APPLICATION OF SEISMIC DATA PROCESSING FOR SEABED IMAGING

The research was conducted in April-May 2010 in North Maluku watersbelonging to the District Luwuk Banggai, Central Sulawesi Province. This area is located atcoordinates 2 ° S - 4 ° S and 123 ° E - 126 ° east. Data processing was done at OceanAcoustics Laboratory, Department of Marine Science and Technology, Bogor AgriculturalUniversity and Marine Geological Institute (MGI) in Bandung. Seismic data processingusing the data in SEG-Y format. The data was computed with Seisee software and bandpass filtering using Matlab. Based on the results of research, it is evident that increasing thefrequency band was followed by the higher the resolution. Sampling point 30 in the form ofsandy clay sediments has an impedance value of 2.49 and the value of reflection coefficientof 0.23. While the sampling point 31 in the form of silty clay in the study showed the valueof the impedance of 1,93 with the reflection coefficient of 0.11

GIS Untuk Integrasi Interpretasi Substrat Dasar Perairan menggunakan Penggolahan Citra ALOS-AVNIR dan Side Scan Sonar

Interpretasi substrat dasar perairan merupakan salah satu kajian penting dalam ilmu kelautan, sebagai kajian utama maupun kajian pendamping untuk kajian fenomena kelautan. Substrat dasar perairan penting untuk diketahui karena sebarannya yang sangat dinamis, di kedalaman perairan yang sama bisa saja terdapat materi substrat yang berbeda dan materi substrat yang sama bisa terdapat di rentang kedalaman yang berbeda. Interpretasi memanfaatkan citra Side Scan Sonar  dan citra satelit ALOS AVNIR-2untuk sebagian perairan Selat Sunda. Metode yang digunakan adalah pengolahan citra (image processing) identifikasi substrat perairan untuk citra Side Scan Sonar dengan Sonarwiz dan penerapan algoritma Lyzenga dan transformasi NDVI (Normalize Different Vegetation Index) untuk data citra satelit. Transformasi NDVI meningkatkan akurasi pemetaan substrat pada citra ALOS AVNIR-2. Hasil pengolahan kedua citra dioverlay menggunakan GIS untuk menampilkan visualisasi sebaran substrat perairan.Kata Kunci :ALOS-AVNIR, Side Scan Sonar, GIS, Lyzeng

TEKNOLOGI AKUSTIK BAWAH AIR: SOLUSI DATA PERIKANAN LAUT INDONESIA

RINGKASANSebagai negara kepulauan, Indonesia memiliki potensi sumberdaya ikan yang besar. Pentingnya informasi keberadaan ikan dan jumlah stok ikan menjadi agenda penting saat ini. Selama ini nelayan dan pelaku industri perikanan tangkap melakukan pencarian ikan berdasarkan pengalaman melaut.  Hal ini juga sangat dikeluhkan dengan tingginya harga solar, satu hari berlayar bisa memerlukan biaya lebih dari Rp.100 juta dalam mencari ikan. Penggunaan teknologi satelit dapat membantu mengukur suhu permukaan laut dan kandungan klorofil di suatu perairan. Tetapi seringkali, lokasi daerah penangkapan ikan yang dideteksi oleh satelit sering tidak tepat. Kerapkali informasi dari satelit tidak dapat diberikan kepada pengusaha perikanan atau masyarakat nelayan secara langsung (online).Kata kunci : teknologi akustik bawah air, stok ikan, habitat ikan, keberadaan ikan, potensi ika

KARAKTERISASI RESERVOIR HIDROKARBON MENGGUNAKAN ATRIBUT SWEETNESS DAN INVERSI IMPEDANSI AKUSTIK DI PERAIRAN UTARA BALI

Reservoir adalah salah satu objek yang menjadi fokus pada tahap eksplorasi dalam industri minyak dan gas. Proses identifikasi dan penggambaran karakter reservoir baik secara kualitatif maupun kuantitatif dilakukan menggunakan data sumur dan data seismik karena kedua data tersebut saling me-lengkapi. Tujuan penelitian ini adalah mengidentifikasi dan menganalisis karakter reservoir hidro-karbon di Perairan Utara Bali menggunakan metode atribut sweetness dan metode inversi impedansi akustik berbasis model. Penelitian ini menggunakan empat buah lintasan seismik laut 2D post-stack time migration dan sebuah data sumur (BLJ-1). Metode atribut sweetness dilakukan dengan menurun-kan informasi data seismik berupa amplitudo dan frekuensi, sedangkan metode inversi impedansi akustik berbasis model dilakukan dengan mengin-tegrasikan data seismik dan data sumur agar di-peroleh sebaran nilai impedansi akustik secara lateral. Hasil penelitian menunjukkan bahwa atribut sweetness dapat mengenali zona reservoir hidrokarbon dari anomali sweet spots pada rentang waktu 750-850 ms. Zona reservoir utamanya tersusun atas batuan karbonat berupa batu gamping (limestone) yang berumur Late Pliocene dan terletak pada kedalaman 680-740 m. Metode inversi berbasis model mampu memberikan nilai korelasi yang tinggi dan galat inversi yang rendah sehingga dapat mendeter-minasi lapisan batuan yang diprediksi mengandung gas. Penggunaan atribut sweetness dan inversi berbasis model, dapat mengidentifikasi dan mampu menggambarkan karakter reservoir dengan baik.Reservoir is an object that be focus at exploration stage of the oil and gas industry. The process of identifying and depicting reservoir characters both qualitatively and quantitatively is carried out using well and seismic data because these two data are complementary. The aim of this study is to identify and analyze the character of hydrocarbon reservoir in North Bali Waters using sweetness attribute method and model-based acoustic impedance inversion method. This study uses four 2D post-stack time migration seismic and a well (BLJ-1) data. The sweetness attribute method is carried out by extracting basic information derivatives from seismic data (amplitude and frequency), while the model-based acoustic impedance inversion method is carried out by integrating seismic and well data in order to obtain the lateral distribution of acoustic impedance values. The results showed that sweet-ness attribute can identify the hydrocarbon reservoir zone from sweet spots anomaly at time window 750-850 ms. The main reservoir zone is composed by carbonate rocks (limestone) aged Late Pliocene and located at 680-740 m depth. Model-based inversion method is able to provide high correlation values and low inversion errors, so it can determines the rock layers that predicted with gas-contain. The use of sweetness attribute and model-based inversion method can identify and describe reservoir characters well

