Rock critical porosity inversion and S-wave velocity prediction*
Zhang Jia-Jia1,2 , Li Hong-Bing1 , and Yao Feng-Chang1
1. Research Institute of Petroleum Exploration and Development, PetroChina, Beijing, 100083, China.
Abstract A critical porosity model is often used to calculate the dry frame elastic modulus by the rock critical porosity value which is affected by many factors. In practice it is hard for us to obtain an accurate critical porosity value and we can generally take only an empirical critical porosity value which often causes errors. In this paper, we propose a method to obtain the rock critical porosity value by inverting P-wave velocity and applying it to predict S-wave velocity. The applications of experiment and log data both show that the critical porosity inversion method can reduce the uncertainty resulting from using an empirical value in the past and provide the accurate critical porosity value for predicting S-wave velocity which signifi cantly improves the prediction accuracy.
Key words ： Gassmann’s equations, dry frame
critical porosity
critical porosity model
S-wave velocity prediction
Received: 2011-04-19;
Fund: This work was sponsored by Important National Science and Technology Specifi c Projects of China (No. 2011ZX05001).
Cite this article:
ZHANG Jia-Jia,LI Hong-Bing,YAO Feng-Chang. Rock critical porosity inversion and S-wave velocity prediction*[J]. APPLIED GEOPHYSICS, 2012, 9(1): 57-64.
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