Analisis Model Kecepatan Gelombang-P pada Coal-Seam Gas Studi Kasus Cekungan Sumatera Selatan, Indonesia

Harnanti Yogaputri Hutami (Program Studi Teknik Geofisika, Jurusan Teknologi Manufaktur dan Kebumian, Institut Teknologi Sumatera)
Fitriyani Fitriyani (Program Studi Teknik Geofisika, Jurusan Teknologi Manufaktur dan Kebumian, Institut Teknologi Sumatera)
Tiara Larasati Priniarti (Program Studi Teknik Geofisika, Jurusan Teknologi Manufaktur dan Kebumian, Institut Teknologi Sumatera)
Handoyo Handoyo (Facultat de ciencies de la Terra, Universitat de Barcelona)

JGE (Jurnal Geofisika Eksplorasi)
Vol 6, No 2 (2020)

The rock physics model is one effective yet challenging way to investigate the coal-seam gas potential in Indonesia. However, because of the complex conditions of the Coal-Seam Gas Reservoirs, it is difficult to establish models. Despite the scarce modeling, this study aims to estimate the relation of gas-saturated within pores of coal seam to the elastic properties of rock, which is P-wave velocity. First, the coal seam minerals are applied to quantify matrix moduli using the Voigt-Reuss-Hill Average method. Pride’s simple equation is used to estimate the elastic properties of the coal seam at dry condition (zero gas saturation). Finally, Biot-Gassmann’s theory is applied to determine the elastic properties of coal seam with fully gas saturated. As the result, the proposed model showed that there is a significant negative correlation between gas content with both density and P-wave velocity of the coal seam. Finally, this P-wave velocity model of gas-saturated coal seams should be properly useful as the quick look for identifying coal seam gas potentials.