Electronic Theses and Dissertation

Saat ini kebutuhan minyak dan gas bumi di Indonesia tidak sebanding dengan produksi minyak dan gas bumi yang dilakukan, hal ini mendorong para geoscientist terus melakukan eksplorasi untuk menemukan sumber cadangan baru termasuk pada ekplorasi batuan induk sebagai sumber dari terbentuknya hidrokarbon dalam system petroleum. Cekungan Sibolga merupakan salah satu cekungan di Indonesia yang menjadi target eksplorasi batuan induk hidrokarbon. Formasi tangla (Tlt) menjadi target studi penelitian ini berdasarkan penemuan batuserpih berwarna hitam yang diduga mampu menghasilkan hidrokarbon. Penelitian ini bertujuan untuk mengetahui kondisi geologi daerah penelitian dengan dilakukannya pemetaan geologi pada daerah penelitian. Selain itu, metode analisis geokimia pada batuserpih Formasi Tangla (Tlt) bertujuan untuk mengetahui potensi batuan induk hidrokarbon meliputi kuantitas, kualitas serta tingkat kematangan. Penelitian ini dilakukan dengan enam (6) metode penelitian yaitu pemetaan geologi, petrografi, total organic carbon, rock eval pyrolysis, kerogen type dan vitrinite reflectance. Pemetaan Geologi dilakukan dengan mengamati tujuh (7) satuan yang ditemukan dilapangan meliputi satuan batugamping (Mutlr), satuan batulempung (Tlt), satuan batulanau (Tlt), satuan tuff pasiran (Tlt), satuan batuandesit (Tlt), satuan tuff (Tlt), satuan endapan lanau (Qh). Berdasarkan pengamatan bentang alam pada daerah penelitian terdiri atas empat (4) bentang alam meliputi bentang alam denudasional unit D3 dan D5, bentang alam vulkanik dengan unit V14, bentang alam fluvial dengan unit F1 dan F3, bentang alam karst dengan unit K3. Hasil analisa kuantitas pada batuserpih formasi tangla (Tlt) menunjukkan nilai total organic carbon= 0,23 0,30, S1= 0-0.01, S2= 0.02-0.15. Hasil analisa kualitas pada batuserpih formasi tangla (Tl) menunjukkan nilai HI= 10-50, kerogen tipe III-IV. Hasil analisa tingkat kematangan pada batuserpih formasi tangla (Tlt) menunjukkan rentan nilai Ro(%)= 0,979-1.086, Tmax= 356-431, TAI= 3. Berdasarkan hasil analisa tersebut, batuserpih formasi tangla (Tlt) termasuk jenis batuan induk dengan karakteristik yang buruk sebagai batuan induk hidrokarbon.
Kata kunci: Cekungan Sibolga, batuan induk hidrokarbon, Formasi Tangla, batuserpih.

Currently, the demand for oil and gas in Indonesia is not proportional to the production of oil and gas. oil and natural gas production, this encourages geoscientists to geoscientists to continue to conduct exploration to find new sources of reserves including exploration of host rocks as a source of hydrocarbon formation in petroleum systems. petroleum system. The Sibolga Basin is one of the basins in Indonesia which is the target of hydrocarbon host rock exploration. Tangla formation (Tlt) formation is the target of this research study based on the discovery of black-colored shale that is thought to be capable of producing hydrocarbons. This research aims to determine the geological conditions of the study area by conducting geological mapping in the study area. geological mapping of the study area. In addition, the geochemical analysis method on Tangla Formation (Tlt) shale rocks aims to determine the potential of host rock for hydrocarbons including quantity, quality and maturity level. hydrocarbons include quantity, quality and maturity level. This research conducted with six (6) research methods namely geological mapping, petrography, total organic carbon, rock eval pyrolysis, kerogen type and vitrinite reflectance. Geological mapping was carried out by observing seven (7) units found in the field, namely in the field include limestone unit (Mutlr), claystone unit (Tlt), siltstone unit (Tlt), siltstone unit (Tlt), and siltstone unit (Tlt). siltstone unit (Tlt), passive tuff unit (Tlt), sandstone unit (Tlt), tuff unit (Tlt), silt unit (Qh). Based on landscape observations in the research area research area consists of four (4) landforms including denudational landforms units D3 and D5, volcanic landforms with unit V14, fluvial landforms with units F1 and F3, fluvial landforms with unit F1 and F3, and fluvial landforms with unit F3. with units F1 and F3, karst landscape with unit K3. Quantity analysis results on the tangla formation shale rock (Tlt) shows the value of total organic carbon = 0.23 0.30, S1 = 0-0.01, S2 = 0.02-0.15. The results of the quality analysis on the shale rock formation tangla (Tl) formation shows the value of HI = 10-50, kerogen type III-IV. The results of the analysis of the level of The maturity analysis of the tangla formation shale rock (Tlt) shows the vulnerable value of Ro (%)= 0.979-1.086, Tmax = 356-431, TAI = 3. Based on the analysis results, tangla formation (Tlt) is a type of host rock with poor characteristics as a hydrocarbon host rock. characteristics as hydrocarbon host rock. Keywords: Sibolga Basin, hydrocarbon host rock, Tangla Formation, shale rocks.