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.
Real time" is the new buzz in the upstream petroleum industry. So far, operators at the lease locations have been the main users of real-time data measured at second or minute increments to manage wells and keep them on production. Engineers usually see only a subset of the data-the daily production volumes and rates, along with a few selected gauge-pressure and temperature readings. The engineers' access to limited data means that they typically see only the result-the production volumes-and not the high-frequency data that may be the reason for a certain production parameter (e.g., choke size, pressures, and temperatures).Supervisory control and data acquisition (SCADA) is the system that connects to the production facilities' controllers and data sources and collects the measured data and stores them in a database. Operators on the platform have direct access to these data and use this information to control the wells and the process equipment. If the engineers see these data at all, they usually get them through a Web-browser interface and in a format they cannot directly use for their analysis. This paper will introduce a new concept of integrating highfrequency real-time data to the oil company's business office, making those data available to engineering staff and operations management, even up to the senior management level. Each level of the organization sees as much of the high-frequency data as it needs or wants to see. The engineers and management have exactly the same view as the operators at the platform and at the same time. This might seem to be a problem at first, but in the long term, it is an empowerment of the operators and brings engineers and operators closer together by working as a team to manage the wells. The data also allow management to monitor the oil and gas production leaving the platform to see if the target business plan volumes are reached or if a well is shut in. This paper will give insights on how access to high-frequency data changed the way of doing the daily work and how it changed the way operators work together with engineers. (Note: All values in the figures within this paper are manipulated and do not necessarily represent reality).
fax 01-972-952-9435. AbstractA technological breakthrough in the well construction process was recently accomplished in the deepwater Gulf of Mexico. An 11-3/4" O.D. liner was successfully installed through a whipstock window cut into a 13-5/8" casing. It was the first documented attempt worldwide to run casing larger than 10-3/4" O.D. through a 13-5/8" window. The job's success can be attributed to thorough planning of well site operations and computer modeling of the proposed installation. The primary components of the planning activity included 1) analysis of available casing exit systems, 2) modeling of the bending and compressive loading on the 11-3/4" liner connections, and 3) detailed modeling of the drag expected during liner running operations both through the whipstock and into the deviated hole to total depth.
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.
The following will outline the Medusa Field development and completion design process highlighting an integrated approach between engineering disciplines and service providers to exploit the enormous amount of exploratory well data. The Medusa development, located in Mississippi Canyon blocks 538 and 582 offshore Louisiana, is a truss SPAR allowing for both dry tree production and multiple subsea tiebacks.A field overview from a geological and reservoir perspective, along with the drilling and field development considerations, will be summarized. The initial phase of the Medusa truss SPAR development includes ten compaction-tolerant FracPac completions in six dry-tree wellbores.Phase II wells included the drilling of two subsea tiebacks.One was drilled and deemed uneconomic while the second, Medusa North, was completed and tied back in early 2005. The paper will show how the information gathered during the drilling phase was applied to the completion design to ensure long-lasting, reliable and profitable wells. Introduction Design of deepwater completions requires a vast amount of planning and communication between all involved engineering disciplines. Bridging the gap between petrophysical, drilling, completions, and operations is imperative to obtaining project profitability through efficient, long-term and robust completions. Mechanical integrity is crucial to any completion design.Deepwater and subsea completions command very high production rates and can require fewer wellbores to develop a field.Add to this the high cost of well intervention and efficient, dependable wells with stacked pay horizons become the primary driver to economic deepwater Gulf of Mexico field development. The quality of a deepwater completion relies heavily on the proper use of reservoir data gathered during the drilling phase.Since it has a direct bearing on the efficiency of the completions, accurate analysis and use of this reservoir data must occur subsequent to the drilling phase.In particular, fluid samples, core samples, and logging data are all imperative. Field Overview The Medusa development, under Mississippi Canyon blocks 538/582 in the Gulf of Mexico, is about 100 miles south of New Orleans, Louisiana in about 2,200-ft of water (Fig. 1). The Medusa prospect originated from the drilling of two exploratory wells from a semi-submersible rig beginning in August 1999.These wells were sidetracked to further delineate the field and gather valuable core, fluid and logging data.Upon drilling of the discovery wells, an evaluation period followed in which economic decisions were made. Once field development was sanctioned, a development drilling program was initiated.Simultaneously, the design and fabrication of the truss SPAR production facility began. Medusa Field Development Timeline 08/99 - Spud Discovery Well 10/99 - Discovery Announced 05/00 - Delineation Drilling Complete 03/01 - Contract Awarded for Floating Production System 07/01 - Development Drilling Begins 03/02 - Development Drilling Complete 02/03 - Hull Installation 05/03 - Topsides Installation 07/03 - Topsides Commissioned 09/03 - Initial Completion 11/03 - First Oil The time from the end of the drilling phase to the commissioning of the production facility was used to analyze all available reservoir data and explore various completion techniques.From this analysis, mechanically sound, high-rate completions were designed and a reservoir depletion plan was developed to efficiently produce the hydrocarbon reserves from the multiple sands in the field.
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