bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Off-Target Effects Due to Basal Bark Treatment for Control of Invasive Fig Trees (Ficus carica)
Authors: Holmes Katherine A. , Berry Alison M.
Published: December 2009

Basal bark treatments involve the application of concentrated herbicide solution on each individual stem of targeted plants. When applied to stands of invasive plants with high stem densities, basal bark treatments may result in the use of large quantities of herbicide in a given area. The effect of basal bark treatments using a solution of 25% triclopyr herbicide and 75% methylated seed oil was tested on research plots located in six different groves of invasive fig, a densely stemmed, problematic invader of riparian forests in California. The experimental treatments resulted in application rates that were equivalent to 28 to 44 kg ae/ha, greatly in excess of the labeled maximum use rate of 9 kg ae/ha (8 lb/ac). At 175 d after application, soils near the fig trunks contained high levels of triclopyr residues (up to 6.6 ppmw), suggesting that the chemical made its way into soils during this period and was not completely degraded. Although the mortality of native plants transplanted into treated fig groves was low (up to 16%), it was significantly greater than the mortality experienced by native plants transplanted into untreated control sites (0%). Although effective in controlling invasive fig trees (> 99% mortality), the high herbicide application rates from basal bark treatment preclude the use of this treatment in large fig groves. These treatments may be appropriate, however, when fig groves are small or isolated enough to prevent overapplication on a per-area basis. In addition, neither limited basal bark applications of triclopyr (< 40% of stems treated) nor foliar spray treatments of 2% glyphosate were effective control measures. Further investigation is needed on ways to control large invasive fig groves.
Invasion Potential of Chinese Tallowtree (Triadica sebifera) in California's Central Valley
Authors: Bower Michael J. , Aslan Clare E. , Rejmánek Marcel
Published: December 2009

The ecological effects of Chinese tallowtree are well documented in the southeastern United States, yet this known invasive plant continues to be planted extensively in California's Central Valley, where it has recently naturalized in several locations. Climate modeling suggests that most of California's lowland riparian habitat is susceptible to invasion by Chinese tallowtree; however, no field tests are available to corroborate this result for California or to identify local environmental constraints that might limit potential habitats. We used observational and experimental methods to evaluate invasion potential of Chinese tallowtree in riparian habitats in California's Central Valley. High invasion potential, indicated by an intersection of the maxima of dispersal probability, germination, and survivorship of seedlings, occurred at low elevations immediately next to perennial waters. The main factor limiting Chinese tallowtree invasion potential in more elevated habitats appears to be lack of seedling drought tolerance. These findings suggest that California's riparian habitats are vulnerable to invasion by Chinese tallowtree, especially downstream of current naturalized populations where water or bird dispersal will deposit seeds in environments ideal for germination and growth.
Differential effects of prenatal stress and glucocorticoid administration on postnatal growth and glucose metabolism in rats
Authors: Franko K L , Forhead A J , Fowden A L
Published: December 2009

Glucocorticoid administration during pregnancy programmes cardiovascular and metabolic functions in the adult offspring. Often, the control procedures are stressful per se and raise maternal glucocorticoid concentrations. This study compared the effects of maternal injection with dexamethasone (dex, 200 μg/kg) or saline with no treatment from 15 to 20 days of rat pregnancy on offspring growth and glucose metabolism. Near term, maternal corticosterone concentrations were higher in the saline-treated dams and lower in the dex-treated dams relative to untreated animals. In both male and female offspring, growth rate was measured for 14 weeks, and glucose tolerance was assessed between 12 and 13 weeks together with body fat content and plasma concentrations of insulin, leptin, and corticosterone between 14 and 15 weeks. Offspring liver was collected at different ages and was analyzed for glycogen content and gluconeogenic enzyme activity. Compared with untreated animals, both dex and saline treatments altered postnatal growth although adult body weight was unaffected. The two treatments had different effects on adult insulin concentrations and on hepatic glycogen content and gluconeogenic enzyme activities both pre- and postnatally. Relative to untreated animals, adult glucose tolerance was improved by maternal saline injection in males but not in females, while it was impaired in female offspring but not in male offspring of the dex-treated dams. Adult glucose tolerance was related to male body fat content but not to female body fat content. Dex and saline treatments of pregnant rats have differential sex-linked effects on the growth and glucose metabolism of their offspring, which indicates that the programming actions of natural and synthetic glucocorticoids may differ.
Interleukin-6 autoantibodies are involved in the pathogenesis of a subset of type 2 diabetes
Authors: Fosgerau K , Galle P , Hansen T , Albrechtsen A , Rieper C de Lemos , Pedersen B Klarlund , Larsen L Kongskov , Thomsen A Randrup , Pedersen O , Hansen M Bagge , Steensberg A
Published: December 2009

