Wireline Well Tractor: Case Histories

Abstract

Abstract The wireline Well Tractor has in the North Sea area completed various wireline jobs in horizontal and extended reach deviated wells. The electric driven Well Tractor has made it possible to perform wireline operations in horizontal and deviated wells such as PLT jobs with surface read out, running of perforation guns, running of specialized tools, setting and pulling of plugs etc. Since March 1996 the Well Tractor has run numerous jobs on Statoils platforms in the North Sea and also jobs for other major oil companies in the North Sea area and North America. This paper describes the implementation of the Well Tractor technology. Logging, plug setting, perforating operations and fishing in wells with a horizontal section of more than 1600 meters are included in the case histories. Introduction The number of horizontal and extended reach wells worldwide is dramatically increasing. It is possible to drill and complete ERD, long horizontal and designer wells with no greater difficulty. However, when a requirement for intervention in these type of wells occurs and in particular for live well intervention, coiled tubing or snubbing operations have up to now been the only options. In many cases and particularly in wells with high well head pressure coiled tubing and snubbing operations are impractical and involve a large amount of costly equipment, personnel and rig time. Logistical problems, in particular for coiled tubing operations are evident, especially for ERD type wells as the coiled tubing reel weight often exceeds the platform crane capacity. The costs for these horizontal and deviated well intervention operations with coiled tubing or snubbing are excessive and in many cases operations such as production logging is simply not performed because of the costs involved. Development Phase Statoil has for the past three years focused on a strategy for reducing intervention costs. As a consequence of this Statoil decided to support and play an active role in the development, testing and implementation of a downhole tractor. Statoil as the head sponsor and Maritime Well Service as the co participating service company supported the development and manufacturing company Welltec. The co-operation and joint efforts of the three companies is the obvious reason for the success of the wireline Well Tractor project. Economical analyses performed in Statoil have revealed considerable cost savings when utilizing wireline tractors for electric line type operations vs. coiled tubing for the same type of operations. Further, it is expected that the market for production logging in ERD- and horizontal wells will increase due to the reduced intervention costs.