Publications

The Halang formation is a representative example of deep water sedimentation with turbiditic system from Middle-Late Miocene in the North Serayu zone. The Halang Formation has more than 800 m thickness consisting of marl, tuffaceous calcareous sandstone, conglomerate and breccia. This study area is located in the Pemalang, Central Java Province and focuses on understanding facies identification, paleoenvironment, and character as a reservoir based on the outcrop and thin section. Two facies were identified based on outcrop data, mid fan and lower fan facies. The mid fan facies consist of Classical Turbidite (CT) and Massive Sandstone (MS) facies associations. The lower fan facies consist of Classical Turbidite (CT) facies associations mostly in the form of flysch deposits (repetition of carbonaceous claystone). Sedimentary structures that developed in the study area were graded bedding, parallel lamination, wavy lamination, convoluted, cross lamination, flute cast and bioturbation. Based on thin section method, this indicates that the Halang Formation has poor to very good porosity ranging from 10% - 25%. Based on weighing method, this formation has fair to very good porosity varying from 10.9% - 23.96%. Permeability analysis using permeameter gas tool determined that this formation has good to very good permeability, various from 28.97 mD - 826,969 mD. Based on all data, it can be concluded that the Halang Formation can be categorized as a fair - good quality reservoir. The Middle Fan sandstone show better reservoir quality than the Lower Fan sandstone.