IJOG : Indonesian Journal on Geoscience
Vol. 9 No. 1 (2022)

Contributions of Loading and Unloading to Overpressure: Analytical Results from The Shelfal Area of The Lower Kutai Basin, Indonesia

Agus M. Ramdhan (Department of Geology and Department of Groundwater Engineering, Institut Teknologi Bandung, Jln. Ganesha 10, Bandung 40132,)
Lambok M. Hutasoit (Department of Geology and Department of Groundwater Engineering, Institut Teknologi Bandung, Jln. Ganesha 10, Bandung 40132,)



Article Info

Publish Date
17 Nov 2021

Abstract

DOI:10.17014/ijog.9.1.1-13A modified Bowers Method is applied to analyze the contribution of loading and unloading to total overpressure magnitude in the shelfal area of the Lower Kutai Basin. The method combines Bowers Method with density-sonic cross plots to differentiate contributors to overpressure. This method has a strong physical background, and has proven to give satisfactory overpressure estimation in the studied area. Several processes related to overpressure and compaction in the studied area have also been deduced: 1) top of overpressure is caused by unloading due to gas generation, 2) gas generation on its own can produce overburden-scale overpressure magnitude, 3) loading starts to contribute to overpressure at depth, where the lithology is dominated by mudrocks, 4) effective stress history experienced by mudrocks before unloading, and 5) the presence of two compaction lines and therefore two associated velocity-effective stress relations.

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Journal Info

Abbrev

IJOG

Publisher

Subject

Earth & Planetary Sciences

Description

The spirit to improve the journal to be more credible is increasing, and in 2012 it invited earth scientists in East and Southeast Asia as well as some western countries to join the journal for the editor positions in the Indonesia Journal of Geology. This is also to realize our present goal to ...