A Comparison between Model Base Hardconstrain, Bandlimited, and Sparse-Spike Seismic Inversion: New Insights for CBM Reservoir Modelling on Muara Enim Formation, South Sumatra

41st HAGI Annual Convention and Exhibition 2016

Mohamad Noor, Faris^1 ; Adipta, Agra^1

Geophysical Engineering Department, Universitas Pembangunan Nasional 'Veteran' Yogyakarta, SWK 104 Northern Ringroad, Yogyakarta, Indonesia^1

关键词: Correlation value;    Geological modeling;    Hard constraints;    High amplitudes;    Inversion methods;    Seismic inversion;    South Sumatra Basin;    Thick coal seam;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/132/1/012031/pdf
DOI  :  10.1088/1755-1315/132/1/012031

来源: IOP

【 摘 要 】

Coal Bed Methane (CBM) as a newly developed resource in Indonesia is one of the alternatives to relieve Indonesia's dependencies on conventional energies. Coal resource of Muara Enim Formation is known as one of the prolific reservoirs in South Sumatra Basin. Seismic inversion and well analysis are done to determine the coal seam characteristics of Muara Enim Formation. This research uses three inversion methods, which are: model base hard-constrain, bandlimited, and sparse-spike inversion. Each type of seismic inversion has its own advantages to display the coal seam and its characteristic. Interpretation result from the analysis data shows that the Muara Enim coal seam has 20 (API) gamma ray value, 1 (gr/cc)-1.4 (gr/cc) from density log, and low AI cutoff value range between 5000-6400 (m/s)∗(g/cc). The distribution of coal seam is laterally thinning northwest to southeast. Coal seam is seen biasedly on model base hard constraint inversion and discontinued on band-limited inversion which isn't similar to the geological model. The appropriate AI inversion is sparse spike inversion which has 0.884757 value from cross plot inversion as the best correlation value among the chosen inversion methods. Sparse Spike inversion its self-has high amplitude as a proper tool to identify coal seam continuity which commonly appears as a thin layer. Cross-sectional sparse spike inversion shows that there are possible new boreholes in CDP 3662-3722, CDP 3586-3622, and CDP 4004-4148 which is seen in seismic data as a thick coal seam.