Four Types Of Offshore Structures

Introduction

Offshore structures are huge steel or concrete structures that are used for the exploration and extraction of oil and gas from the earth’s crust (Sadeghi, 2007). Offshore structures have always been an integral part of the oil and gas industry. In fact, most of them have been rampantly developed over the last three to four decades driven by the need to exploit deeper water. With the depletion of easy-to-reach fields in shallow water and the ever growing demand for oil and gas, offshore structures have slowly evolved into many different types. Most of the offshore structures today are designed not only to accommodate different environments, speeding up design, fabrication and installation, but most importantly to minimize costs

Both of these categories have their own sub-categories, each with their own advantages and disadvantages. However, subsea completions which are placed on the seafloor to support equipment are not considered to be a part of the offshore structures in generally accepted use of the term (Frieze, 2001).

According to John (2014), generally, there are four types of fixed structures and four types of floating structures. Some company may classify some types of floating structures into articulated structure, however such classification is not commonly

The main advantage of FPSO is that it is a standalone structure that does not need external infrastructure such as pipelines or storage. The offloading of crude oil to a shuttle tanker is done at regular intervals which range from days to weeks, subject to the production and storage capacity of the FPSO. Not only that, FPSO can also be used to explore marginal wells in deep water where fixed platform is not feasible.

According to Miller (2001), FPSO is known for its low construction cost because of the minimal infrastructure required. The FPSO is also reusable. In addition to that, FPSO’s quick disconnect capability enables it to be used in iceberg prone areas. However, FPSO also has several drawbacks which includes low deck load capacity and little storage capability. It also has poor stability in rough seas and may experience damage to risers due to motion.

The cost of operation of offshore