Geomechanical Modeling of Salt Cavern Stability for Carbon Dioxide Storage in Northeast Thailand

Abstract

Greenhouse gases like carbon dioxide (CO2) are crucial regarding global atmospheric temperatures. In Thailand, CO2 emissions quadrupled over the past 3 decades since 1989. The power generation sector is the main contributor by burning fossil fuels to produce electricity. These emissions are among the main reasons for Global Warming. Therefore, the power generating industry has come under scrutiny and been pressed by society to take responsibility. Carbon Capture and Storage (CCS) is one of the many methods to deal with CO2 emissions. Generally, CO2 is captured and stored in geological formations, e.g. rock salt deposits which are found in many regions worldwide. Consequently, salt caverns have been intensively studied regarding their usage for CO2 storage because of their favourable characteristics, e.g. low permeability and self-healing capabilities which can prevent the leakage of CO2. Additionally, creation of salt caverns by cost-efficient solution mining is economically beneficial as overall cost for CCS are reduced. In this case study, northeast Thailand was chosen as location for CO2 storage because the sources of CO2 (mainly natural gas power plants) are in immediate vicinity of potential sinks. Northeast Thailand exhibits large deposits of evaporite minerals (including rock salt), which are part of the Maha Sarakham Formation. Salt layers within the formation are suitable to store CO2 in its supercritical fluid (SCF) state. For local communities the safety of these storage facilities is of utmost importance. Therefore, it is imperative to maximize cavern stability and safety factor as well as to minimize volume shrinkage and ground subsidence, which can be achieved by adequate cavern design.