. The EC MSP program presents both challenges and opportunities for the oil and gas industry. It is critical that the oil and gas industry develop an understanding of marine spatial management issues, stakeholders and process and engage proactively and constructively in EC marine zoning developments. MSP in Europe, and elsewhere, has serious implication for future access to petroleum resources. The oil and gas industry can realize important business benefits by building relationships with other ocean industries as part of broader private sector leadership and collaboration in responding to EC MSP. Development of a coordinated ocean business community approach to MSP will contribute to the ability and capacity of the oil and gas industry to actively engage in ocean zoning efforts in other regions.
Effect of Common Impurities on the Phase Behaviour of Carbon Dioxide Rich Systems: Minimizing the Risk of Hydrate Formation and Two-Phase Flow
Authors: Chapoy Antonin , Burgass Rod , Tohidi Bahman , Austell J. Michael , Eickhoff Charles
Published: December 2009

CO2 produced by carbon capture processes is generally not pure and can contain impurities such as N2, H2, CO, H2S and water. The presence of these impurities could lead to challenging flow assurance issues. The presence of water may result in ice and/or gas hydrate formation and cause blockage. Reducing the water content is commonly required to reduce the potential for corrosion but for an offshore pipeline system it is also used as a means of preventing gas hydrate problems; however, there is little information on the dehydration requirements. Furthermore, the gaseous CO2 rich stream is generally compressed to be transported as liquid or dense-phase in order to avoid two-phase flow and increase the density of the system. The presence of the above impurities will also change the system's bubble point pressure, hence affecting the compression requirement.

The aim of this communication is to evaluate the risk of hydrate formation in a rich carbon dioxide stream and to study the phase behaviour of CO2 in the presence of common impurities. An experimental methodology was developed for measuring water content in CO2 rich phase in equilibrium with hydrates. The water content in equilibrium with hydrates at simulated pipeline conditions (e.g., 4 °C up to 190 bar) as well as after simulated choke conditions (e.g., at -2 °C and around 50 bar) were measured for pure CO2 and a mixture of 2 mole% H2 and 98 mole% CO2. Bubble point measurements were also carried out for this binary mixture for temperatures ranging from -20 °C to 25 °C.

A thermodynamic approach was employed to model the phase equilibria. The experimental data available in the literature on gas solubility in water in binary systems were used in tuning the BIPs. The thermodynamic model was used to predict the phase behaviour and the hydrate dissociation conditions of various CO2 rich streams in the presence of free water and various levels of dehydration (250 ppm and 500 ppm). The results are in good agreement with the available experimental data. The developed experimental methodology and thermodynamic model could provide the necessary data in determining the required dehydration level for CO2 rich systems, as well as minimum pipeline pressure required to avoid two phase flow, hydrates, and water condensation.
Developing KPIs That Drive Process Safety Improvement
Authors: Brown Megan
Published: December 2009

A case study is provided describing Lloyd's Register's development of a set of Key Performance Indicators (KPIs) for Process Safety Management (PSM) for an oil and gas client.

The development process is described in this paper along with discussion of how the KPIs were developed and designed to support the client in gaining a clearer picture of their current Process Safety performance and to drive the improvement of that performance.

This paper includes discussion of the number of KPIs that are introduced, the sequencing of introduction of KPIs, the associated implementation requirements, the reporting of the metrics to management at all levels in the organisation, and the value provided by both the measurement and reporting of the KPIs.
Assessment of Suppliers in Low Cost Countries: How to Proceed, What to Expect
Authors: Charron Michel , Gérard Philippe
Published: December 2009

Introduction

The assessment of suppliers became recently a critical step in the supply chain organizations. Indeed the process is not new but the importance of assessing candidates tremendously increased due to several factors: Local content requirements, variety of local technical regulations, Language and cultural issues, relative weight of the Asian continent in the global worldwide production capacity all need be taken into account simultaneously in an assessment campaign.

The conclusions indicated in this document result from the work done on more than 150 sites, 30% of which in the republic of Russia 60% in China, 10 % in other countries such as India, Turkey USA and Europe. As far as Russia is concerned reference is made to Total Russia willingness to perform in depth assessments of local resources in view of the Kharyaga Phase 3 development project.

