Vuotto, Alexander
(2016)
Examining the Effect of Fundamental Properties of Cement Hydration on Hydrostatic Pressure Reduction to Better Understand Stray Gas Migration.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
During wellbore cementing, stray gas migration may occur when a pressure imbalance exists within the hydrating cement slurry, where the pore pressure is less than that of the surrounding formation gas pressure. A fluid column of hydrating cement slurry with appropriate density will provide sufficient hydrostatic pressure to prevent formation gas from invading and migrating through the cemented column. As cement hydration progresses, slurry behavior gradually shifts from that of a liquid to an impermeable solid. This transition is associated with a reduction in hydrostatic pressure, potentially leaving the annulus susceptible to the invasion and migration of untargeted formation gas. The current industry approach relies on measurements of static gel strength of the hydrating cement slurry to define the period of gas migration susceptibility, which is referred to as transition time. The transition time is minimized to reduce gas migration potential; however, many limitations exist with this approach. In order to improve the understanding of gas migration susceptibility, a study was performed to accurately characterize hydrostatic pressure reduction within a cemented annulus using fundamental parameters, such as degree of hydration and capillary porosity. Laboratory tests were conducted using the University of Pittsburgh’s wellbore simulation chamber to simulate various depths of interest. By using fundamental parameters, microstructural development and cement material properties may be predicted at any time and depth along the wellbore and related to the occurrence of gas migration. This study shows that the development of hydration can be predicted as a function of the curing conditions, the mixture design, and the cement composition. Hydration can also be directly linked to strength and constitutive properties of the hydrating cement slurry.
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Details
| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
25 January 2016 |
| Date Type: |
Publication |
| Defense Date: |
24 November 2015 |
| Approval Date: |
25 January 2016 |
| Submission Date: |
2 December 2015 |
| Access Restriction: |
5 year -- Restrict access to University of Pittsburgh for a period of 5 years. |
| Number of Pages: |
141 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Civil and Environmental Engineering |
| Degree: |
MS - Master of Science |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
cement hydration
gas migration
fundamental parameter
isothermal calorimetry
hydrostatic pressure reduction
microstructural development |
| Date Deposited: |
25 Jan 2016 15:42 |
| Last Modified: |
25 Jan 2021 06:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/26556 |
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