Research on active heave compensation for offshore rig

Drilling on the ocean is very different form on the land, in this process, the drilling platform is floating in the form fluctuations on the ocean, and the carrying drill bit is in the depth of several kilometers of undersea drilling. Ocean drilling platform floating on the action of the wave, produce heave up and down movement, the position of the drill bit at the bottom of the hole will change with this movement, have a significant impact for drilling activities and equipment. Therefore, in order to ensure the normal use of offshore drilling, we must heave compensation system to improve drilling efficiency and safety, and extend the service life of drilling equipments. This article brings in a new heave compensation system on the basis of the winch, describes how the system works and the idea of compensating controls. We design the controller with the use of fuzzy-PI control algorithm. It combines the advantages of the fuzzy control rules and the conventional PI controller. Do not need to establish a precise mathematical model of the controlled object, and the parameters can be self-tuning. The results of experiment show that the control strategy can efficient compensate the displacement which caused by the wave, and has the advantages of high control precision, fast response.