Simulation and analysis of lithology heterogeneity on CO2 geological sequestration in deep saline aquifer: a case study of the Ordos Basin

Abstract

A simplified two-dimensional axisymmetric model was established based on a typical continental sedimentary basin in China to simulate the thermal evolution of wellbore and reservoir during the injection of CO 2 by taking consideration of lithology heterogeneity of reservoir. By comparing with two simple one-dimensional theory models, the lithology heterogeneity influence on CO 2 mass flow rate distribution along depth in the wellbore is identified. Results suggested that the interaction of multiple layers in the heterogeneous reservoir will influence the CO 2 mass flow rate distribution along depth in the wellbore so as to impact the corresponding temperature and pressure evolution in the wellbore and reservoir. Layer burial depth (or relative location), porosity, permeability and thickness are all important factors that affect CO 2 mass flow rate in wellbore. The variation of CO 2 mass flow rate in the wellbore will change the CO 2 temperature flowing into each layers through impact the heat extraction from rocks, compressibility of CO 2 and potential energy loss, and by varying the CO 2 hydrostatic pressure and pressure drop due to friction to determine the CO 2 injection pressure. Layer burial depth, porosity, permeability and thickness are all important factors that affect the CO 2 mass flow rate distribution in the wellbore. This study may help deepen our understanding of CO 2 flow and thermal evolution in the actual heterogeneous reservoir and provide important knowledge supplement for the liquid injection (especially CO 2 ) into underground, such as deep saline aquifer, depleted oil/gas reservoir and coal bed.

Dynamic Behavior of CO2 in a Wellbore and Storage Formation: Wellbore-Coupled and Salt-Precipitation Processes during Geologic CO2 Sequestration

“…Due to magnitude difference of actual CO 2 injection rates throughout the screen interval, both viscous and buoyancy forces differently acted on CO 2 plume between Case 1 and Case 2 [44]. Furthermore, relatively warm CO 2 (e.g., 52…”

“…Most importantly, development of the localized salt was dependent on the degree of buoyancy force on CO 2 plume, which was governed by the injection rate and thermophysical properties of CO 2 . Even though thermophysical CO 2 properties could be changed significantly after CO 2 experiencing the wellbore processes, only a few studies were considered the wellbore processes impacting on CO 2 behavior in the storage formation [22,24,[43][44][45].…”

“…The primary reason for such simplification arises from technical difficulties solving both the wellbore and porous media flow at the same time. Nevertheless, it is recognized that fully coupled wellbore-reservoir models, capable of accounting for nonisothermal two-phase (CO 2 and brine or water) flow, are necessary to evaluate the influence of wellbore flow on injected CO 2 within the storage formation [44,49]. Due to this reason, the purpose of this study was to advance current understanding related to the wellbore flow process by investigating the change of both pressure and temperature profiles within the wellbore, and subsequently, CO 2 migration, and resulting accumulation of solid salt in the storage formation.…”

Numerical Investigation into the Impact of CO2-Water-Rock Interactions on CO2 Injectivity at the Shenhua CCS Demonstration Project, China

“…Analyses of geohydrological, mechanical, thermal, and geochemical processes involved in Shenhua CCS project have been reported [29][30][31][32][33]. However, few of these have focused on the considerable CO 2 injectivity increase during CO 2 injection period.…”

“…However, few of these have focused on the considerable CO 2 injectivity increase during CO 2 injection period. Liu et al [33] examined this unique phenomenon through numerical simulation and concluded that it could be explained through heterogeneities in reservoir permeability. However their approach did not consider the possible role of CO 2 -water-rock interactions on CO 2 injectivity.…”