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Abstract Wellbore obstructions are a common dilemma and typically must be removed as they can severely restrict a well’s production capability and have proven to be very costly. For instance, scale formation will eventually result in lower yields and well failure, while a fish left in a well can hamper future wellbore operations. The thru-tubing well intervention impact hammer was designed to dislodge fish or scale from a wellbore, by delivering an upward or downward impact force. The tool is activated by flow, in combination with compressive or tensile force, depending on the required impact. In operations that require bi-directional forces, both the single-acting up (SAU) and single- acting down (SAD) can be used concurrently on the same bottom-hole assembly (BHA). This paper describes the performance of "fluid activated impact hammers" for fishing operations. Case histories of recent field results are also discussed which illustrate the efficient removal of wellbore obstructions in deviated wells. This enables the well to be put back on production quickly and saves cost. The impact hammers are utilized in various applications, such as shifting sleeves, shearing pins, breaking disks, assisting with fishing operations and scale removal; in fact, any application where high frequency localized impacts are required. The tool’s impact force can be adjusted to accommodate the specific parameters of an operation. Its maximum capacity is up to 80,000 lb (36,000kg) per impact depending on tool size. The impact hammers enable operators to cost-effectively remove a wireline-retrievable packer (WRP), where conventional wireline techniques have failed and jars had proved impractical. The design allows adjustment of the impact force by manipulating the tension or compression weight on the tool. This maximizes operational efficiency, by enabling the impact hammer to function in numerous situations and the individual up and down hammer components enable the BHA design to accommodate specific jarring direction.
- Production and Well Operations > Well Intervention > Through tubing well intervention (0.70)
- Well Drilling > Wellbore Design > Wellbore integrity (0.68)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Inhibition and remediation of hydrates, scale, paraffin / wax and asphaltene (0.68)
- (3 more...)
Case History: Pilot Project With Coiled Tubing Drilling in Offshore South China Sea
Abdul Rahman, A. A. (PETRONAS Carigali Sdn. Bhd) | Hamzah, N. E. (PETRONAS Carigali Sdn. Bhd) | Ahmad Fauzi, N.. (PETRONAS Carigali Sdn. Bhd) | Safiin, N.. (PETRONAS Carigali Sdn. Bhd) | Khalid, M. Z. (PETRONAS Carigali Sdn. Bhd) | Syaifullah, N.. (PETRONAS Carigali Sdn. Bhd) | Jenie, J. R. (Schlumberger) | Hariry, H. E. (Schlumberger)
Abstract The sustained and relatively high value of oil and natural gas has resulted in an unprecedented level of drilling activity and implementation of innovative methods to recover as much hydrocarbon as possible, and as quickly as possible. The resulting demand for conventional drilling rigs for programs has forced the rates high and the availability low, making use of the units difficult to justify for use in declining fields with less significant amounts of recoverable product. The by-passed reserves remaining accessible in these depleted fields exist in volumes worthy of pursuit, but must be done economically. In many fields, operators, either intentionally or unintentionally, bypass pay zones during initial development by focusing only on the best zones. Accessing bypassed thinly laminated formations can be economically attractive but poses several challenges, especially due to aged platforms and completion string in place, also offshore environment is adding its own challenges. Coiled Tubing Drilling (CTD) has yet to establish itself in an offshore environment. Numerous one-off projects have been tried, but commitment was never made to a number of wells to see through the learning curve and realize the potential of the application. Offshore South China Sea have a huge quantity of candidates on existing installations, installations that, due to water depths and sub sea conditions require large, expensive rigs to drill or re-enter wells. Technically the wells can be accessed with coiled tubing with drilling parameters seen regularly in other projects. The challenges for this pilot project will be equipment specification and set up, efficiently exiting the casing, and management of wellbore stability in open hole drilling and completion techniques. The main objective of this pilot project is to bring proven technology to offshore environment to access small bypassed reserves economically and provide an alternative to conventional drilling. The well candidates were selected with strict work scope to avoid going beyond the regular CTD application to ensure learning curve and lessons learned can be implemented throughout the project and achieve the objective. This paper will described the preparation, execution, achievement and lessons learned from this 4 wells pilot project in offshore South China Sea.
