RIASSUNTO
Abstract
In these times of record operating costs, stakeholders place paramount importance on avoiding unnecessary, unproductive trips in the well. In well intervention applications such as milling, cutting, washing over and casing exit work, the lack of accurate information about downhole conditions often leads to wasted time and money.
As wells become deeper, more tortuous and technically challenging to intervene, the need to know more about what is actually occurring at the downhole tools becomes even more critical. Traditional surface-based indicators and gauges often provide inaccurate readings of the forces exerted at and around downhole tools.
This paper discusses a new, MWD-style ""smart?? intervention performance sub that contains a variety of sensors and electronics that gather critical downhole measurements and transmit them to surface. The smart tool affords the operator a completely new level of control with real-time decision-making capabilities that can lead to more efficient and reliable wellbore intervention jobs and significantly reduce operators' risk exposure.
The paper will describe the smart tool and present several case histories where the smart intervention performance sub was integrated into well intervention bottomhole assemblies. Data from the smart tool was then transmitted using mud pulse telemetry and viewed at surface. The same data was also transmitted onshore to a real-time operating center, thus allowing a broader audience of experts to witness the early field trial applications.
The field trials verified several capabilities. Vacuum filter operation could be observed in real time, casing windows could be quantified with a window quality indicator, lightweight fish could be identified in real time at the bottom of deep, deviated wells, and packer setting forces and overpull could be accurately monitored downhole in a variety of depths and deviations. This summarizes the capabilities explored during deepwater system integration tests.
Introduction
Well intervention jobs are specialized, often critical, operations performed by experienced and well-trained tool experts. The more critical the operation, the more accurate this statement, and never more so than when conducting casing exit and fishing operations such as multilateral (ML) junction creation, milling, cutting, and washing over. Complex well intervention operations of a critical nature bring with them an inherent element of risk. The nature of this particular risk is that unseen sub-surface conditions and events can manifest themselves as unplanned non-productive time (NPT) with potentially severe consequences for fiscal prudence.
Well intervention operations cover a huge expanse of well and rig activities. The processes and techniques discussed here, however, are not yet sufficiently advanced to be applied across the whole gamut of operations, so in the context of this paper, the term ""well intervention?? will apply to workover systems; fishing and milling, including packer setting and recovery; casing exit systems [sidetracking or junction creation], and wellbore cleanup.
Well intervention operations are traditionally performed using surface-acquired parameter measurements such as RPM and hook load; complemented by a tool expert's sense of feel and anticipation. It is well known that the industry is entering a period where such experience is becoming scarce. These factors, combined with ever-increasing well reach and complexity, act to increase the risk to wellbores. Drilling, on the other hand, has benefited from new technologies that optimize complex well construction to the extent that, compared to only a few decades ago, drilling operations have evolved into highly efficient and predictable processes. It is this drilling optimization technology that has been adapted to form the basis of a new smart intervention system that boosts performance by allowing downhole parameters to be displayed at surface to enable real-time decision-making and full process optimization in well intervention operations.