Subsurface Characterization Based on Densities, Heat Sources and Thickness of Sediments Obtained From Inverse Modelling of Gravity Data

Using geophysical methods and measuring physical properties of subsurface rocks are good solutions for investigating the subsurface structures and exploring underground buried resources (such as oil, gas, water, minerals, etc.). This research investigates the anomaly sources of Zagros and the Red Sea by using the derivative filters, regularized filters, analytic signal, local-phase filter, 3D-inverse modelling with the Li-Oldenburg method. For this purpose, these filters are first applied to artificial models to determine the capability of each of these filters, a comparisons is also will be made between edge detection filters and finally applied to the real gravity of Zagros and Red Sea regions (taken from the EGM2008 Global Model). The overall result is that the effective depth of the sources of gravity anomalies of the Red Sea is approximately 200 km, and incoherently, up to a depth of 300 km. The effective depth of the Zagros anomalies sources is also about 180 km and since then it has continued inconsistently up to 400 km.

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PEMODELAN DAN ANALISA STRUKTUR BAWAH PERMUKAAN DAERAH PROSPEK PANASBUMI KEPAHIANG BERDASARKAN METODE GAYABERAT

Jurnal Geofisika Eksplorasi ◽

10.23960/jge.v4i2.14 ◽

2020 ◽

Vol 4 (2) ◽

pp. 47-61

Author(s):

Roy Bryanson Sihombing ◽

Rustadi Rustadi

Keyword(s):

Gravity Data ◽

Bouguer Anomaly ◽

Research Area ◽

Inverse Modelling ◽

3D Inversion ◽

Vertical Derivative ◽

The North ◽

A Value ◽

Value Range ◽

Range Of Values

Research has been conducted in Kepahiang area using gravity data with the aim of identify faults based on analysis of the Second Vertical Derivative (SVD) and interpreting structure sub-surface of the based on 3D inverse modelling from Bouguer anomaly and residual anomaly. The research area have an Bouguer anomaly between 38 mGal - 74 mGal, where the high Bouguer anomaly value has a value range of 63,2 mGal - 74 mGal located in the southwest direction of the research area. Whereas the low Bouguer anomaly value has a range of values 38 mGal - 47 mGal located in the north of the research area. To know the existence of fault structure in research area, conducted filtering Second Vertical Derivative (SVD) on the map Bouguer anomaly, regional and residual. The structure faulting is shown with contour of zero and between the contours of high and low. From the analysis of SVD complete anomaly Bouguer and SVD residual anomaly there are 8 (eight) faulting, while from SVD regional anomaly there are 4 (four) fault. 3D inversion modeling of the residual anomaly was done to prove the existence of the fault analyzed based on filtering Second Vertical Derivative (SVD). Based on the results of inversion 3D residual anomaly been gained one (1) reservoir in a northern direction research area and two (2) in the direction of west the research area by a contrast the density of -0,0719356 gr/cc until -0,236053 gr/cc with a depth of 0 meters up to 4.705 meters.

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