Masters Theses

Abstract

"A formation's minimum in-situ stress is an important parameter to determine for hydraulic fracturing. While minimum in-situ stress, and its orientation, can be measured from triaxial tests on core, it is more common to measure it as closure stress, by performing pressure testing of wells in the field. Closure stress is considered equal to, or a good approximation of the minimum in-situ stress for most cases. The analytical methods applied to such pressure testing include the square root of time plot, G function plot and the G-dP/dG plot. These plots require the engineer to fit tangent lines to the data, and the intersection of the tangent lines defines closure stress. The answer obtained is somewhat subjective, and a range of values of closure stress may result depending on how the tangents are fitted to the data. In 1989, Lee and Haimson described a statistical method for determining closure stress in water wells. Their work demonstrated the application of a non-linear regression technique for determining an upper and lower bound for closure stress. This work applies the non-linear regression method to both a water well and a gas well, and compares closure stress found with a statistical analysis to the values determined from square root of time plots. Results from this analysis show that for a water well domain, there is close agreement between closure stress derived from the square root of time plot and the value determined from statistical analysis. A slightly larger difference occurs between these values in the gas well example, indicating that a statistical analysis of closure stress may be of greater significance in analyzing oil/gas wells"--Abstract, Page iii.

Advisor(s)

Dunn-Norman, Shari

Committee Member(s)

Samaranayake, V. A.
Britt, Larry K.
Flori, Ralph E.

Department(s)

Geosciences and Geological and Petroleum Engineering

Degree Name

M.S. in Petroleum Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2013

Pagination

xii, 114 pages

Note about bibliography

Includes bibliographical references.

Rights

© 2013 Soumitra Bhaskar Nande, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Subject Headings

Pressure -- Testing -- Mathematical modelsOil wells -- Hydraulic fracturingWells

Thesis Number

T 10299

Electronic OCLC #

853457310

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