Reservoir stratigraphic heterogeneity within the Lower Cretaceous Muddy Sandstone in the Powder River Basin, northeast Wyoming, U.S.A.: Implications for carbon dioxide sequestration

Abstract

The Muddy Sandstone in the Powder River Basin (PRB), northeast Wyoming, is a promising reservoir for CO 2 sequestration because: (1) existing wells for hydrocarbon production can be used for CO 2 injection when a field is depleted; and (2) data are available to assess the ability and capacity to trap CO 2 . Here, I provide new data and compile published results to: (1) characterize four oil and gas fields (the Amos Draw, Kitty, Hilight, and Sand Dunes fields) in the PRB with respect to lithofacies, sedimentary environment, sandstone composition, sand-body geometry, and porosity and permeability; and (2) assess the controls on reservoir heterogeneity and the CO 2 sequestration potential.Five lithofacies are recognized based on core description and log responses. They are interpreted as offshore, lower-middle wave-dominated shoreface, weathering zone, fluvial incised-valley, and tideinfluenced estuarine depositional environments. The Muddy Sandstone contains predominantly quartz, with total quartz higher than 70 percent of the total framework grains. The percentage of feldspar is generally less than 5 percent, except for the Rozet Member in the Amos Draw Field, which is up to 22 percent. Sandstone petrographic examination also shows that the Muddy Sandstone can be divided into four groups based on the relative abundance of pore space, carbonate cement, and matrix. Sandstone with high porosity up to 23 percent is found in the shoreface lithofacies in the Amos Draw and Hilight fields and is also found in the estuarine lithofacies in the Kitty Field. The incised-valley lithofacies is of particularly low porosity due to high matrix content and carbonate cementation. The measured porosity in the sandstone varies between 1 percent and 23 percent, and the permeability is generally less than 10 millidarcys (mD). The variation of porosity is consistent with the observation in thin sections. XRD results show that the pore-filling clay minerals include kaolinite, chlorite, illite, and smectite. Core and well log correlation show that sandstone formed in lower-middle shoreface environments is laterally extensive and of uniform thickness, whereas sandstone of fluvial and estuarine origins is more variable in lateral extent and thickness. Based on examination of lithofacies, sandstone geometry, and thin section petrography, I suggest that the best reservoir interval for CO 2 sequestration in the Amos Draw Field is the lower Rozet Member, in the Sand Dunes and Hilight fields is the Springen Ranch Member, and in the Kitty Field is the Ute Member. Variables examined in this study provide important inputs for calculating CO 2 capacity potential and predicting chemical reactivity after CO 2 injection.Reservoir quality of the Muddy Sandstone is highly heterogeneous, and the complexity may be attributed to a combination of depositional environment, history of relative sea-level change during deposition, and type and extent of diagenetic alteration. The Muddy Sandstone, along with the overlying Mowry Shale, represents one third-order de...

Measuring anisotropic permeability using a cubic shale sample in a triaxial cell

“…Armitage et al, 2011;Bhandari et al, 2015;Burger and Belitz, 1997;Chen et al, 2009;Farrell et al, 2014;Kwon et al, 2004;Mokhtari et al, 2013;Soeder, 1988). However, the resultant individual subcore samples may not represent the true permeability anisotropy of highly heterogeneous rocks such as shales and muddy sandstones (Chen et al, 2014;Fan, 2014). Subcores can also be sequentially cored in different directions before testing, but because the core becomes smaller at each subcore process, this is also problematic for heterogeneous samples (Chan and Cameron Kenny, 1973).…”

Assessing the potential of composite confining systems for secure and long-term CO2 retention in geosequestration

“…Heterogeneity of geologic formations may manifest itself with different characteristics across different scales. At the reservoir scale, stratigraphic heterogeneity appears as distinct lithofacies, creating intraformational barriers in sand bodies 1 . Intraformational barriers primarily comprise fine-grained facies such as mudstones, siltstones, and shales with low porosity and permeability and medium to high capillary entry pressure.…”

Measurement of Shale Anisotropic Permeability and Its Impact on Shale Gas Production

“…Armitage et al, 2011;Bhandari et al, 2015;Burger and Belitz, 1997;Chen et al, 2009;Farrell, et al, 2014;Kwon et al, 2004;Mokhtari et al, 2013;Soeder, 1988). However, the disadvantage of using subcored samples is that different subcore sample may not represent the true permeability anisotropy if the rock is highly heterogeneous, for instance the muddy sandstones and shales (Chen et al, 2014;Fan, 2014). Using cubic rock samples is seemingly straightforward in measuring permeability anisotropy because geometrically each direction is the same.…”