bluuebunny/crossref_metadata_2025 huggingface dataset:
Effective Thru Tubing Gravel Pack Methods in Attaka Field
Authors: Lee C. C. , Darby M. C. , Popp T. R.
Published: December 2007

Effective sand control has long been a concern within unconsolidated sandstone formation in the Attaka Oil field in East Kalimantan. Many of the producing wells have stopped production due to the influx of formation sand. These wells have low rate marginal reserves, which cannot economically justify re-completion with conventional gravel packing techniques.

Two Thru-Tubing Gravel Pack (TTGP) completion methods utilizing 1.5" Coiled Tubing (CT) were introduced in Attaka Field with selective based on the wellbore configuration. These techniques utilize methods transferred from Unocal's Gulf of Mexico operations. The first method is a Pack-off Method with gravel pack screen and packoff assembly for use in the monobore completion. The second method is a vent screen utilizing a mechanical plug back tool (MPBT) that can be run through 3-1/2" production tubing into 7" casing.1 The sand retention performance after the TTGP completions have been exemplary. Production tests show an increase in net production rate that is in line with inflow calculations. This paper reviews the job design, operational procedure and observed results of these two successful TTGP methods in the Attaka field. Six case histories and conclusions from the overall results are also presented.

A newly developed visco-elastic surfactant-based (VES) polymer-free fluid was used as the gravel carrier fluid. Rheology, fluid loss and gravel settling data are presented.
New-Generation Underbalanced Drilling 4-Phase Surface Separation Technique Improves Operational Safety, Efficiency, and Data Management Capabilities
Authors: Bullock Ray , Karigan Joe , Wiemers Tim , McMillan Scott
Published: December 2007

During the past five years, it has been well documented that drilling in underbalanced wellbore conditions can increase well productivity. This finding has led to a resurgence of interest in applying this concept. In wells where relatively high rates of produced hydrocarbon are anticipated, however, the traditional drilling flow-back systems have not always been successful in providing the safety, operational efficiency, and data management capabilities needed.

This paper focuses on a new, built-for-purpose, underbalanced drilling, 4-phase, surface-separation and well-control system that couples the mechanical flow requirements of the underbalanced drilling environment with the safety and efficiency of a process facilities design.

The discussion will focus on the design intent, prototype testing, commissioning and first operations of the system.

The system incorporates: Progressive separation and solids-handling techniques to improve separation efficiency.Programmable Logic Controller (PLC) technology to improve operational safety in the event of emergency or process upset conditions.Strict adherence to codes and industry practices, ASME B&PV (pressure vessels), ASME B31.3 (piping systems), API RP 14C (surface safety systems), NACE MR0175 (H2S service metallurgy), API RP 500 (Electrical Installations), etc.State-of-the-art real time data acquisition, data transmission and reservoir modelling techniques to better control the drilling process.

The system can safely and efficiently control and measure all returns, both drilling and production, while wells are being drilled by underbalanced means.

The system was designed and built in 1999 and underwent pre-commissioning and testing in December of that year. Pre-job commissioning was carried out in two locations during the first and second quarters of 2000.

The system provides a fully integrated underbalanced surface system capable of meeting the requirements of today's prolific underbalanced drilling candidates. Since commissioning, the system has been used on several underbalanced wells, and the results of the first deployments demonstrate that underbalanced drilling programs exhibiting high rates of produced hydrocarbon on surface can be undertaken without compromising operational safety, flexibility and integrity. Elements of data such as reservoir pressure; flow rates; gas composition; and mechanical drilling data can be incorporated into a single job database that can facilitate on-site data access, data manipulation, data transmissibility and analytical capability. Thus, timely and more effective on-site decision making results.
Simultaneous Snubbing and Drilling Operation on Long Reach Multi Lateral Improves Field Economics
Authors: Tupper Dale , Anderson Bryan
Published: December 2007

When Petronas Carigali, the national oil company of Malaysia, planned the development of its platform EWDP-A offshore Sabah, they did so on the basis of using coiled tubing for any thru-tubing workover operations which were needed while the drilling rig was still in place. In this way the drilling rig could be fully utilized for drilling operations, thus maximizing the efficiency of, and minimizing the total time for, the development. Well EW 117 was completed on this platform as a level 6 Multilateral in July 2000 with dual 3-1/2" tubing strings accessing two laterals with measured depths of 14,910ft. and 15,236ft., respectively. The clean-out and perforation operations commenced with coiled tubing with the rig assisting. However, due to a combination of the tortuosity and the lengthy horizontal sections of the laterals, it was not possible to reach bottom with coiled tubing because of the high frictional forces encountered.

After consideration of several alternatives a feasibility study was undertaken to explore the possibility of using a Hydraulic Workover (Snubbing) unit to perform the -thru-tubing operations concurrent with the continuing drilling activity. The study concluded that, with some custom designed handling equipment, a special tapered workstring and strict adherence to a permissible concurrent activity matrix, this approach was indeed feasible. The operation was performed in February 2001 and the well made available for production by the beginning of March. Throughout the workover operation the drilling rig sequence remained in accordance with plans, apart from a period of 14 hours downtime while moving the Snubbing unit into its working location.

