Sedimentary Facies and Hydrocarbon Reservoir Potential of Sand Flat in the Upper Part of Tapak Formation in Banyumas Area, Central Java

Abstract

The upper part of Tapak Formation in Kali Cimande consists of alternating sandstones, siltstone and mudstone. The alternating sequence showed a fining and thinning upward bedding pattern. The facies association of the alternation built up by sand flat facies, which characterized by medium sandstone, moderate sorted, with cross-lamination sedimentary structures and mostly on the top of sandstone layer found a bioturbation trace fossils (Skolithos). Mixed flat facies, which is characterized by an alternation of thin layered sandstones with mudstone and siltstone, with lenticular, wavy, and flaser sedimentary structures, contained many forms of bioturbation, such Planolites, Thallasinoides, Lockeia, and Ophiomorpha. Mud flat facies association, is characterized by a repeated of claystone with thin sandstone intercalation, where the ratio of clay content more than 95 % of the total layers, contained abundantly with trace fossil Lockeia. Upper Tapak Formation plays as moderate reservoir potential. The thick sandstone in sand flat facies with moderate to poorly sorted and moderate porosity is required to provide hydrocarbon flows in Banyumas Basin.Bagian atas Formasi Tapak di Kali Cimande terdiri dari perselingan batupasir-batulanau dan mudstone. Sekuen perselingan menunjukkan pola perlapisan menghalus dan menipis ke atas. Asosiasi fasies tersebut terdiri dari fasies sand flat, yang dicirikan oleh batu pasir sedang, pemilahan sedang, struktur sedimen silang-siur serta fosil jejak bioturbasi (Skolithos) pada bagian puncak kebanyakan lapisan batu pasir. Fasies mixed flat, dicirikan oleh perselingan batupasir berlapis tipis dengan mudstone dan batulanau, serta struktur sedimen lentikular, perlapisan bergelombang, dan flaser, mengandung banyak bioturbasi, seperti Planolites, Thallasinoides, Lockeia, serta Ophiomorpha. Asosiasi Fasies sand flat, dicirikan oleh perulangan batulempung dengan sisipan batupasir tipis, dengan kandungan lempung lebih dari 95% total lapisan, serta fosil jejak Lockeia yang melimpah. Formasi Tapak Atas berperan sebagai reservoir potensial sedang. Bagian batupasir tebal di fasies sand flat dengan pemilahan sedang hingga buruk dan porositas sedang diperlukan untuk menyediakan aliran hidrokarbon di Cekungan Banyumas.

Characteristics of Carbonate Facies and Depositional Environment of Tapak Formation in the Ajibarang Area, Central Java, Indonesia

“…Ma'arif [5] studied the lower part of the Tapak Formation and identified it was deposited as part of the deep sea levee and middle fan channel. The detailed information and history of hydrocarbon exploration in the Tapak Formation is still not adequate [4]. This study on the limestone of the Tapak Formation will provide more information about the petroleum system in Central Java, Indonesia.…”

“…Amin [3] identified that the depositional environment of Tapak Formation ranged from tidal to deep marine. Based on sedimentary facies and microfossil content, Rizal [4] identified that the upper part of the Tapak Formation is characterized by alternating sandstone, siltstone, and mudstone, with fining and thinning upward sequence. Rizal [4] also identified that the sandstone of the upper part of the Tapak Formation could play as reservoir potential, as this sandstone has 10 to 15% porosity.…”

“…Based on sedimentary facies and microfossil content, Rizal [4] identified that the upper part of the Tapak Formation is characterized by alternating sandstone, siltstone, and mudstone, with fining and thinning upward sequence. Rizal [4] also identified that the sandstone of the upper part of the Tapak Formation could play as reservoir potential, as this sandstone has 10 to 15% porosity. Ma'arif [5] studied the lower part of the Tapak Formation and identified it was deposited as part of the deep sea levee and middle fan channel.…”

Heavy Oil Seapage Characteristic in Cipari Area, Banyumas Central Java

“…Local people call this oil seep as "oli", probably came from Dutch language "olie" which means oil. Several authors had reported and published studies regarding to this oil seep (Mulhadiyono, 1973;Subroto, et.al., 2005;Armandita, et.al., 2009, Rizal, et. al., 2018.…”

The Architectural Element Distribution of Cinambo Formation in Jatigede Area, Sumedang District, West Java - Indonesia

“…On the island of Java itself, starting from West Java to East Java, there are very many turbidite deposits during Miocene to Pliocene. Some of them in West Java and Central Java have been investigated by Rizal et al (2016Rizal et al ( , 2017 and Praptisih et al (2012) explain the sedimentation facies of turbidite deposits aged Mio-Pliocene, and Rizal (2018) explain the relationship the relationship of turbidite deposits with hydrocarbon reservoir potential. Deep sea sediments generally have the potential for hydrocarbon systems, as they have been proven in the Kutei Basin, Brunei, Tarakan, North Sumatra, East Java, and Palawan Basin (Kusumastuti et al, 2001) and the Bintuni Basin (Nugrahanto et al, 2001).…”