Delft University of Technology
Faculty Mechanical, Maritime and Materials Engineering Transport Technology
P.M. Meijer Conceptual design of a new riser joint handling system
Masters thesis, Report 2007.TEL.7144, Transport Engineering and Logistics.
A riser string is a pipe connection between the top of the drilling hole and the drill ship. A riser string is used in the drilling process on a drill ship to return drilling mud to the drill ship and to support the drill pipe. Building the riser string is a time consuming operation because it consists of about 140 heavy elements. Because the first steps in the drilling process are done without a riser string, this time could be used to build the riser string parallel (simultaneously) to the first drilling steps.
The object of this assignment is to design a riser handling system, which can operate parallel to the drilling process. Other requirements are: 1. A significant shorter processing time.
2. Significant lower costs compared to the alternative for the system. The alternative is to build a complete second drilling derrick (drilling tower) beside the existing drilling derrick.
The design process started by splitting the total process into different functions. The most important function is the movement of the riser joint from horizontal to vertical position.
For the erecting function there are four feasible solutions left. 1. By an hinged arm
2. By a track
3. By a hinged arm driven by pushing it down on one side 4. In the conventional way
With use of the morphologic scheme six complete concepts are developed and evaluated. The best three concepts are:
1. The first system uses the conventional way to erect the riser joint and also has a rotating buffer frame. This frame enables the system to erect a riser joint on the front side and lowering the whole string on the other side of the frame. This decreases the process time significant.
2. The second concept uses a simple beam with hydraulic cylinders attached. These cylinders lower the total riser string. The beam can grip a riser joint and is erected using a small winch.
3. The last concept uses a track through which the riser joint is moved on a spreader. The tracks have a dedicated shape to enable the spreader to erect the riser joint, stab the connection and lower the whole riser string.
The last concept is considered as most promising, because of the combination of the following issues: 1. It is a reliable design
2. The costs are low 3. The process time is low
Finally general design calculations are done on the main parts of the track concept. The concept doesn't have any constructive problems, although in a certain position of the spreader getting stuck could be a problem. This is solved by applying an extra force in the direction of movement, by means of a winch.
Reports on Transport Engineering and Logistics (in Dutch)