This paper will review the problem encountered, the motive forces applicable, the feasibility study and the resultant custom designed equipment and workover operation. It will discuss on the integrated team approach and detailed planning, in which active participation from Petronas Carigali, the drilling contractor and several service companies resulted in a successful operation.
Computer Applications to Enhance Production Optimisation and Process Efficiency
Authors: Scott Claire E.
Published: December 2007

Even where production is largely constrained by gas demand through fixed contracts, revenue from hyrdocarbon liquid recovery can be maximised through optimisation of well production and process efficiency.

Significant improvement in oil and condensate recovery has been achieved at Shell Todd Oil Services Ltd (STOS) using computer applications developed within the Operating Company, focussing on value enhancement as well as cost reduction. Installation of PI (Plant Information) has been fundamental in the development of these user-friendly PC based tools.

KAOS (Kapuni Apportioned Optimisation Spreadsheet) combines thermodynamic understanding of the process with well characteristic data to form a non-linear optimisation tool in MS Excel. It is used successfully by field operators to optimise production by prioritising wells and predicting optimal operating conditions. An extension of this tool quantifies condensate deferment and loss caused by sub-optimal operation, to highlight improvement opportunities. The KAOS model also forms the foundation for a Dynamic Production Forecasting tool, currently being developed for condensate shipping and maintenance scheduling.

Data from PI is used to advantage in another MS Excel based tool developed to monitor efficiency of an offshore gas compression system on a continuous basis. The model brings together all process information, including ambient conditions, so that operations and interactions can be conceived in a way that was not possible before PI. A more intimate knowledge of the process has enabled enhancement of oil recovery through rationalisation of maintenance, improvement in plant performance and assurance of integrity.
Efficient Technology Application to Optimize Wellbore Placement of Horizontal Wells by Utilizing Reservoir Navigation System: Case Study
Authors: Al-Mubarak H. K. , Al-Faraj O. A. , Salamy S. P. , Al-Ali H. A.
Published: December 2007

Currently, horizontal wells in Saudi Aramco have been designed to improve recovery efficiency, to increase reservoir drainage area and to delay gas and water coning. Data transmission has utilized INSITE™ (Integrated System for Information and Technology Engineering) system to transmit real time drilling and well log data during the drilling of multi-lateral horizontal wells. Simply, the system transmits real time engineering data (Inclination, Azimuth, Depths and Well log) from the field to the desktop computer at the office.

The real time data transmition system enabled office staff to accomplish the following objectives: ➢Geo-steer the wellbore trajectory to the target reservoir➢Avoid reservoir faults and compartments in unknown areas➢Maximize wellbore length with a multi-lateral completion➢Save rig time by enhancing decision-making capability

This paper presents a case study of INSITE™ in difficult environments. The results show that this well was drilled in challenging environments and completed successfully as a multi-lateral producer. The results are discussed and recommendations made to improve the system for future applications.
Effect of Tool Joints on Contact Force and Axial Force Transfer in Horizontal Wellbores
Authors: Duman O. B. , Miska S. , Kuru E.
Published: December 2007

An experimental study has been conducted to investigate the effect of tool joints on the buckling/post-buckling behavior of drill pipes constrained in straight horizontal wellbores. Buckling/post-buckling behavior of drill pipes has been traditionally investigated using continuous pipes. To our knowledge, this is the first time that the effect of tool joints is included in such a study.

The University of Tulsa Drilling Research Projects experimental buckling facility has been used to carry out the desired experiments.

Axial loads at the both ends of the pipe and contact forces at the tool joints were measured. Change in drillpipe configuration was also investigated visually as the axial load increased.

Some of the new findings of this study can be summarized as follows: Sequential occurrence of buckling/post buckling configuration of jointed pipe is similar to that of continuous pipes that have been reported previously by various investigators. In other words, in both cases, the pipes buckle first laterally, and then helically as the axial compressive load increases.The presence of tool joints does not affect the critical lateral (sinusoidal) buckling load significantly. However, it increases the critical load causing helical pipe configuration (helical buckling) by about 20 %.Efficiency of the axial load transfer is improved by about 40 % with the tool joints.

