VERIFIKASI POSISI PIPA BAWAH LAUT PASCA PEMASANGAN (STUDI KASUS : BALIKPAPAN PLATFORM)
TUGAS AKHIR Karya tulis sebagai salah satu syarat untuk memperoleh gelar Sarjana
Oleh MUHAMMAD FIRDAUS NIM. 15108028
PROGRAM STUDI TEKNIK GEODESI DAN GEOMATIKA FAKULTAS ILMU DAN TEKNOLOGI KEBUMIAN INSTITUT TEKNOLOGI BANDUNG 2012
LEMBAR PENGESAHAN
Tugas Akhir Sarjana VERIFIKASI POSISI PIPA BAWAH LAUT PASCA PEMASANGAN (STUDI KASUS : BALIKPAPAN PLATFORM) Adalah benar dibuat saya sendiri dan belum pernah dibuat dan diserahkan sebelumnya baik sebagian ataupun seluruhnya, baik oleh saya maupun orang lain, baik di ITB maupun institusi pendidikan lainnya. Bandung, Agustus 2012 Penulis
Muhammad Firdaus NIM. 15108028 Bandung, Agustus 2012 Pembimbing I
Pembimbing II
Dr. Ir. Eka Djunarsjah, MT NIP. 19670727 199403 1 006
Ir .Syamsul Bachri, M.Eng, PhD NIP. 19540328 198010 1 001
Disahkan oleh, Program Studi Teknik Geodesi dan Geomatika Ketua,
Dr. Ir. Kosasih Prijatna., M.Sc NIP. 19600702 198810 1 00
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ABSTRAK
Pipa bawah laut memerlukan desain awal yang sempurna dan proses instalasi yang teliti agar keseluruhan proses pembangunan pipa berhasil dan cost effective. Pembangunan pipa dibagi menjadi tiga tahapan, yaitu survei pra-pemasangan pipa bawah laut, pemasangan pipa bawah laut, dan survei pasca-pemasangan pipa bawah laut.
Verifikasi pipa bawah laut termasuk ke dalam kegiatan survei pasca-pemasangan dengan tujuan utama untuk mendapatkan posisi absolute dari pipa bawah laut tersebut. Penulis melakukan pengolahan data multibeam echosounder dengan menggunakan perangkat lunak QINSy. Selain itu, dilakukan juga analisis mengenai perbandingan posisi dari rencana pipa dengan posisi pipa hasil dari pengolahan data multibeam
echosounder.
Hasil
analisis
kemudian
akan
digunakan
untuk
pertimbangan dalam perencanaan pembangunan pipa pada wilayah yang sama.
Hasil pengolahan data multibeam echosounder menunjukkan terdapat perbedaan posisi perencanaan dan posisi aktual dari pipa. Perbedaan posisi tersebut terjadi pada bagian lengkungan dari pipa dengan perbedaan sejauh 5.4 m. Perbedaan yang terdapat pada lengkungan dari pipa ini masih dapat diterima, dikarenakan tidak ada posisi pipa yang free-span dan juga tidak mengakibatkan pipa ini berbenturan dengan pipa yang lainnya.
Kata Kunci : Pipa Bawah Laut, Verifikasi, Multibeam Echosounder.
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ABSTRACT
Subsea pipeline requires a perfect design and a meticulous installation process therefor the entire pipeline construction process will be successful and costeffectively. Construction of the subsea pipeline is divided into three stages; pre-lay survey, subsea pipeline installation, and as-laid survey.
Verification of subsea pipeline is a part of as-laid survey, with the main objective to get the final position of the installed subsea pipeline. In this thesis, the writer done a multibeam echosounder data processing using the QINSy software for acquiring the final position coordinate. In addition, there is also performed an analysis of the comparative position of the subsea pipeline route plan to the position of the pipe results from multibeam echosounder data processing. The analysis will then be used for consideration in planning for the construction of the subsea pipeline in the same area.
