ABSTRACT: Assessment of lacustrine and deltaic contributions to oils from Indonesia

Ellis, Leroy¹, Albert G. Holba², and Ron Noble³
(1) Terra Nova Technologies, Dallas, TX 
(2) ARCO Exploration and Production Technology, Inc, Plano, TX 
(3) ARCO Indonesia, Plano, TX

A suite of novel biomarker correlations have been successfully employed to distinguish and assess lacustrine and fluvial/deltaic organic matter contributions to oils sampled from the Sunda, Lombok, Arjuna, NW Java and Kangean Basins, Indonesia. Sunda and Lombok Basin oils analyzed in this study are considered to be derived exclusively from source rocks deposited in a lacustrine depositional setting. Sunda Basin oils, NF-1 and Karmila A-2, show a relatively higher contribution of terrestrial organic matter, and may indicate subtle differences in the lacustrine depositional setting for the source rocks of these oils within the Sunda Basin. Arjuna and NW Java oils analyzed in this study are considered to be derived exclusively from source rocks deposited in a fluvial/delatic depositional setting. Arjuna Basin oils, KK-2, B and E, show subtle geochemical differences to other Arjuna Basin oils, that is suggested to reflect a relatively more marine influenced delta-front/pro-delta depositional setting. Kangean Basin oils analyzed in this study can be correlated to either lacustrine or fluvial/delatic sources, with no apparent mixed inputs occurring. West Kangean-2 and Sepanjang Island-1 samples were classified as exclusively lacustrine in nature while all other Kangean Basin oil samples (including Pagerundan condensates) were classified as originating from fluvial/delatic sources. Application of detailed MS/MS source specific biomarker technology is also demonstrated.

AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia