Masters Theses

Abstract

"A new technique for determining capillary pressure curves with a centrifuge has been developed and tested. Capillary pressure curves were determined for six cores by this technique and were compared to the curves for the same cores determined by the semi-permeable barrier technique. The technique differs from previously reported centrifuge techniques in that the centrifuge was slowly accelerated from zero to the maximum desired speed, rather than being held constant at particular, progressively higher speeds. An important advantage of this technique over other methods for determining capillary pressure curves is the short time required to obtain the desired amount of data over the chosen pressure range. For example, to obtain thirty data points between 1.2 and 104 psig with a 1.55 inch long, 3/4 inch diameter core using a brine-air system, 6.6 hours were required with this technique. Similar data with the constant-speed step centrifuge technique would require about 90 hours according to information obtained during this investigation. Using the semi-permeable barrier technique, twelve points for the capillary pressure curve with a maximum pressure of 32 psig would require about two months.

An equally important development of this thesis is an analytic method for the conversion of the data from a centrifuge experiment to capillary pressure curve data. Previously there has been only an approximate conversion available.

The capillary pressure curves determined by the constant-acceleration technique appear to be as accurate as those determined by other techniques. In addition it is felt that the accuracy of this technique could be further improved if certain variables, not treated in this experiment, were investigated. Among these are dynamic distortion of the centrifuge equipment and imperfect initial saturation of the cores.

Only two centrifuge acceleration rates were investigated. For the cores tested, which had air permeabilities between 59 and 1470 millidarcys, the higher acceleration rate of about 7.7 rev/min2, which resulted in a run time of less than 7 hours, gave results comparable to those of the slower rate of about 3.9 rev/min2. For these particular cores, the 7.7 2 rev/min acceleration can be considered the minimum necessary. However, less permeable cores might require a slower acceleration.

A numerical method for converting the experimental data to capillary pressure curves was programmed on a Royal McBee LGP-30 digital computer. In some cases these results were comparable to the hand calculated results which entailed graphical smoothing of the experimental data and visual slope taking. It is felt that a digital computer solution of the same type but involving data smoothing and higher order interpolation formulas for use on a larger computer would give results comparable to the hand calculated results in all cases"--Abstract, pages ii-iii.

Advisor(s)

Govier, John P., 1913-1998

Committee Member(s)

Maxwell, James C.
Vaughn, George E., Jr., 1925-1997
Lee, Ralph E., 1921-2010

Department(s)

Mining Engineering

Degree Name

M.S. in Mining Engineering

Comments

Master of Science, Mining Engineering -- Petroleum Engineering Option

Publisher

Missouri School of Mines and Metallurgy

Publication Date

1963

Pagination

vi, 55 pages

Note about bibliography

Includes bibliographical references (page 54).

Rights

© 1963 Robert N. Hoffman, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Thesis Number

T 1454

Print OCLC #

5950296

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