| dc.description.abstract | As more attention is paid to the exploration and production of oil and gas resources offshore, Russian companies keep looking for new fields to increase the hydrocarbons production in the Arctic. The development of the Silurian and Lower Devonian age deposits is the next step to increase the profitability of the IRGBS (Ice Resistant Gravity Based Structure) Prirazlomnaya, the first project in the Russian Arctic. Silurian and Devonian deposits underlay below the production deposits (Permian age), the depth of deposits varies from 4 to 6 km, the optimal drilling site is located about 2—3 km from IRGBS Prirazlomnaya. The exploratory well PH-5 stopped drilling on the depth 4460 m because of the ice conditions. According to exploratory drilling, the Silurian and Lower Devonian age deposits are characterized by high pressure and high temperature (HPHT). In the present moment, the project of developing Silurian and Lower Devonian deposits is on the pre-feed studying. There are 3 ways to develop deposits: to drill and produce oil from the IRGBS Prirazlomnaya, to install a mini—platform or to use subsea production systems with tie—in to the platform.
The basic concept is to drill and develop deposits from the IRGBS Prirazlomnaya. However, many challenges and insoluble problems were found on the pre—feed studying. Although CAPEX of drilling and production from IRGBS Prirazlomnaya is less in comparison with alternative concepts, the cumulative production does not reach maximum value. Therefore, the concept of using subsea production systems with tie—in to IRGBS Prirazlomnaya becomes the next possible option.
Arctic region brings the following challenges: extreme weather conditions such as cold temperatures and storms; the scarce and distant infrastructure, which affects the transfer personnel and equipment; a short ice-free season that limits operational flexibility and introduces the need for an effective ice-monitoring plan; prolonged periods of darkness and daylight; oil spill response planning. The oils from Permian and HP/HT Silurian and Lower Devonian deposits have to be blended to protect the processing and offloading facilities of IRGBS Prirazlomnaya due to different properties (viscosity, density, etc.). A serious risk is damage from ice ridges through either direct contact or upper sediments movements. Thus, trenching of pipelines and glory holes for protection of subsea production systems and pipelines is necessary to ensure uninterrupted production process in the Pechora Sea. The utilization of associated gas is a crucial problem for all offshore projects. 150 million m3 of associated gas was produced with oil in 2017; some amount of gas was converted to energy for domestic needs, and some was flared. The production from Silurian and Devonian deposits increases the total amount of associated gas up to 20 %. In this Master thesis, it is considered that after the processing facilities of IRGBS Prirazlomnaya, all associated gas will be pumped to Silurian and Lower Devonian deposits to maintain reservoir pressure. Based on consideration of possible technical solutions, potential challenges and economic evaluation the conclusions will be given. | nb_NO |