- Asia > China (0.81)
- North America > United States > Texas (0.28)
- Oceania > Australia > Victoria > Bass Strait > Gippsland Basin (0.99)
- Europe > United Kingdom > North Sea (0.89)
- Europe > Norway > North Sea (0.89)
- (2 more...)
Abstract Today and industry wide, management of well integrity is a common issue, and relates to both old and new producing fields. It is apparent that many fields were not designed with the concept of 'well lifecycle management' and were probably constructed for a life of about 15 - 20 years. A producing well that is 30 years old is quite common (e.g. North Sea production started in 1975) and for wells in locations such as the Middle East some fields are more than 40 or 50 years old. In line with its expansion and transition to becoming a major independent oil company through its recent discoveries of very large oilfields in Ghana and Uganda, Tullow Oil needed to broaden its existing well integrity policy and practices. This is to fit with a projected 4 to 5 fold increase in oil production in the next few years and increase its well count to over 500 wells. In order to evaluate the processes in-place, the "Seven Pillars of Well Integrity Management" were defined as the fundamental requirements of an ideal system. These were used to identify gaps in existing practices which were systematically and thoroughly addressed by Tullow. Tullow now has one centralized well integrity management process that is described in detail through a company policy. This incorporates a software system to collect and manage key construction and operational data from all operated wells. Though monitored and audited from a corporate perspective, the integrity system is run by each asset to suit local operational demands and requirements. This paper documents the learning process that was experienced by Tullow in their path to deliver a company wide system that would suit varying production scenarios in four different operating environments, with a broad range of cultures and technical challenges and ultimately be expandable to suit the growth of the company.
- North America > United States (0.68)
- Europe > United Kingdom > North Sea (0.35)
- Europe > Norway > North Sea (0.25)
- (2 more...)
- Asia > Bangladesh > Block 9 Production Sharing Contract > Block 9 > Bangora Field (0.99)
- Africa > Ghana > Gulf of Guinea > Tano Basin > West Cape Three Points Block > Jubilee Field (0.99)
- Well Drilling > Wellbore Design > Wellbore integrity (1.00)
- Well Completion (1.00)
- Information Technology > Software (0.49)
- Information Technology > Communications (0.46)
- Information Technology > Artificial Intelligence > Machine Learning (0.34)
Abstract For successful delivery of Well Integrity, there needs to be an understanding of the risks that can cause undesirable events such as safety hazards or loss of containment. Performing a risk assessment on a well, or type of well, will help determine and rank the potential risks and provide information that allows limited resources to be applied in the most effective manner. The main objectives of performing a risk assessment include: Follow a formal process to assess risk consistently and to enable comparison between well barrier failure mode scenarios; Qualitatively assess well barrier failure risk for every segment of a well; Document suggestions that are offered by the risk assessment team for mitigating well barrier failure risk; and Provide a report of the methodology, failure mode scenarios, risk ranking, and potential mitigation actions for use as a reference tool for managing well integrity on a routine basis. The Well Integrity Risk Assessment Model follows a common qualitative risk assessment process; a team-based, structured brainstorming format, utilizing the What-If Methodology, to identify potential hazards associated with well barrier failure modes. In addition, the model has the following attributes: Incorporates a unique method to segment well barriers into discrete sections, successively "failing" each section for evaluation. The list of analyzed well barrier failure modes, along with their risk ranking, becomes the risk register for the well or type of well. Is adaptable for assessing well barrier failure modes on a single well, or a group of wells, having the same general design parameters. An entire well portfolio can be assessed quickly by analyzing types of wells rather than individual wells. Can be used to assess well barrier failure risk for any type of well. The model can easily be modified to conform to any company's risk model. The Well Integrity Risk Assessment Model has been proven to: Successfully assess well barrier failure risk for thousands of wells; Focus specifically on well barrier failure modes, and as a result is an effective tool that should be incorporated into a "Best in Class" Well Integrity Program; Be utilized as a management tool to provide guidance for how limited resources can be used effectively to continuously deliver well integrity.
