Field-based simulation of a demonstration site for carbon dioxide sequestration in low-permeability saline aquifers in the Ordos Basin, China

Abstract

Saline formations are considered to be candidates for carbon sequestration due to their great depths, large storage volumes, and widespread occurrence. However, injecting carbon dioxide into low-permeability reservoirs is challenging. An active demonstration project for carbon dioxide sequestration in the Ordos Basin, China, began in 2010. The site is characterized by a deep, multi-layered saline reservoir with permeability mostly below 1.0×10-14 m2. Field observations so far suggest that only small-to-moderate pressure buildup has taken place due to injection. The Triassic Liujiagou sandstone at the top of the reservoir has surprisingly high injectivity and accepts approximately 80 % of the injected mass at the site. Based on these key observations, a three-dimensional numerical model was developed and applied, to predict the plume dynamics and pressure propagation, and in the assessment of storage safety. The model is assembled with the most recent data and the simulations are calibrated to the latest available observations. The model explains most of the observed phenomena at the site. With the current operation scheme, the CO2 plume at the uppermost reservoir would reach a lateral distance of 658 m by the end of the project in 2015, and approximately 1,000 m after 100 years since injection. The resulting pressure buildup in the reservoir was below 5 MPa, far below the threshold to cause fracturing of the sealing cap (around 33 MPa)

Investigation on the Relationship between Wellhead Injection Pressure and Injection Rate for Practical Injection Control in CO2 Geological Storage Projects

“…(3) Curves B and C in Figure 9 do not overlap, revealing that increase in thickness of the upper reservoir has greater effect on enlarging the allowable WH and WH in the multireservoir injection simultaneously, compared with increasing the thickness of the lower reservoir. It indicates that the injected fluid majorly enters the upper reservoirs, which is consistent with the conclusions of Rutqvist and Tsang [36], Liu et al [31], and Xie et al [37,38] based on TOUGH2. Furthermore, as described above, the critical reservoir in this case is the first reservoir, which means that increase in thickness of the critical reservoir is most effective for the increase of total available capacity of the entire storage site.…”

Impacts of stratum dip angle on CO2 geological storage amount and security

“…China, as a major CO 2 emission country, has had a positive response to CO 2 emission reduction activities. The first CCS demonstration project in a deep saline aquifer has been constructed in the Ordos Basin of Inner Mongolia, China . A CO 2 ‐enhanced, coal bed, methane recovery demonstrative project has been implemented in the Qinshui Basin of Shanxi Province …”

“…It can cope with long‐duration CO 2 geological storage problems, and make up for space and time restrictions experienced by laboratory experiment and field testing. Among such models, TOUGH2, a non‐isothermal multiphase flow simulation software, has been widely used in the United States, Europe, Australia, Japan, and China . A user‐interface computer (visualization) code, TOUGHVISUAL, has been developed for TOUGH2 and TOUGHREACT to deal with the modeling of complex geological conditions .…”

“…A user‐interface computer (visualization) code, TOUGHVISUAL, has been developed for TOUGH2 and TOUGHREACT to deal with the modeling of complex geological conditions . The Ordos CCS demonstration project has been well researched . Based on to the latest available observations, Xie et al .…”

“…Based on to the latest available observations, Xie et al . executed a 3‐dimensional numerical model to study the migration of CO 2 in reservoir formations . Liu et al .…”