Structural Pile Grouting

Grouted pile sleeve connections for offshore structures

Foundocean’s involvement in structural grouting dates from the Umm Shaif and Zakum oil fields in the 1960s. This experience was transferred to the North Sea in the early 1970s for the installation of the BP Forties platforms. Since that time Foundocean have worked on the successful installation and grouting of numerous jacket and template structures in all producing areas of the world. Our comprehensive track record encompasses more than 275 structures and over 2,000 high strength structural sleeve connections.

To meet the high technical and performance specifications of offshore clients, Foundocean have developed their unique Continuous Recirculating Jet Mixers. These mixers are custom designed for producing very high strength grouts without the use of costly additives. Over a period of many years foundocean’s grout mixers have achieved a high level of consistency in their production of high strength grouts which as allowed platform designers to reduce the length of grouted pile-sleeve connections. This has resulted in substantial savings in fabrication costs.

Innovation in grout mixer design is an ongoing process at Foundocean. Recent improvements have included:

• Replacing nuclear density meters with accoustic gauges
• Fully automated mixing
• Reduction in the size of mixers to permit transportation in standard shipping containers 

Unlike standard grout mixers, which operate by mixing in batches, Foundocean’s mixers produce grout in a continuous process. This is achieved by recirculating the grout around a loop through a mixing pump, jet and tank. Cement and water  are added at a controlled rate and the  mixed grout is continuously removed to a holding tank from which it is pumped to the structure. The quality of the grout is constantly monitored by means of a density control system.
The grout mixer is just one component in the offshore grouting process. Successful and efficient offshore operations result from a combination of a wide range of skills and equipment including

• Detailed quality assurance and control procedures
• Offshore materials testing laboratories and skilled lab technicians
• High capacity grout pumps to deliver grout to the structure
• Hose winches capable of deploying grout hose to the deepest structures
• A cement silo fleet with a capacity in excess of 2000 tonnes
• Skilled and experienced engineers, operatives and mechanics
• ROV operated subsea grout connection systems
• ROV deployed grout density monitoring

Our involvement in offshore operations is not just limited to mixing and pumping cement grout. Foundocean will take responsibility for the entire grouting operation including inflation of grout seals, cement transfer activities, supervision of grout hose deployment and participation in offshore planning meetings.

Successful structural grouting relies on both experience and detailed preparation. Foundocean develops specific procedures for every project. These describe every detail of the grouting operation and provide contingency procedures to address all possible events. On completion of a project, detailed reports are provided covering all offshore operations and materials testing results.