EGU22-945
https://doi.org/10.5194/egusphere-egu22-945
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Controls on Sonic Velocity in Dolostones

Moaz Salih1, Ammar El-Husseiny1, John J.G. Reijmer1,2, Hassan Eltom1, Abdallah Abdelkarim1, and Mike A. Kaminski1
Moaz Salih et al.
  • 1King Fahd University of Petroleum & Minerals, College of Petroleum Engineering and Geosciences, Geosciences, Saudi Arabia (m3az89@yahoo.com)
  • 2Independent Consultant, 1188JB Amstelveen, The Netherlands

Dolostones represent one of the major hydrocarbon reservoirs in the world. Understanding the elastic behavior of these units is crucial for hydrocarbon exploration and/or development. In this study, 100 samples from five formations within the Arabian Platform, were used to examine the main controlling factors on the sonic velocity of dolostones. A combination of field and laboratory analyses were conducted on the collected samples including; thin-section petrography, SEM, XRD, digital image analysis, porosity and permeability measurements, velocity measurements, and rock physics modeling. The studied samples have a wide range of porosity (1- 45%, averaging 18.5 %), and permeability (0.01 2000 mD, averaging 196 mD). Compressional VP and shear wave VS velocity ranges from 3.0 - 6.7 km/s, and 1.6 3.7 km/s, respectively. In general, porosity-velocity trajectory is showing a negative relationship with a coefficient of determination R2 of 0.82. However, some samples are deviated from this trendline due to their inherited and diagenetic parameters. These parameters include texture, mineralogy, pore type, and crystal size. Fabric-preserving dolostones have, relatively, higher velocities than non-fabric preserving dolostones. Although 95% of the studied samples are dominated by dolomite, samples with higher content of calcite and quartz, have lower velocities. Moldic and vuggy pore-dominated samples have, relatively, higher velocities than samples dominated by intercrystalline pores and microporosity. For non-fabric preserving dolostones, samples with larger crystals show higher velocities than samples with smaller crystals. Using equivalent pore aspect ratio (EPAR), a clear distinction between permeable (>10 mD) and tight (< 10 mD) samples can observed, where most of the permeable samples have high EPAR values, while the tight samples have low EPAR values. The result of this study might significantly help in the interpretation and understanding of the sonic logs and seismic data from dolostone strata.

How to cite: Salih, M., El-Husseiny, A., Reijmer, J. J. G., Eltom, H., Abdelkarim, A., and Kaminski, M. A.: Controls on Sonic Velocity in Dolostones, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-945, https://doi.org/10.5194/egusphere-egu22-945, 2022.