Results of this study will help to improve the design of operational parameters for drilling with jointed pipes as well as using coiled tubing. In particular, improved axial load transfer performance would allow drillers to use higher weight on bit and consequently faster and possibly less costly drilling.
Expandable Tubular Technology in PDO – An Expandable Sand Screen Case History
Authors: Al -Shandoodi Majid , van Noort Roger
Published: December 2007

This paper outlines a short introduction of the status of the implementation of Expandable Tubular Technology in PDO in general and the job history of a short Expandable Sand Screen (ESS) installation in cased hole. It highlights the benefits of using ESS for such applications in terms of cost and production. This ESS installation also involved the first use of a modified section of a casing patch as a hanging mechanism.
Innovative Metal Seal Roller Cone Bit Cuts Drilling Costs in Abu Dhabi Onshore Fields by 42%
Authors: Shouman Atef H. , Hegab Mahmoud Sultan , Abdelshafy Osama M. , Zaki Mohsen
Published: December 2007

The positive economic impact of a metal bearing seal on roller cone bits used in conjunction with downhole motors and steerable systems in a Abu Dhabi Onshore fields has been dramatic. The metal seal has proven its ability to extend seal/bearing life of roller cone bits significantly (one million bit revolutions or 1000 krevs without seal failure are common) relative to elastomer sealed bits. This bearing, along with an improved cutting structure, has resulted in more on bottom drilling time.

The metal seal technology is especially useful when used on steerable motor assemblies. The bits have been successfully applied to kick-off from vertical and generally drill the 8-1/2" build section between 8°-14°/100 ft to the landing point at 90°, through interbedded formations ranging from soft shales to medium-hard limestones. Unconfined Compressive Strength varies from 5,000 psi to 15,000 psi. As the bits were applied throughout the region, the manufacturer used step changes to improve the cutting structure and hydraulics to further enhance bit performance and durability.

The authors will document significant cost reduction through improved bit performance in high-speed directional applications for the new metal bearing seal design compared to the best performing elastomer sealed bits. The study will include data from 386 bit runs totaling over 232,734 feet and 15,821 drilling hours documenting a decrease of 42% in cost per foot or a saving of US$3,836,400 over a three year period between April 1998 - March 2001.
Occupational Health Management - A Model for Success
Authors: Austin W. B. , Boelens P. R. M. , Dunkley N. R. T. , Al-Maskery K.
Published: December 2007

In 1997, an external review of the Company's occupational health management program found significant shortcomings that were not in line with the Company vision "to be recognized as one of the world's best E&P operators". Steps were taken to improve the management of occupational health within the Company and throughout its contractor workforce. This paper will describe the key elements of a successful model that has been developed and utilized. These key elements include a Driving Force, a Dedicated Team, a Deliberate Approach, Delivered Results, and a Dynamic Future.
Joint Safety Venture for HSE Management on Offshore Oil / Gas Installations
Authors: Gourh Ramesh C. , Chakraborty A B.
Published: December 2007

Joint Safety Venture (JSV) for the Health, Safety & Environment (HSE) management was formed by an operating company along with a contractor company for its common work sites to facilitate achieve the goal of loss prevention by controlling the accidental losses to people, product, process, property and environment. The other loss prevention steps undertaken were the development of safe and environment friendly practices, system development to solve problems related to common work areas, better compliance to HSE statutory regulations and sharing of HSE training and development program.

Both companies (A National oil company & an International oil field service provider company) that formed joint safety venture, had a working relationship in the oil field operations for the past 37 years and these companies were committed towards safety and environment protection, attached paramount importance to the HSE, for the long term sustainable business operations.

The scope of this paper covers in detail about the formation of joint safety venture (JSV) between the two leading companies, its genesis, issuance of charter statement, JSV organization, strategy adoption, setting objectives, preparation of plans, selection of activities, execution and monitoring methodology, performance parameters, planned visits to the work sites, management reviews, future development program and other steps for the continued involvement of all personnel.

The nature of the work undertaken by the JSV was targeted mainly towards the improvement in the HSE standards at work sites through the involvement of personnel, information sharing and experience. The functioning of JSV continued for nearly two years at the selected pilot sites that resulted in enhanced awareness, reduction in accidents, near misses, losses and better compliance to the rules and guidelines besides an overall satisfactory performance. The JSV is a new concept & trend towards information sharing, teamwork and mutual cooperation towards HSE management.

This paper deals primarily with the sharing of experience.
Low Back Pain: An on the Job Occupational Health Issue
Authors: Razavi Jalees K. , Cheng Jim
Published: December 2007

Low back pain (LBP) is the commonest cause of disability in persons under 46 years of age.1

LBP remains one of the most difficult challenges that face health care providers, as there are 9 important factors that compound the ability to manage, minimize the cost and predict its outcome: Low back pain is a symptom and not a disease yet it remains the commonest used term to describe the diagnosis.2Low back pain can be caused due to injury or disease process.2There are many diseases in systems other than musculo-skeletal systems that cause LBP.2Most types of back pain closely mimic each other.2Part of the problem is due to the fact that the region of the low back is extremely complex, both anatomically and functionally.3Another difficulty is the inability to objectively define a measurement for pain. 3A large part of the problem is the cultural need to medicalize LBP, linking the symptoms to radiological abnormalities requested by physicians. 2Physicians' insufficient understanding of the topic and its management leading to patient advocacy.2,3Poor medical results of occupationally related LBP in institutions unprepared to deal with this problem.2,3

