Degree

Doctor of Philosophy (PhD)

Department

Craft and Hawkins Department of Petroleum Engineering

Document Type

Dissertation

Abstract

Reservoir characterization is a key factor for effective management of commercial-scale Geologic CO2 Storage (GCS) projects. Pressure/rate transient analyses (PTA/RTA) have evolved as reliable tools for assessing hydrocarbon and GCS reservoirs. Injection rate and pressure data are routinely measured as a part of GCS projects’ surveillance, or during transient well testing. The data contain valuable information about the subsurface that can be extracted. The extracted information enables the operator to evaluate the effectiveness of injection operations, and to make remedial/corrective interventions. In this current work, different analytical and numerical techniques are presented to characterize, assess, and maximize the economic and volumetric value of the target formations devoted for CO2 storage.

The objectives of this study are achieved through developing novel analytical models that describe the evolution of bottomhole pressure during or after CO2 injection at a constant-rate. The analytical models are derived through solving the governing equations that describe CO2-brine flow in the reservoir. The models are solved using rigorous mathematical techniques considering simplifying assumptions about rock and fluid properties. Based on the developed analytical models, graphical interpretation methodologies are introduced to analyze injection rate and pressure data using PTA and RTA techniques. The analytical models and the interpretation methodologies are validated against numerical simulations and real field datasets to demonstrate their robustness and practical application. The simulations are conducted on representative geological models using commercial reservoir simulation tools.

Results indicate that the interpretation methodologies can be reliably utilized to (1) infer the fluid mobilities and radial extent of the CO2 dry-out zone to assess CO2 injectivity, (2) monitor the spatial-temporal evolution of CO2 plume to constrain CO2 in the designated storage area, and (3) predict the ultimate storage capacity of a target formation to assess the feasibility of the GCS project to accommodate the large supply of CO2. Then, to maximize the economic and volumetric value of a given fixed pore space, simulations studies are performed to investigate the factors that affect CO2 injectivity and subsequent storage capacity. This includes investigating the injection well operating conditions, and physical processes controlling CO2 distribution around the injection well.

Date

6-25-2024

Committee Chair

Zeidouni, Mehdi

DOI

https://doi.org/10.31390/gradschool_dissertations.6505

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