Objective
The objective of the project is to develop a Wireline Unit for servicing and maintenance operations of subsea wellheads.
The wireline unit shall be operated from smaller sized surface support vessels and the system will reduce the need for standard workover riser systems operated from heavy drilling rigs.
A system supported by small vessels will not only lead to cost savings as a result of a considerable reduction in mobilization/demobilization time, but as more vessels are available in this category wireline operations can be planned on shorter notice thus reducing the production loss period.
A report covering the work in Phase 1 was released in December 1988. This report describes the different stages in the development of the design concept from the first to the final chosen scheme. The conclusion of the work is that the most economical and simple solution is a subsea winch placed on the lubricator directly exposed to sea water. The seal between winch and lubricator is a stuffing box. The novelty of the approach is the remotely controlled winch placed on top of the lubricator.
A conceptual design report was released in August 1990. This report comprises the background for the system layout. As a result position of the top of the system to a horizontal position at the base of the system close to the wellhead.
The spooling system has been designed to operate submerged in sea water both taking corrosion problems and additional hydrodynamic loadings as moving parts into account.
Sea water is used as lubrication in most of the moving parts of the system. Due to not harmonized environmental restrictions in the Member States of the EEC the lubrication system had to be designed with no use of bearing containing asbestos.
It is the intention of this project to develop and test a Subsea Wireline Unit. In doing this we will break away from the present trend of routing the wirelines from the ship through a stuffing box to the tubing. Instead the system will consist of the following components :
1) A subsea wireline unit which contains winches and control system for wireline operations. This unit will be landed on the subsea christmas tree (after the tree cap has been removed). The unit is fully capable of sustaining the well pressures.
2) From this position wireline operations in the tubing can take place under full well pressure by remote control from the support vessel via an umbilical. Once connected to the top of the x-mas tree and made ready for operation, wireline services can be performed unaffected by surface weather conditions.
As the wireline winch is a part of the Subsea Wireline Unit, relevant wireline tools/equipment required for the actual downhole work to be performed, have to be hooked-up/connected to the wireline itsself and loaded into the Subsea Wireline Unit prior to launching the complete system.
A prototype of the unit will be designed, procured and assembled by the project group. Fabrication of certain items will be subcontracted to relevant shops and suppliers based on tendering. The testing will be made by the project group at selected test sites.
Programme(s)
Topic(s)
Call for proposal
Data not availableFunding Scheme
DEM - Demonstration contractsCoordinator
2900 Hellerup
Denmark