Interleukin-6 (IL6) is critically involved in inflammation and metabolism. About 1% of people produce IL6 autoantibodies (aAb-IL6) that impair IL6 signaling in vivo. We tested the hypothesis that the prevalence of such aAb-IL6 is increased in type 2 diabetic patients and that aAb-IL6 plays a direct role in causing hyperglycemia. In humans, the prevalence of circulating high-affinity neutralizing aAb-IL6 was 2.5% in the type 2 diabetic patients and 1% in the controls (odds ratio 2.5, 95% confidence interval 1.2–4.9, P=0.01). To test for the role of aAb-IL6 in causing hyperglycemia, such aAb-IL6 were induced in mice by a validated vaccination procedure. Mice with plasma levels of aAb-IL6 similar to the 2.5% type 2 diabetic patients developed obesity and impaired glucose tolerance (area under the curve (AUC) glucose, 2056±62 vs 1793±62, P=0.05) as compared with sham-vaccinated mice, when challenged with a high-fat diet. Mice with very high plasma levels of aAb-IL6 developed elevated fasting plasma glucose (mM, 4.8±0.4 vs 3.3±0.1, P<0.001) and impaired glucose tolerance (AUC glucose, 1340±38 vs 916±25, P<0.001) as compared with sham-control mice on normal chow. In conclusion, the prevalence of plasma aAb-IL6 at levels known to impair IL6 signaling in vivo is increased 2.5-fold in people with type 2 diabetes. In mice, matching levels of aAb-IL6 cause obesity and hyperglycemia. These data suggest that a small subset of type 2 diabetes may in part evolve from an autoimmune attack against IL6.
Inclined Gravity Downhole Oil-Water Separator: Using Laboratory Experimental Results for Predicting the Impact of Its Application in High Rate Production Wells
Authors: Fitnawan Eko A. Y. , Rivera Rocio M. , Golan Michael
Published: December 2009

As an oilfield goes mature, an increased water cut can significantly decrease the maximum fluid production rate or even stop the production entirely. Therefore, separating produced water from the wellstream as early as possible is a potential way to maximize oil production.

A novel inclined gravity downhole oil-water separator concept has been introduced and patented by ABB Research Ltd., which combines gravitational separation with distributed water tapping along the incline separator tube. The concept depicts that the downhole separator can be installed somewhere above the production packer and below SCSSV (surface-controlled subsurface safety valve). Gravitational forces create a separated water or water rich layer at the lower side of the pipe. This segregated water rich layer is drained using distributed tapping points along the separation tube and then flow to surface via annulus, whilst the oil rich layer flow through the tubing continue up to surface. Several experimental tests have been performed and this paper describes how to use the experimental results into a well performance simulator to predict how the inclined gravity downhole oil-water separator modifies the performance of high production rate wells.

The study includes the well performance effect of separator setting depth, setting inclination, tubing size and tubing configuration. Well performance sensitivity due to water cut and separation efficiency is also discussed. The simulation results show that inclined downhole oil-water separation is very beneficial and able to increase oil production up to 82% for the selected wells with 81–87% water cut.
Anti-Collision Risk Management for Real-World Well Placement
Authors: Poedjono Benny , Van Chinh Phan , Lombardo Guy J. , Phillips W.
Published: December 2009

Current trends in drilling require a proven and comprehensive approach to assessing and managing the risks of wellbore collisions. This paper outlines the scope and nature of the challenges in collision risk management, and provides an overview of a systematic, field-tested approach to identifying, evaluating, eliminating and/or mitigating those risks. Key aspects of the process are explained in detail and a recent field application on a large platform offshore Indonesia is discussed to illustrate the key values of the risk management process. These include maximizing resource recovery by permitting the safe, precise placement of wellbores, and minimizing the financial and human cost of losses from incidents avoided or mitigated.
A Proactive Approach to Environmental Responsibility in Product Development
Authors: Welton Thomas D. , Cassidy Juanita
Published: December 2009

Environmental regulations vary from region to region and from country to country. The North Sea regulations are some of the most stringent in ensuring that environmentally acceptable chemicals are used in the oil and gas industry. Although it is not imperative that North Sea regulations be adhered to in other regions, being mindful of these regulations early in the product development cycle is both a corporate responsibility and good business practice. Many exploration and production companies are adopting initiatives which drive environmental consciousness. It is critical that the service sector respond.

This paper describes the methods that have been used to proactively develop the most environmentally acceptable acid-stimulation chemicals while balancing local regulations and business drivers. The products being highlighted are acidizing chemicals, which are a particular challenge since it is difficult to develop chemicals that function in highly corrosive environments yet have acceptable biodegradation characteristics or toxicity levels.

In 2005, a study evaluated the feasibility of removing objectionable chemical components from the service company's acid stimulation product line. Based on the result of the study, a systematic program to prioritize product replacement based upon the greatest environmental impact has been established. In 2008, a follow-up study was conducted to evaluate progress and to expand the scope of objectionable chemical components considered to include the Gulf of Mexico and operator-driven criteria. This systematic program has evolved into a process to evaluate the environmental acceptability of all components of new products during the development cycle.

