Testing clumped isotopes as a reservoir characterization tool: a comparison with fluid inclusions in a dolomitized sedimentary carbonate reservoir buried to 2–4 km

Constraining basin thermal history is a key part of reservoir characterization in carbonate rocks. Conventional palaeothermometric approaches cannot always be used: fluid inclusions may be reset or not present, while δ18O palaeothermometry requires an assumption on the parent fluid composition. The clumped isotope palaeothermometer, however, is a promising technique for constraining the thermal history of basins. In this study, we test if clumped isotopes record temperatures of recrystallization in deeply-buried dolomitic reservoirs, through comparison with fluid-inclusion data. The studied reservoir is the Cretaceous Pinda Formation, offshore Angola, a deeply-buried dolomitized sedimentary carbonate hydrocarbon reservoir. It provides an ideal test case as samples from industry wells are available over a relatively wide burial depth range of c. 2000–4000 m below seafloor (mbsf) and the constituent …