Finding how CO2 storage under the sea affects the rock
To help combat the climate crisis, CO2 is being pumped deep below the sea into depleted oil fields. There it becomes trapped in pores in the rock and dissolves into brine also trapped within the rocks.
Knowing how this process changes the pore structure and strength of the rocks is critical to effectively storing the carbon, and engineers in Scotland are using a Windmill data acquisition system to help them with this research.
Led by Peter Ameh of the University of Edinburgh and Abubakar Tafawa Balewa University, Nigeria, the researchers obtained five sandstone samples from around 1640 m down in a potential CO2 storage site in Scotland. They measured their samples' weights, volumes, porosity and strain behaviour before and after saturating them with various phaseCO2-brine.
The team used a Microlink 751 multifunction data acquisition and control unit. They ran Windmill Software to set the Microlink at 15-bits per channel with a 0-10 V dc range and a precision of 0.05%. The Microlink records the displacement data from a LVDT (linear variable differential transducer). The Windmill software displays data as it is collected.
The Microlink can measure temperature, strain, pressure, voltage and current through 16 analogue input channels. It can switch up to 32 digital outputs and monitor up to 32 digital inputs. It can also count events with up to 8 counters. You can connect eight Microlinks to one PC giving 128 analogue inputs and 256 digital inputs and outputs. Use Windmill software to choose from four analogue input ranges or automatic ranging to let the software match the input signal as closely as possible. You can also use Windmill to select the resolution from 7 options: choose high throughput or high resolution.
The researchers say that the result of this work is useful for predicting the change in the geometry of pores and the strain of saline reservoir rocks in planned and existing giant CO2 sites.
Further Reading Peter, A., Jin, X., Fan, X. et al. Effect of CO2 Phase on Pore Geometry of Saline Reservoir Rock. Rock Mech Rock Eng 55, 1907-1930 (2022). https://doi.org/10.1007/s00603-021-02658-x
Microlink 751: Multi-Function Data Acquisition and Control, Windmill Software Limited