Many psychological factors are thought to be causative in development, exacerbation and/or maintenance of chronic LBP.4
Deepwater Development Environmental Issues and Challenges
Authors: Armstrong L. J. , Jean P. , Puz G.
Published: December 2007

As the development of oil and gas moves into deeper waters, new environmental issues and challenges present themselves to oil companies. The environmental issues arise for several different reasons including: Technologies used in shallow waters are no longer adequate for water depths over 1000 meters. As a result, the environmental consequences of some of the newer deepwater technologies are not well understood. This requires the standard impact assessments for drilling, subsea production systems and FPSOs (Floating Production, Storage, and Offloading) vessels to be revisited.The environmental setting in deep water is very different than in shallow water. The deep ocean is poorly understood in terms of physical properties and their importance. Also, hydrocarbon seeps and thermal vents provide habitat for newly discovered or poorly understood benthic organisms. Pelagic organisms, similar to those found in shallow waters, may have adaptive modifications for deeper waters. Therefore, impacts to the environment need to be considered relative to these organisms.Water depth and distance from the coast present challenges for discharge management and emergency response. The routine discharges associated with oil operations can be different in the deepwater environment in terms of quantities and mixing. Unintended releases, such as oil spills, can provide new challenges for emergency response.

This paper provides a summary of the environmental issues and challenges identified during several deepwater projects, as well as issues identified and published by others world-wide. Ongoing research and proposed future research efforts are identified, where available.
Engineering and Operational Issues Associated with Commingled Drill Cuttings and Produced Water Re-injection Schemes
Authors: Hagan Joseph T. , Murray Laurence R. , Meling T. , Guo Quanxin , McLennan John D. , Abou-Sayed Ahmed S. , Kristiansen T. G.
Published: December 2007

Current BP Group Environmental Expectations of zero discharge of oilfield waste to the environment by 2005 and reduction in land-fill disposal options are driving the Company towards innovative disposal schemes that offer attractive and significant environmental and operational cost benefits. One of the current BP initiatives is to merge the synergies of both produced water and drilling cuttings into a single commingled re-injection scheme in the same well. Merging the two technologies for waste disposal in the same formation in the same well becomes a very attractive option, if the well can be engineered and completed to meet the specific objectives of disposing of large volumes of produced water and periodic disposal of drill cuttings from in-fill wells. The main advantages of such a disposal scheme are: Better assurance of fracture containment for disposal of oil-contaminated cuttings.Reduced cost of both operations because of fewer wells and reduced chemicals cost than would be required for separate drill cuttings and produced water disposal schemes.Potential recovery of disposal cost with secondary recovery, if suitable targets are available.

BP has successfully implemented commingled re-injection of produced water and drill cuttings in the Wytch Farm and Valhall fields. These commingled re-injection schemes were implemented to address urgent operational need to manage drill cuttings disposal when only water injector wells or producers were available. This paper addresses key engineering issues and risks, which are being evaluated as part of an ongoing BP project to develop engineering guidelines for commingled produced water (PWRI) and drill cuttings (DCRI) re-injection. The paper outlines synergies and differences in current DCRI and PWRI processes and the dominant parameters that are likely to control successful commingled re-injection process.
Health Integration into Upstream Operations and Business Systems
Authors: Zampello F. C. , Lindemann K. C.
Published: December 2007

Most companies today have adopted a systems approach to managing activities related to safety, health, and the environment. Corporate guidance is usually general in nature and business segments must elaborate on the requirements and focus efforts on particular risks or activities (or both). This paper describes how one company has developed a standard health management system to cover upstream operations; developed common procedures to meet system requirements, address anticipated risks, and establish consistent programs; and worked with the various business divisions to integrate system requirements and common procedures into established business operations.

The health management system is one of several standard upstream management systems. The primary objective of the health system is to prevent safety, health, and environment (SHE) incidents associated with health issues. The scope of the upstream health system addresses traditional work site occupational health "OH" risks (e.g., chemical and physical agents), public health risks and medical care delivery issues. Public health and medical care issues are key concerns for pre-production and new operations in remote locations or developing countries. The standard system contains three processes: (1) Managing Site Health Risks, (2) Managing Employee Health, and (3) Managing Primary and Emergency Medical Care.

This process includes hazard identification, risk assessment, control measures and communications and training as shown below.
Zero Tolerance Program to Enhance Safety Awareness During Well Services Jobs
Authors: Farooqui Mohammad A. , Saudi Mohamed M. , Al-Ghurairi Fadhel A. , Blanke Allen T.
Published: December 2007

Saudi Aramco has implemented a very successful and effective program to emphasize the awareness of safety during the increasingly complex rigless well services jobs in its maturing oil fields and during development activities in its new gas fields. The need for developing a structured approach to safe execution of field jobs was heightened due to increasing utilization of horizontal well completions that pose a higher risk and require greater logistical support during rigless jobs and the initiation of an aggressive deep gas development program

The objective of the Zero Tolerance Program is to complete all field jobs without incident, injury or loss of resources while maximizing benefits and gaining knowledge to sustain the process of continuous employee development.

