Page 158 - A Practical Companion to Reservoir Stimulation

PRACTICAL COMPANION TO RESERVOIR STIMULATION

P-2
ity sand is available from several sources. In the United
Proppant Selection
States, premium sands come from Illinois, Minnesota and
Wisconsin. They are mined from the Jordan Sandstone and
To select a proppant with a desired fracture conductivity for a the St. Peter Sandstone. These sands are often referred to as
specific treatment, both the reservoir producing capacity and “northern white sand,” “northern sand,” “white sand,” “Ottawa
the proppant permeability must be considered. The size and sand,” “Jordan sand,” “St. Peter’s sand” and “Wonewoc
type of the proppant must then be considered when designing sand.” Even though these sands may come from different
an appropriate fracturing treatment. sources and may even have different appearances, they per-
P-2.1: ljpes of Proppants form similarly during conductivity testing. While the two
Table P-1 contains the size, specific gravity and porosity of premiym sands may be easily distinguished by color, their
performance during conductivity testing shows they are very
the most common proppants. These data, using Eq. 8-48, similar.
allow the calculation of the propped fracture width (Table P- Standard grade sands come from the Hickory Sandstone
2) if the total mass of proppant injected and the, generated near Brady, Texas. These sands have a darker color than many
fracture area are known. The ratio of these two variables is of the northern sands. Some of the common names are “Texas
often referred to as the proppant concentration within the brown sand,” “brown sand,” “Brady sand” and “hickory
fracture. In addition, Table P-2 contains the average number sand.” Although not considered premium sands, at lower
of particle diameters for each proppant width. Finally, the closure stresses the brown sands have a higher proppant-pack
actual propped width will be somewhat reduced as a result permeability than their northern counterparts.
of particle embedment, a serious problem in very soft for- The conductivity of sand can be improved by applying a
mations. thin coating of resin to the sand grains. The resin coating
Of the several types of proppants available for hydraulic helps increase the strength of the sand, reduces the amount of
fracturing, sand is the most common. Today, fracturing qual- fines created as the proppant undergoes fatigue and spreads

Type Mesh Size Particle Size (in.) Specific Gravity Porosity
Northern White Sand 12/20 0.0496 2.65 0.38
16/30 0.035 2.65 0.39
20140 0.0248 2.65 0.40
Texas Brown Sand 12/20 0.0496 2.65 0.39
16/30 0.035 2.65 0.40
20140 0.0248 2.65 0.42
Curable Resin-Coated Sand 12/20 0.0496 2.56 0.43
16/30 0.035 2.56 0.43
20140 0.0248 2.55 0.41
Precured Resin-Coated Sand 12/20 0.0496 2.55 0.38
16/30 0.035 2.56 0.37
20140 0.0248 2.55 0.37
ISP 12/20 0.0248 1 3’18 I 0.42
0.0496
20140 3.23 0.42
ISP-Lightweight Sintered Bauxite 20140 0.0248 2.72 0.40
16/20 0.04 3.7 0.43
20140 0.0248 3.7 0.42
40170 0.01 24 3.7 0.42
Zirconium Oxide 20140 0.0248 3.15 0.42

Table P-1-Typical proppants and their characteristics. (Note that porosity decreases under closure stress.)

P-2