- Well Drilling > Wellbore Design > Wellbore integrity (1.00)
- Well Completion > Well Integrity > Design for well integrity (1.00)
- Management > Risk Management and Decision-Making > Risk, uncertainty, and risk assessment (1.00)
- Health, Safety, Environment & Sustainability > Safety > Operational safety (1.00)
Abstract Well integrity management presents a wide variety of challenges for the industry today. With aging fields and more complex completion techniques coming into play, more efficient methods of well diagnostics and remediation are demanded. In the GOM, 45% of the wells have sustained casing pressure; therefore, the importance of having a resource that can provide an effective, accurate method of leak detection is abundantly clear. Typical methods of leak detection today include the use of spinners, temperature tools and noise logs. Mechanical means such as calipers and isolation packers are also employed. While effective for larger leaks, these methods can produce nebulous results with smaller leaks and can be time consuming. The frequency spectrum a leak produces is a function of differential pressure, leak magnitude, and leak geometry. These properties determine whether the frequency is audible, ultrasonic, or both. Typically, smaller volume leaks with a relatively high differential pressure will generate an ultrasonic signal. Based on this premise, an ultrasonic logging tool was developed and proven that detects frequency spectrums typically produced by leaks. The tool has a series of band pass filters which remove virtually all audible noise associated with tool movement, allowing continuous logging. Because ultrasonic energy will pass through compressed gas and steel, the tool can detect leaks in secondary barriers as well. Further, as ultrasonic energy attenuates quickly, the tool locates leaks with a high degree of accuracy. Using this tool, leaks as small as 0.005 gpm have been quickly located with an accuracy of a foot or less. This paper will describe a down-hole ultrasonic leak detection tool and provide case histories of where the ultrasonic leak detection tool was used to find leaks that other methods were unable to locate. A comparison of the results from conventional leak detection methods will be discussed as well.
Abstract Pressure activated sealant was used to repair casing leaks in two Prudhoe Bay, Alaska oil wells without the use of a rig workover. The significance of the treatments, development of job screening criteria, and job planning and execution are reviewed. Production casing leaks are a frequent problem in mature oil fields, particularly where there is corrosion. Wells with casing leaks usually do not meet well operating criteria so they must be shut-in, causing a loss in valuable production. Casing leaks normally require a rig workover to repair since the tubing often has to be removed. Rig workovers are very expensive in offshore locations, remote areas, and harsh climates. Special pressure activated sealants, diagnostic tools, and treatment techniques have been developed to find and repair casing leaks without removing the tubing. Case studies of three Prudhoe Bay production wells describe how pressure activated sealant successfully repaired the small casing leaks in two wells without removing the tubing. The third well was not treated because it did not meet the screening criteria. One case study was unusual because the sealant fixed four deep casing leaks with one treatment. The case studies show how refinements in diagnostic techniques, candidate screening, and treatment planning and execution have resulted in the successful application of pressure activated sealant to repairing casing leaks in producing wells and in one case repaired four leaks with one treatment. Using pressure activated sealant to repair casing leaks can result in significant cost savings and return wells to production sooner. The treatment can be particularly useful in mature fields with corrosion problems and in offshore, remote, and arctic fields where rig workovers are expensive and rig availability is limited. Introduction Repairing casing leaks is one of the more challenging issues facing operators of mature oil and gas fields. Casing leaks are a frequent problem in mature oil fields, particularly where there is corrosion. Wells with casing leaks usually do not meet well operating criteria so they must be shut-in, deferring and possibly causing a loss in valuable production. Casing leaks normally require a rig workover to repair since the tubing has to be removed. Rig workovers are very expensive and are often time consuming in offshore locations, remote areas, or harsh climates. Also, the repair usually requires cement or other solidifying material pumped into the "A" annulus. This can make future workovers and other well operations difficult and impractical.
- Well Drilling > Wellbore Design > Wellbore integrity (1.00)
- Well Drilling > Casing and Cementing (1.00)