Supplier assessment, how to proceed: main steps

* A first aspect of this Quality assurance tool is that the assessment is performed for a given plant / factory or site. Not of a Company or Brand, this results from the need to evaluate the design, purchase, fabrication, test etc.. facilities. Some examples of assessment led to the conclusion that two neighbouring buildings were fully acceptable for one of them totally unacceptable for the other.
Utilizing Simultaneous Capture of T1 and T2 NMR Data to Solve Reservoir Evaluation Issues
Authors: Marchel Ronald J. , Smith Charles H. , Ramakrishna Sandeep
Published: December 2009

Deep basin drilling along the Wichita Mountain front in the Anadarko basin of western Oklahoma poses one of the most difficult log interpretation issues. Advances in the acquisition and processing of 3D seismic have enabled the drilling and production of targets that previously could not be imaged. Although the increased abilities to identify and target the desired objective horizon in the well have enhanced prospect economics, the petrophysical evaluation of prospective zones has never been straightforward.

Well-to-well correlations are difficult because of rapid facies changes in the Pennsylvanian Granite Wash, along with complex folding and faulting in deeper horizons along the Wichita Mountain Front. Nearby wells are often not connected because of the rapid facies changes and the intense faulting and folding. High density/neutron porosities do not relate directly to permeability, nor does high resistivity relate directly to hydrocarbon production.

Advances in the analysis of nuclear magnetic resonance (NMR) T2 data have enabled producibility (permeability) information to be extracted from this data. The measurements of NMR T1 data have provided an excellent approximation of fluid typing. We worked together in order to arrive at a useful solution that would provide these data sets in a continuous logging pass.

An algorithm was developed that greatly enhances the economics of drilling and completion by simultaneously measuring these data (T1 and T2) in a usable form and enabling the correct evaluation of these reservoirs.
KickRisk—A Well Specific Approach to the Quantification of Well Control Risks
Authors: Arild Ø. , Ford E. P. , Løberg T. , Baringbing J. W. T.
Published: December 2009

The drilling of wells for which there is a small pressure margin is often challenging with respect to well control issues. A kick, which occurs if the wellbore pressure drops below the pore pressure, is one of the major risks being dealt with in the planning phase of the well. A kick can occur due to several factors, such as human errors, equipment failures or a wrong pore pressure prognosis. Since the ultimate consequence of a kick may be a blowout, it is essential to be able to assess and reduce the probability of a kick occurring.

In order to be able to quantitatively assess well control risks, a tool and methodology called KickRisk has been developed for supporting technical and operational decisions in the well planning phase. The methodology is based on a probabilistic framework which takes into account a variety of factors that may cause a kick, and the calculations are executed by means of Monte Carlo simulation. The methodology allows the analyst to: ○Quantify the probability of kick and fracturing○Systematize all information relevant to the occurrence of a kick○Pinpoint critical factors○Evaluate alternative solutions on e.g. well design and operational procedures○Quantify the effect of risk reducing measures

This paper will present the overall probabilistic approach and the composition of the KickRisk model. Further, it will be shown how the KickRisk methodology can be incorporated into a risk management workflow. The practical application of the methodology will be explained through a case study.
The Effective Contractor Management in International Oil Cooperation
Authors: Hou Xiru , Zhang Qing , Qu Xiangyu , Ma Zhongming
Published: December 2009

Contractors are increasingly selected to provide technology or services, and many oilfield companies require contractor to undertake the activities in a special way before starting to work. They raise any issue that may become a Health, Safety, Environment (HSE) concern. When selecting the contractors they should be required to have the prequalification, training, experience and competence, and environmental knowledge, so that they can work in a safe and healthy manner and comply with appropriate standards.

The keys to successful contractor management are mutual understanding of the contract and a good business relationship, and the contractor should demonstrate a complete understanding of the performance standards. However, how effectively the contractor is achieving the contractual objectives, therefore, periodic communication and coordination with the contractor should be established to ensure contractor adherence to standards and compliance with project processes and schedules, and relative environmental regulations and act.

The purpose of this article is to provide for the effective management of occupational health and safety issues during the selection and engagement of a contractor by Company and to outline the process and procedure for control and supervision during contractor activities on site or on behalf of the company in accordance with the requirements of the HSE Management Systems. Some risk assessment and post contract assessment will be summarized and strengthened in this article.
Case Study of Down-hole Tool Development to Deploy Sand Screens in ERD Wells, Extending the Boundaries, Saving Opex, Reducing Risk and Improving Operational Efficiency
Authors: Gillespie Doug , Bradford Keith , Elliott Rod
Published: December 2009

Sand control screens are a commonly deployed method in the Oil & Gas industry to aid production in well bores, typically where the formation is such that "standard" completion methods would fail quickly through sand incursion. Sand control screens are used to enhance wellbore stability and optimise productivity when run in unconsolidated formations.

