Page 248 - Standard Handbook Petroleum Natural Gas Engineering VOLUME2

Pressure Transient Testing of Oil and Gas Wells 217

ference tests are conducted by producing from or injecting into at least one well
and observing the pressure response in at least one shut-in observation well. A
change in rate (pressure) at the active producer or injector will cause a pressure
interference at the observation well. A special form of multiple-rate testing is
the pulse test in which the pressure caused by alternating periods of production
(or injection) and shut-in periods is monitored at one or more observation wells.
Multiple-rate tests are used to determine if wells are in communication with each
other in the same reservoir as well as to provide estimates of formation
permeability and the product of porosity and total compressibility.

Miller-Dyes-Hutchinson (MDH) Plot. One of the most useful methods of
pressure test analysis is that of Miller, Dyes, and Hutchinson [229]. The MDH
method is a plot of bottomhole pressure versus log time on semilog paper. A
schematic of an MDH plot for a pressure buildup test is depicted in Figure 5-133;
the region is identified where MDH and Horner plots are applicable.
Horner Plot. In the Horner plot [230] bottomhole pressure is plotted against
log(t + At)/At. The Horner method should be applied only to infinite-acting
reservoirs; for radial flow, the Horner plot will be a straight line. Several

FRONT END EFFECTS SEMILOG STRAIGHT LINE BOUNDARY EFFECTS
(SKIN, WBS. FRACTURES) (INFINITE ACTING) [INTERFERENCE)

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