Multibeam echosounder data processing results showed that there are differences in the position of planning and the actual position of the subsea pipeline. Difference occurs in the position of the winding pipe with a difference as far as 5.4 m. The differences found in the winding pipe are still in acceptable condition, because there is no free-span pipe and this pipe does not result in conflict with the other existing subsea pipeline.
Keywords: Subsea Pipeline, Verification, Multibeam echosounder
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DAFTAR ISI
LEMBAR PENGESAHAN ......................................................................................... ii ABSTRAK .................................................................................................................. iii ABSTRACT .................................................................................................................. iv DAFTAR ISI ................................................................................................................ v DAFTAR GAMBAR ................................................................................................. vii DAFTAR TABEL ....................................................................................................... ix BAB 1 .......................................................................................................................... 1 PENDAHULUAN ....................................................................................................... 1 1.1
Latar Belakang .............................................................................................. 1
1.2
Rumusan Masalah ......................................................................................... 3
1.3
Ruang Lingkup .............................................................................................. 3
1.4
Tujuan Penulisan ........................................................................................... 3
1.5
Metodologi Penelitian ................................................................................... 3
1.6
Sistematika Penulisan .................................................................................... 5
TEORI DASAR ........................................................................................................... 6 2.1
Pemasangan Pipa Bawah Laut....................................................................... 6
2.1.1
Pre-Lay Survey....................................................................................... 6
2.1.2
Peletakan Pipa Bawah Laut .................................................................... 7
2.1.3
Tie-in/Riser Installation ....................................................................... 12
2.1.4
Trenching Operation ............................................................................ 13
2.1.5
As Laid Survey ..................................................................................... 14
2.2
Verifikasi Posisi Pipa Bawah Laut .............................................................. 16
2.2.1
Survei Batimetri ................................................................................... 16
2.2.2
Multibeam Echosounder ...................................................................... 19
2.2.3
Sub Bottom Profiler ............................................................................. 26
VERIFIKASI POSISI PIPA BAWAH LAUT PASCA PEMASANGAN ................ 28 3.1
Pendahuluan ................................................................................................ 28
3.2
Lokasi Survei Verifikasi Posisi Pipa Bawah Laut ....................................... 28
3.3
Parameter Geodetik ..................................................................................... 28 v
3.4
Alat Yang Digunakan .................................................................................. 30
3.5
Kalibrasi Yang Dilakukan ........................................................................... 30
3.5.1
Kalibrasi Sistem Penentuan Posisi ....................................................... 30
3.5.2
Kalibrasi pada Multibeam Echosounder .............................................. 31
3.6
Offset Kapal ................................................................................................. 34
3.7
Data Jalur Survei ......................................................................................... 35
3.8
Pengolahan Data .......................................................................................... 36
3.8.1
Pengolahan Data Pasang Surut ............................................................ 36
3.8.2
Pengolahan Data Sound Velocity ......................................................... 37
3.8.3
Pengolahan Data MBES ....................................................................... 38
3.8.4
Pengolahan Data SBP .......................................................................... 40
ANALISIS ................................................................................................................. 41 4.1
Perbandingan Posisi Rencana dan Posisi Aktual Pipa ................................ 41
4.2
Analisis Faktor Penyebab Perbedaan Posisi Pipa........................................ 43
4.2.1