A common challenge occurs when formation sand is mixed through reservoir fluids, when run in unconsolidated sandstones. This mixture of sand and fluid can lead to problems such as plugging, damage to monitoring tools and erosion of equipment exposed to these abrasive fluids. Sand control screens act as a filter, to allow reservoir fluid ingress to the completion string keeping the sand content out. The very nature of the screens means they are quite delicate and easily susceptible to damage.

In recent years, Extended Reach Deployment or ‘ERD’ wells have become more common, ever longer and more challenging in order to get completions to TD. Furthermore, this problem becomes exaggerated when running delicate completion strings with sand control screens. More so when you consider it is not desirable to have the completion aggressively pushed or rotated.

This paper outlines the common problems identified with Sand control Screen Deployment. Furthermore it will look at how a new deployment tool overcame these issues within set operational restrictions, with reference to documented field results.
Magnus: Utilisation of Conductor Sharing Wellhead Technology to Access Additional Hydrocarbons via a Slot-Constrained Platform
Authors: Hicks S. E. , Moore A. , Honey M. , Farmer I. R. , Smart B. , Ekseth R. , Brown D.
Published: December 2009

The Magnus platform, UK Northern North Sea, has been producing since 1983 with all 20 original slots now occupied. Additional infill and ERD production targets were identified and a means of access was required whilst maintaining base field production. Platform modification was selected due to significant commercial advantage over alternative developments. The Magnus jacket was modified to permit running of four additional large conductors into which two smaller casings could respectively be installed.

A tapered jacket profile necessitated preinstalled conductor guide frames to build to 4° inclination at seabed; requiring initial use of the large conductor as a conduit for drilling assemblies. Custom manufactured and specialist equipment was designed and procured to enable successful under-reaming to 54" and installation of 46" conductor. Drilling assembly design and initial pilot-hole profile were deemed critical to subsequent success in running rigid open-ended 46" conductor. Well-critical structural cement was pumped to seabed via world-first use of a 16" inflatable packer and inner string. World-first unguided installation of two 18-5/8" casing strings inside 46" conductor was then achieved. The 18-5/8" casing strings were cemented in place using light cement to preserve (shallow) casing shoe integrity. High resolution multi-shot gyro surveys and a newly developed ‘gamma-wipe’ survey technique were utilised to obtain critical 18-5/8" relative shoe orientation information prior to subsequent kick-off.

Two wells were successfully batch-set to the 13-3/8" casing shoe via one conductor. To mitigate anti-collision risk, safety valve location has been deepened to permit future drilling of all planned trajectories from the new conductor slots (given shallow close approaches).

Modification of existing wellhead technology for close proximity has proved successful. Access to additional Magnus resources via an otherwise full template has been delivered by this Conductor Sharing Wellhead (CSW) technology.
Facilities and Infrastructure Redevelopments and Rejuvenation—A Fast-Track Solution for the Don Area Development
Authors: Matthew Craig
Published: December 2009

The Don Area is located in the Northern North Sea. It comprises the West Don and Don Southwest (Don SW) oil fields, both of which were fallow until 2006. Initial development plans had anticipated a subsea tieback to a nearby host - a relatively slow, costly and potentially complex approach.

Petrofac Energy Developments, who became ‘Operator’ in 2006, conducted an in-depth review of the Don Area, concluding that the refurbishment of an existing Floating Production Facility (FPF) - the Northern Producer - would offer a more cost effective solution by reducing capex and delivering first oil earlier than competing options. Using the FPF would also cut development time, minimize the degree of offshore work required, keep associated costs down, safeguard jobs and radically improve the economic case for the project.

First oil was achieved in April 2009, less than a year after the field development programme (FDP) was formally approved by the UK government's Department for Business Enterprise & Regulatory Reform (BERR).

This paper addresses the key factors that helped decide between competing development concepts. It outlines the field facilities and general approach to the development work along with modifications to the production unit, offtake options and collective benefits. It thereby provides a context in which we can examine the potential for similar development opportunities in the future.

