Seismic expression of carbonate build-up karstification: karst modelling strategies and insights from synthetic seismic

Abstract

Many ancient carbonate build-ups are impacted by meteoric diagenetic processes including karstification. However, very little is known about the acoustic properties and seismic expression of karstified reservoirs. This paper investigates potential seismic expressions of karstified buildups by means of synthetic seismic modelling. The overall stratigraphic architecture and rock physical properties are derived from published examples of southeast Asian carbonate buildups. Various karst systems, corresponding to distinct stages of karstification of varying intensity, have been superimposed to the background facies-related acoustic model. Three-dimensional synthetic seismic cubes have been computed from the karst-bearing acoustic model and by testing various wavelet frequencies. The proposed approach allowed several types of palaeokarsts to be reproduced, from dendritic karst and flank margin caves to cave networks, in amplitude sections. However, geometrical seismic attributes, like coherency, cannot be accurately reproduced with modelling based on the available literature data. In addition, the exploration of this synthetic seismic shows that non-stratiform diagenetic bodies (i.e leached carbonate wedge in a mixing zone), appears as stratiform even in very high resolution seismic. Thus, their detection and characterisation require advanced techniques or prior knowledge such as borehole data.

Seismic characterization of Cenomanian–Turonian carbonate platform based on sedimentological and geophysical investigation of onshore analogue outcrop (northern Lebanon)

“…Karst features have been interpreted in terms of seismic facies as chaotic seismic reflections with low amplitude (Burberry et al., 2016; Embry et al., 2021; Hendry et al., 2021; Hu et al., 2023; Sayago et al., 2012). This can be related to the petrophysical properties of karstified rocks often characterized by lower AI values compared to the surrounding rock units (Fournillon et al., 2021).…”

Fracture Network Analysis of Karstified Subis Limestone Build-Up in Niah, Sarawak

“…The Subis Limestone is commonly used as an analogue for Central Luconia carbonates. Previous studies on the Subis Limestone have focused on the biostratigraphy and sedimentology of carbonate rocks [25][26][27][28][29] and speleology [24,[30][31][32] with no mention of the fracturation history of the outcrop.…”

“…biostratigraphy and sedimentology of carbonate rocks [25][26][27][28][29] and speleology [24,[30][31][32] with no mention of the fracturation history of the outcrop.…”

Metodologia para Confecção de Mapas Potenciométricos em Aquíferos Cársticos e Físsuro-Cársticos: Estudo de Caso na Alta Bacia do Rio Corrente, Mambaí, GO

“…Os aquíferos físsuro-cársticos são reservatórios mistos representados por lentes carbonáticas associadas a rochas não carbonatadas (principalmente rochas pelíticas) que apresentam simultaneamente porosidade secundária planar e porosidade secundária por dissolução cárstica. Quando o carbonato é contínuo ou as lentes são muito espessas ou lateralmente amalgamadas (dezenas de metros de espessura e milhares de metros de extensão), os aquíferos devem ser tratados como sistemas fraturados e cársticos individuais (Fournillon et al, 2021).…”