Kondisi Perairan Pada Lokasi Pemasangan Pipa Bawah Laut............. 43
4.2.2
Peralatan yang Digunakan Pada Survei ............................................... 44
4.3
Analisis Efek Perbedaan Posisi Pipa ........................................................... 44
KESIMPULAN DAN SARAN .................................................................................. 46 5.1
Kesimpulan .................................................................................................. 46
5.2
Saran ............................................................................................................ 47
DAFTAR PUSTAKA ................................................................................................ 48
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DAFTAR GAMBAR
Gambar 1.1 Diagram Metode Penelitian ...................................................................... 4 Gambar 2.1 Surface Tow Pipeline Installation [Guo,et al. 2005] ................................ 8 Gambar 2.2 Tow-in Pipeline Installation [Anonim, 2009] .......................................... 8 Gambar 2.3 S-Lay Pipeline Installation [Guo,et al. 2005]........................................... 9 Gambar 2.4 Pipa yang Didorong Oleh Stringer [Anonim,2012] ................................. 9 Gambar 2.5 J-Lay Pipeline Installation [Guo,et al. 2005] ......................................... 10 Gambar 2.6 Pemasangan Pipa Dengan Metode Reel Barge [Kaskus, 2010] ............. 11 Gambar 2.7 Vertical Reel Barge [Anonim, 2012] ..................................................... 12 Gambar 2.8 Pemasangan Riser [Anonim, 2009]........................................................ 12 Gambar 2.9 Pemendaman Pipa Bawah Laut [Anonim, 2009] ................................... 14 Gambar 2.10 ROV (Remotely Operated Vehicle) [Novosin,2012] ........................... 15 Gambar 2.11 Metode DGPS [Irawan, 2010] .............................................................. 18 Gambar 2.12 Reduksi Kedalaman ............................................................................. 18 Gambar 2.13 Reduksi Kedalaman Akibat Pergerakan Kapal .................................... 19 Gambar 2.14 Kalibrasi Waktu Tunggu [Brennan.2009] ............................................ 22 Gambar 2.15 Kalibrasi Roll [Brennan,2009] ............................................................. 23 Gambar 2.16 Kalibrasi Pitch [Brennan,2009] ........................................................... 24 Gambar 2.17 Kalibrasi Yaw [Brennan,2009] ............................................................ 24 Gambar 2.18 Offset Lokasi Dari Sensor Wahana Survei [Mann. 1996] ................... 25 Gambar 2.19 Survei Sub Bottom Profiler (SBP) [Geostar, 2009] ............................. 26 Gambar 3.1 Lokasi Survei......................................................................................... 29 Gambar 3.2 Kondisi Roll Sebelum Kalibrasi ............................................................. 31 Gambar 3.3 Kondisi Roll Setelah Kalibrasi ............................................................... 32 Gambar 3.4 Kondisi Pitch Sebelum Kalibrasi ........................................................... 32 Gambar 3.5 Kondisi Pitch Setelah Kalibrasi.............................................................. 33 Gambar 3.6 Kondisi Yaw Sebelum Kalibrasi ............................................................ 33 Gambar 3.7 Kondisi Yaw Setelah Kalibrasi .............................................................. 34 Gambar 3.8 Offset Kapal MGS Geosurvey ............................................................... 35 Gambar 3.9 Jalur Survei ............................................................................................. 36 Gambar 3.10 Grafik Hasil Pengamatan Pasut Di Delta Mahakam ............................ 37 vii
Gambar 3.12 Grafik SVP di Lokasi Pengukuran ....................................................... 38 Gambar 3.13 Diagram Prosesing Data MBES ........................................................... 39 Gambar 3.14 Hasil Pengolahan data MBES .............................................................. 40 Gambar 3.15 Hasil Gambar SBP ............................................................................... 40 Gambar 4.1 Gambar Garis Jalur Rencana Pipa .......................................................... 41 Gambar 4.2 Gambar Overlay Data MBES dan Data Rencana Jalur Pipa .................. 42 Gambar 4.3 Perbedaan Pada Bagian Lengkungan Dari Pipa ..................................... 43 Gambar 5.1 Grafik Perbandingan Posisi Pipa ............................................................ 46
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DAFTAR TABEL
Tabel 3.1 Parameter Geodes\yang Digunakan ........................................................... 28 Tabel 3.2 Proyeksi yang Digunakan .......................................................................... 29 Tabel 3.3 Alat yang Digunakan ................................................................................. 30 Tabel 3.4 Deskripsi Jalur Survei Untuk Kalibrasi ..................................................... 31 Tabel 3.5 Hasil Kalibrasi MBES ................................................................................ 34
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