The program comprises four basic elements: Human Resources Development.Planning.Safe and Effective Job Execution.Post-job Evaluation "Continued Excellence".

Although engineers generally follow various guidelines and procedures covered under these categories, the Zero Tolerance Program provides the advantage of putting these critical factors in a formal, structured document to ensure effective and consistent implementation.

The paper covers details of these elements and also discusses tracking and accountability procedures to ensure that the program is effectively implemented. An aggressive implementation campaign of this structured program among the field personnel has greatly enhanced the awareness of safety related issues during rigless well services operations in the field.
Improving HSE Performance by Management of Human Factors
Authors: Pipitsangchand Susama , Somta Pichet
Published: December 2007

Management of human factors is recognized as an essential role in the control of risk. Human factors cover a wide range of issues, which include the perceptual mental and physical capabilities of people and the interactions of individuals with their job and working environments, the influence of equipment and systems design on human performance, and the organizational characteristics that influence safety related behavior at work (1). At PTTEP statistics over a number of years were analyzed; the result showed that "human factors" was the root cause behind most accidents.

In order to improve human behavior, several schemes were introduced all aimed at increasing HSE awareness and consciousnesses of all personnel. These approaches included: HSE training improvement;Monthly HSE publication (HSE bulletin);Safety alert;HSE information board;HSE promotion campaigns such as monthly quiz, unsafe act / condition reporting campaign;HSE exhibition week;Contractor HSE forum; etc.

It is also a real challenge to assess the achievement of the above schemes. One of the assessment tools is the HSE awareness survey. A HSE awareness questionnaire was created. It is not only to evaluate the level of health, safety and environmental awareness of company personnel but also to provide a guideline for improving HSE promotion and communication of the company, as a result.

The HSE awareness survey results for the past 3 years showed that the level of HSE awareness progressively increased when comparing the results of 1998 with 2000. There was about 15% improvement. Whereas, the trend in the number of recordable incidents per million man-hours is steadily decreased. The 2000 results were nearly half of 1998.
Integrating Environmental Impact Evaluation into a Quality, Health, Safety and Environmental Management System
Authors: Sweeney Denis , Hughes John , Cockshell Dave
Published: December 2007

This paper presents a management tool, known as Environmentally Compliant Operations – Seismic Environmental Impact System (EcoSeis*), that monitors and assesses the environmental performance of land seismic activities and the subsequent integration of this management tool into a Quality, Health, Safety and Environmental Management System (qHSE-MS).

EcoSeis uses a process called "Goal Attainment Scaling," (GAS) which was developed in the 1960s and 1970s as a tool for monitoring and evaluation in the field of human services. This tool was adapted by the petroleum industry through collaboration between government—Primary Industries and Resources, South Australia (PIRSA)—industry and environmental interest groups.

EcoSeis provides a credible means for establishing environmental objectives that are relevant and appropriate to the activities being undertakena practical means for evaluating the level of attainment of those objectivesan independent means for assessing the performance of company management systems, from process and outcome perspectives.

The integration of EcoSeis into a QHSE-MS enables a mechanism whereby, should land seismic field activity fail to meet the desired criteria, appropriate prevention and mitigation measures are put in place.

This paper presents the results of such a process while conducting land seismic surveys in the arid dunefield and floodplain land systems in the South Australian sector of the Cooper basin situated in the northeastern corner of that state (Fig. 1). Results have shown that the integration of EcoSeis into a QHSE-MS provides the necessary loop closure to ensure the ongoing development of processes and techniques to reduce environmental impact.
Assessing the Effectiveness of a Corporate Driving Safety Program by Studying the Correlation between Frequency and Severity of Motor Vehicle Accidents and Compliance with Corporate Policy
Authors: Silverstone Mark
Published: December 2007

Our largest oilfield risk with respect to injury and loss of life is the motor vehicle accident. Consequently, some companies dedicate substantial resources to efforts to reduce these losses. Measuring the effectiveness of this use of resources is conventionally confined to analyzing the overall motor vehicle accident rate; however, this technique for monitoring effectiveness does not identify which specific parts of the driving risk management program might actually contribute to a reduction in accident rates, and how.

The objective of this work is to assess the efficacy of an oilfield service company's risk management strategies with respect to motor vehicle accidents. The strategies are summarized in the company's worldwide motor vehicle driving policy, which stipulates four principal requirements: use of seat belts, driver training, journey management and electronic driving performance monitors.

A total of 144 motor vehicle accidents in Venezuela were examined to determine compliance with these four policy requirements. The results indicate a reduction in the frequency and severity of "catastrophic," "major" and "serious" accidents with increasing compliance. No relationship seems to exist between compliance and "light" accidents. Furthermore, "catastrophic," "major" and "serious" accidents seem to be associated with particular noncompliance factors: lack of seat belt use in "catastrophic" accidents, lack of training and monitors in "major" accidents, and journey management of night driving in "serious" accidents.

