Reservoir Characterization for Carbon Capture and Storage of Nong Bua Basin, Central Thailand

Abstract

In the last decade, people have faced disasters that are becoming more severe and widespread. Most disasters occur naturally due to global evolution on Earth. Global warming, one of the severe disasters, has been a critical issue of discussion among professionals. Certainly, global warming has been recorded by geological evidence as an inevitable phenomenon occurring in the Earth's atmosphere. Human activities, such as the emission of a large volume of greenhouse gases into the Earth’s atmosphere, also play a role in causing an increasing rate of global warming. When people realize the impact of global warming on the existence of humanity, the practice of changing daily behaviors and performing various kinds of techniques including carbon capture and storage (CCS) has been introduced to slow down the rate of global warming. CCS has been an acceptable technique for reducing greenhouse gas emissions into the atmosphere and mitigating global warming. The principal technical procedures of CCS comprise capturing greenhouse gases such as carbon dioxide from the emission source, transporting them to the sink site location, and permanently storing them in a suitable place, such as a rock formation under the ground. Many countries in various regions worldwide have performed the CCS with due diligence because the CCS operation deals with a large number of factors, is time-consuming, and has a very high operation cost. The selection of underground storage formation is crucial for CCS operation. The suitable storage formation can be either the saline aquifer or the depleted hydrocarbon-bearing formation. Many successful CCS pilot projects have been implemented and reported. Of course, Thailand cannot avoid being affected by global warming. The selection of CCS operation in Thailand is, therefore, one option used to manage and mitigate the effects of global warming. The preliminary site selection screening for suitable sink sites in Thailand has been introduced. Out of 74 onshore and offshore basins in Thailand, five onshore basins have been announced as potential areas. Nong Bua Basin, central Thailand, is one of the five selected locations. The basin was developed as an asymmetrical half-graben, underlain by the Pre-Tertiary basement, and filled by Tertiary rocks of the Phitanulok Group. Five litho-stratigraphic units of the Phitanulok Group deposited in various depositional environments were reported. The joint interpretation of seismic and geophysical well logging data indicated two potential formations for CCS operation. First, the lowermost Nong Bua Formation is situated on the Pre-Tertiary basement and deposited in the fluvial environment. The main lithology of the Nong Bua Formation is interpreted as the sandstone. Second, the Lan Krabu Formation is situated on the Nong Bua Formation and deposited in the fluvio-lacustrine environment. The main lithology of the Lan Krabu Formation is the sequence of interbedded sandstone and shale. This research focused on the selection of a suitable saline aquifer as the storage formation. For reservoir and caprock characterization, four main parameters calculated from geophysical well logging data at the borehole location including formation depth, net reservoir thickness, porosity, permeability, caprock thickness, and structural type determined from seismic data were considered. Fault interpretation from seismic data is performed to evaluate the closure potential. The storage capacities of the formations are estimated from seismic attribute mapping and seismic inversion analysis.

Keywords: Carbon capture and storage; Nong Bua Basin; Central Thailand; Nong Bua Formation; Lan Krabu Formation