A range of applications, such as subsurface fluid storage facilities, geothermal wells, and CO2 storage wells, are concerned about leakage along wellbores. The research described in this dissertation was largely directed toward wellbore leakage concerns for the US Strategic Petroleum Reserve (SPR). For SPR wellbores, multiple fluids are likely to exist in fractures and flow paths associated with leaky wellbores, including liquids (e.g., liquid hydrocarbon - crude oil) and gases (e.g., gas ex-solved from liquid and/or nitrogen from MIT tests). Anomalous pressure records have been observed at the wellhead of SPR wellbores, indicative of wellbore leakage. In a few cases, the anomalous behavior has led to a significant leakage rate and failure of the MIT. The research undertaken is aimed at investigating the behavior of single and two-phase fluid (gas and oil) flow through wellbore flaws. The research focuses on investigating previously unrecognized potential leakage pathways and examining how fluid flow, particularly two-phase flow and chemically active fluids, affects leakage through wellbore flaws.
The work conducted for this project is presented in four separate chapters. Each of these chapters is focused on a topic which is expected to affect the behavior of flow through leaky wellbores. The chapters contained in this dissertation are: (1) Characterization of wellbore casing corrosion product as a permeable porous medium; (2) Alteration in micro-mechanical characteristics of wellbore cement fracture surfaces due to fluid exposure; (3) Relative permeabilities for two-phase flow through wellbore cement fractures; (4) Alteration of flowrate due to crude oil leakage through the cement fractures. The research has uncovered and characterized previously unrecognized possible leakage pathways, as well as comprehended fluid flow via the leakage paths. Two-phase flow and chemically active fluid flow through wellbore flaws including cement fractures are discussed in detail. The results and mechanisms reported in this study may be useful when investigating the difference between observed and predicted leakage rate. They may also help improving the simulation predictions by incorporating the results from the current study.
Wellbore; Cement; Leakage; Corrosion; Crude oil
Sandia National Laboratories; U.S. Department of Energy;
Level of Degree
First Committee Member (Chair)
John C. Stormont
Second Committee Member
Mahmoud Reda Taha
Third Committee Member
Hans Joakim Skadsem
Fourth Committee Member
Anwar, Ishtiaque. "INVESTIGATION OF ISSUES CONCERNING WELLBORE LEAKAGE." (2023). https://digitalrepository.unm.edu/ce_etds/305
Available for download on Friday, August 01, 2025