SPE 14254
Acoustic Determination of Producing Bottomhole
Pressure
James N. McCoy, SPE, Echometer Co.; Augusto L. Podio
SPE, U. of Texas; Ken L. Huddleston, SPE, Echometer Co.
This paper discusses the acoustic
determination of producing bottomhole pressure (BHP). Two different
techniques are presented for wells that have liquid above the formation
and gas flowing upward through the gaseous liquid column. One technique
involves the acoustic measurement of the liquid level and the
casing-pressure buildup rate when the casinghead valve is closed. When
these data are used along with an empirically derived correlation given
here, the gradient of the gaseous liquid column in the annulus can be
obtained. This technique offers a reasonably accurate procedure for
determining the producing BHP of a well by acoustic means. The second
method involves two acoustic measurements. A backpressure valve is used in
the casing head to depress and to stabilize the liquid level at two
positions while the well is produced at a constant rate. The gradient of
the gaseous liquid column is then calculated and extrapolated to the
formation depth.
This paper discusses results from the
field testing of numerous wells where the actual gradients of gaseous
liquid columns were measured in a variety of casing/tubing sizes, oil
gravities, gas flow rates, and pressures.
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