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Rock-Physics Model of Volcanic Rocks, an Example from Junggar Basin of China
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 80th EAGE Conference and Exhibition 2018, Jun 2018, Volume 2018, p.1 - 5
Abstract
With the difficulty of oil and gas exploration increasing in conventional reservoirs, volcanic rocks have been attached more and more importance. Rock-physics model gives us insights into the macroscopic responses of micro-factors. The modelling of volcanic rocks relies on three major steps. First, a multi-mineral volumetric interpretation model is proposed including quartz, feldspar, ferromagnesian, shale and pores. The log response equations for density, interval transit time, gamma ray and compensated neutron porosity are developed, which are solved by the Complex method to calculate the mineral contents. Second, according to the characteristics of pores, gas cavity (spherical pores with aspect ratio˜ 1), dissolved pore (aspect ratio˜ 0.1) and crack (aspect ratio˜ 0.01) are taken into account simultaneously to calculate the modulus of framework of the rock. Finally, in view of the partial saturation of fluid in the porous media, patchy saturation model is introduced to calculate the elastic modulus of saturated rock. Based on the rock physics model, the shear wave velocity can be estimated effectively with the relative error less than 10% basically.