Several product-development case studies will be described. One study focuses on product development for the North Sea, a second for the Gulf of Mexico, and a third for Asia. These products were deployed globally as a result of their exceptional performance, much-improved environmental characteristics, and cost-effectiveness.
The Use of Voice-Recognition for Electronic Medical Records – A Personal Experience
Authors: Kuo Wei-Hua
Published: December 2009

The advent of PC-based voice-recognition software for medical dictation began over 10 years ago. In those early days, due to the limitations of computer speed and memory, the learning curve was steep and adaptation was limited. The "training period" was measured in weeks and there were professional one-on-one trainers to teach the use of voice recognition for dictation purposes. Despite such great efforts, the error rates were high and a great deal of time was needed to correct errors by voice commands or keyboard entry. The voice-recognition medical records dictation system fell short of expectation, until recently.

Nowadays, commercial voice-recognition software has made tremendous strides, taking advantage of the increased processing speed of parallel computing and vast memory size – Moore's Law at work. It is now feasible to setup a low cost medical dictation system, and get it to work in days. The learning curve is much abbreviated and with improved accuracy. Nevertheless, dictating into a voice recognition system requires the user to speak into the microphone clearly and distinctly, at a pre-determined pace. Although such speech cadence appears artificial, it is not difficult to get accustomed to and is not an impediment to its use.

The voice-recognition software is also capable of acting as a voice-activated system to control computer functions, such as selecting desktop icons, opening and closing menus, and switching between open windows. Moreover, the system has a self-learning capability: When a user corrects an error with either keyboard strokes or voice commands, the software recognizes the error and will improve its accuracy next time.
Repetitive Stress Injury Prevention RSIP Program Implementation in IBU
Authors: Ardiansyah Reza , Wahyuni Army
Published: December 2009

A comprehensive Repetitive Stress Injury Prevention (RSIP) system is needed to control and mitigate the development of RSI risk in Chevron IndoAsia Business Unit (IBU) employees.

The scope of RSIP system includes: A recognized method to assess the RSI risk to computer or workstation users.Awareness of RSI risks to all employees.Employee workstation assessment, performed by qualified evaluators, to evaluate risk, and provide a method to mitigate any identified risks.A behavioral approach to encourage proper work habits and behaviors including the encouragement of early reporting of discomfort.Timely response and follow through to resolution for employees with discomfort, in conjunction with medical assessment.A process to ensure that ergonomic furnishings, accessories, and software are acquired to meet Company minimum standards.

As an embryo program, IBU ergonomic proactive approach has expanded to emerge as RSIP system. This system is an IBU standard accepted by management as a way to prevent RSIs. As the result of full implementation of RSIP system High participation of ergonomic self assessment through Online Ergonomic Self Assessment (OES) WorkWell by employees and contractors with access to company computers.Adequate number of QWE (Qualified Workstation Evaluator)Ergonomic aids such as keyboard trays and adjustable chairs are available to all employees who work mostly at office.Behavior Based Safety observation shows the overall ergonomics at risk behaviors tend to reduce while safe behaviors tend to increase.Mandatory computer ergonomic break software installed at all computers

To maintain sustainability of RSIP system implementation, there are several area of improvement identified among others, Increase the number of employees who complete the self assessmentMonitoring the compliance of computer generated ergonomic breaks to increase the acceptance of breaks standard.Develop RSIP Online system to encourage people for early reporting and rapid response to ergonomic pain or discomfort.
Integrating Process Safety Aspects in a HSE Management System
Authors: Mapus Richard Anak , Sintian Clista Binti , Yusof M Radzuan Bin , Maulana Abdul Ghafar Bin
Published: December 2009

DESCRIPTION

This paper describes the challenges faced by PETRONAS Carigali in implementing Process Safety Management (PSM) as part of the effort to enhance Health, Safety and Environment Management System (HSE MS) with process safety aspects in PETRONAS Carigali. This is a five year journey starting in 2006. Process safety management in PETRONAS Carigali is embedded within the Health Safety & Environment Management system (HSEMS). The HSEMS was introduced in PETRONAS Carigali in 1995 with the intent to standardize HSE management practices. Various practices from safety, health and environment were aligned, consolidated and initiated to form this structured system. Over time, staff and contractors' HSE awareness and practices improved. The occupational safety records indicate positive trends. However, process upsets and asset failures did not indicate similar trends. It was discovered that the assets and process safety aspects have not been adequately described and provided for in the system.

APPLICATIONS

Eight process safety aspects namely Management of Change (MOC), Process Hazard Analysis (PHA), Process Safety Information (PSI), Pre Activity Safety Review (PASR), Mechanical Integrity (MI), Design Integrity (DI), Proprietary Licensed Technology Assessment (PLTA) and Operating Procedures (OP) were included in HSEMS enhancement. Concerted efforts were taken to review the HSE practices in engineering and operations to identify specific process safety gaps.

