Analisis Keandalan Mooring Lines Studi Kasus : FSO Abherka

Raditya Putra, Garry (2021) Analisis Keandalan Mooring Lines Studi Kasus : FSO Abherka. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Floating Storange & Offloading (FSO) adalah salah satu objek penting dari perusahaan minyak dan gas. Fungsinya sebagai penyimpan hasil eksploitasi migas di perairan sangat menuntut dari perancangan desain yang baik. Salah satunya adalah perancangan mooring lines dari FSO. Mooring lines dari FSO akan menghadapi kondisi lingkungan yang bervariasi sehingga dituntut untuk memiliki keandalan yang baik. PT. Pertamina (PERSERO) selaku BUMN yang bergerak di bidang minyak dan gas, membutuhkan FSO yang memiliki mooring lines yang handal. Salah satu FSO yang dimiliki oleh PT. Pertamina (Persero) adalah FSO Abherka. FSO Abherka memiliki dimensi LOA 242.90 m, LPP 232 m, Lebar 41.6 m, Tinggi 19.7 m, Sarat 12.894 m dan bobot mati 85829 ton. FSO ini dipasang di Selat Madura yang memiliki kedalaman perairan 100 m dengan variasi kontur kurang lebih 2 m, dan terletak pada koordinat lintang 6.66222 S dan bujur 112.93364 E. Mooring lines pada FSO Abherka adalah spread mooring dengan 4 cluster yang masing – masing clusternya memiliki 3 mooring rope. Pada tesis ini, penulis telah menganalisis kekuatan mooring lines dalam keadaan intact maupun damage dengan menggunakan software DNV Genie dan DNV HydroD. Dari studi kasus ini dimodelkan hidrodinamika FSO yang kemudian didapat kekuatan mooring rope dari Orcaflex dari kondisi lingkungan dengan variasi gelombang, angin, dan arus. Dari studi kasus ini, didapat kekuatan mooring lines pada kombinasi kasus dari penulis dan lingkungan, yang kemudian penulis akan mencari keandalan mooring lines dari 2 kasus : 1 intact dan 1 damage dari kondisi paling bahaya. Pada studi kasus mencari keandalan mooring lines ini, penulis menggunakan metode Mean Value First Order Second Moment. Dan dari studi kasus ini didapat probabilitas kegagalan pada kondisi intact sebesar 9.94E-06 dan kondisi damage sebesar 1.28E-02, serta keandalan mooring lines pada kondisi intact sebesar 0.999 dan kondisi damage sebesar 0.987. Berdasarkan hasil perhitungan keandalan yang ditetapkan oleh DNV sesuai DNV-OS E301, hasil yang didapat memenuhi kriteria keandalan yang ditetapkan.
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Floating Storange & Offloading (FSO) is one of the important objects of oil and gas companies. Its function as a storage for the results of oil and gas exploitation in the waters is very demanding of a good design. One of them is the design of mooring lines from the FSO. The mooring lines of the FSO will face various environmental conditions so that they are required to have good reliability. PT. Pertamina (PERSERO) as a state-owned company engaged in the oil and gas sector, needs an FSO that has reliable mooring lines. One of the FSOs owned by PT. Pertamina (Persero) is FSO Abherka. Abherka FSO has dimensions of LOA 242.90 m, LPP 232 m, Breadth 41.6 m, Height 19.7 m, Draft 12,894 m and a deadweight of 85829 tons. This FSO is installed in the Madura Strait which has a water depth of 100 m with contour variations of plus minus 2 m, and is located at latitude 6.66222 S and longitude 112.93364 E. Mooring lines in FSO Abherka was spread mooring with 4 cluster then each cluster has 3 mooring ropes. In this thesis, the author has analyzed the strength of mooring lines in intact and damage conditions using DNV software Genie and DNV HydroD. From this case study, a hydrodynamic FSO was modeled, which then obtained the strength of the mooring rope from Orcaflex from environmental conditions with variations in waves, wind and currents. From this case study, we get the strength of the mooring lines in the combination of cases from the author and the environment, which then the authors will look for the reliability of the mooring lines from 2 cases: 1 intact and 1 damage from the most dangerous conditions. In the case study to find the reliability of these mooring lines, the author uses the Mean Value First Order Second Moment method. And from this case study, the probability of failure in the intact condition is 9.94E-06 and the damage condition is 1.28E-02, and the reliability of the mooring lines in the intact condition is 0.999 and the damage condition is 0.987. Based on the reliability calculation results set by DNV according to DNV-OS E301, the results obtained meet the established reliability criteria.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Keandalan, Mooring Lines, Floating Storage Offloading, Bangunan Lepas Pantai, Reliability, Offshore
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures
Divisions:	Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38101-(S2) Master Thesis
Depositing User:	Garry Raditya Putra
Date Deposited:	04 Mar 2021 02:51
Last Modified:	04 Mar 2021 02:51
URI:	http://repository.its.ac.id/id/eprint/83396

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