Nowadays major drilling and production facilities are located offshore, so to install this equipment the oil and gas industry majorly reply on an efficient and safe way. The industry has developed a number of ways to overcome heavy lift challenges offshore through experience and innovation.
There are two main methods of marine installation of heavy equipment. The conventional way to install major facilities, such as topsides and production equipment, is through lift barges, while the other method which is gaining acceptance in offshore installation is the floatover method. Additionally, there are new techniques for performing heavy lift operations which are being developed.
1. Offshore installation – Lift Barges
For past many years, heavy lift cranes have been deployed in offshore oil and gas fields for installation purposes. Heavy-lift barges are used to both transport the equipment offshore and lift it into place via powerful cranes.
For ease of installation and to use smaller capacity of crane, major marine installations can be divided into modular lifts. For example, a processing facility can be fabricated in multiple modules that are then installed offshore one by one as per the construction planning and scheduling.
2. Offishore installation – Floatover Installation
As the floatover technology is both time- and cost-efficient it is gaining popularity in today offshore industry. Floatover installation through semisubmersible vessels is a viable option for marine installation operations. A vessel with a hydraulic pumping system is employed for this method of marine installation that allows the vessel to submerge itself under the water, and then reemerge.
Floatover marine installation allows onshore mating of equipment, and further transporting the equipment to location, as well as installing it. Here, the semisubmersible vessel floats into place and takes on water to partially descend under water. The equipment is lowered into place and installed, and the vessel then floats out from under it. Then, hydraulic pumps drive the water out of the vessel, which reemerges from the water.
Source: rigzon, worldoil websites.