The uniqueness of this project is that it utilizes internal resources. The intentions were to build ownership, in house competencies and generate closer communication and sharing among the various operating units. The methodologies and lessons learnt could be used for similar purposes by others.
Compressed Natural Gas for Indonesia
Authors: Wang X. , Economides A. M. , Marongiu-Porcu M. , Economides M. J.
Published: December 2009

While Indonesia has traditionally been a major exporter of liquid natural gas (LNG) to Japan, Korea, Taiwan and China, compressed natural gas (CNG) should be seriously considered, especially for the transportation of fuel within the Indonesian archipelago itself.

CNG is an alternative that has been proposed in recent years but has yet to be implemented on a large scale because the emphasis for investments has primarily been on LNG and because CNG applications have not been well delineated. Some people still believe that LNG and CNG are competitors. They are not.

The key is to find the areas, both geographic and volumetric, of least-overlapping applications. It has often been stated that CNG is more attractive for shorter distances and smaller offshore markets which are not connected to pipelines or large LNG accepting facilities. For short distances, less than1000 km, LNG cannot compete with CNG for any volume of gas. Even at longer distances (e.g., 2,000 km), until the recent collapse of gas prices, CNG is still more attractive at volumes of up to 10 Bcm/yr (or 350 Bcf/yr), assuming that offshore pipelines are not economically or physically feasible. For smaller volumes, such as 1 to 2 Bcm/yr, and long distances, CNG is the only solution to bring natural gas to many markets. We have also found that higher prices of natural gas, either at the source (cost) or at the destination (sale price), increase the volume of gas at which CNG is more attractive than LNG.

Indonesia is an obvious place for such applications and we present cases for the transportation of natural gas as CNG from Borneo and Sumatra to Java and Bali. We quantify the volumes of gas that delineate CNG's superiority and show the impact of gas prices on the indicated gas volumes to be transported.
Characterization of Biodiversity: A Multi-Technique Approach to Study Fish Diversity Associated with Off-shore Platforms
Authors: Andaloro F. , Consoli P. , Romeo T. , Mostarda E. , Azzurro E. , Ferraro M.
Published: December 2009

In the last decades the ecological role of off-shore platforms as a suitable habitat for fish species has been acknowledged in the context of marine conservation and investigated by an increasing number of studies. Fish communities associated with these artificial structures have been analyzed by different approaches such as hydroacoustic surveys, experimental fishing and remotely operated vehicles (ROVs) in many areas of the world. These techniques were generally used separately providing both qualitative and quantitative data at a different level of accuracy.

In the present project, fish diversity associated with Mediterranean gas platforms was studied for the first time by integrating four different methods. More in detail, fishing surveys, video recordings from remotely operated vehicles (ROVs), remote sensing and underwater visual census (UVC) by means of SCUBA divers were employed.

This multi-technique approach allowed for the collection of complementary data and a complete characterization of the fish community. Fish diversity resulted higher than would have been by using each method separately. The use of innovative techniques (ROV, UVC and Remote Sensing) permitted to explore the inner part of the platforms which is typically difficult to study. More in detail, UVC was the most efficient technique to census fish species strictly associated with the pillars. This technique allowed for the censusing of crypto-benthic fish species which represented an important and generally unnoticed component of the biodiversity associated with these structures. These species, which use these artificial structures as a trophic and reproductive substrate, accounted for the 22% of the total species richness. The contemporary application of different techniques to study the platforms fish community allowed also for an evaluation of limits and potentialities of each method also in relation to their costs and scientific outputs. This information can be easily used to formulate investigation protocols also replicable in other areas.
Promising Results from First Deployments of Rotary Steerable Technology in Vietnam Basement Granite
Authors: Mohamed Nooraini Bt. , Tan Johnnie H.P. , Hasmatali Daryl , Ming Lim Kien , Heisig Gerald
Published: December 2009

The oil-bearing fractured granite basement reservoirs in Vietnam are developed mostly with 8 ½" directional reservoir sections drilled with conventional steerable motors and insert roller cone bits. Although successful, the high weight on bit (WOB) required to achieve acceptable rates of penetration (ROP) results in reduction of bit and motor life with runs rarely exceeding 40 drilling hours. Additional steerable motor drilling challenges in the granite include high abrasive BHA wear, destructive drilling dynamics and directional control problems in the reservoir.

