Analisis Integritas Struktural Berbasis Risiko Pada Jacket Wellhead Platform Akibat Penambahan Hydraulic Workover Unit

Dewanthi, Lintang Aura (2026) Analisis Integritas Struktural Berbasis Risiko Pada Jacket Wellhead Platform Akibat Penambahan Hydraulic Workover Unit. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Penambahan beban Hydraulic Workover Unit (HWU) untuk kegiatan workover berpotensi memengaruhi integritas struktur sehingga diperlukan evaluasi terhadap kondisi struktur. Penelitian ini bertujuan mengevaluasi integritas struktur jacket wellhead platform yang telah beroperasi lebih dari 50 tahun dengan membandingkan dua kondisi, yaitu sebelum dan sesudah penambahan HWU. Evaluasi dilakukan melalui analisis inplace dan analisis pushover statik nonlinear menggunakan perangkat lunak SACS, serta analisis risiko menggunakan pendekatan distribusi log-normal. Hasil penelitian menunjukkan bahwa penambahan HWU meningkatkan nilai Unity Check (UC) maksimum pada kondisi operasi dari 0.78 menjadi 2.58, sedangkan pada kondisi ekstrem meningkat dari 0.55 menjadi 0.59. Hasil analisis pushover menunjukkan nilai Reserve Strength Ratio (RSR) minimum sebesar 3.51 sebelum penambahan HWU dan 3.16 setelah penambahan HWU, yang keduanya masih memenuhi kriteria API RP 2A-WSD untuk platform kategori unmanned. Analisis risiko menunjukkan nilai Consequence of Failure (CoF) sebesar 5,2 serta peningkatan nilai Probability of Failure ("PoF" ) dari 4.56×10-1 menjadi 5.42×10-1 yang menempatkan tingkat risiko global berada pada kategori High Risk. Secara keseluruhan, penambahan beban HWU mengikis cadangan kekuatan struktur sehingga membuat kondisi dengan HWU lebih mendekati titik kegagalan, ditandai dengan munculnya kondisi overstress pada elemen main deck. Meskipun platform masih memiliki kapasitas global yang memadai (RSR ≥ 0.8), diperlukan tindakan penguatan (strengthening/mitigation) terlebih dahulu pada elemen yang mengalami overstress untuk menjamin keselamatan operasi.
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The additional loading from the Hydraulic Workover Unit (HWU) during workover operations has the potential to compromise structural integrity, thereby necessitating a structural evaluation. This study aims to evaluate the structural integrity of a jacket wellhead platform that has been in service for over 50 years by comparing two conditions: before and after the addition of the HWU. The evaluation was conducted through in-place analysis and nonlinear static pushover analysis using SACS software, as well as risk assessment utilizing a log-normal distribution approach. The results indicate that the addition of the HWU increases the maximum Unity Check (UC) under operating conditions from 0.78 to 2.58, whereas under extreme conditions, it increases from 0.55 to 0.59. The pushover analysis shows a minimum Reserve Strength Ratio (RSR) of 3.51 prior to the HWU addition and 3.16 after the HWU addition, both of which satisfy the API RP 2A-WSD criteria for unmanned platforms. The risk assessment reveals a Consequence of Failure (CoF) value of 5.2 and an increase in the Probability of Failure ("PoF" ) from 4.56×10^(-1) to 5.42×10^(-1), placing the overall global risk in the High-Risk category. Overall, the additional HWU load diminishes the structural strength margin, bringing the condition with the HWU closer to the point of failure, as characterized by localized overstress on the main deck members. Although the platform retains adequate global structural capacity ("RSR"≥0.8), structural strengthening or mitigation measures are required on the overstressed members prior to operations to ensure operational safety.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Analisis Inplace, Analisis Pushover, Analisis Risiko, Hydraulic Workover Unit ======================================================================================================================== Hydraulic Workover Unit, Inplace Analysis, Pushover Analysis, Risk Analysis
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures
Divisions:	Faculty of Marine Technology (MARTECH) > Offshore Engineering > 54040-(S1) Undergraduate Thesis
Depositing User:	Lintang Aura Dewanthi
Date Deposited:	29 Jul 2026 01:04
Last Modified:	29 Jul 2026 01:04
URI:	http://repository.its.ac.id/id/eprint/139271

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