Management, contract strategies and organisational factors played a critical role in the ability of the Operator to deliver this project in record time. In utilising its internal service group expertise, knowledge and resources, the Operator streamlined the project structure and limited reliance on external suppliers. This, in turn, significantly reduced development time and expenditure, optimising oil recovery and returns on investment.

This paper looks at how the application of organisational adaptability, technical knowledge and regional experience helps to achieve a common objective to transform marginal fallow fields into attractive commercial propositions.
Wellbore Instability in Forties: Diagnosis of Root Causes for Improved Drilling Performance
Authors: McIntyre Brett , Dixon Rachel , Mohamed Farid , O'Rourke Tom , Liu Chang , Islam Syed Anzarul , Donald Adam
Published: December 2009

Success in developing and maintaining wells in mature fields is heavily dictated by cost reduction to maintain profitability and maximize production life of the filed. Achieving this relies on better well planning and optimized drilling performances with reduced drilling non productive time. Pertinent to this is the ability to understand mechanisms of wellbore failures, predict and manage operational risks such as wellbore instability, sand production, or hydraulic fracturing. This paper describes how analysis of the historic drilling events have been incorporated to refine mechanical earth models and provides key inputs needed to optimise well plans and adapt drilling practices to changing field conditions. Capturing and classifying historic drilling events is a fundamental key process in understanding the mechanism and causes of well bore failures. A workflow has been engineered to perform such task systematically and efficiently in a field scale multi-well environment. The users are provided with a collaborative common environment to visualize and understand relationships between drilling events in an earth model context. Driven by this new-found understanding, a more accurate prediction of where, when, and how specific problems are likely to manifest themselves can be made. Ultimately it enables closer collaboration between domains and the knowledge gained can be rapidly incorporated into future well planning and drilling operations, while mitigating risks and therefore reducing costs.
Title Pore-Pressure Depletion and Effective Stress Issues in the Gulf of Mexico's Lower Tertiary Play
Authors: Boitnott G.N. , Miller T.W. , Shafer J.L.
Published: December 2009

In this paper we present the results of our study of pore pressure depletion in the Gulf of Mexico's Lower Tertiary Play. Permeability and velocity measurements collected during multiple cycle stress paths are presented. We demonstrate how the data are used for evaluating effective stress coefficient and the calculation of net effective stress for compaction, permeability, and elastic wave velocities.

Rock properties models for the deep water Lower Tertiary sandstones need better calibration for conditions of high initial pore pressures and large pore pressure depletions. Available data indicates that inelastic pore compaction at high drawdowns is possible and significant permeability reduction may occur due to both elastic and inelastic deformations. Velocity changes in response to pore pressure need better calibration in order to improve both characterization and eventual reservoir monitoring activities.

Core measurements used to calibrate logs, interpret seismic data, and constrain reservoir simulations are commonly made at low pore pressures. To mimic reservoir conditions, the tests are performed at reduced external stresses, so as to compensate for the low pore pressures (Pp) used in rock testing. It is common practice to choose a net effective stress that is thought to result in identical rock properties. We show that due to a variety of pore pressure phenomena, the net effective stress for each property is different, and is a direct result of the fact that pore pressure and external stresses act in different ways, causing different stress distributions and deformations within the grains.

Our results lead to the conclusion that the "effective stress" should not be thought of as an equivalent state of stress. Failure to properly apply effective stress concepts can lead to potentially significant errors. For example, laboratory measurements of brine permeability indicate that for these sandstones, the routine core permeability measurements at low pore pressure may underestimate the in-situ rock permeability by 20% to 50% and underestimate permeability reduction due to depletion. Other examples include pore pressure effects that influence interpretation of stress and pore pressure from sonic and seismic data, where the effective stress coefficient has the added complexity of including both rock and fluid components.
Technical & Social Issue of H2S Environment Within Drilling & Operations of Oil & Gas Industry. "Case Study of JOB PPEJ, Sukowati Field - Tuban Block, East Java"
Authors: Syaifudin Suyanto , Oemar Suryadi , Lotong Marthen , Diana Aries
Published: December 2009

In the recent news and publication, many reports have appeared-telling us that some people around Sukowati Drilling Pad exposed by H2S toxic gas and the exposure people got hospitalization. Since 2006 at JOB PPEJ Sukowati field, recorded four incidents in the base line H2S. All of the incidents occur during the drilling activities. JOB PPEJ, BPMigas, and Ditjen Migas spends a lot of energy, time and money in dealing the problem both with community, news paper, and related government.

