Shale Gas Resources of Talang Akar and Lahat Formation at Topaz Area, Indonesia

Yuliandri, Indra¹; Anggela, Melianie; Yusmen, Dedi; Kurniawan, Medy; and Latuconsina, Musalam
¹[email protected]

Shale gas is one of the alternative energy that has potency in Indonesia. Based on Government’s study, shale gas potency in Indonesia is around 574 TCF that spread in seven basins. It is bigger than CBM and conventional gas, which is about 453 TCF and conventional gas 334, 5 TCF respectively. Many oil and gas players (local and international) interesting to do an integrated study about shale gas resources.

Topaz area is located in South Sumatera Basin that produce oil and gas from conventional method with the primary objective reservoir is Baturaja Formation. Based on study at Topaz Area, Late Oligocene-Early Miocene Talang Akar and Early Oligocene Lahat Formation have shale gas potential resources to develop. Both of these formations act as a source rock and reservoir in conventional method due to sand and shale content. An integrated data such as geology, geochemical, geomechanical and petrophysic from existing data can identify shale gas potency in these formations. Shale gas production per well can be calculated and predicted after shale gas potency identified. By analyzing shale gas parameters such as maturity, thickness, depth, TOC, Kerogen Type and Brittleness Index, shale gas potency in Talang Akar and Lahat Formation can be identified.

Estimation of gas in place can be calculated from free gas and adsorb gas in both formations. Free gas is a gas that trapped in rock matrix porosity and/or natural fractures which can be calculated by Lewis equation, while adsorbed gas is stored mainly on the internal surfaces of the organic material. There are no core samples available in this target, so estimation adsorbed gas based on Jarvie TOC vs Gas Content Chart can be used.

From petrophysical parameters and well design (directional drilling and hydraulic fracturing), profile production per well can be predicted. The first production is peak production that supposed from free gas which trapped in pores and/or natural fractures in this formation. The plateau will be showed after ±3 years production. Many wells are needed to maintain production profile from one field.

AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013