Analisis Pengaruh Beban Squall Terhadap Operabilitas Semi-Submersible Saat Kondisi Drilling

Pradana, Muhammad Aqshal Thorri (2023) Analisis Pengaruh Beban Squall Terhadap Operabilitas Semi-Submersible Saat Kondisi Drilling. Other thesis, Institut Teknologi Sepuluh Nopember.

Text 04311940000048-Undergraduate_Thesis.pdf - Accepted Version Restricted to Repository staff only until 1 April 2025. Download (7MB) | Request a copy

Abstract

Salah satu teknologi yang mendukung eksplorasi migas lepas pantai ialah MODU Semisubmersible. Kemampuan semi submersible untuk menenggelamkan ponton dan kolom dengan ballast menjadi keunggulan dalam kestabilan gerakan. Saat operasi pengeboran, MODU semi submersible perlu mempertahankan posisinya menggunakan sistem tambat. Dalam perencanaannya hanya berdasarkan kondisi lingkungan berdasarkan tingkat severity, padahal dalam kondisi riil lingkungan dapat berubah-ubah tidak menentu seperti peristiwa angin squall. Squall merupakan peristiwa kenaikan kecepatan angin yang terjadi secara mendadak dan peristiwa tersebut diikuti oleh perubahan arah yang terjadi secara tiba-tiba. Penelitian ini akan menganalisis dampak squall terhadap operabilitas MODU semisubmersible berdasarkan kriteria API RP 2SK dan API RP 16Q serta perubahan sea state akibat squall. Dengan tinjauan Laut Natuna yang sering diterjang Sumatera Squall di kedalaman 88.56 m, ditempatkan MODU semisubmersible dengan rencana sistem tambat berupa spread mooring bersudut sebar simetris 30° - 60°. Squall dengan durasi 5.5 menit digunakan dalam analisis ini. Selain itu, dalam analisis digunakan variasi Hs 1.5 m, 2.0 m, 2.5 m, 3.0 m, dan 3.5 m. Analisis yang digunakan ialah metode time domain dengan durasi simulasi 1800 detik sesuai dengan profil angin dan pembebanan dari lima arah yakni 0°, 45°, 90°, 135°, dan 180°. Dari hasil simulasi saat Hs tertinggi, terjadi peningkatan yang signifikan pada mooring line tension dengan rerata kenaikan tension dari kondisi normal ke squall sebesar 76.79% dengan kenaikan terbesar ketika mendapat beban dari arah following seas sebesar 90.67%. Selain itu, ball joint angle yang terbentuk juga mengalami peningkatan dengan rerata 71.17% untuk sumbu-x dan 50.31% untuk sumbu-y dengan kenaikan terbesar terjadi ketika beban datang dari following seas sebesar 91.53%. Sehingga dari analisis kedua parameter tersebut dilakukan asesmen berdasarkan kriteria operasi dan didapat bahwa batas Hs agar MODU dapat beroperasi ketika Hs ≤ 2.85 m.
===============================================================================================================================
One of the technologies that supports offshore oil and gas exploration is the MODU Semisubmersible. The semi-submersible's ability to submerge the pontoons and columns with ballast provides an advantage in stabilizing movement. During drilling operations, the MODU semi-submersible needs to maintain its position using a mooring system. In its planning, it is based only on environmental conditions based on the level of severity, while in real conditions the environment can change unpredictably, such as the occurrence of squalls. A squall is a sudden increase in wind speed followed by a sudden change in direction. This study will analyze the impact of squalls on the operability of the MODU semi-submersible based on API RP 2SK and API RP 16Q criteria and changes in sea state due to squalls. With a review of the Natuna Sea, which is often hit by Sumatra Squalls at a depth of 88.56 m, the MODU semi-submersible is placed with a planned mooring system in the form of a symmetrical spread mooring angle of 30° - 60°. A squall with a duration of 5.5 minutes is used in this analysis. In addition, variations of Hs 1.5 m, 2.0 m, 2.5 m, 3.0 m, and 3.5 m are used in the analysis. The analysis used is the time domain method with a simulation duration of 1800 seconds according to the wind profile and loading from five directions, namely 0°, 45°, 90°, 135°, and 180°. From the simulation results, when Hs is at its highest, there is a significant increase in mooring line tension with an average increase in tension from normal conditions to squalls of 76.79%, with the largest increase occurring when the load comes from following seas at 90.67%. In addition, the ball joint angle formed also increases with an average of 71.17% for the x-axis and 50.31% for the y-axis, with the largest increase occurring when the load comes from following seas at 91.53%. Thus, an assessment based on operational criteria is conducted from the analysis of these two parameters, and it is found that the limit of Hs for the MODU to operate is when Hs ≤ 2.85 m.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	squall, MODU Semisubmersible, Operabilitas, Ball joint angle, Tarikan tali tambat, Squall, MODU Semisubmersible, Operability, Ball joint angle, Mooring line Tension
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM161 Ships--Hydrodynamics
Divisions:	Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis
Depositing User:	Muhammad Aqshal Thorri Pradana
Date Deposited:	30 Mar 2023 04:40
Last Modified:	30 Mar 2023 04:40
URI:	http://repository.its.ac.id/id/eprint/97820

Actions (login required)

View Item