JOB PPEJ is located in Bojonegoro & Tuban, East Java. The main operation areas concentrated and living in proximity with the community. H2S content in each producing well has a variety 0.6 – 3.8%. Successfully production & exploration within H2S environment started on 1996 at Mudi Field and the year of 2000 starting to explore Sukowati Field.

Hydrogen sulfide presents is a potential hazard. To ensure protection against exposure, JOB PPEJ was applying H2S safety management to protect public health and safety. As part of harmonization, The Local District Disaster Mitigation Task Force Plan (PKDB, Penanggulangan Keadaan darurat & Bahaya) is also initiated into contingency plan. PKDB Team works under Bupati direction to accompany JOB PPEJ operations which is the team consists of Local Government, Army, and Polri, and each of Kepala Desa/Camat.

All of H2S incident at Sukowati Field become big issue written by journalist since the location vicinity to the community area then information access is very easy and fully open. Based on hospitalization data caused by those incidents, only a few persons in the village and or in a house complain or feel and affected by the bad smell, they in illness condition, old, pregnant condition, and suffer from a disease. They hospitalize only in a few days then back home. No one irritant symptom as H2S main effect. If so expose by H2S, the first receiver is JOB PPEJ personnel whom work in drilling rig area.

With unique condition and non technical aspect of H2S environment, now JOB PPEJ with BPMigas and Ditjen Migas were working on it to review, evaluate, and implement both technical and non technical aspect on where drilling rig working on vicinity area. Conveying with this program, socialization to the journalist and Police about Migas activities was being in progressed to solve the current and potential issue refers to previous incident.
Reservoir Characterisation Through Joint Interpretation of CSEM, Seismic and Well Data
Authors: MacGregor Lucy M. , Harris Peter
Published: December 2009

It is well-known that CSEM data are sensitive to the presence of hydrocarbons, but the diffusive energy propagation results in low resolution images. Seismic data are much better suited to resolving structure and some rock properties, notably porosity, but attempts to map fluids from seismic data may be misleading due to the ambiguity between fluid and lithology effects. Careful combination of both types of data based on consistent rock physics helps to overcome their individual weaknesses. In this paper we describe a data integration study on the Luva gas field, resulting in estimates of gas volume and other reservoir properties such as porosity and shaliness.
Reservoir Modeling in Shale-Gas Reservoirs
Authors: Cipolla C. L. , Lolon E. P. , Erdle J. C. , Rubin B.
Published: December 2009

The exploitation of unconventional gas reservoirs has become an ever increasing component of North American gas supply. The economic viability of many unconventional gas developments hinges on effective stimulation of extremely low permeability rock by creating very complex fracture networks that connect huge reservoir surface area to the wellbore. In addition, gas desorption may be a significant component of overall gas recovery in many shale-gas reservoirs. The widespread application of microseismic mapping has significantly improved our understanding of hydraulic fracture growth in unconventional gas reservoirs (primarily shale) and led to better stimulation designs. However, the overall effectiveness of stimulation treatments is difficult to determine from microseismic mapping, as the location of proppant and distribution of conductivity in the fracture network cannot be measured (and are critical parameters that control well performance). Therefore it is important to develop reservoir modeling approaches that properly characterize fluid flow in and the properties of a complex fracture network, tight matrix, and primary hydraulic fracture (if present) to evaluate well performance and understand critical parameters that affect gas recovery.

The paper illustrates the impact of gas desorption on production profile and ultimate gas recovery in shale reservoirs, showing that in some shale-gas reservoirs desorption may be a minor component of gas recovery. In addition, the paper details the impact of changing closure stress distribution in the fracture network on well productivity and gas recovery. In shale-gas reservoirs with lower Young’s modulus rock, stress dependent network fracture conductivity may significantly reduce ultimate gas recovery. The paper includes an example that contrasts the application of numerical reservoir simulation and advanced decline curve analyses to illustrate issues associated with conventional production data analysis techniques when applied to unconventional reservoirs.

Selected examples from the Barnett shale are included that incorporate microseismic fracture mapping and production data to illustrate the application of the production modeling to evaluate well performance in unconventional gas reservoirs. This paper highlights production modeling and analysis techniques that aid in evaluating stimulation and completion strategies in unconventional gas reservoirs.