Identifikasi sebaran gas biogenik berdasarkan Analisis Data Geomagnetic: Studi Kasus Desa Batang-Batang Laok Kecamatan Batang-Batang Kabupaten Sumenep

ABSTRACT

Data were collected using a Proton Precession Magnetometer (PPM) type magnetometer with the G-856 type. The research area is 700 meters x 700 meters with a distance between measurement points of 50 meters. Interpretation is done qualitatively and quantitatively. Qualitative is done with the help of Software Surfer 13 and Software Magpick. Meanwhile, the quantitative interpretation is done with the Oasis Montaj Software.The qualitative interpretation results obtained a local anomaly contour map that has anomaly variation values between -35 to 40 nT. Based on the susceptibility value of low to moderate magnetic anomaly, it shows sedimentary rock, namely claystone containing biogenic gas. The distribution of biogenic gas is in the east of the study area. Based on the results of the quantitative interpretation of the study area, it is composed of several types of rock, including claystone with a susceptibility value of 0.0002 SI, marl with a susceptibility value of 0.018SI, limestone with a susceptibility value of 0.0003 SI and claystone which is thought to contain biogenic gas, with a susceptibility value of 0.0002 SI. The gas appears on the surface due to the activity of drilling community wells that penetrate the gas migration space to the surface.

ABSTRAK

Pengambilan data dilakukan dengan menggunakan alat magnetometer jenis Proton Precession Magnetometer (PPM) dengan tipe G-856. Luas daerah penelitian 700 meter x 700 meter dengan jarak antar titik pengukuran 50 meter. Interpretasi dilakukan secara kualitatif dan kuantitatif. Untuk kualitatif dilakukan dengan bantuan Software Surfer 13 dan Software Magpick. Sedangkan untuk interpretasi kuantitatif dilakukan dengan Software Oasis Montaj.
Hasil interpretasi kualitatif diperoleh peta kontur anomali lokal yang memiliki nilai variasi anomali antara -35 sampai dengan 40 nT. Berdasarkan nilai suseptibilitas batuan anomali magnetik rendah hingga sedang menunjukkan batuan sedimen yaitu batulempung yang mengandung gas biogenik. Persebaran gas biogenik berada di sebelah timur daerah penelitian. Berdasarkan hasil interpretasi kuantitatif daerah penelitian tersusun dari beberapa jenis batuan diantaranya yaitu batulempung dengan nilai suseptiblitas 0.0002 SI, napal dengan nilai suseptibilitas 0.018 SI, batugamping dengan nilai suseptibilitas 0,0003 SI dan batulempung yang diduga mengandung gas biogenik, dengan nilai suseptibilitas 0.0002 SI. Gas tersebut muncul di permukaan akibat adanya aktifitas pemboran sumur warga yang menembus ruang migrasi gas ke permukaan.