Systematic Influences of Internal Pore Structure on Compressional Sonic Velocity and Quality Factor in Sandstone
M.N.A. Akbar, M. Dobróka and N.P. Szabó
Event name: 81st EAGE Conference and Exhibition 2019
Session: Poster: Seismic Interpretation - Rock Physics B
Publication date: 03 June 2019
Info: Extended abstract, PDF ( 1.39Mb )
Price: € 20
The main purpose of this study is to investigate on how acoustic velocity and quality factor correlating with porosity, permeability and Internal pore structure in porous rocks. A re-arrangement is made on the Kozeny equation to perform rock typing on the basis of pore structure similarity. The proposed rock typing method allows investigating the main influential factors that control acoustic velocity and quality factor. This study employs 67 sandstone core samples with measured parameters of porosity ϕ, permeability k, clay content Vcl, compressional velocity Vp and quality factor Qp. Several rock groups are resulted from rock typing with its Kozeny constant. The relations of Vp and Qp versus ϕ, k, (k/ϕ)^0.5, or (k/ϕ^3) are constructed. The important finding is that Vp and Qp tend to be high with an increase in Kozeny constant. However, for a given ϕ for all the groups, Vp and Qp increase remarkably with a decrease in Kozeny constant. These all mean that Vp and Qp increase with either an increase in the complexity of pore systems or, at the same pore complexity, a decrease in specific internal surface area. Finally, the empirical equations are derived to estimate velocity and quality factor of the rock.