As a first for Vietnam basement granite drilling, in September 2008 an 8 ½" reservoir section was drilled utilizing rotary steerable technology. A distance of 1650 m was drilled in 3 runs while building inclination from 18° to 78°. The first two runs featured a motor-powered rotary steerable system (RSS), while the last run was drilled with a standard RSS. All three bottom hole assemblies included a drilling dynamics tool and resistivity imaging tool transmitting information that allowed real time drilling optimization decisions. Comparison of RSS to steerable motor runs shows that although little improvement in ROP was achieved, the distance drilled per bit run was increased by 30 – 40 %, resulting in fewer trips for the section. In addition, more effective directional control from the RSS delivered optimized well placement resulting in additional performance improvements. Overall the use of RSS technology delivered the highest average footage drilled per day in this field.
Modelling Phase Equilibria of Complicated Systems Containing Petroleum Reservoir Fluids
Authors: Haghighi Hooman , Chapoy Antonin , Tohidi Bahman
Published: December 2009

Formation of gas hydrates can lead to serious operational, economic and safety problems in the petroleum industry due to potential blockage of oil and gas transmission lines and processing facilities. Thermodynamic inhibitors are widely used to reduce the risks associated with gas hydrate formation. In practice, the aqueous phase in which inhibitors are added already contains electrolytes from either drilling/completion fluids or from formation water. In such mixed inhibitor systems, both co-solvents and strong electrolytes are present in the aqueous phase, making the thermodynamics of these highly non-ideal systems difficult to model.

Hydrate/aqueous and hydrocarbon PVTX thermodynamic modelling at Heriot-Watt University (HWHYD) dates back over 25 years. In the latest version of the HWHYD model (2.1), a new approach has been introduced and applied for modelling phase equilibria in systems containing components which can form hydrogen bonds (e.g. water, methanol, ethanol, mono-ethylene glycol, and etc) and hydrocarbon mixtures using a robust general-purpose implementation of the CPA (Cubic Plus Association) model. This work is evaluating the capability of this model for conventional and challenging hydrates calculations, including; (1) gas hydrate in low water content gases, (2) hydrate stability zone in the presence of high concentration of inhibitor(s) or salt(s) and/or high pressure conditions, (3) hydrate stability zone of oil/condensate in the presence of produced water and inhibitors, and (4) prediction of hydrate inhibitor distribution in multiphase systems. The results show that the Heriot-Watt Hydrate (HWHYD 2.1) software predictions are consistently in a good agreement with experimental data.
Production Data Management and Reporting System to Optimize Production Analysis
Authors: Karmawijaya Muchamad Iman , Rahardja Budi
Published: December 2009

PDMAR (Production Data Management and Reporting) is software to manage oil and gas operation and production data. It supports integration of automation system and business network that providing fast and accurate production information. It includes production database, data acquisition from automation level, data entry modules, oil and gas allocation modules, formula builder, expert system, data validation, security, asset management modules, link to other applications, and integrated reporting and data browser. It provides customizable configuration modules that enable user to create and modify table that appropriate with their field condition.

PDMAR uses commercial RDBMS to store data. It uses latest Microsoft .NET Framework technology and web services to keep pace on speed, efficient, and effective data storage and transfer. They would browse daily report that contains daily production, operation, latest well test, HSE status, oil and gas allocation, chemical storage, transportation, utilities, etc through web interface easily. Data interfacing are performed automatically from major commercial historian database as well as oil and gas production software.

PDMAR has been installed in many onshore and offshore facilities. With optimized data transfer, operator will transfer data in less time. Data link between control layer and management level automates field operator's job thus give more reliable and precise data capture. For remote and distributed well field, mobile system that incorporated with handheld device help operator to record important data to main database using automatic synchronization.

Engineer and management use less time to analyze production and operation data than before. They receive daily production report in precise time every morning through email and website. They now focuses on analyze data than collecting data before. There is only one validated data version that is used for daily report.
Realities of Spill Response: Waste Remediation Strategies
Authors: Massoura S. T. , Sommerville M.
Published: December 2009

Marine oil pollution receives much attention all over the world due to the perception of the magnitude, longevity and extent of damage it inflicts on the environment. In reality the impacts on the marine environment and coastline when the incident is well managed are often short-lived. The waste generated, however, may present a longer-term problem if not correctly managed and treated. The aim of the paper is to examine some of the remediation techniques now being used for treatment of oily wastes and the criteria for determining and selecting the most appropriate techniques. In doing so the paper examines various techniques and oil spill incidents in which they were used to illustrate the issues.

The management of waste streams is dependant on the type of pollutant, the composition of the impacted area, cleanup methods employed, nature of removed material and finally the volume of waste generated. The remediation techniques available can be broadly grouped into physicochemical, biological and thermal techniques. While all have limitations such as increasing the area of contaminated material, potential groundwater contamination, air emissions or need for long-term management, these are more acceptable than the historic landfill disposal strategies. It has been determined that these techniques have potential separately, or in combination, to increase the rate of degradation of contaminants. The residual contamination concentrations which will be acceptable are not universally agreed but defined by an assessment of the health, ecological risks of the contaminants. Remedial technologies must be chosen based on their ability to achieve those goals in a cost-effective and timely manner.

