Drilling jack-up response to the diverse air gaps

Abstract

The continues rapid demand rise and subsequently prices in the world, encourage the oil and gas industries to produce excessively, to achieve to this purpose, new wells will be dug and old ones will be worked over, the process of performing major maintenance or remedial treatments on an oil or gas well. Various statistical reports indicate that at least 30% of oil and gas wells have been dug by jack-up, showing its importance in the process of oil extraction. Due to the existence of severe storm or harsh conditions, they are subjected to combined loads, waves, wind, current, mission loads and weights. In addition to the specifics of the environment, the magnitude and proportion of these loads are a function of the water depth, air gap (i.e., the distance between the water line and the hull baseline) and the distance the footings penetrate into the seabed. The purpose of this paper is to describe jack-up response, subjected to the combined loads with different air gaps distances. In order to achieve this goal, widely recommended air gaps, are modeled in some well-known commercial software packages based on valid references such as SNAME, DNV codes, GL rules and MODU. Finally, the effect of different air gaps on the stiffness of the jack-up is investigated. All present findings can be served as benchmark data for engineers to accurately model their jack-up structures in the future. © 2011, Advanced Engineering Solutions.