Page 245 - A Practical Companion to Reservoir Stimulation

PRACTICAL COMPANION TO RESERVOIR STIMULATION

felt-tip marker is used to make a distinguishing character additives are calculated on the basis of clean fluid volume.
approximately %in. high on the flat side of the bottle. The Once proppant is added to the fluid, only a portion of the rate
bottle is then shaken for 10 sec. The character on the bottle is fluid. Compensations must be made to the additive rates to
should be distinguishable at arm’s length when looking through account for the amount of proppant in the slurry. Tables P-19
the bottle. through P-21 can be used to find the volume of fluid and the
volume of proppant for various proppant concentrations.
P-8.3: Material Balance The densitometers used to calculate proppant density
Preplanning the material balance of the treatment is one of measure the true density of the fluid and then calculate the
the most critical steps toward precise execution. The supervi- pounds of proppant added per gallon. The following equation
sor in charge of pumping operations must know exactly how can be used to validate the proppant concentration based on
much material is needed, how much has already been pumped the slurry density:
and how much remains on location. This dynamic problem
must be closely followed throughout the treatment. First, the p= ~ Mass (P-14)
treatment must be outlined into various stages. These stages Volume
often follow the proppant stages, but for very largejobs may Therefore,
also have to be shortened into timed stages. All additives
should be cross checked in approximately 15-min intervals weight of base fluid + weight of proppant
throughout a treatment. Each fluid and additive on location P= volume of base fluid + volume of proppant . (P-15)
should be accounted for at every timed step. Figure P-89 is an
example of a useful format for tracking the progress of a and
treatment. During the treatment, adjustments should be made
for any deviation from the plan. P= weight of base fluid + ppga (P-16)
Proppant stages are based on adding a volume of proppant gal + p p PPB” x
a
to a gallon of fluid; therefore, the terms “pounds of proppant
added” (ppga) or “pounds per gallon” (ppg) are used to For a base fluid density of 8.4 ppg, sand with a density of 22.1
designate these stages. The ppga term is preferred since ppg ppg and a proppant stage of 3 ppga, the densitometer should
connotates a true density, which is not true in this case. All read 10.4 ppg.

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16 20 30 40 50 70 100 200
Pan Pan Pan Pan Pan Pan Pan Pan

Table P-18-Fracturing sand sizes.

P- 84