Facies-based petroleum system of northern onshore Sarawak Basin

• Main Author: Mustaffa, Siti Noor Ashikin
• Format: Conference or Workshop Item
• Published: 2021
• Subjects: GE Environmental Sciences; TN Mining engineering. Metallurgy
• Online Access: http://eprints.um.edu.my/35702/; https://www.scopus.com/inward/record.uri?eid=2-s2.0-85111010906&doi=10.3997%2f2214-4609.202171018&partnerID=40&md5=d38fdd13d838b5468aff4141bf0e81bc

This work presents the facies-based petroleum system of the Tatau-Bintulu area in northern Sarawak, represented by the Belaga-Tatau-Nyalau formations. The Nyalau Formation exposures can be closely related to the offshore hydrocarbon-producing Balingian Province of Cycle I/II. Twelve facies associations are recognized from the formations, which form elements of larger-scale facies successions. The Belaga-Tatau-Nyalau formations are interpreted as mixed tide- and wave-influenced coastal to deep marine depositional system. The facies identified and the geological setting of the area are evaluated for potential elements in a petroleum system. Wave-dominated shoreface succession forms good reservoir-seal with shoreface sand overlain by muddy estuarine-bay. The fluvial channel forms good quality stacked reservoir enclosed by carbonaceous mud and coal bed, followed by the deposition of heterolithic-mud filled tidal channel sealed by muddy estuarine-bay, forming moderate-poor reservoir-seal potential. Tidal bar and mouth bar form broad amalgamated sand bodies with good horizontal and vertical flow properties, overlain either by muddy bay or prodelta mud. The distal turbidite sand forms moderate to poor reservoir with the interbedded basinal mud impeding the upward flow of hydrocarbon. As such, Belaga-Tatau-Nyalau formations possess a viable petroleum system depending on the facies that made up the geological element in a depositional environment. © EAGE Asia Pacific Virtual Geoscience Week 2021. All rights reserved.