Role of digital rock physics in successful implementation of sub-surface carbon storage

Title : Role of digital rock physics in successful implementation of sub-surface carbon storage

Abstract:

The rapid increase in greenhouse gas emissions has become a pressing global issue as these have debilitating impact on climate. Carbon Capture and Storage (CCS) is a method to reduce such emissions and mitigate their impact on environment through capture and storage of the carbon dioxide in the subsurface reservoirs. Prior to injecting the captured CO₂, it is necessary to identify suitable storage sites and characterize the reservoirs for long-term storage. Digital Rock Physics (DRP) enables the characterization of a reservoir by analysing the scanned volumes of the core rock samples extracted from these reservoirs. The two key parameters used to quantify subsurface rocks are porosity, which determines storage capacity, and permeability, which determines flow capacity. By utilizing 3D image volume data obtained from Micro Xray Computed Tomography scans, information on the physical properties of the rock -including porosity and permeability- can be extracted.

In the present work, we study the rock samples which are analogues to the subsurface rocks from Lithuanian reservoirs. Three-dimensional image volume data has been acquired using Micro Xray Computed Tomography and machine learning algorithm has been used for computation of optimized porosity and permeability values from a three-dimensional digital volume(s) of the core sample(s). Once the porosity is estimated, the next step is to then understand the flow behavior of the rock in presence of different fluids like CO₂ and Hydrogen. To gain insight into different aspects of porosity and its distribution on overall flow behavior of the rock, three dimensional representative elementary subsurface volumes were generated as mini models. The behavior of the rock was then analyzed by conducting flow simulations on these mini-models.

 Audience Take Away:

• Carbon Capture and Storage (CCS) is a potent method to reduce greenhouse gas emissions by capturing and storing carbon dioxide in subsurface reservoirs.
• Digital Rock Physics can help in analyzing the reservoir behavior when injected with CO2 or H2 and in assessing the long-term storage capacity of a reservoir.
• Image based 3D quantification of the porosity and permeability helps to understand the distribution of pore space and the flow behavior in presence of different fluids respectively.
• Incorporating different subsurface uncertainties is possible during flow simulations to understand the impact of subsurface heterogeneity on fluid flow.

Biography:

Ms. Shruti Malik earned her Ph.D. degree from Indian Institute of Technology, Roorkee, India. In her Ph.D. research work, she performed the rock property estimation on the digital volumes of the rock samples obtained through Micro x-ray CT-scanning technique. Subsequently, she performed measurements on core samples from carbonate reservoirs to map their heterogeneity and determine their static and dynamic properties. Currently, she is working as a post-doctoral researcher in the Department of Mathematical Modelling, Kaunas University of Technology (KTU), Lithuania, supported by a research grant from Research Council of Lithuania (RCL). Her work is focused on blending the digital rock physics with AI & ML techniques to assess the impact of CO2 & H2 storage on the sub-surface reservoirs.