Finally the paper looks to the future of each technique based on parameters such as effectiveness, reasonableness, cost, practicability, durability, technological and scientific advances, and discusses future implementation in accordance with good practice and quality assurance procedures.
Safety Studies: Advanced Modeling Tools Offer Ways to Mitigate Costs
Authors: Bertrane M. , Ledoux H. , Mendes M. F. , Neumann N. A.
Published: December 2009

The increase of oil production in most oil companies is based on offshore facilities. These installations are characterized by high density of equipment and piping and, in most situations, elevated production capacity. Direct impacts of such characteristics are: risk increase associated with hydrocarbon releases, reduced time for evacuation and the requirement of specific safety systems, assuring safe evacuation of the personnel.

This paper presents and discusses the methodology used for simulating gas releases and dispersion inside offshore facilities, as well as fire accidents. Based on practical examples, it will be analyzed how those computational analyses can be used to optimize the overall safety level, reducing the consequences of fires and explosion, and preventing other types of problems -such as high temperature over the Helideck or high concentration of smoke, avoiding the use of the fire-fighting system. Significant results obtained in the last 20 years of analysis are discussed for Semi-submersible and Fixed Platforms, FSO and FPSO, with plants capable of processing from 15,000 to 200,000 barrels per day.
A New Design for Advanced Well Completion
Authors: Madsen Martin
Published: December 2009

Advanced well completions (AWC) have shown great benefits not only with respect to production optimization, but also data collection were they provide very useful PLT type information on a zonal basis (ref. 1, 2, 3).

However, as many of the wells with advanced completions have matured and more data been acquired over longer production periods, some a better understanding of the production behaviour has been gained.

Installing an inner tubing with associated flow control valves in a horizontal liner causes restrictions to the flow, and an increased pressure drop. One the StatoilHydro operated Visund field, one has observed that at certain well conditions (related to combinations of rate, water cut (WC) and gas oil rate (GOR) this pressure drop leads to a noticeable reduced well potential, and thereby a reduced overall robustness of the well design. By increasing the production liner diameter in the reservoir section, one may be able to install advanced completion equipment with bigger dimensions. This allows the benefits of the downhole zonal control to be realised without hindering the well potential.

Data from two wells one the Visund field, has been used to demonstrate the benefits related to increasing the diameter of the production liner, and consequently the dimensions of the advanced completion components. A hydraulic well model has been constructed comprising one producer and one gas injector. When the models are matched to actual rates (and well conditions), the effect of varying the flowing diameter (= inner tubing diameter) is studied. The results show that there is an upside with regards to flexibility and well potential with such an optimized completion design. In relation to the model findings, the consequences for the drilling and completion design and processes are outlined.
Integrated Surveillance Enhancing Quality of Decisions and Reservoir Description in Harding
Authors: Zett Adrian , Webster Mike , Davies Chris , Zhang Pinggang , Mukerji Parijat
Published: December 2009

A key factor in managing mature fields is to identify adequate surveillance in each phase of its life. The complexity increases when the field is developed with horizontal wells. Differences in data quality and resolution should be taken into consideration when planning such surveillance. Current uncertainties in Harding relate to unreliable well conformance data using conventional production logs and assumptions in the reservoir description which are sub seismic resolution. We describe the learning from a horizontal well in the Harding Field, where appropriate surveillance enhanced reservoir understanding and quality of decision making.

Based on the initial understanding from the reservoir model, an insert string well work option was proposed to reduce water cut. Historically in this field, conventional production logging provided unreliable well conformance data in horizontal multiphase flow. To improve the characterization at the well scale, an array production log was deployed for the first time on this field.

The flowing results revealed that the insert string solution was inappropriate and would result in lost oil production. The shut in data identified cross flow between two zones separated by a shale section. In the initial model this shale was mapped only at local level. Post surveillance it was remapped on seismic as an extensive baffle having an impact on an area with more mobile oil to recover. There is potential upside with a new infill target being identified towards the toe of this well. Most of the initial decisions about the insert string were based on seismic and modeling work. The new array production log data brought additional information into the model increasing confidence in the results. Data resolution at the well level matters and this highlights the need to take more production log measurements to calibrate the seismic response and improve the reservoir model.
‘S’ is for More than Just Safety
Authors: Kain Andrew
Published: December 2009

Kidnap for ransom, piracy, terrorist attack, criminality, war, expropriation and wider political risk, are all challenges the upstream sector has faced over the last 12-month period. These challenges will continue, and it is highly probable that they will actually increase. Challenges to the discipline of ‘Health, Safety and Environment’ include the very environments in which the energy sector operates, particularly as frontier locations are explored and as many existing regions of operation are affected by instability, conflict, extremism and other security and political risks.