Apparently, in order to reduce the frequency of "light" accidents and further reduce the rate of "catastrophic," "major" and "serious" accidents, implementing more policy features and increasing compliance with present policy may be necessary.
Public Health Tool Kits
Authors: Balge Marci Z. , Krieger Gary R.
Published: December 2007

Exploration and Production projects can potentially create adverse health impacts for workers and surrounding communities unless appropriate public health control programs are designed, implemented and monitored on an ongoing basis. These infectious disease control programs can be grouped based on potential source etiologies: respiratory (person-to-person), vector related, animal (rodents, snakes, food sanitation, water borne, blood borne and sexually transmitted diseases (STDs) or by preventive and protective measures: tsetse fly traps, chemoprophylaxis, impregnated bednets, universal precautions, immunizations, etc.
Incident and Accident Investigation – Methods and Lessons Learned in the Norwegian Oil and Gas Industry
Authors: Holmefjord Agathe , Nielsen Liv
Published: December 2007

Preventing the next accident is a key issue in high risk industries such as the Norwegian offshore oil and gas industry. During the last five years of the positive results in HSE performance on the Norwegian continental shelf has declined. Indicators of this negative trend are: –incident and accidents occurring in the offshore oil and gas industry in Norway have become more frequent and severe–the operators ability to prevent the next accident could be questioned, since several of these incidents and accidents have been reoccurring events

In this paper, concepts, theories and methods relevant to accident investigation in the petroleum industry will be shortly described. Theories and methods used in accident investigation in the Nordic nuclear industry will be presented. We learned that these methods worked also in an offshore context.
First Field Implementation of the Short-Trip Module: A Coiled Tubing Fatigue Reduction System
Authors: Zhou Wei , Cassee Udo , Radovan Rolovic
Published: December 2007

Prudhoe Bay Alaska is a mature oilfield where coiled tubing (CT) drilled sidetracks are the preferred method for gaining access to small reserves. For the CT drilling provider, and ultimately the client, the cost of the CT is a significant component of the overall operational cost and increasing the life of the working CT directly impacts operational economics.

A primary contributor to CT fatigue is plastic deformation. This occurs when the CT is spooled on and off the reel and also when it passes through the injector head. Both these events subject the CT to bending stress and any attempt to reduce the number of such cycles will increase the CT life. Particular operations such as window milling, stuck coil, drilling in open hole require the CT to be moved short distances in and out of the well which increase the number of CT fatigue cycles.

The Short-Trip Module (STM) has been developed to minimize fatigue peaks during these short movements. The system allows small (maximum 20 ft) CT movements in and out of the well without the need to turn the CT reel. This is done by keeping the CT reel stationary and letting the CT, between the reel and injector head, form a natural parabolic arch. Depending on the circulating pressure and CT movement schedule the fatigue can be reduced over 50% in CT fatigue life prediction model.

This paper will detail the theory and design of the STM as well as the issues of its integration onto a CT drilling unit.
Modified CT Limits Analysis for Practical Well Intervention Design
Authors: McSpadden A. , Newman K.
Published: December 2007

An alternative to the standard graphical presentation of CT operating limits is proposed in this paper to facilitate design of CT well interventions and to guide operational decisions in critical, at-risk procedures. Typical issues in intervention design include maximum safe overpull and maximum safe circulating and annular fluid pressures and the interplay between these parameters. However, CT job designers are sometimes unfamiliar with the interrelation between tension and fluid pressures. In particular, the relationship between surface weight and actual tubing stress is often overlooked. This interrelation can be explained and interpreted via the concepts of effective and real force. Based on a presentation of effective and real force, this paper proposes a graphical presentation of CT limits which references effective force, specifically surface weight. Using this modified stress graph, safe operating limits can be more clearly inferred from actual job parameters such as surface weight and pressure.
Shallow Gas Pilot for Coiled Tubing Drilling: A Case History
Authors: Bass Arvell , Staal B. J.
Published: December 2007

Coiled tubing drilling (CTD) has to date not yet evolved to be a worldwide, long lasting application, to be used on a daily basis, other than in places such like Alaska, Canada, and Venezuela. Locations with an extensive history and expertise of coiled tubing drilling. In these locations CTD has economical and technical advantages over conventional drilling operations.

However it seems that the drilling market in Argentina provided the right opportunities for another CTD operation. A plan was developed to drill thirty wells in the central part of Argentina, known as Golfo San Jorge.

This case history describes the set up of the project, drilling techniques used and difficulties experienced, lessons learned and the future of CTD in Argentina.
Improving the Performance of Coiled Tubing Underbalanced Horizontal Drilling Operations
Authors: Fraser R. G. , Ravensbergen J.
Published: December 2007

The paper will address the specific issues associated with underbalance horizontal drilling using two phase flow. Firstly, the challenges that were overcome in devising a ";safe"; method of deploying a directional drilling BHA into a live well will be presented together with a review of the deployment performance results from over a 100 different horizontal drilling operations.

