Power Spectral Density Analysis using Low Frequency Passive Seismic for Direct Hydrocarbon Indicator in Kendal Sub-Basin Area
1Maman Rohaman, 2Alfathony Krisnabudhi, 2Hasan Tri Atmojo, 1Fauzan Abiyyu Pratama, 1Perla Hanun Aprillarosanti, 1Ayu Ismiatul Umamah

1Geophysical Engineering. Universitas Pembangunan Veteran Yogyakarta, Yogyakarta, Indonesia
2Geological Engineering. Universitas Pembangunan Veteran Yogyakarta, Yogyakarta, Indonesia

Abstract

Kendal Sub-basin is a part of the North Sarayu Basin. Some potential source rocks that produced the hydrocarbon are Paleogene and Neogene source rock. The presence of hydrocarbon can be identified from several wells in this area. The main reservoir is the Cipluk Formation, which consists of volcanic sandstone. The reservoir play types are divided into two play types: stratigraphic and structural trap. This focus area is the fault thrust area. The thrust fault trend in this area is northwest-southeast, with a dip relative to the south. Therefore, it is possible to migrate hydrocarbon from the deeper area in the south. The power spectral density (PSD) is performed to analyze this active petroleum system. This analysis utilizes waveform data from the acquisition in May 2024. This data in the time domain is transformed into the frequency domain using the Fourier transform. In the frequency domain, PSD is calculated by using a complex number of the data. The result of PSD analysis indicates the local anomaly in the frequency range of 2-3.5 Hz. This anomaly indicates that the presence of hydrocarbon affects wave propagation from the natural source to the receiver. In that frequency range, the value of PSD-IZ is 0.867.

Keywords: passive seismic, low-frequency, spectral, north serayu, waveform

Topic: Engineering