Today's need to provide deepwater subsea well servicing has created many new challenges for the industry. For example, pulling a deepwater subsea wellhead or crown plug can require an extreme pulling force. The difficulties experienced can be compounded by conditions when the plug has been in place for extended periods of time as well as the more demanding deepwater conditions, such as high differential forces and settlement on top of the plug that contribute to the need for the higher pulling forces. These conditions often exceed the capabilities of conventional slickline services. As exploration continues to venture into more challenging environments, service companies have had to increase the scope of capabilities of their equipment to meet the challenges brought about by the new environments that require capability for tools to pull high tensile loads. The deepwater subsea arena has been particularly challenging, and this paper will focus on a slickline innovation ? an extended-stroke electro mechanical device ? that can provide deepwater subsea well interventions more cost-effectively than other service alternatives. The tool is a slickline-deployed electro-mechanical device that is operated by batteries rather than explosives or hydrostatic pressurized tools and can produce a high linear pulling force. Since first being introduced, the electro-mechanical device has undergone several changes that have increased its capabilities and functionality. For example, it has recently been configured for pulling subsea wellhead plugs. This paper will present three case histories that discuss the first use of the ‘extended stroke’ electro mechanical device in the Gulf of Mexico in which it was capable of pulling plugs at a water depth of 5,339 feet as well as several subsequent case histories. Using the slickline electro-mechanical device rather than coiled-tubing resulted in substantial savings in both the cost of deployment and rig time. Introduction Subsea well intervention can be costly when one considers that the first task often required is to pull the subsea crown plugs in the wellhead. The hydrostatic pressure associated with the fluid in the riser creates the large pressure differential across the wellhead plugs that seal the cross sectional area. Conventional slickline services have limited constant pulling force due to the finite strength limits of the wire. Deepwater and debris above wellhead plugs often compound the required pulling force because of the additional hydrostatic pressure across the plugs. These forces are well above the tensile-strength limit of slickline wire. A subsea wellhead plug requires a steady pull along the entire length of the seal bore as it is withdrawn. Conventional slickline is limited to creating extremely high but short-duration impact loads; however, brief impact loads are not suitable for unseating subsea wellhead plugs, because they have a tendency to reseat after each impact load and are forced back on seat by hydrostatic pressure from above. Therefore, using mechanical or hydraulic jars to simplify the delivered force does not effectively retrieve the plug from the wellhead. When conventional slickline service is not capable of pulling a subsea wellhead plug, coiled tubing service methods may be used. However, the cost of the service can be compromised significantly because of the additional deployment time, rig up time, and additional tripping time required. Since slickline is usually considered to be the most economical method for well intervention, the need for a system that could pull subsea well head plugs using slickline became more apparent.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe ongoing need for greater operational cost efficiency has encouraged oil companies to seek new methods that can simplify completion processes and reduce the number of required well interventions. This focus has resulted in new challenges for engineering/manufacturing and service companies to develop multi-functional equipment. To meet the challenges, a new generation of completion equipment with capabilities that would have been considered impossible ten years ago has been introduced to the oilfield. This equipment has been designed to not only reduce the number of interventions normally required in traditional completion scenarios but also to meet challenges of safety and reliability that can surpass the cost of contingency measures should the product fail.The development of one such device, the "disappearing plug," which serves as a plugging device for setting a hydraulic-type packer, will be the focus of this paper. When run in with the completion, the tubing will fill automatically through an auto-fill device, and then, will close during one of the pressure cycles. The fluid-expendable plug material disintegrates on the last pressure cycle, which allows fulltubing-drift production and eliminates the need for a slickline or coiled-tubing run to retrieve a plugging device as would be the case with conventional methods.While the industry average for successful installation of interventionless devices has still not reached the sought-after 100% reliability, when these concepts have been successful, the expected economic job goals have been surpassed. When successful in offshore, horizontal, and/or high angle wells where slickline or coiled tubing intervention after completion is significantly more costly, these interventionless technologies have proven to be even more beneficial.The paper will discuss development of the plug, some of the failures that occurred, how these difficulties were addressed, and finally, will discuss several recently run installations. These clearly show the extent of the economic benefit that can be realized.Disappearing plug technology currently improves economics by eliminating the need for slickline and coiledtubing interventions in plugging operations. When setting hydraulic packers, this not only reduces operating costs but also the risks associated with interventions and plug failures. One of its most significant contributions, however, becomes apparent when considering the future trends of the industryinterventionless and intelligent well technologies.The disappearing plug will undoubtedly play an important role in the actualization of these future well trends.

