Analisis Operabilitas Pada Operasi Penurunan Pipeline End Manifold Dengan Metode Dinamis

Nainggolan, Yosua Nistelrooy (2026) Analisis Operabilitas Pada Operasi Penurunan Pipeline End Manifold Dengan Metode Dinamis. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Industri minyak dan gas bumi lepas pantai di Indonesia terus berkembang seiring meningkatnya kebutuhan produksi nasional dan salah satu komponen penting dalam sistem produksi bawah laut (subsea production system) adalah Pipeline End Manifold (PLEM), yang berfungsi sebagai penghubung antara pipeline dan fasilitas subsea lainnya untuk mengalirkan fluida. Proses instalasi PLEM dilakukan dengan metode lifting through wave zone, di mana struktur diturunkan secara bertahap mulai dari ketika struktur in air, splash zone, submerged deep, hingga landing in seabed. Penelitian ini bertujuan untuk menemukan tahapan paling kritis serta mengetahui respon terhadap sistem lifting selama operasi penurunan PLEM dan menganalisis operabilitas sistem penurunan PLEM berdasarkan kriteria yang telah ditentukan guna mengevaluasi batas kondisi lingkungan yang aman untuk operasi. Tahap analisis dilakukan melalui analisis statis terlebih dahulu untuk memastikan kesetimbangan sistem penurunan kemudian dilanjutkan dengan analisis dinamis time domain untuk mengetahui tension yang berubah sepanjang waktu operasi. Pada penelitian ini didapatkan tahapan paling kritis adalah splash zone dengan DAF (Dynamic Amplification Factor) maksimum mencapai 3.23 dan beberapa hasil konversi DAF yang melampaui DAF yang disarankan oleh DNV, yaitu 1.20. Tension maksimum yang terjadi pada tali hoisting dan sling secara berurutan mencapai 2964.52 kN dan 1554.325 kN, dengan arah pembebanan dari sisi port kapal teridentifikasi lebih kritis. Analisis kekuatan struktur PLEM menunjukkan kondisi aman tanpa melampaui tegangan ijin, ditandai dengan Unity Check (UC) maksimum sebesar 0.211 pada kondisi above water level yang kemudian menurun menjadi 0.169 pada kondisi below water level. Berdasarkan integrasi evaluasi operabilitas terhadap kriteria-kriteria standar DNV (batas amplitudo vertikal, start of slack, safety factor, dan crane utilization), jendela operasi (operational window) yang aman direkomendasikan pada batas tinggi gelombang signifikan (Hs) 1.0 meter dengan periode puncak gelombang (Tp) 5 detik, yang menghasilkan tingkat operabilitas sebesar 93.20% dan downtime 6.80% untuk operasi penurunan PLEM di lokasi penelitian. Penelitian ini diharapkan dapat memberikan kontribusi dalam bentuk evaluasi operabilitas serta rekomendasi kondisi lingkungan operasional yang dapat digunakan sebagai acuan perencanaan dan pengambilan keputusan pada operasi penurunan struktur subsea di masa mendatang.
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The offshore oil and gas industry in Indonesia continues to grow alongside the increasing national production demand, and one essential component in the subsea production system is the Pipeline End Manifold (PLEM), which serves as a connector between pipelines and other subsea facilities for fluid transfer. The PLEM installation process is conducted using the lifting through wave zone method, where the structure is gradually lowered from the in-air stage, through the splash zone and deep submerged stages, until landing on the seabed. This study aims to determine the most critical stage and evaluate the response of the lifting system during the PLEM lowering operation, as well as to analyze the operability of the PLEM lowering system based on predetermined criteria to evaluate safe environmental limits for the operation. The analysis phase initially employed a static analysis to ensure the equilibrium of the lowering system, followed by a time-domain dynamic analysis to determine the varying tension throughout the operational period. The results indicated that the splash zone is the most critical stage, with a maximum Dynamic Amplification Factor (DAF) reaching 3.23, and several converted DAF results exceeding the DNV recommended limit of 1.20. The maximum tension occurring in the hoisting wire and slings reached 2964.52 kN and 1554.325 kN, respectively, with the environmental heading from the port side of the vessel identified as more critical. The structural strength analysis of the PLEM demonstrated safe conditions without exceeding the allowable stress, indicated by a maximum Unity Check (UC) of 0.211 in the above-water condition, which subsequently decreased to 0.169 in the below-water condition. Based on the integrated operability evaluation against the DNV standard criteria (vertical amplitude limit, start of slack, safety factor, and crane utilization), a safe operational window is recommended at a maximum significant wave height (Hs) of 1.0 meter with a peak wave period (Tp) of 5 seconds, yielding an operability rate of 93.20% and a downtime of 6.80% for the PLEM lowering operation at the research location. This research is expected to contribute by providing an operability evaluation and operational environmental condition recommendations that can serve as a reference for planning and decision-making in future subsea structure lowering operations.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Analisis dinamis, Operabilitas, Penurunan, PLEM, Dynamic analysis, Lowering, Operability, PLEM.
Subjects:	V Naval Science > V Naval Science (General)
Divisions:	Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis
Depositing User:	Yosua Nistelrooy Nainggolan
Date Deposited:	30 Jul 2026 04:44
Last Modified:	30 Jul 2026 04:44
URI:	http://repository.its.ac.id/id/eprint/139605

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