S24A-07
Monitoring CO2 injection with a buried geophone array: Stage 2C of CO2CRC Otway Project

Tuesday, 15 December 2015: 17:40
305 (Moscone South)
Boris Gurevich1,2, Milovan Urosevic1,2, Roman Pevzner1,2, Konstantin Tertyshnikov1,2, Valeriya Shulakova2,3, Stanislav Glubokovskikh1,2, Dmitry Popik1,2, Anton Kepic1,2, Michelle Robertson4, Barry M Freifeld4, Thomas M Daley4 and Rajindar Singh2, (1)Curtin University, Perth, Australia, (2)CO2CRC, Perth, Australia, (3)CSIRO Energy, Perth, Australia, (4)Lawrence Berkeley National Laboratory, Berkeley, CA, United States
Abstract:
The Stage 2 of the CO2CRC project involves injection of a small quantity of CO2, 15 Kt, into the Paaratte formation, a saline aquifer located at a depth of around 1500 m in the Otway basin, Victoria, Australia. The project aims to investigate the limits of time lapse seismic methodologies in order to devise an optimal monitoring program. That includes time lapse signal and noise prediction, time lapse data acquisition design and finally data analysis. The strength of the time lapse (TL) seismic is governed by the magnitudes of both the time lapse signal and time lapse noise. They are in turn both dependent on numerous factors which need to be addressed through modelling studies and data acquisition technologies.

Geological information is used to build a detailed 3D static model for the dynamic reservoir simulations and analysis of CO2 plume distribution for small quantities of CO2 injected into the deepest Paaratte member. Various lithological scenarios and variations in permeability distribution are tested until arriving at the “most likely” solution. The final model is used initially for 1D and subsequently for the full 3D time lapse modelling. These time lapse modelling results, combined with field tests and noise analysis, show clearly that small quantities of CO2 injected into a relatively thin (~20 m in thickness) saline aquifer would benefit from utilizing a permanent 3D seismic array to achieve desired repeatability, that is reduction in time lapse seismic noise.

Buried receiver array was designed and deployed at the CO2CRC Otway during January and February. The array comprises 908 high-sensitivity geophones deployed at 4 m depth below the surface. Baseline 3D was acquired in March 2015. Some 3003 shots were acquired by a crew of 7 people over 9 days. Benchmark tests show a significant improvement in data quality compared to surface geophones.

With this approach there are no cables or other seismic infrastructure on the surface. This significantly reduces the impact of the survey on farming activities. The total project cost will also be reduced over the period of two years in comparison to the surface seismic array.

We acknowledge the funding provided by the Australian government to support this CO2CRC research project. We also acknowledge the funding from ANLEC R&D and the Victorian Government for the Stage 2C project.

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