RIASSUNTO
Abstract
Traditionally, when wells in extreme environments required service, slickline, which had always been considered as the most cost-effective service option, was unable to provide the services because the available slickline tool options could not maintain integrity in the extreme well environments now being explored and developed. To address the requirements of the new scope of conditions in extreme environments, new methods that would meet a greater scope of needs were developed. The innovations include prejob wire-tension-modeling software and a state-of-the-art timed-release tool that provides successful intervention in difficult scenarios that normally could not have been considered as slickline candidates.
This paper will discuss these developments and how they have enabled slickline to be a more cost-efficient alternative for the operations that had to be performed by other service options when intervention was required in extreme depths or in or highly deviated wells.
A tool that can be timed to release the wire from the tool string at the rope socket without surface intervention has been developed to reduce the risks associated with stuck strings and dropping of conventional wire cutters. In addition, pre-job wire-tension modeling software is now available. How the newly developed slickline techniques can be used to mitigate the risks associated with the challenges created by the extremely deep and highly deviated wells will be discussed along with the enhanced cost efficiency and safety provided by these innovations. Implementation of the smart-release tool into the tool string will also be discussed.
Introduction
Ultra deep and highly deviated wells have created many challenges when wells require slickline services. Because of the depths and deviations now being attempted, service questions have surfaced as to the capabilities of slickline to perform adequately in the more extreme environments. There are many issues that have been raised along with questions, such as:
1. Can the tool string reach target and be pulled out?
2. Can work be performed at the target depth?
3. What happens if a tool string becomes stuck in a deep or deviated well bore?
4. How can the tool string be released at the rope socket to prevent costly fishing operations?
5. Can the entire length of wire be successfully recovered, if the tool string becomes stuck?
6. Might deviations prevent conventional wire-cutting tools from successfully cutting the wire when necessary?
This paper discusses the new methods and tools that were designed to address the challenges mentioned above, since the primary needs for any operation are to reduce non-productive time and operating costs as much as possible.
History of Slickline Capabilities in the Oilfield
Slickline well intervention has been the industry's basic low-cost well intervention service for many years (Larimore et al., 1997a; Larimore et al.; 1996; Larimore et al.; 1997b; Foster et al., 2001). Until recently, well intervention conducted on slickline was limited to mechanical surface-wire manipulation of downhole tools. As battery technology and packaging of electronic equipment were improved, the technologies were adapted to electromechanical slickline tools (Gazda et al., 1995; McDaniel et al., 2008; Goiffon, J., 1996; Gazda et al., 1995)
Another limitation for slickline service for many years has been the concept that slickline intervention was applicable to vertical or near vertical wells only. Therefore, wells with depths greater than 15,000 feet and deviations greater than 70 degrees were believed to exceed the capability of slickline well intervention.