CO2 Sequestration Assessment Using Multicomponent 3D Seismic Data: Rock Springs Uplift, Wyoming

Geophysical analysis plays a crucial role in the assessing, measuring, and monitoring of CO2 sequestration. Seismic data allows the extraction of lithologic and fluid properties via inversion techniques that aid in identifying CO2 storage compartments and monitoring of fluid injection into the subsurface. Although the industry standard is to analyze the vertical component (PP reflection) data, converted-wave reflections (P-to-S conversion) can be used to help determine density information with higher reliability due to the sensitive variations of the S-waves to density. Multi-component seismic data is processed for PP and PS reflections, and pre-stack simultaneous inversion is applied to the data to generate elastic properties of the subsurface to complete a reservoir assessment for CO2 sequestration in the Rock Springs Uplift, Wyoming. Rock physics and sensitivity analysis at the well location shows that a 5% porosity increase at the target intervals corresponds to a 16% - 19% decrease in  and , making these attributes optimal for CO2 sequestration assessment in the area. A porosity volume is generated by a least-squares linear regression with  at the well location that displays a 93% correlation. The resultant porosity relation is applied to the  inverted volume, and the average porosity values obtained at the Weber and Nugget sandstones throughout the survey are 9% – 14% and 12% – 18%, respectively. Extracted porosity maps from the target formations display high-porosity anomalies in the eastern section of the survey and are interpreted for the P30, P60, and P90 case. The anomalous areas are utilized jointly with isopach and porosity maps to determine the range of CO2 mass for storage capacity and ranges from 120 Mt to 561 Mt. Considering the efficiency storage factors between 0.2 – 1, the daily CO2 emissions from the Jim Bridger power plant of 16 Mt, pressure and temperature conditions of CO2 of 701 bars and 366 oK at the target depth, the duration for sequestration range from 7 years to 34 years for the large high-porosity anomalous area. A CO2 injection model is created, and a well for sequestration is proposed at a latitude of 41o42’34.799” and a longitude of -108o47’54.019”.