Secondly, BHA performance issues associated with two-phase flow will be reviewed and results presented. This will include such issues as un-constrained vibration (encountered when the hole is not liquid full) and such effects as explosive decompression and the consequent reduction of elastomer performance.

Perhaps most important will be a discussion of the issues associated with cuttings transport in two phase flow and the methodology devised to reduce (and in many cases eliminate) wiper trips by varying the circulating conditions using a circulating valve incorporated into the BHA. Data from actual jobs will be presented to demonstrate how effective the process has become in regular field operations.

Lost time statistics for coiled tubing underbalanced drilling operations will be summarised and performance improvements highlighted.
Control and Monitoring Techniques of Miscible Gas Injection Project in the Furrial Field, Venezuela
Authors: Barreto Miguel , Itriago Luis , Millan Norelia
Published: December 2007

The Furrial field is the most important oil field in the East of Venezuela, with 6880 Millions Barrels of oil initial in place. The initial pressure is 11.000 psi at a depth of 13.800 ft and it has an average temperature of 298°F.

To prevent the pressure decline in the reservoir and avoid asphaltene precipitation problems, flank water injection (450 Mbwpd) project was implemented in 1992 and a miscible gas injection scheme initiated in 1998, in the crest of the Naricual Superior reservoir with seven wells injecting a total of 400 MMscfpd. The goal of these projects is to increase the final recovery from the field.

Due to the large thickness of the oil column (800 feet), considerable heterogeneity of the reservoir properties and large damage zones (high skin) observed in the producers and injectors wells, the gas-injectors exhibit channeling problems and decrease in injectivity. As a results premature breakthrough of gas in the producing wells is observed through sands of high permeability. This put risks to the oil production and the pressure maintenance program and limits the sweep efficiency of the displacement process.

In this paper, techniques and tools used to monitor and control the gas injection are presented. They are used to diagnostic and to correct the problems of injectivity losses and gas channeling problems. The techniques are: Control and monitoring at real time of main injection parameters such as heavy component (C3+) and water (H2O) content in the gas injection stream, pressure and temperature of injection stream, injection rates and opening size (%) of flow valve.Diagnostic: Flow logging tests, saturation logging tests, chromatographic analysis of produced gas and injection of chemical tracers.Preventive measures to eliminate channeling and low injectivity problems such as stepwise perforation, steam tube stimulation, improving gas conformance by applying Multigel, use of sand plugs, etc.

Finally, we will present the learned lessons and best practices of the miscible gas injection project in the hope it will serve as a world reference for similar projects.
Analytical Solutions for 1-D Countercurrent Imbibition in Water-Wet Media
Authors: Kashchiev Dimo , Firoozabadi Abbas
Published: December 2007

Analytical solutions for the initial stage of one-dimensional countercurrent flow of water and oil in porous media are presented. Expressions are obtained for the time dependence of the water saturation profile and the oil recovered during spontaneous countercurrent imbibition in rod-like, cylindrical and spherical cores for which water is the wetting liquid. Some of the analytical solutions are found to be in good agreement with existing numerical solutions and available experimental data for oil recovery from cores with strong water wettability.
Ultra-low Concentration Surfactants for Sandstone and Limestone Floods
Authors: Berger P. D. , Lee C. H.
Published: December 2007

A new type of surfactant has been developed that can be used at very low concentrations to produce ultra-low interfacial tensions (IFT) for sandstone and limestone formations. These surfactants can be used for Alkaline Surfactant Polymer (ASP) floods, surfactant floods and as an adjuvant for water floods. These new types of surfactants differ from traditional surfactants used in ASP and surfactant floods by offering the following advantages: Low concentration levels – They are effective at low concentration levels normally used for ASP but do not require alkali to produce low interfacial tensions in sandstone formations. For limestone formations, sodium carbonate is normally preferred to reduce adsorption however it is not needed to produce ultra-low IFTs.Salt tolerance – They are very salt tolerant. Case studies using this new type surfactant in brines with ~110,000 PPM total dissolved solids (TDS) and ~2500 PPM divalent cations show excellent interfacial tension lowering, even at 0.05% surfactant levels. The injection water does not need to be treated or softened, which can result in a tremendous cost saving for IOR applications.Emulsion, corrosion, and scale reduction – Problems such as emulsion formation, scale, corrosion, etc. are minimized because only low concentrations of surfactant are needed and alkali is not required to produce ultra-low interfacial tensions.

