American Oil and Gas Reporter - February 2015 - 66

SpecialReport: Unconventional Resource Science
FIGURE 4
STP, Rate and Proppant Concentration (Stages 18-29)
3,000

15

10,000

40

2,000

10

5,000

20

1,000

0

0

Rate (bpm)

STP (psi)

0

200

5

0
600

400

Sand (psa) BH Sand (psa) In-Line (psa)

60

5.5 95⁄8 (psi)

15,000

0

Elapsed Time (min)

FIGURE 5A
Average STP, Rate and ISIP (All Stages)
10,000

45

9,000

40

8,000

35
30

6,000
25
5,000
20
4,000

Rate (bpm)

Pressure (psi)

7,000

15

3,000

10

2,000
Average Surface Treating Pressure (psi)

1,000

5

ISIP
Average Rate (bpm)

0

0
0

5

10

15
Number of Stages

20

25

30

FIGURE 5B
Average Water and Proppant Used (All Stages)
180,000

2,500

160,000
2,000

140,000

Proppant (lbm)

1,500
100,000
80,000
1,000
60,000
40,000

500

20,000

Proppant per Stage

Fluid Volumes per Stage

0

0
5
0

10

15
Number of Stages

66 THE AMERICAN OIL & GAS REPORTER

20

25

30

Clean Volumes (bbl)

120,000

the well clean, function test the BHA,
and continue with the fracturing operation
for the stage.
The treatment design for the last stage
was changed to add a sand-laden substage
with a proppant concentration of 5 psa to
the pump schedule. That increased the
proppant pumped for this stage to 167,485
pounds and fluids to 2,017 barrels. Figure
4 shows the STP, rate and proppant concentration for stages 18-29, which were
completed in approximately 10 hours on
the final day of the operation.
Since the entire lateral section was
drilled within the third Bone Spring formation, the instantaneous shut in pressure
was similar for every stage, averaging of
4,250 psi (Figure 5A). The average STP
also was similar for every stage, except
that it was higher at the beginning of
stages 5, 6 and 9.
All frac sleeves were opened successfully, and all 29 zones were stimulated
effectively in a single trip. The average
pump rate was 39.7 bbl/minute and average
surface treating pressure was 7,238 psi.
The total volume of fluids pumped for
the job was 47,550 barrels; the total
amount of proppant was 2,371,960 pounds
of Atlas 20/40-mesh sand. Figure 5B
shows fluid volumes and proppant quantities for every stage.
The CTFS packer was used for the
entire fracturing operation without needing
to be replaced. It was used to open all
the frac sleeves and isolate all 29 stages.
It was function tested several times between stages to ensure that it was working
properly.
Bottom-Hole Data
The bottom-hole pressure and temperature data recorded using the memory
gauges assisted in post-job performance
analysis and in optimizing future fracturing
treatment designs for neighboring wells.
As noted, two memory pressure transducers were deployed above the packer
and one below the packer as part of the
CT BHA. The lower pressure showed a
straight line during the fracturing process,
indicating that the packer was holding
pressure and there was no communication
between stages.
Figure 6 shows how bottom-hole fracturing pressure varied from one stage to
another for stages 12-29. In the case of a
multicluster plug-and-perf completion,
most fluids are placed in the clusters that
require less fracturing pressure, leaving
some clusters unstimulated and unable
American Oil and Gas Reporter - February 2015

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