b'AEGC 2023Short abstractswas delineated over the eastern magnetic anomaly within Queensland and adjacent states. Three different maturity western magnetic target showing a broader deeper gravityscenarios, immature, mature and overmature are considered. low. Initial drilling targeted the eastern coincident magnetic/ A good match is observed between modelled compressional gravity anomaly and subsequently intersected widespreadand shear impedances and original well log curves for the IOCG type alteration and Cu mineralisation. Several linesimmature case. Finally, forward modelling is conducted for of Offset Dipole-Dipole Induced Polarisation (IP) data werethe three maturity conditions to observe changes in seismic collected aiming to understand the chargeability responsesignature within Toolebuc interval.of the drilled IOCG system and detect any other ore grade width mineralisation in the interpreted alteration zone. The IP survey highlighted two moderate chargeability anomalies,A geophysically relevant proton conduction model for one coincident with the eastern magnetic anomaly andthe upper mantle.another 2 km southwest in a magnetically quieter area. While the drilling around eastern magnetic anomaly encounteredSarath Patabendigedaracopper sulphides associated with the IOCG system, theCSIROsouthwestern feature did not yield a comparable amount of sulphides in the Proterozoic basement. Further analysisWater in mantle minerals significantly affects the chemical and and downhole logging for some selected holes confirmedphysical conditions of the interior of the Earth. Water may be the chargeability response from the surface IP survey couldretained hydroxyl groups in minerals or as free fluid inclusions be a combination of altered magnetite +/- sulphides in thewhich reduce viscosity in mantle rocks, reduces the melting basement as well as pyrite logged in the cover sequence.temperature in the upper mantle and modifies phase equilibria It was shown that while 3D inversion products from offsetand petrological processes. Several studies furthermore suggest Dipole-Dipole data are useful, they should never be used asthat the presence of water in mantle rocks is a key factor in the a standalone product. Inline Dipole-Dipole data, pseudo- initiation of plate tectonics.sections and forward modelling along with petrophysics/downhole logging provides much better insight intoThe content of water in the mantle can be estimated geological interpretation and exploration targeting. petrologically from examination of materials returned from mantle xenoliths or mantle-derived magmas, with an inherent time delay of tens of millions of years. However, Impact of kerogen thermal maturity on rock-physicsindirect real-time in situ observation is possible through modelling of Toolebuc formation. electromagnetic geophysical methods (magnetotellurics) due to the techniques extreme sensitivity to the presence of Partha Pratim Mandal 1 Rob Ross1, Brendon Mitchell2, Brentonwater in rocks. This method requires an understanding of the Richards2, Elizabeth Baruch-Jurado2 and Melissa Vallee2 relationships between water in mantle minerals, diffusion, and 1 Qeyeelectrical conductivity.2 Origin Energy Electrical conductivity of mantle minerals has been studied Source rock characterisation of low permeability andusing impedance spectroscopy and tracer diffusion techniques. heterogenous organic-rich shales (ORS) remains challenging.These studies revealed that water dramatically enhances Following the success of exploration drilling to locatethe electrical conductivity of mantle minerals (e.g., Olivine, organic-rich intervals, field development and production ofPyroxene and Garnet). Despite agreement on the overall these unconventional reservoirs is largely dependent uponeffect of water on electrical conductivities of these minerals, characterising the spatial distribution of organic-rich sweetcurrent conductivity models for dominant mantle minerals spots (kerogen content), maturity level, and geomechanicalprovide values that contrast by many orders of magnitude properties using seismic datasets. Potential hydrocarbonwith predictions derived from geophysical observations. This generation followed by substantial overpressure conditionscould be due to poor estimates of the relative contributions of originate from the thermal maturity of ORS. In quantitativegrain and grain boundary conductivities. In this work, in-grain interpretation of seismic data, a rock physics model calibratedand grain-boundary proton diffusion was separately measured with wireline logs is used to model the rocks physicalin order to reconcile this discrepancy. Experimental data and properties under in situ conditions. The thermal maturityresults of a series of studies are presented in order to expand of kerogen has a significant effect on the elastic propertiesour understanding of water diffusion in mantle minerals and its of ORS. Rock physics models for kerogen thermal maturityeffects on electrical conductivity.are built by combining petroleum systems and geochemical properties of various kerogen types. Three accompanying factors of thermal maturation of kerogen are included in theAutomated permeability prediction from basic model to derive physical properties of kerogen: (i) creationpetrophysical logs.of organic pores at nano-meter scale (ii) breakdown of the labile kerogen to fluids and (iii) solidification of remainingPuskar Pramanik 1 Partha PratimMandal 2 and kerogen. A differential effective medium model is used toSubhadeepSarkar 3compute effective elastic moduli of a pore framework which1 Indian Institute of Technology ( Indian School of Mines ) Dhanbad considers both organic and in-organic rock fraction. Fluid2 Qeye substitution of each rock fraction is performed with the3 SchlumbergerGassmann equation and upscaling of combined rock fraction is performed via Backus averaging. The model is applied on aPermeability logs are crucial to estimating reservoir productivity vertical well penetrating the shale oil prospect of the Toolebucand play an important role in the overall economic analysis formation in the Eromanga and Carpenteria Basins locatedof the field. However, there is no direct procedure to estimate 131 PREVIEW FEBRUARY 2023'