A SEQUENCE STRATIGRAPHIC DEPOSITIONAL MODEL OF NEOPROTEROZOIC STRATA, YOWALGA AREA, OFFICER BASIN,WESTERN AUSTRALIA

2000 ◽  
Vol 40 (1) ◽  
pp. 15 ◽  
Author(s):  
S.N. Apak ◽  
H.T. Moors
Keyword(s):  
Seismic Data ◽  
Sequence Stratigraphic ◽  
Petroleum Systems ◽  
Stratigraphic Analysis ◽  
Regional Correlation ◽  
Depositional Settings ◽  
Potential Reservoir ◽  
Storm Wave ◽  
Flooding Events ◽  
Stacking Patterns

Additional data and further studies have now improved geological, geophysical, and geochemical understanding of the Neoproterozoic strata of the Officer Basin. New sequence stratigraphic analysis of continuously cored drillholes (particularly Empress–1/1A), extended throughout the area with wireline log and seismic correlations, provide enhanced recognition of depositional fades and thus basin architecture. Four major flooding events and fifteen sedimentary successions, interpreted as parasequence sets by regional correlation, are recognised across the Yowalga area. These parasequence sets are traceable using seismic data, with flooding events identified on cores and logs producing regional or local reflectors with good amplitude and continuity.Sedimen tary cycles are dominantly mixed carbonates- siliciclastics with primarily progradational stacking patterns. These imply transgressive and regressive cycles in a basin with low bathymetric relief. Depositional settings range from supratidal to just below storm wave base.This interpretation improves the prediction of potential petroleum systems. An architectural model for each formation allows prediction of depositional trends including potential reservoir, source rock and seal in the Yowalga area.

DEPOSITIONAL SEQUENCE MODEL FOR THE POST-BARROW GROUP NEOCOMIAN SUCCESSION, BARROW AND EXMOUTH SUB-BASINS, WESTERN AUSTRALIA

1993 ◽  
Vol 33 (1) ◽  
pp. 151
Author(s):  
Peter A. Arditto
Keyword(s):  
Seismic Data ◽  
Sensu Stricto ◽  
Well Log ◽  
Depositional Sequence ◽  
Sequence Stratigraphic ◽  
Exmouth Plateau ◽  
Stratigraphic Analysis ◽  
Cast Doubt ◽  
Well Data ◽  
Stratigraphic Nomenclature

Structural traps at the top 'Barrow Group' are the most successful oil exploration targets in the Barrow/Exmouth Sub-basins. However, a reinterpretation of recent exploration activities undertaken by BHP Petroleum Pty Ltd, combined with regional investigations on the Exmouth Plateau, has cast doubt on the validity of accepted stratigraphic nomenclature for the Neocomian succession. A more geologically rational subdivision of the upper part of the Neocomian succession into two discrete sequence stratigraphic units is proposed.Key seismic data from the Exmouth Plateau, tied into wells with good age control, have enabled precise recognition of the Intra-Valanginian Unconformity within the currently-defined Barrow Group. The Barrow Group (sensu stricto) is redefined in this paper as the Barrow Megasequence (restricted to a Berriasian age succession), comprising a rapid progradational phase, which was abruptly terminated by the Intra-Valanginian event.Local erosion of the Barrow Megasequence along the Novara Arch through an Early Valanginian uplift, during the ensuing Valanginian regional transgression, contributed to the development of a parasitic clastic wedge, previously referred to as the Upper Barrow Delta on the Exmouth Plateau and here named the Zeepaard Sequence, with a nominated section in Zeepaard-1. The Zeepaard sequence is terminated by a Top Valanginian unconformity, upon which a final deltaic clastic pulse was deposited as the Birdrong Sequence. Each successive clastic wedge had a more limited development, with the basinward progradation terminating well short of the underlying stratigraphic unit. The Birdrong Sequence was terminated by an Intra-Hauterivian unconformity upon which the highly glauconitic, thin, Mardie Greensand Member of the Muderong Sequence was developed.The Zeepaard Sequence and overlying Birdrong Sequence can be characterised using both seismic and well log character. Well data in particular has enabled detailed stratigraphic mapping of the Birdrong Sequence which is thin and generally not seismically resolvable across the Barrow Sub-basin. This paper presents a detailed sequence stratigraphic analysis of the Birdrong Sequence using well log data.

