Shale Characterization of the Lower Baong Formation as a Potential Reservoir in a Shale Hydrocarbon System in Langkat-Aru, North Sumatra
Denny Suwanda Djohor1), Benyamin Sapiie2), Emmy Relawati3), Agus Guntoro4),
1, 4 Fakultas Teknologi Kebumian dan Energi, Universitas TrisaktiJakarta (11440)
denny_sd[at]trisakti.ac.id, agus_g[at]trisakti.ac.id
2,3 Fakultas Ilmu Teknologi Kebumian, Institut Teknologi Bandung (40132)
bsapiie[at]gc.itb.ac.id,emmy[at]gc.itb.ac.id,
Abstract
Detailed studies of shale characteristics as reservoirs in shale hydrocarbon unconventional systems using surface data to illustrate lithofacial and geomechanical models, have not been widely used in Indonesia. Therefore, the potential for shale as a reservoir in shale hydrocarbon systems is not well known, due to the lack of surface data and subsurface data, especially core rock data. Research on the characteristics of lithofacies shale from lower Baong Formation and the integration with the geomechanical characteristics (brittleness index), can be an initial method identifying zones that have potential as reservoirs in shale hydrocarbon systems. This research is expected to be useful for the future of oil and gas exploration in Indonesia, especially in mature sedimentary basins, thus encouraging the discovery of new reserves in Indonesia. The stages of research consists of several: collecting data from field observations, processing data and laboratory analyses, followed by analyzing data on the patterns resulting from data processing; presented in the form of track stratigraphic columns and lithofacies characteristics integrated with geomechanical data. The results of the study are as follows: a) The results of the compressive test (Sch. Hammer Test) show that the lithology found in the field shows different stress values, for siltstone and claystone showing the highest value (slightly strong rock) compared to claystone carbonate sand silt (slightly soft rock); b) Based on the results of laboratory analysis conducted, it was concluded that the characteristics of the lower Baong Formation lithology can be divided into 11 Litofasies, namely: Calc. Mud-Shale, Calc. Sandy Mudstone, Calc. Claystone and Sandy Claystone (NN5), Calc. Mudstone, Claystone and Calc. Silty Claystone (NN6) and Mud-Shale, Calc. Siltstone, Sandy Mudstone and Calc. Clay-Shale (NN7); c) The results of calculation of Brittleness Index (BI) obtained by litofasies which have the highest BI value are Sandy Claystone and Sandy Mudstone, while for litofasies that have low BI values are Claystone; d) Litofacation of Sandy Claystone and Sandy Mudstone with the highest BI value, is a zone that has the potential as a reservoir in the shale hydrocarbon system; e) this research shows that the lower Baong Formation in detail have varied lithological and geomechanical characteristics.
Keywords: reservoir, unconventional, shale hydrocarbons, lithofasies, geomechanics, Lower Baong Formation
Topic: Geology