Teknologi Low-Frequency Acoustic untuk Identifikasi Gas Hidrat Berdasarkan Perubahan Karakter Seismik di Perairan Laut Aru

Gas hydrate is a type of hydrocarbon formed like crystals and is formed in the seabed sediment layer. Water temperature and pressure affected the area where gas hydrates are formed; gas hydrates are composed of gas and water elements. Gas hydrates have the potential as an alternative to current uses of oils and gasses. The identification of gas hydrates on the seabed can be detected using low-frequency acoustic, seismic technology. This research aims to identify the presence of gas hydrate in Aru Sea waters based on changes in the seismic character of the gas hydrate. The method used is seismic data processing with ProMAX software. This research uses seismic data for the 3.01 trajectory acquired by the Marine Geology Research and Development Center in 2016 in the Aru Sea. Based on the data processed, gas hydrate was detected on the 3.01 line with a depth of 5,925 meters. Gas hydrate indicator on the seabed is characterized by cutting stratigraphy, reversing its polarity, high amplitude, and shape following the seabed.

Development of Quantitative Single Beam Echosounder for Measuring Fish Backscattering

Target strength (TS) of marine fish is a key factor for target identification and stock quantification. Validation of measurement and model comparisons in fisheries acoustics is difficult, due to the uncertainty in ground truth obtained in the ocean. To overcome this problem is to utilize laboratory measurements, where fish parameter is more well controlled. In this research, the dorsal‐aspect TS of fish was measured as a function of the incidence angle in a water tank using a quantitative echo sounder. The measurement was compared with the theoretical prediction using the distorted‐wave born approximation (DWBA) model. TS of fish was proportional to body length and the directivity of TS was strongly dependent on its orientation. Computational DWBA modeling, experimental details, and data/model comparison were presented

Distribution of Fish Target Strength in Malang Rapat Seawater of Bintan Island, Kepulauan Riau Province

Malang Rapat is an area located in east Bintan Island. As a part of coastal communities, fisheries were the primary sector for public revenue in Malang Rapat. A qualified method is needed to determine the abundance and distribution of fish were required. Hydroacoustic technology is one method to solve this problem. This research aimed was to determine the value of fish target strength and to determine the pattern of fish distribution behavior in Malang Rapat, Kepulauan Riau Province, on September 23 and 24, 2016, using scientific echosounder Simrad EK15. The result indicated that fish target strength in Malang Rapat was -60 dB to -42 dB. This value was useful to estimate the length of fish ranged from 3 cm to 31 cm. The highest mean target strength based on depth was -48 dB at 10 m in the daytime and -52 dB at 3 m in the nighttime. The abundance of fish was found at night, precisely 3 meters from the surface of the water. The highest frequency appearance target strength range from -60 dB to -58 dB with 3.94 to 4.95 cm estimated fish length

Acoustic Detection and Characterization of Marine Sediment with Shallow Seismic Technology in Rambat Waters, Bangka Belitung

High resolution of marine seismic reflection seismic were used to detect the layers of seafloor sediment and to interpret the seismic data geologically. The objectives of this study weres to detect and to characterize the seafloor sediment in the Rambat area, West Bangka, Bangka Belitung. Acquisition data was held on 10-24 August 2012 located between 105.1°00\u2700" - 105.5°00\u2700 " N and 1.7°00\u2700"-1.9° 00\u2700" W. Several methods used to process the data were geometry processing, band pass filter, predictive deconvolution, and Autocoralation Gain Control (AGC) in order to reduce the multiple noise and to ease the data interpretation. Seismic cross section found in Cross Rambat (CRMBT) line 11 exhibited sedimentation process of the sea floor which rocky substrates. The process was assumed to be occurred due to legal and illegal mining activities for long period of time

PEMETAAN DAN KLASIFIKASI SEDIMEN DENGAN INSTRUMEN SIDE SCAN SONAR DI PERAIRAN BALONGAN, INDRAMAYU-JAWA BARAT

Berdasarkan hasil deteksi dasar laut menggunakan side scan sonar dalam pencitraan benda-benda di dasar laut dapat menghasilkan berbagai variasi gambar yang digunakan untuk pencitraan objek-objek dasar laut, selain itu dapat memberikan informasi dalam pengembangan wilayah pantai. Tujuan dari penelitian ini adalah visualisasi atau pemetaan dasar perairan dan klasifikasi sedimen atau objek di dasar laut secara kualitatif, sehingga dapat diketahui keadaan dasar laut. Interpretasi dan klasifikasi data akustik side scan sonar dilakukan secara kualitatif dengan menggunakan software Sonar Pro untuk melihat bentuk geometris dan keunikan dari suatu objek. Pengambilan contoh sedimen dilakukan pada 6 jalur transek dengan jarak antar transek 0.5 km. Setiap transek terdapat 3 buah stasiun sampel sedimen dan jumlah total adalah 18 sampel sedimen. Berdasarkan hasil pemetaan dasar laut daerah Balongan terdapat buangan sedimen, paritan dan kerukan sedimen, selain itu terdapat objek seperti box, mooring, potongan pipa, tali, pole