Rachman, Dimas Maulana Analisis Kekuatan Konstruksi Pondasi Winch Roller untuk Airgun Umbilicals pada Kapal Survei Seismik Geomarin IV. Undergraduate thesis, UNSPECIFIED.
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Abstract
Survei seismik dalam kegiatan eksplorasi minyak dan gas dilakukan untuk mengetahui kondisi geologis di daerah tertentu. Pada prinsipnya, gelombang suara ditembakkan dari permukaan air oleh sumber suara yang disebut dengan airgun yang tersambung dengan deck melalui umbilicals, lalu gelombang suara pantulan akan diterima oleh sensor hydrophone pada streamer. Keduanya ditarik bersamaan pada kecepatan 5 knot. Interaksi hidrodinamis antara beban-beban lingkungan dan gerakan di antara komponen menyebabkan gaya tarik pada umbilicals yang selanjutnya diterima oleh konstruksi pondasi winch roller pada deck. Gaya tarik ini didapatkan dengan menganalisis interaksi antara kapal survei Gomarin IV dan konfigurasi peralatan seismik (streamer dan airgun). Response Amplitude Operators kapal survei Geomarin IV dan dimensi-dimensi peralatan seismik dibutuhkan dalam analisis gaya tarik. Gaya tarik pada umbilicals terbesar yang terjadi sebesar 23.70 kN saat head sea (heading 1800) pada setiap line. Kemudian DNV menyaratkan konstruksi pondasi winch roller harus mampu menahan beban 1.1 kali gaya tarik maksimum yang terjadi. Gaya tarik maksimum ini kemudian diaplikasikan pada model finite element konstruksi pondasi winch roller. Dapat diketahui bahwa tegangan von Mises maksimum yang terjadi adalah 27.64 MPa. Nilai ini jauh dari yield stress baja A36, atau 27.64 MPA << 250 MPA, dengan nilai faktor keamanan sebesar 9.05. Dengan demikian konstruksi pondasi winch roller untuk airgun umbilicals adalah sangat aman dan kuat.
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Marine seismic survey in the oil and gas exploration is done to understand the geological condition of a certain region. This is done by blasting a sound wave from the water surface from a source called “airguns” which is connected to the vessel deck by “umbilicals”. The reflected sound wave will be received by “hydrophone” sensors on the “streamers”. Both the airguns and the streamers are towed behind the vessel at the tow speed of 5 knots. Hydrodynamics interaction between the environment and the motion of the equipments will create a tension in the umbilicals which is transferred to the winch roller foundation. This tension can be obtained by analyzing the interaction between Geomarin IV with the seismic survey equipments (airguns and streamers). Response Amplitude Operators of Geomarin IV and the dimensions of seismic survey equipments are needed for the tension analysis. The maximum umbilical tension obtained is 23.70 kN for head sea (heading 1800) at each line. DNV suggests that the winch roller construction must have the capability to withstand load which is 1.1 times bigger than the maximum tension. This maximum tension is applied to the finite element model of the winch roller construction. From the finite element analysis, the maximum von Mises stress is 27.64 MPa, which is significantly below the A36 yield stress, or 27.64 MPA << 250 MPA. This value gives a safety factor of 9.05, thus the construction of airgun umbilicals winch roller foundation has the required strength to ensure that the seismic survey can be proceeded without structural fail.
| Item Type: | Thesis (Undergraduate) |
|---|---|
| Subjects: | V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering |
| Depositing User: | Dimas Maulana Rachman |
| Date Deposited: | 24 Jan 2018 06:17 |
| Last Modified: | 06 Mar 2019 07:36 |
| URI: | http://repository.its.ac.id/id/eprint/45122 |
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