Examples and data using the new surfactants in both limestone and sandstone applications with various crude oils and brines are presented.
The Effect of Rock Surface Characteristics on Reservoir Wettability
Authors: Vijapurapu Chandra S. , Rao Dandina N. , Kun Lian
Published: December 2007

Significant strides have been made in recent years in gaining better understanding of the role of fluid compositions on reservoir wettability. However, our knowledge of the effects that the solid surface characteristics have on establishing and altering wettability is quite limited. This study examines the effect of rock mineralogy and surface roughness on wettability in rock-brine-hydrocarbon systems. The wettability is characterized by using two different techniques. The Wilhelmy plate technique has been used to obtain dynamic (advancing and receding) contact angles averaged over the surface area of the solid substrate used. These results are compared with point-values of dynamic contact angles measured using the dual-drop dual-crystal (DDDC) technique for both smooth and rough solid surfaces of different mineralogy and roughness. The surfaces have been characterized using an optical profilometer and Scanning Electron Microscopy. Fluids from the Yates reservoir in West Texas have been used. While the Wilhelmy Plate Technique displayed insensitivity, the DDDC Technique showed significant effects of mineralogy and roughness on dynamic contact angles.
Optimized Gas-Well Stimulating Using CO2-Miscible, Viscosified Hydrocarbon Fracturing Fluids
Authors: Taylor Robert , Khallad Abe , Cheng Alick , Barree Bob , Byrnes Jennifer , Kelly Karen , Conway Mike , Caufield Ray , Tourigny Sheri
Published: December 2007

The use of CO2-miscible, viscosified hydrocarbon fracturing fluids has been proven to be a very effective gas-well stimulation technique in Canada and the United States. Fluid recovery is enhanced after stimulation by this process. Anderson and Gruber presented the original concepts used in paper CIM 95-45, entitled "Carbonated Hydrocarbons for Improved Gas Well Fracturing Results." 1

This paper provides results of wells recently stimulated. Simplifications to the fluid and job design processes, and additional design considerations are introduced. New CO2 solubility data generated at 50°C, 85°C, and 120°C with 30%, 40%, and 50% CO2 in four different fracturing fluids are presented to provide a wider range of design data. Compositional data for a number of specialty fracturing fluids are introduced to illustrate their enhanced fluid-recovery capability compared to heavier fluids such as kerosene and diesel.
Testing for CO2 Sequestration and Enhanced Methane Production from Coal
Authors: Mavor Matthew J. , Gunter William D. , Robinson John R. , Law David H-S. , Gale John
Published: December 2007

The process of capturing CO2 from industrial point sources and storing it in geological formations is being evaluated to reduce the rate of accumulation of this greenhouse gas (GHG) in the atmosphere. Injection of CO2 into coal seams is one method of permanently storing CO2, which can accelerate coalbed methane production, offsetting the cost of sequestration. There is considerable risk both geologically and in the engineering design that can make the large investments required for sequestration uneconomic. This paper describes a program of successive pilots that can be used to determine the technical and economic feasibility of the process at a location of interest. The information is based upon experience gained by the Alberta Research Council during theoretical and field studies performed in Alberta Canada.
Estimating Gas Decline-Exponent Before Decline-Curve Analysis
Authors: Chen Her-Yuan , Teufel Lawrence W.
Published: December 2007

This paper presents simple and practical equations to estimate a priori the decline-exponent for decline-curve analysis of gas wells. The proposed equations are applicable for gas wells with closed boundaries and constant rock properties. Data required includes initial reservoir pressure, bottomhole flowing pressure, and fluid properties. These data are that required in a typical decline-curve analysis (i.e., no extra data is required). A field example is presented to verify the developed concept and to demonstrate the utility.
Comparison of Dimensionless Inflow Performance Relationships for Gas Wells
Authors: Trick Mona D. , Palmai Frank J. , Chase Robert W.
Published: December 2007

Dimensionless inflow performance relationships (IPRs) provide a method to model the sandface deliverability of gas wells when only data from a single drawdown or buildup test are available. This paper compares the predictions from 3 dimensionless IPRs (Mishra and Caudle1, Billiter and Lee2 and Chase and Alkandari3) with measured inflow performance coefficients from 4 point modified isochronal tests from 31 Alberta wells. The dimensionless IPRs from Mishra and Caudle1 and Chase and Alkandari3 closely match the predictions from measured inflow performance coefficients. Assuming that the n equals 1.0 overpredicts flow rate on average by 19%. The advantages of using the LIT equation (also known as laminar-inertial-turbulent, Houpert or Forchheimer equation) rather than the Rawlins- Schellhardt equation are discussed.
Use of Vogel Equation to Estimate Drainage-Area Static Pressure and Skin Factor
Authors: Parra Raul A. Medina
Published: December 2007

A mathematical adaptation of the Vogel correlation was developed to obtain the drainage-area average pressure (P̄) and the skin factor (s) values from multi-stabilized-rate (flow-after-flow) tests data. A methodology is presented to smooth, validate and compute the data of these tests. The analysis of a theoretical example is presented to show the application of the methodology. The proposed graphic method Pwf vs. J contributes to verify the applicability of Vogel model to a specific data set.