As an industry the energy sector is highly regulated, and is policed by the discipline of HSE. Qualifications and certification for deployment to the UK's own backyard, the North Sea, are plentiful. It is thus somewhat surprising that often nothing more is required of personnel prior to their deployment to areas of operation further afield, where potential security challenges are more prevelant. Those tasked with crisis management responsibility are also often under-prepared for this role, and the unique challenges to be faced.

This paper discusses the industry's successes and failures in terms of security risk mitigation and the requirement for the "Security S" to be incorporated into the wider remit of HSE management. It highlights what can and has been done to minimise the risk to personnel operating in challenging environments.
Laggan & Tormore—Development of Two New Deepwater Gas Condensate Fields and Associated Gas Export Infrastructure
Authors: Cutler Jeremy
Published: December 2009

The Laggan and Tormore gas condensate fields are situated in 600m water depth some 140km north-west of the Shetland Islands. The region is served by limited oil and gas infrastructure and so called "stranded gas" fields have been left undeveloped to date; primarily due to the significant investment required to establish an export route to market in this remote and harsh environment.

After several years of extensive development engineering studies and commercial negotiations, the Laggan and Tormore partners, led by TOTAL E&P UK Ltd (TEP UK), are moving towards sanction of a major project that could lead to first production of gas from this challenging region by 2014. The proposed project facilities consist of a subsea template-manifold above each of the Laggan and Tormore reservoirs with production from up to eight subsea wells commingled and exported multiphase to the Shetland Islands via two 18" 140km rigid steel flowlines. A new gas processing facility sized for 500 MMscfd and operated by TEP UK will be constructed onshore close to the existing Sullom Voe oil terminal. A new 30" 230km gas export pipeline sized for circa 665 MMscfd will transport the processed gas to a tie-in point on the FUKA pipeline close to the abandoned MCP01 platform.

Development of the Laggan-Tormore gas fields would represent a major achievement for the licence partnership and a significant milestone in the overall development of the West of Shetland region. The "Shetland Islands Regional Gas Export" system (SIRGE) will offer a new export route for gas from an area previously bottlenecked by the existing limited gas export infrastructure. Linked to the new onshore gas processing terminal, SIRGE should reduce the development cost for new entrants, thereby promoting the future growth potential of the region.

The West of Shetland region is unique for its combination of extreme metocean conditions and a demanding environmental context characterised by its distinctive wildlife and rugged onshore terrain. The long distance subsea tie-back chosen for Laggan-Tormore brings with it significant technical challenges in terms of flow assurance and construction / installation planning together with a complex regulatory framework associated with environmental considerations, multiple stakeholders and land access approvals.

Reaching this milestone has involved a significant investment in both financial and human resources to complete the technical engineering and sub-surface studies as well as the complex commercial negotiations to define the eventual development concept and gas evacuation route. The Third Party Investment Process carried out in 2008 offered the key West of Shetland stakeholders an opportunity to invest in a gas evacuation system sized for the region.

This paper summarises the Laggan-Tormore development process to date as well as the key technical challenges to bring this major new project to fruition and establish a new gas export infrastructure serving the West of Shetland region in years to come.
Real-Time Decisions With Improved Confidence Using Azimuthal Deep Resistivity and At-Bit Gamma Imaging While Drilling
Authors: Harris Michael , Byrd David , Archibald Michael , Naupari Carlos , Bittar Michael , Chemali Roland
Published: December 2009

Recent advances in logging-while-drilling (LWD) have thrust geoscientists in the fast world of real-time decisions. The interpretation of images and logs for successful well positioning requires a higher level of urgency and criticality than with post-well formation evaluations. When advising drilling engineers about well steering, geoscientists have little room for second guessing or revisiting even very recent decisions. The method described in this paper takes advantage of newly developed LWD sensors. The new information helps increase confidence and reduces errors when making real-time steering decisions.

Geosteering experience consistently shows that the formation discovered as the well progresses is significantly different from the pre-drill models. Even in simple layered environments, it is often difficult to recognize in what layer is the well moving. Within a particular layer, there is often ambiguity regarding the relative well position. Crossing into a shale or across a subseismic fault creates an emergency for bringing the well back to the predicted course. Modern azimuthal deep resistivity provides the means to see to a greater radial investigation the formation surrounding the well, but the acquired raw data is complex and must be organized and interpreted instantly.