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The ongoing need for greater operational cost efficiency has encouraged oil companies to seek new methods that can simplify completion processes and reduce the number of required well interventions. This focus has resulted in new challenges for engineering/manufacturing and service companies to develop multi-functional equipment. To meet these challenges, a new generation of completion equipment with capabilities that would have been considered impossible ten years ago has been introduced to the oilfield. This equipment has been designed to not only reduce the number of interventions normally required in traditional completion scenarios but also to meet challenges of safety and reliability that can surpass the cost of contingency measures should the product fail. The development of one such device, the "disappearing plug," which serves as a plugging device for setting a hydraulic-type packer, will be the focus of this paper. When run in with the completion, the tubing will fill automatically through an auto-fill device, and then, will close during one of the pressure cycles. The fluid-expendable plug material disintegrates on the last pressure cycle, which allows full-tubing-drift production and eliminates the need for a slickline or coiled-tubing run to retrieve a plugging device as would be the case with conventional methods. While the industry average for successful installation of interventionless devices has still not reached the sought-after 100% reliability, when these concepts have been successful, the expected economic job goals have been surpassed.When successful in offshore, horizontal, and/or high angle wells where slickline or coiled tubing intervention after completion is significantly more costly, these interventionless technologies have proven to be even more beneficial. The paper will discuss development of the plug, some of the failures that occurred, how these difficulties were addressed, and finally, will discuss several recently run installations. These clearly show the extent of the economic benefit that can be realized. Disappearing plug technology currently improves economics by eliminating the need for slickline and coiled-tubing interventions in plugging operations. When setting hydraulic packers, this not only reduces operating costs but also the risks associated with interventions and plug failures. One of its most significant contributions, however, becomes apparent when considering the future trends of the industry—interventionless and intelligent well technologies. The disappearing plug will undoubtedly play an important role in the actualization of these future well trends. Introduction For many years, the oil industry has sought out ways to incorporate new completion devices that do not require intervention to complete the well.1,2,3,4 Minimizing or eliminating this need can reduce completion and operating costs significantly, particularly in offshore, high-angle, and horizontal completions where slickline or coiled-tubing intervention are often more costly and pose greater operational risks. Developing interventionless devices that can overcome adverse well conditions has presented many challenges, and thus, the devices usually have been limited to single-function operation. Most of them are mechanical in design but limited-life, battery-operated electronic components are often included in the designs. The mechanical devices are generally controlled with hydrostatic pressure and applied pressure pulses from the surface. Acoustic and electro-magnetic actuation techniques have also been explored for manipulating these devices.

A process for the removal (and recovery) of vanadium from carbonate leach solution has been developedo PbSO. is used to precipitate vanadium and is regenerated by treating the lead vanadate precipitate with H_SO, , Vanadium concentration can be reduced to any desired levels or removed completely^ with essentially no carbonate or uranixim losses, RpSO. is the only reagent consumed making the process superior to FeSOi precipitation of vanadium on an economic as well as efficiency basis. The removal of vanadium from carbonate leach solutions improves the efficiency and economics of subsequent uranium recovery process. An economic evaluation compares the lead vanadate-caustic process with other possible processes for recovery of uranium and vanadiTjm from carbonate leach solutions»