KARAKTERISASI RESERVOIR MENGGUNAKAN ANALISIS INVERSI IMPEDANSI AKUSTIK DAN MULTIATRIBUT SEISMIK PADA LAPANGAN “PERDANA” CEKUNGAN SUMATERA TENGAH; RESERVOIR CHARACTERIZATION USING ACOUSTIC IMPEDANCE INVERSION AND SEISMIC MULTIATRIBUTE ANALYSIS IN “PERDANA” FIELD CENTRAL SUMATERA BASIN

Lestari, Katiti, Sudarmaji

2015 | Skripsi | FMIPA

This research was performed in “Perdana” Field, Sihapas Group, Central Sumatera Basin. “Perdana” Field is a mature field which entering the declining phase, but it is still estimated to have big potencies to produce oil & gas. The research was aimed for mapping lithology distribution of sandstone reservoir of Sihapas Group as targeted zone and also to help deciding the location of next development well. This research used 3D PSTM (Pre-Stack Time Migration) seismic data, four vertical wells with each checkshot data, well top (marker) data, and geological data. Top of targeted zone was limited by “Sihapas” horizon, while the bottom of targeted zone was limited by “Pematang” horizon. This research used model based acoustic impedance inversion and linear regression multiattribute methods. Acoustic impedance inversion analysis would result in acoustic impedance pseudo volume which then would be used as external attribute in seismic multiattribute analysis process. Before seismic multiattribute analysis process, crossplot analysis was performed to decide which parameter that would be sensitive for separating lithology which then be used in linear regression multiattribute analysis. The parameters used were Gammma-Ray and Density. The result which obtained from inversion analysis were acoustic impedance volume and slicing map, while the result from linear regression multattribute were Gamma-Ray pseudo volume, density pseudo volume, and also slicing map. Based on pseudo volume and slicing map result, it is shown that reservoir distribution which associated with sandstone in “Perdana” Field, Sihapas Group has the acoustic impedance value ranging from 18500-24000 (fts?)?(gcc?), while Gamma-Ray ranging from 34-75 API, and density ranging from 2.26-2.33 (gcc?). According to these parameters, it is shown that in the targeted zone, the reservoir distribution which associated with sandstone is interpreted to be located spreading from southeast area to the middle area of research zone. In addition, area which is expected to be favorable place for next development wells is located in the eastern zone of research area, to be precise in the third closure in the east.

Kata Kunci : inversion; seismic multiattribute; acoustic impedance; Gamma-Ray; density