American Oil and Gas Reporter - December 2021 - 67

SpecialReport: Stimulation & Completions
Figure 2B shows Stage 54 in Well A1
spotting a one-to-two (HCR-to-water)
ratio during wireline pump down. This
well took ~22 minutes, resulting in approximately
nine minutes of time saved
to reach the designed frac rate between
consecutive stages. The compatibility of
HCR with the wireline cable enabled the
operator to spot acid with the wireline
tool. This allowed the frac crew to start
pumping acid into the formation immediately
following a well swab, instead of
displacing a wellbore volume of water
prior to acid contacting the perforations.
Satisfactory acid relief was observed
on all stages and the designed frac rate
was achieved faster than using conventional
15% HCl with an average rate that
was three barrels/minute higher at slightly
lower average pressure.
Comparing the other wells that were
completed on the same pad, only one of
those wells used HCR on Stage 54 (Well
A2), while the other two wells used a
conventional 15% HCl spearhead. Well
A2 showed a similar progression in a
rapidly increasing rate, while wells A3
and A4 showed the slower progression
to build up to the designed frac rate.
Figure 3A shows Stage 29 in Well A2
(from the same zipper group as A1), which
used HCR during wireline pump down.
The time frame in which the designed
rate was achieved is shown in red. Figure
3B shows Stage 29 in Well A3 (zipper
group A2 with Well A3), which utilized
15% HCl as a traditional spearhead.
On average across the entire trial, the
stages utilizing HCR averaged an eightminute
reduction in time to complete the
stage design versus the ones that did not.
Overall, this operational efficiency provided
substantial cost savings.
The data collected from the stage
summaries indicate that the stages using
HCR versus the ones using HCl had an
average decrease in total stage time of
8-10 minutes as well as an increase in
average pump rate up to three bbl/minute.
Averages were taken from similar stage
numbers across each well to normalize
the data as much as possible. Average
pump times were 58 minutes for A1 and
62 minutes for A2 compared with 67
and 69 minutes for the A3 and A4 15%
HCl wells, respectively. Average rates
were 72.4 bbl/minute for Well A1, 68.5
for A2, 69.3 for A3, and 70.8 for A4.
Expanded Application
Following the success of the field
trial, HCR was integrated into the completions
program for all carbonate target
stages. The usage and efficiency improved
over the next three well pads,
FIGURE 2A
Well A1 Stage 53 (15% HCI)
10,000
10,500
3,000
10,000
8,000
8,500
5,000
8,000
6,000
6,500
7,000
6,000
4,000
4,500
9,000
4,000
2,000
2,500
11,000
2,000
500
13,000
06/03/19
19:55
FIGURE 2B
Well A1 Stage 54 (1:2 HCR)
10,000
10,500
3,000
10,000
8,000
8,500
5,000
8,000
6,000
6,500
7,000
6,000
4,000
4,500
9,000
4,000
2,000
2,500
11,000
2,000
500
13,000
06/03/19
23:15
Treatment Plot
Time
06/03/19
23:45
Revolution
DECEMBER 2021 67
06/04/19
00:15
Treating Pressure (psi)
Meas'd Btmh Press (psi)
Hydr Pressure (psi)
6203B Backside (psi)
Slurry Rate (bpm)
Inline 2 Conc (ppg)
Blender Conc (ppg)
Btm Prop Conc (ppg)
150
20
20
20
120
16
16
16
90
12
12
12
60
8
8
8
30
4
4
4
06/03/19
20:30
06/03/19
21:05
Treating Pressure (psi)
Meas'd Btmh Press (psi)
Hydr Pressure (psi)
6203B Backside (psi)
Slurry Rate (bpm)
Inline 2 Conc (ppg)
Blender Conc (ppg)
Btm Prop Conc (ppg)
150
20
20
20
120
16
16
16
90
12
12
12
60
8
8
8
30
4
4
4
encompassing 27 wells and more than
2,500 total stages completed where HCR
was the acid used to initiate formation
breakdown. The results of these wells
reflected the initial success of the trial
and reduced pump time by 8-10 minutes
per stage on average. These operational
efficiencies gave the operator flexibility
to maximize other frac operations within
its completion program.
This significant reduction in " flat time "
per stage facilitated more than just savings.
By reducing the cost of each incremental
American Oil and Gas Reporter - December 2021

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