Event-based low-frequency impedance modeling using well logs and seismic attributes

Acoustic impedance is a rock property that, under specific conditions, can be derived from seismic data and can provide important insights into reservoir parameters—such as porosity, lithology, fluid content, etc. Direct measurements of acoustic impedance are available from sonic and density well logs. Seismic inversion, a process of converting seismic data into relative impedance, provides estimates of relative acoustic impedance away from the well locations. Because absolute acoustic impedance can be related to other rock properties, the inverted relative seismic impedance could be used to predict these properties away from the wells if the missing low frequencies could be reliably calculated and compensated for. In chalk, seismic inversion finds its most significant application in porosity prediction.