Date of Graduation

2014

Document Type

Dissertation

Degree Type

PhD

College

Statler College of Engineering and Mineral Resources

Department

Petroleum and Natural Gas Engineering

Committee Chair

Shahab D Mohaghegh

Committee Co-Chair

Samuel Ameri

Committee Member

Grant Bromhal

Committee Member

Ebrahim Fathi

Committee Member

Eduardo A Proano

Committee Member

Thomas H Wilson

Abstract

Capability of underground carbon dioxide storage to confine and sustain injected CO2 for a very long time is the main concern for geologic CO2 sequestration. If a leakage from a geological sink occurs, it is crucial to find the approximate amount and location of the leak in order to implement proper remediation activity.;An overwhelming majority of research and development for storage site monitoring has been concentrated on atmospheric, surface or near surface monitoring of the sequestered CO2. This study is different it aims to monitor the integrity of CO2 storage at the reservoir level. This work proposes developing in-situ CO2 Monitoring and Verification technology based on the implementation of Permanent Down-hole Gauges (PDG) or "Smart Wells" along with Artificial Intelligence and Data Mining (AI&DM). The technology attempts to identify the characteristic of the CO2 leakage by de-convolving the pressure signals collected at the Smart Well sites.;Citronelle field, a saline reservoir located in Mobile County (Alabama, US) was considered for this study. A reservoir simulation model for CO 2 sequestration in the Citronelle field was developed and history matched. The presence of the PDGs were considered in the reservoir model at the injection well and an observation well. High frequency pressure data from sensors were collected based on different synthetic CO2 leakage scenarios in the model. Due to complexity of the pressure signal behaviors, a Machine Learning based technique was introduced to build an Intelligent Leakage Detection System (ILDS).;The ILDS was able to detect leakage characteristics in a short time (less than a day) demonstrating high precision in quantifying leakage characteristics subject to complex rate behaviors. The performance of ILDS was examined under different conditions such as multiple well leakages, cap rock leakage, availability of an additional monitoring well, presence of pressure drift and noise in sensor and uncertainty in the reservoir model.

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