The Technique of Seismic Inversion and Use of the Relation Between Inversion Results and Porosity Log for Predicting Porosity of a Carbonate Reservoir in a South Iranian Oil Field

Abstract

Determination of petrophysical parameters by using available data has a specific situation in exploration and production study in the oil and gas industries. For example, estimating of corrected porosity as a petrophysical parameter can help in decisions that have high financial risk, such as drilling. Therefore, the study of seismic data, extraction of seismic attributes from them, and incorporation of these attributes by well log data is an important key for detection of reservoir properties. Acoustic impedance a key parameter for seismic and direct geologic interpretation and for detecting lateral lithologic variation, can be defined as the product of density and velocity. Seismic inversion is used to estimate detailed seismic and rock properties, such as acoustic impedance and porosity, from seismic data. The method is widely used and proven successful by the petroleum industry, but has thus far not been widely adopted for academic studies. Acoustic impedance data and the derived porosity distribution facilitate detailed studies of lithology, compaction, and fluid flow in the shallow subsurface. A comparison of reflection and impedance data support the notion that seismic reflection events arise from bed boundaries rather than from lateral changes in impedance, even where these are significant. The main result of the seismic inversion study is a profile showing the absolute variations in acoustic impedance and porosity along wells. This article outlines a workflow and reports the application of model-based seismic inversion and its relation with porosity in Balal oil field in the south of Iran.