Mesoscale Assessment of CO₂ Storage Potential and Geological Suitability for Target Area Selection in the Sichuan Basin

Abstract

In China, south of the Yangtze River, there are a large number of carbon sources, while the Sichuan Basin is the largest sedimentary basin; it makes sense to select the targets for CO 2 geological storage (CGUS) early demonstration. For CO 2 enhanced oil and gas, coal bed methane recovery (CO 2 -EOR, EGR, and ECBM), or storage in these depleted fields, the existing oil, gas fields, or coal seams could be the target areas in the mesoscale. This paper proposed a methodology of GIS superimposed multisource information assessment of geological suitability for CO 2 enhanced water recovery (CO 2 -EWR) or only storage in deep saline aquifers. The potential per unit area of deep saline aquifers CO 2 storage in Central Sichuan is generally greater than 50 × 10 4 t/km 2 at P50 probability level, with Xujiahe group being the main reservoir. CO 2 storage potential of depleted gas fields is 53.73 × 10 8 t, while it is 33.85 × 10 8 t by using CO 2 -EGR technology. This paper recommended that early implementation of CGUS could be carried out in the deep saline aquifers and depleted gas fields in the Sichuan Basin, especially that of the latter because of excellent traps, rich geological data, and well-run infrastructures.

Assessment and uncertainty quantification of onshore geological CO2 storage capacity in China

“…These are not included in our assessment because of (i) their large distances from major emission sources and (ii) socio-political concerns that reduce the potential of these basins to firmly establish CO2 storage projects. Table 1 lists some key characteristics of the selected basins (B1-B10) collected from prior studies (e.g., Zeng et al, 2013;Diao et al, 2017;Fan et al, 2014;Wang et al, 2014;Jin et al, 2017;Wang et al, 2018). Such information is required for the assessment of carbon storage capacity, following Equations ( 1)-( 13) in Section 3.…”

“…This modeling choice is consistent with scenarios where prior information (e.g., measurements) on model parameters is not available and enables one to give equal weight to each value across the space of variability of a given parameter. We refer to information reported in the literature (Zeng et al, 2013;Diao et al, 2017;Fan et al, 2014;Wang et al, 2014;Jin et al, 2017;Wang et al, 2018) and consider broad ranges of variability for the values of each uncertain model parameter 𝜃 𝑖 (see Table 2). Selection of the support ranges of each 𝜃 𝑖 values is set to represent broad ranges of variability based on typical measurement uncertainties (see, e.g., Sifuentes et al, 2009;Li and Liu, 2016;Ajayi et al, 2019;Barros et al, 2021).…”

“…Basins in north-eastern China are chiefly characterized by a marked overall thickness of sedimentary bodies and several sets of reservoir-caprock layers, offering a setting of potential interest for geological storage of captured CO2(Zeng et al, 2013). In this scenario,Diao et al (2017) document that argillite (mudstone and shale) and evaporites (gypsum and rock salt) constitute the most commonly found caprocks for oil and gas fields in China; caprocks formed by carbonate rocks and frozen genesis caps are also found in some fields.Sandstone reservoir formations in Erlian sub-basins are buried at depths of 1-3 km and potential storage sites are formed by structural and fault traps Wang et al (2018). showed that key lithological traits of the Dongying and Shahejie formations in the Bohai bay Basin encompass pebbly sandstone, siltstone, sandstone intercalated with mudstone, and oil shale.…”

“…Mudstone interbedded with fine-grained sandstone of the Pliocene Wulantuke formation and mudstone intercalated with fine-grained sandstone and marlite of the Miocene Wuyuan formation form the caprock in the Hetao Basin, silt to medium-grained sandstone of the Oligocene Linhe formation (thickness of 260-340 m) providing a good potential for storage.Saline aquifers in the Sichuan Basin are characterized by an overall very low porosity and permeability. Otherwise, natural gas fields in the Sichuan Basin are characterized by suitable caprock conditions for CO2 storage(Diao et al, 2017). The reader is referred to the work ofSun et al (2021) for an exemplary stratigraphy of the Sichuan Basin Su et at (2013).…”

Preliminary Numerical Modeling of CO2 Geological Storage in the Huangcaoxia Gas Reservoir in the Eastern Sichuan Basin, China

“…Based on the previous preliminary evaluation considering the CO 2 storage capacity (>10 million tons) and gas production status (nearly depleted), there are four potential gas fields for CO 2 storage in depleted gas reservoirs in the eastern Sichuan Basin: Dachigan, Wolonghe, Huangcaoxia, and Shiyougou [22] (Figure 1). Table 1 lists the main features of the four potential sites.…”