The Relationship Of Rock Properties And Elastic Properties By Using Integrated Seismic Quantitative Interpretation Methods To Characterize Carbonate Facies Banggai Basin

Abstract

The exploration activity in Eastern of Indonesia are mostly concern on carbonates play. The unique characteristics of carbonate and its complexity needs to be evaluated by using integrated methods. Extracting information about reservoir quality from seismic data is a key challenge in exploration, appraisal and production of hydrocarbons. The location of research area are in Banggai Basin within the Senoro – Toili Block on the eastern arm of Sulawesi. Several rocks are presence at Miocene carbonate section that potentially pointed as reservoir, ranging from bioclastic carbonates platform facies of Tomori and Minahaki Formations to reefal carbonates buildup of Mantawa member. Traditionally, seismic interpretation has been essentially qualitative. The geometrical expression of seismic reflectors was mapped in space and traveltime, but little emphasis is put on the physical understanding of seismic amplitude variations, however, seismic interpreters have put increasing emphasis on more quantitative techniques for seismic interpretation, as these can validate hydrocarbon anomalies and give additional information during prospect evaluation and reservoir characterization (P. Avseth, T. Mukerji and G. Mavko 2005 and Cambridge University Press, 2010). Traditionally seismic facies interpretation has been predominantly qualitative, based on seismic traveltimes. The traditional methodology consisted of purely visual inspection of geometric patterns in the seismic reflections (e.g., Mitchum et al., 1977; Weimer and Link,1991). Robust and flexible methods for estimation of reservoir properties from seismic data are essential for quantitative interpretation in reservoir characterization and monitoring. Several methods are commonly used to assess reservoir conditions from seismic reflection amplitudes. The conventional way is to perform qualitative seismic interpretation to outline geological structures and reservoir architecture from seismic reflection events, their geometry and character. There are so many parameter and uncertainty to evaluate the carbonates reservoir. Therefore, the integration of rock properties and elastic properties will be comprehensive ways to evaluate the carbonates reservoir. Hence, seismic quantitative interpretation will be used as the main methods, including post-stack amplitude analysis, offset-dependent amplitude analysis (AVO analysis), acoustic and elastic impedance inversion beside carbonates diagenesis analysis, lab analysis (petrography), and petrophysical analysis. Quantitative interpretation addresses a direct link between parameters describing reservoir properties (e.g. porosity, lithology and fluid saturation) and its effective (or upscaled) rock properties (e.g. compressional and shear impedances and velocities) that may be inferred from seismic observations at a scale characterized by the seismic wavelength. Hence, a stronger integration of rock physics in reservoir characterization is a reasonable approach to achieve a more quantitative interpretation. Forward rock physics modelling of effective rock properties from reservoir properties can be challenging if input model parameters are poorly constrained, but is commonly feasible. Our approach is to introduce fundamental rock physics relations, which help to quantify the geophysical signatures of rock and fluid properties. Since rock properties are a consequence of geologic processes, we begin to quantify the seismic signatures of various geologic trends. Objective of this research is to integrating both the data and expertise of geophysics and geology for carbonate reservoir characterization. The final product of the research will be the matched sensitive parameter that shows relationship on rock properties and elastic properties, including P-wave and S-wave impedances and also AVO analysis and classification to characterize the carbonate reservoir by its facies in Banggai Basin. The research highlight quantitative seismic interpretation method to reduce uncertainty and perform quantitative reservoir characterization in seismic data especially in carbonate reservoir.

AAPG Datapages/Search and Discovery Article #90331©2018 AAPG Asia Pacific Region GTW, Back to the Future – The Past and Future of Oil and Gas Production in the Asia Pacific Region, Bangkok, Thailand, September 26-27, 2018