Abstract

ABBASI, Saiq Shakeel; LIU, Jiangping; HAMEED, Nayima  and  EHSAN, Muhsan. A modified approach for Elastic Impedance Inversion due to the variation in the value of Κ. Earth Sci. Res. J. [online]. 2018, vol.22, n.3, pp.205-213. ISSN 1794-6190.  https://doi.org/10.15446/esrj.v22n3.61135.

Elastic impedance inversion is the latest development in the field of hydrocarbon exploration and production. The present research focuses on the improvement of the use of elastic impedance inversion, easing exploration of hydrocarbons. The seismic velocities change with variation in geological constraints. Constant Κ, which is S-wave to P-wave ratio of the nth layer and n+1 layer across the interface, it must be changed accordingly. This research focuses on testing the effects of Κ as a constant in the elastic impedance equation. As using the same value of Κ for all types of formations can give rise to severe errors in the interpretation of data. The importance of the value of Κ for particular Amplitude Variation with Offset AVO type (I-IV) is studied using different Elastic Impedance Equations. The Reflection Coefficient (RC) curves for each AVO class are generated using Zoeppritz approximation and Elastic Impedance equations. The comparison of RC curves shows significant variations at far offsets in each AVO type using the Constant value of Κ. When Κ Calculated is used, AVO type I and Type II shows a good match at near, mid and far offsets. Type III does not change due to the changing value of Κ. Type IV gives good agreement at near and intermediate offsets. This variation in curves, with the change in the value of Κ, indicates that it is a significant factor of interpretation using elastic impedance. The application of findings on well logs has given a satisfactory confirmation of the present results. This research can be helpful to resolve severe errors in the interpretation due to the constant value of Κ.

Keywords : Zoeppritz; Amplitude Variation with Offset (AVO) Classification; Inversion; Fatti EI and Connolly EI, Well-log; K value.

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