Ghifari, Bana Fitro (2019) Analisa Tegangan Pada Proses Abandonment and Recovery Pipa Bawah Laut 12" di Subang, Jawa Barat saat Instalasi Dengan Metode S-Lay. Other thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Dalam proses instalasi pipa bawah laut tidak selamanya akan berjalan sesuai dengan yang direncanakan. Adakalanya beberapa permasalahan muncul yang mengakibatkan proses instalasi harus dihentikan sementara dengan alasan keselamatan. Beberapa hal yang dapat mengganggu jalannya proses instalasi antara lain kondisi cuaca buruk, kegagalan fungsi dari alat pendukung atau terjadinya kerusakan pada pipa yang akan diinstalasi. Oleh karena itu perlu dilakukan prosedur tertentu untuk penghentian sementara proses instalasi. abandonment and recovery merupakan prosedur yang dilakukan dimana proses instalasi dapat dihentikan sementara dengan menurunkan pipa bawah laut secara keseluruhan untuk sementara kemudian dinaikkan kembali ke atas barge dengan bantuan winch ketika kondisi sudah aman untuk melanjutkan proses instalasi. Pada penelitian ini proses abandonment and recovery akan dilakukan pada 3 kedalaman laut yakni 32 m, 37 m dan 42 m. Untuk memodelkan proses abandonment and recovery digunakan software OFFPIPE 3. Proses pemodelan dilakukan dengan mengubah panjang kabel selama proses abandonment and recovery berlangsung. Panjang kabel yang akan digunakan adalah 76 m, 180 m, 230 m dan 280 m yang telah mewakili kondisi pipa mulai diatas barge hingga sebelum pipa menyentuh dasar laut. Dari hasil analisa yang dilakukan selama proses abandonment and recovery tegangan ekuivalen maksimum yang terjadi pada pipa dihasilkan pada kedalaman 42 m dengan arah pembebanan 180⁰ dengan nilai 390.69 MPa setara dengan 86.62% SMYS yang terjadi di roller ke 1 stinger. Tegangan tersebut memiliki nilai dibawah dari nilai yang disyaratkan oleh DNV OS F101 (87% SMYS) sehingga dapat disimpulkan pipa tidak mengalami tegangan yang berlebih selama proses abandonment and recovery berlangsung. Selain itu pengecekan local buckling pada pipa di masing-masing kedalaman yang mengalami bending moment dan axial force maksimum juga memiliki nilai UC≤1 yang berarti pipa tidak mengalami local buckling. Nilai UC dari pengecekan local buckling pada pipa dengan kedalaman 32 m, 37 m, dan 42 m masing-masing adalah 0.53, 0.65, dan 0.72.
================================================================================================During submarine pipeline installation process it will not always run as planned. Sometimes few problems arise which cause the installation process to be stopped temporarily for safety reasons. Something that can interfere with the installation process includes bad weather conditions, malfunction of supporting devices or damage to the pipes to be installed. Therefore it is necessary to do certain procedures for the temporary termination of the installation process. Abandonment and recovery is a procedure that is carried out where the installation process can be temporarily stopped by temporarily lowering the subsea pipeline and then raising it back to the barge with the help of a winch when the conditions are safe to continue the installation process. In this study the procedure will be done in three different water depth which is 32 m, 37 m and 42 m. OFFPIPE 3 is used to modeling the abandonment and recovery process. The modeling process is done by changing cables length during the abandonment and recovery process. The length of cable to be used is 76 m, 180 m, 230 m and 280 m which represents the condition of the pipe starting above the barge until it almost touches the seabed. From the results of the analysis carried out during the process of abandonment and recovery, the maximum equivalent stress that occurs in the pipeline is produced at a depth of 42 m with a loading direction of 180⁰ with a value of 390.69 MPa or 86.62% SMYS occurring on the 1st roller of stinger. The equivalent stress has a value less than the allowable value by DNV OS F101 (87% SMYS) so it can be concluded that the pipeline does not experience overstress during the process. In addition, the local buckling check of the pipeline at each depth which has the maximum value of bending moment and axial force also has a UC value ≤1, which means local buckling does not occured to the pipeline. The UC values from local buckling checks on pipeline with depths of 32 m, 37 m, and 42 m were 0.53, 0.65 and 0.72 respectively.
| Item Type: | Thesis (Other) |
|---|---|
| Uncontrolled Keywords: | abandonment and recovery, instalasi, local buckling, OFFPIPE, tegangan ekuivalen |
| Subjects: | T Technology > TC Hydraulic engineering. Ocean engineering > TC1665 Offshore structures--Materials. T Technology > TN Mining engineering. Metallurgy > TN879.5 Petroleum pipelines |
| Divisions: | Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis |
| Depositing User: | Ghifari Bana Fitro |
| Date Deposited: | 24 Jun 2024 06:00 |
| Last Modified: | 24 Jun 2024 06:00 |
| URI: | http://repository.its.ac.id/id/eprint/68786 |
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