Subsea Template Lifting Operations in the Sea of Okhotsk

Abstract

Sea of Okhotsk is characterized by harsh environmental conditions. The navigation period lasts approximately 5 months (June – October). Sea ice starts to form in November with 0.8-1.1 m thickness. Vessel icing is possible from October. Note that there are many oil and gas fields in the Sakhalin offshore which means that marine installation operations should be performed. The area with possible subsea field developments will be considered in this project (Yuzhno-Kirinskoye field). The focus is on environmental conditions analysis (icing and sea description) as these are the most important for marine operations. We are not expected to carry out such operations when there is drifting sea ice. Kirinskoye field subsea manifold installation example will be introduced to define some parameters for subsea manifold (mass, dimensions). Basing on manifold parameters a vessel for lifting operations will be chosen. Calculations and analysis are based on the parameters of a particular typical vessel. Some discussions about lifting operations and environmental conditions standards (DNV) will be added. The weather window estimation process will be shown in this report. A probabilistic approach with Monte Carlo simulation will be used in calculations. It is important to know the probability of exceeding the operational limiting criteria value of wave height and icing rate. In the report relevant theory is included to perform calculations.