Studi Kasus Tegangan Riser Saat Proses Upending Dengan Bantuan Sling Pada Davit Lift

Nazurah, Alvin Syafiq (2022) Studi Kasus Tegangan Riser Saat Proses Upending Dengan Bantuan Sling Pada Davit Lift. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Kebutuhan minyak dan gas mengalami peningkatan setiap tahunnya sehingga proses pengeboran dan transportasi minyak dan gas harus dipercepat. Moda transportasi minyak dan gas yang paling efektif dan optimal yaitu pipa bawah laut. Riser merupakan bagian penting pada proses transportasi, karena sebagai pipa penghubung antara fasilitas diatas permukaan air dan pipa bawah laut. Proses yang paling penting dalam menggunakan riser maupun pipa bawah laut adalah proses instalasi, karena saat instalasi pipa akan mengalami kenaikan tegangan. Pada tugas akhir ini penulis akan melakukan studi kasus tegangan riser saat proses upending (perputaran riser dari posisi horizontal ke posisi vertikal) dengan variasi kondisi sling normal pada davit lift dan kondisi beberapa (dua dari tiga) sling terhenti, bisa dikarenakan kesalahan operator atau kesalahan mesin dan menginput beban lingkungan beruada gelombang dan arus dari arah 0°, 45°, 90°, dan 135°. Code yang digunakan untuk validasi tegangan riser yaitu ASME B31.4 (2019) dan code untuk proses instalasi riser yaitu DNVGL-ST-N001 (2016). Software yang digunakan untuk simulasi selama 800 detik, pemodelan dan mengetahui tegangan riser saat upending yaitu Microsoft Excel, MOSES, dan Orca Flex. Tegangan yang digunakan adalah tegangan von misses maksimum, tegangan saat kondisi normal sebesar 168,353 MPa atau 37,412% SMYS riser dan Unity Check (UC) sebesar 0,416 dengan beban lingkungan dari arah 90°. Sedangkan saat kondisi beberapa (dua dari tiga) sling terhenti pada detik ke 300 sampai 400 tegangan yang terjadi sebesar 216,166 MPa atau 48,037% SMYS riser dan Unity Check (UC) sebesar 0,534 dengan beban lingkungan dari arah 90°. Terhentinya sling mengakibatkan terjadinya kenaikan tegangan pada riser, tetapi riser saat upending masih tergolong aman karena nilai Unity Check (UC) masih dibawah 1 (satu).
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The need for oil and gas increases every year so that the process of drilling and transportation of oil and gas must be accelerated. The most effective and optimal mode of oil and gas transportation is the submarine pipeline. The riser is an important part of the transportation process, because it acts as a connecting pipe between above-water facilities and subsea pipelines. The most important process in using a riser or subsea pipe is the installation process, because during installation the pipe will experience an increase in stress. In this final project the author will conduct a case study of the riser stress during the upending process (rotation of the riser from a horizontal position to a vertical position) with variations in normal sling conditions on the davit lift and the condition of several (two of three) slings stopping, it could be due to operator error or machine error. and input the environmental load in the form of waves and currents from the direction of 0°, 45°, 90°, and 135°. The code used to validate the riser voltage is ASME B31.4 (2019) and the code for the riser installation process is DNVGL-ST-N001 (2016). The software used for simulation for 800 seconds, modeling and knowing the riser voltage when upending are Microsoft Excel, MOSES, and Orca Flex. The voltage used is the maximum von misses stress, the stress under normal conditions is 168,353 MPa or 37,412% SMYS riser and Unity Check (UC) is 0.416 with an environmental load of 90°. Meanwhile, when the condition of several (two of three) slings stops at the 300th to 400th seconds, the stress is 216,166 MPa or 48,037% SMYS riser and Unity Check (UC) is 0.534 with environmental load from 90°. Stopping the sling causes an increase in the voltage on the riser, but the riser when upending is still relatively safe because the Unity Check (UC) value is still below 1 (one).

Item Type:	Thesis (Undergraduate)
Uncontrolled Keywords:	Pipa Bawah Laut, Riser, Tegangan Von Misses, Sling Davit Lift, Upending, Offshore Pipeline, Riser, Von Misses Stress, Sling Davit Lift.
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures
Divisions:	Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis
Depositing User:	Alvin Syafiq Nazurah
Date Deposited:	02 Feb 2022 04:39
Last Modified:	02 Feb 2022 04:39
URI:	http://repository.its.ac.id/id/eprint/92647

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