A recent geosteering operation was successfully completed using the azimuthal deep resistivity information and combining it with near bit gamma images for maximum reservoir contact. Resistivity readings in opposite quadrants were monitored and compared. When they were similar, the well was too far below the roof and must be steered upward; when they separated, the magnitude and direction of the separation was uniquely related to the approaching boundary and correlated with pre-well model. The diagnosis was confirmed and often anticipated by a higher level measurement: the geosignal. Because of its early detection of approaching boundaries, the geosignal facilitates proactive decisions. The well achieved full reservoir contact with no uncontrolled exit. The image from the near-bit gamma was used only when landing the well and when finally exiting the reservoir. Between these two milestones, gamma images had only a verification role, confirming throughout that the well stayed clear of shale intervals.
Managing Safety & Risk Issues in Upstream Field Development—Case Studies
Authors: Phang Christina , Yng Voon Jye , Leong Christie
Published: December 2009

An important element of a field development project would be ensuring that relevant safety features are incorporated within the design of the facilities such that the risk to personnel working on the facilities are deemed to be tolerable from a company or regulatory perspective. It has been observed that different oil and gas operators have varying requirements with regards to the breadth and depth of the suite of formal safety assessment studies that are conducted at the different development stages. This paper will present an overview of the practices adopted by various operators based on the experienced gained through ERM's involvement in major field development in the Asia Pacific region. Similarities and diversity of the approach taken will be explored with the aim of sharing best practices that are applied in the industry.

The paper will explore the optimum results gain by conducting the safety assessments, including the use of Quantitative Risk Assessment as a management decision tool, during the early stages of the development projects taking into account the available information available. The paper will also include a discussion on the degree of effort required in achieving a final configuration where the risks to personnel working on the facilities are demonstrated to be As Low As Reasonably Practicable (ALARP) such that the investment in reducing the risks is not grossly disproportionate to the benefits that may be achieved.
Case Study: Successful Application of a Novel Conformance Treatment in an Extended Reach Horizontal Well in the Al Shaheen Field, Offshore Qatar
Authors: Pedersen M. H. , Lechner M. , Pon Z. A. , Brink D. , Abbasy I. , Jaafar M. R.
Published: December 2009

The thin and laterally extensive Al Shaheen reservoirs are developed with extended reach horizontal wells and large-scale water injection, which over the last decade has proved to be a proficient and environmentally favorable recovery scheme. This paper describes how injection water short circuiting between two horizontal wells in excess of 20,000 ft was eliminated with a conformance treatment without the necessity of a costly and operationally risky well intervention. Traditionally, reservoir management in terms of injection or production profile modification has been achieved with rig-based work-over operations applying mechanical solutions such as cement or isolation straddles. Work-over operations utilizing drilling rigs are, however, expensive, pose inherent operational risks and delay the implementation of the ongoing development plans. When water injection was recently commenced in a well taking part of an existing line drive pattern, an immediate pressure and watercut response was observed in the adjacent producer. Attempts were made to mitigate the effect of the communication, but water injection eventually had to be ceased to allow sustainable flow from the production well. The very pronounced response in the producer suggested that short circuiting was occurring through a fracture providing conductivity several orders of magnitude higher than the prevailing matrix conductivity.

A comprehensive multi-disciplinary review of static and dynamic data lead to the assessment that the fracture communication could be eliminated utilizing a conformance treatment and following laboratory testing and design, a crystalline superabsorbent copolymer was pumped from a stimulation vessel as part of an intervention- and rig-less operation. After the conformance treatment, injection was resumed with no adverse effects on the performance of the adjacent producer. The treatment is estimated to have recovered lost oil reserves of some 3 MMstb and to have reduced cost with more than USD 8 million compared to a conventional rig-based work-over operation.
CO2CRC Otway Project, Australia: Parameters Influencing Dynamic Modeling of CO2 Injection into a Depleted Gas Reservoir
Authors: Bouquet S. , Gendrin A. , Labregere D. , Le Nir I. , Dance T. , Xu J. , Cinar Y.
Published: December 2009

The CO2CRC Otway Project, in Victoria, Australia, is one of the first projects of CO2 storage in a depleted gas reservoir. CO2 injection in the sandstone reservoir, at a depth of 2,000 mSS, started in March 2008 with the objective to inject up to 100,000 tonnes of CO2 over two years.

This study compares the level of predictability obtained with different cases depending on the initial data, using the same numerical compositional simulation package. We use recorded data (production and injection) to build a new numerical reservoir model. A dynamic model had already been built before the injection well started (Xu et al., 2006) and was validated by history matching using the gas production data reported. In this paper, we used the same updated static model (Dance et al. 2007) as used for the pre-injection model, which is based on the production data and the data obtained from the injection well (CRC-1). With this updated static model, a different dynamic model is built using injection data and through a newly developed simulator option, which better simulates the CO2-water behavior. The injection rate and pressure data from CRC-1 are now available and the actual breakthrough time – at which the CO2 plume reached the monitoring well (Naylor-1) located 300 m away from CRC-1 – can be history matched. Various relative permeability curves including new laboratory measurements performed on a core taken from the reservoir formation (Waarre C) were used. The results from the updated dynamic modeling using this measured relative permeability data are compared to results using data from literature. In general, experimental measurements for drainage and imbibition processes are not available

This study gives a better understanding of the parameters which strongly influence simulated CO2 behavior. It shows the relation between the data availability and prediction reliability.