Source rocks maturity

Keywords plate tectonics, sedimentary basins, source rocks, maturation, migration, reservoir rocks, traps, seismic, gravity survey, magnetic survey, geochemistry, mudlogs, field studies. 

Objecfive Method Basin Source Rock Maturation Migration Rese rvoir Rock Trap Fluids oil, gas, water... 

John R. Wilmshurst, Dip RMIT, BSc, PhD, University of Melbourne, commenced work on exploration methods for base and precious metals within the CSIRO Division of Mineral Chemistry at North Ryde in 1972. His particular interest was the weathering of metalliferous minerals and he was involved with developing and applying an in-house mercury detector for base-metal and precious-metal exploration. He is presently working in the CSIRO Division of Petroleum Resources, developing tools for source-rock maturity estimation. 

Barth, T. Bjorlykke, K. (1993) Organic acids from source rock maturation generation potentials, transport mechanisms and relevance for mineral diagenesis. Appl. Geochem., 8, 325-337. 

Tirrawarra Sandstone, either meteoric invasion or source-rock maturation probably accounts for the association of authigenic kaolinite patches with siderite spar displaying dissolution (Fig. 4B). 

We have defined in-house calibrations of source roek maturity from various petroleum systems, assessed as source roek vitrinite reflectance equivalent as a proxy for maximum source rock temperature. The molecular parameter versus Ro% calibrations referred to below are either based on published source rock parameters we have validated to our satisfaction (e.g. Schaefer Littke 1988) or from in-house work on source rock maturity sequences. Inevitably, as all oils are mixtures we cannot accurately define point maturities for reservoired oils but by judicious choice of calibrant source-rock samples we feel the calibrations referred to are as robust as is possible in dealing with spatially and temporally complex entities such as source basins. The oil maturities we report are those interpreted classically based on correlations between measured oil molecular ratios and the... 

V.7. PVT modelling was performed using the internal PVT simulator of PetroMod as well as PVTsim V.12 for control purposes. The source rock to which the kinetic model was applied was located in the lower left margin of the model. The small structural closures in the model (Fig. 5) trapped only minor amounts of the migrating fluid phase, such that the composition within each reservoir was representative of a composition dominated by the instantaneous phase of the generated fluid. The composition of the fluid in the lowermost reservoir was characteristic for the current source rock maturity at any time step. The entire 2D section was modelled to reflect deposition in a very short time span. Carrier and reservoir properties were constant and relative permeability of hydrocarbon gas and oil phases irrelevant as the... 

Maturity. Conventional biomarker maturity indicators suggest that source rock maturity has... 

Finally, with respect to the influence of source rock maturity, it is instructive to examine the distribution of C7+ pseudo-components in Magnolia oils. Representative component profiles of cleaned samples from the two end-member Magnolia oils (see Fig. 7) are shown in Figure... 

Sulphur content and total acid number (TAN) of Magnolia oils and condensates inversely correlate with liquid API gravity (Table 1). Although sulphur and TAN are known to increase as a consequence of biodegradation (Behar Albrecht 1984 Meredith et al. 2000 Watson et al. 2002), both may be influenced by source rock maturity (Dias et al. 2002). In view of the discussion above, low maturity is viewed as being more likely responsible for the modestly elevated sulphur and TAN content in some of the Magnolia fluids. 

Kerogen content The type and quantity defines the quality of the source rock material and correlates to the hydrocarbon generation efficiency. The kerogen content also provides indications of source rock maturity and residual hydrocarbon generation capacity. 

Source rock maturity. In a study of the diagenesis and burial history of the Lower Cretaceous Travis Peak Formation in eastern Texas, Dutton (1987) reported measured vitrinite reflectance values for Travis Peak shales generally ranged from 1.0 to 1.2%. Westcott Hood... 

Dykstra J (1987) Compaction correction for burial history curves applications to Lopatin s method for source rock maturation determination. Geobyte 2(4) i6-z3 Espitalie J (1986) Use of as maturation index for different types of organic matter. Comparison with vitrinite reflectance. Therm. Model. Sediment. Basins. 1st IFP Explor. Res. Conf. Carcans. June 3-7, Paris, p 475-496... 

Yin P, Surdam RC, Boese S, MacGowan DB, Miknis F (1993) Simulation of hydrocarbon source rock maturation by hydrous pyrolysis. In Andrew S, Strook B (eds) Fiftieth anniversary field conference guidebook. Wyoming Geol Assoc, Casper, pp 359-373... 

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