GADJAH MADA GEOPHYSICS 

EXPLORATION GROUP

RESEARCH OBJECTIVES

We are interested in Geophysical exploration, seismic profilling (reflection or refraction), though we employ all other geophysical techniques when appropriate, and also attempt to integrate geological information to compute & analyze geophysical data closely into our models.

PEOPLE

This Group led by Drs. Sismanto, MSi. The members are students who interested in Geophysical exploration.

RESEARCH LINKAGES

• Cooperation with PERTAMINA and its Foreign Partner Oil and Service Companies, where the students of Geophysics Sub Department done their on job trainings and completing their thesis.

RESEARCH

AVO (AMPLITUDE VARIATION WITH OFFSET) ANOMALY

MAPPING IN “BETARA DEEP” AREA, JABUNG BLOCK, JAMBI

 By:

 Purbo Santoso

AVO (Amplitude Variation with Offset) anomaly is often indicates the existence of gas accumulation, therefore it is important to look for AVO anomalies in an exploration area. 

An attempt to carry out  AVO mapping has been conducted in the Air Benakat and Gumai formation of the Betara Deep area, Jabung block, Jambi. In order to get more detail results, each formation was divided into three intervals, i.e. Air Benakat A (top of Air Benakat – 80 ms under the top), Air Benakat B (between Air Benakat A and C), and Air Benakat C (base of Air Benakat – 80 ms over the base) for the Air Benakat formation, while the Gumai formation consists of Gumai A (top of Gumai – 140 ms under the top),  Gumai B (between Gumai A and C), and Gumai C (base of Gumai – 140 ms over the base). AVO mapping was conducted in these  intervals by using data of P*G attribute as a result of AVO processing of the Betara Deep’s seismic data.

Most of distribution of AVO anomalies in the Air Benakat formation was found in Air Benakat B, Air Benakat A had less anomalies than Air Benakat B, and the least distribution was in Air Benakat C. In the Gumai formation, Gumai A had more AVO anomalies than Gumai B, whereas Gumai C had no anomalies at all.

In overall, more AVO anomalies were found in the Air Benakat formation than that found in the Gumai formation, and AVO anomalies in both formations can be found in the southern part of the Betara Deep where there were a lot of fault structures that may be considered as hydrocarbon trap.