Delineating Depositional Environment through Lithostratigraphy and 2D Sequence Stratigraphy of a Typical Ramp Succession: In the Obom Field Niger Delta

2021 ◽  
Author(s):  
Onome Okobiebi ◽  
Becky Okobiebi
Keyword(s):  
Sequence Stratigraphy ◽  
Niger Delta ◽  
Depositional Environment ◽  
Facies Analysis ◽  
Seismic Analysis ◽  
3D Modelling ◽  
Sequence Stratigraphic ◽  
Stratigraphic Analysis ◽  
Depositional Patterns ◽  
Stacking Patterns

Abstract Modelling the most appropriate depositional environment is essential in the reservoir characterisation and 3D modelling of oil bearing sands and the integration of various workflows reduces the uncertainty in deciding the appropriate depositional model which serves as a precursor into petrophysical property distribution during 3D modelling. This paper elaborates a robust study of the integration facies analysis, 2D sequence Stratigraphy and biostratigraphy data in depicting the environment of deposition of the OBOM field. The lithological description of the G8 to the F5 reservoirs ranged from finning upward sequence and blocky shaped sequence as channel sands and coursing upward shoreface deposits. Mineralogical descriptions of the penetrated sands were also carried out, especially on the F5 reservoir in which the presence of radioactive minerals was decisive to constrain the depositional environment to lower shoreface. In the Sequence stratigraphic analysis two 3rd Order depositional cycles was identified from top to bottom in the field. This is substantiated by the facies trend, facies cross plot and cycles indicators like maximum flooding surfaces identified by regional marker shales, biofacies population and biodiversity charts and sequence stratigraphic methods like sequence thickness, bed stacking patterns and facies depositional patterns with regards sea level change. It was noticed that reservoir thickness reduces from the bottom to the top with the proximal channel sands in deep intervals gradually overlain by distal upper shoreface sands and lower shoreface sands at the shallower intervals. The gross depositional environment was a transgressive marine settings ranging from the lower shoreface and channelized upper shoreface deposits. The results from the integration of facies analysis, biofacies, seismic analysis and sequence stratigraphy results reduces uncertainty in depositional environment models.

Petroleum Systems Analysis of The Tungkal PSC Area, South Sumatra – A Means of Adding New Life to A Mature Area

2020 ◽  
Author(s):  
A. Livsey
Keyword(s):  
Seismic Data ◽  
Systems Analysis ◽  
Generation Model ◽  
Hydrocarbon Accumulation ◽  
Petroleum Systems ◽  
Oil Generation ◽  
Exploration Risk ◽  
Exploration Area ◽  
Hydrocarbon Charge ◽  
Surface Geology

South Sumatra is considered a mature exploration area, with over 2500MMbbls of oil and 9.5TCF of gas produced. However a recent large gas discovery in the Kali Berau Dalam-2 well in this basin, highlights that significant new reserve additions can still be made in these areas by the re-evaluation of the regional petroleum systems, both by identification of new plays or extension of plays to unexplored areas. In many mature areas the exploration and concession award history often results in successively more focused exploration programmes in smaller areas. This can lead to an increased emphasis on reservoir and trap delineation without further evaluation of the regional petroleum systems and, in particular, the hydrocarbon charge component. The Tungkal PSC area is a good example of an area that has undergone a long exploration history involving numerous operators with successive focus on block scale petroleum geology at the expense of the more regional controls on hydrocarbon prospectivity. An improved understanding of hydrocarbon accumulation in the Tungkal PSC required both using regional petroleum systems analysis and hydrocarbon charge modelling. While the Tungkal PSC operators had acquired high quality seismic data and drilled a number of wells, these were mainly focused on improving production from the existing field (Mengoepeh). More recent exploration-driven work highlighted the need for a new look at the hydrocarbon charge history but it was clear that little work had been done in the past few year to better understand exploration risk. This paper summarises the methodology employed and the results obtained, from a study, carried out in 2014-15, to better understand hydrocarbon accumulation within the current Tungkal PSC area. It has involved integration of available well and seismic data from the current and historical PSC area with published regional paleogeographic models, regional surface geology and structure maps, together with a regional oil generation model. This approach has allowed a better understanding of the genesis of the discovered hydrocarbons and identification of areas for future exploration interest.

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