Identify the Oil Seepage in Plantungan Geothermal Manifestation, Kendal Using HVSR Method

Abstract

The presence of oil seepage to the surface indicates that at least an active petroleum system is present subsurface. Oil seepage that occurred in Plantungan, Kendal, Central Java, has been known since 1971 and still produces seepage until today. On the research area, three oil seepages point were found. Plantungan region is located in East Serayu Zone underlain by volcanic area, and based on the Geology Map, the research area is located in Banjarnegara-Pekalongan Sheet. To understand the geology condition of the research area, a subsurface mapping is needed, even though the mapping does not provide the depth of bedrock and reservoir, data recording using HVSR (Horizontal to Vertical Spectrum Ratio) method that has been done in 18 points is able to provide Vp and density profile to understand the distribution of oil seepage. The oil seepage is most prominent close to SB09 location, however the result from crossplot found that the value of highest Vp×density is on SB12A with 4,306,197 kg/m2s, and lowest Vp×density in on SB17A with 302,305.3 kg/m2s.

Keywords

• oil seepage
• oil seepage in volcanic area
• oil seeps in geothermal manifestation
• acoustic impedance
• hvsr method
• spectra ratio method