Biocide Best Practices

Jordan McNally

• How we started

• Things to consider

• New challenges

• Result Target

• Data Gathering

• Example Trial

• Overall Comparison

• Conclusions

Outline

2

How we started

• Water Management group started

looking at biocides used in 2013

to control costs on water recycling

projects

• We were using glut-quat for

stimulation and drill out operations

• Moved to using an oxidizer

biocide

• Cost consistency

• real time verification

• Consistency

3

0.25 0.5 1 1.5

$$/

bb

l

gpt

Biocide Comparison

glut/quat

ClO2

• Sources of contamination

• Drilling mud

• Stimulation fluid

• Drillout fluid

• Production activity

• Application

• There is no one size fits all biocide

• Area specific

• Water specific

Things to Consider

4

• Produced water

• Fresh water

• High iodide levels

• High pH

• Frac chemistry

New Challenges

5

Results Target

• Target levels

• 1 or less bug bottle turn is

great

• 1-3 is okay

• More than 3 unsatisfactory

• Use serial dilution test method

• Log based measurement of

bacteria

• 6 month bacteria free

treatment is considered a

success

6

Serial Dilution Technique, API RP 38

# of Positive Bottle Turns Bacteria Population (Colonies per mL)

1 1 - 10

2 10 - 100

3 100 - 1,000

4 1,000 - 10,000

5 10,000 - 100,000

6 100,000 - 1,000,000

Photo taken by Matt Patric

• 3/3 bug bottle shooting

• Sample points

• Contingency plans for downtime

• Daily reports

• pH

• ORPs

• Residual targets

• FAC

• Oxidizer residual

During Job Testing

7

• In house bug bottle testing

• Test frequency: 1, 3, 7, 14,

21, 28 days, and every

month for 6 months.

• Test Procedure

• Sample location

• Heater Treater vs

Wellhead

Post Job Testing

8

0

1

2

3

4

5

6

Wellhead Heater Treater

Sample Location

SRB

APB

1. Look at history in an area

• Pervious biocides used

• H2S present

2. Water type

3. Pick good well candidates

• Closely grouped wells

• Infill projects

4. Work with chemical providers for recommendations on biocides to

trial

5. Perform kill studies to determine dosage

6. Monitor results

Experimental Design

9

Example: Different Oxidizer Trial

• Is there something more

cost effective we could be

using and still get the

same or better results?

• Tried Bleach +

Preservative B vs ClO2 +

Preservative B

10

Well Stim Biocide

Well 1

ClO2 + .2 gpt

Preservative B

Well 2

Bleach + .2 gpt

Preservative B

Well 3

Bleach + .2 gpt

Preservative B

Well 4

Bleach + .2 gpt

Preservative B

Well 5

ClO2 + .2 gpt

Preservative B

Well 6

ClO2 + .2 gpt

Preservative B

Well 7

ClO2 + .2 gpt

Preservative B

Oxidizer Trial Results

• Bleach performed just as

well as ClO2

• Save 14% by switching to

bleach with a

preservative instead of

ClO2

11

0.00

1.00

2.00

3.00

4.00

5.00

6.00

SRBs APBs

Oxidizer Comparision

ClO2 +Preservative B

Bleach +Preservative B

• Looked to see if we could

use a different preservative

maintain results and

potentially save money.

• Tried Preservative B against

Preservative D.

Bleach + Preservative Comparison Trial

12

Well Stim Biocide

Well 1

200 ppm bleach + 300 ppm

Preservative D

Well 2

200 ppm bleach + 300 ppm

Preservative D

Well 3

250 ppm Bleach + 200 ppm

Preservative B

Well 4

250 ppm Bleach + 200 ppm

Preservative B

Well 5

250 ppm Bleach + 200 ppm

Preservative B

Well 6

300 ppm Bleach + 200 ppm

Preservative B

• Both preservatives

performed well.

• Concluded we could use

Preservative D in place of

Preservative B since they

yield similar results.

Results

13

0

1

2

3

4

5

6

Average SRB Average APB

Bleach + Preservative Comparison

Preservative D

Preservative B

Overall Biocide Comparison

14

0

1

2

3

4

5

6

Average SRB Average APB

Overall Comparison

Bleach + 100 ppm Preservative B

Bleach + 200 ppm Preservative B

ClO2 + 200 ppm Preservative B

ClO2

Bleach + 150 ppm Preservative D

ClO2 + 150 ppm Preservative D

Biocides

Price, % of starting price

glut/quat 100%

ClO2 cost when we switched 100%

current ClO2 cost 30%

ClO2 + Preservative B 49%

Bleach + Preservative C 44%

Bleach + Preservative D 33%

Costs

15

0%

20%

40%

60%

80%

100%

120%

Price, % of starting price

Prices

glut/quat

ClO2 cost whenwe switched

current ClO2 cost

ClO2 +Preservative B

Bleach +Preservative C

Bleach +Preservative D

• A bacteria monitoring program is important and must be

looked at regularly.

• There is no one size fits all biocide, trials should be

performed in different fields to see which biocide works

in each area.

• Pre and post testing is crucial for successful & economic

biocide program

Final Thoughts

16

17

Questions?