Comparison of Biocides id Using a New Microbial Detection Tool

Transcription

1 Comparison of Biocides id Using a New Microbial Detection Tool Edward Corrin Multi-Chem Production Chemicals Stanley Leong OSP Microcheck Inc. Pat Whalen LuminUltra Technologies Ltd. Presented at: 2 nd International Symposium on Applied Microbiology and Molecular Biology in Oil Systems (ISMOS-2) June 19,

2 Introduction Microbial contamination in the oil and gas industry is prevalent in both upstream and downstream activities. Fouling, corrosion, and spoiling of additives can lead to increased production costs ($$$). Problem prevention must begin with understanding both the nature and location of microbial proliferation: If you don t monitor it, you can t control it! A wide variety of microbial monitoring tools are available to characterize microorganisms in the field. 2

3 Microbial Monitoring Tools Microscope Culture Tests Molecular Indicators Inferential Parameters 3

4 Scope This study sought to investigate a new microbial monitoring tool based on the measurement of Adenosine Triphosphate (ATP) for use in the field for oil and gas industry applications. This new method was compared with the industry standard (culture tests / MPN) in a controlled laboratory evaluation of three biocides. Results from each different microbial indicator were compared to better understand d microbial response to biocide id additions. All testing was performed in Houston, TX. 4

5 Methods Produced water was collected from the Barnett Shale Formation; portions were incubated for 5 days to culture native Sulphate Reducing Bacteria (SRB) and Acid Producing Bacteria (APB). All samples were tested using four methods: SRB Dilution Bottles / MPN (Modified Postgate s B media) APB Dilution Bottles / MPN (Phenol Red Dextrose media) SRB Check Bottle / MPN (Dehydrated media) Quench-Gone Aqueous (QGA) ATP Test 5

6 QGA Method for Adenosine Triphosphate Quantification of micro-organisms via ATP has a long history in food hygiene and certain water applications. Use in oil and gas industry has been restricted due to interference from dissolved solids, hydrocarbons, and residual biocides. QGA test method is 2 nd Generation; based on a method optimized for wastewater and gets around those interferences. 6

7 Why 2 nd Generation ATP Testing? 1. Quantitative sample transfer using syringe and micropipettes ensures accuracy it all starts with the sub-sample! 2. Superior chemistry provides complete recovery of ATP by achieving complete extraction. 3. Optimized methods and chemistry ensure that interferences are minimized (salinity, oil, biocides, extra-cellular ATP). 4. Use of external ATP standard (UltraCheck 1) converts RLU to actual ATP concentration and compensates for assay variance (Enzyme batch & age, temperature, instrument) ATP testing is rapid, user friendly, and field applicable. 7

8 Sample Preparation Produced water (ph ~ 6, TDS ~ 7%) was spiked with equal parts of each culture to create the master sample. Sub-samples were then treated with one of 3 biocides at 3 dosages. One control subsample was retained untreated. Biocide 50 mg/l 100 mg/l 200 mg/l Bronopol X X X Gluteraldehyde X X X DDAC Quat X X X Samples were allowed to stand at room temperature t under a nitrogen blanket to maintain anaerobic conditions and tested at 1 hour and 24 hours. 8

9 Experimental Design From Field 5 day Culture Produced Cultured Cultured Water SRB APB Control Bronopol Gluteraldehyde DDAC Amine Quat 1 hour, 24 hours 9

10 Results APB Dilution Bottles BIOCIDE & DOSAGE APB Dilution (log CFU/mL) 1 hr % Inhb 24 hr % Inhb Control mg/l Bronopol 2 0% 0 99% 100 mg/l Bronopol 2 0% 0 99% 200 mg/l Bronopol 0 99% 0 99% 50 mg/l Gluteraldehyde ld d 0 99% 0 99% 100 mg/l Gluteraldehyde 0 99% 0 99% 200 mg/l Gluteraldehyde 0 99% 0 99% 50 mg/l DDAC 2 0% 2 0% 100 mg/l DDAC 2 0% 2 0% 200 mg/l DDAC 2 0% 2 0% Gluteraldehyde provides an immediate and complete reduction; Bronopol reduction is slower but effective. DDAC not effective. 10

11 Results SRB Dilution Bottles BIOCIDE & DOSAGE SRB Dilution (log CFU/mL) 1 hr % Inhb 24 hr % Inhb Control mg/l Bronopol 6 0% 6 0% 100 mg/l Bronopol 6 0% 5 90% 200 mg/l Bronopol 6 0% 4 99% 50 mg/l Gluteraldehyde ld d 0 >99.99% 99% 0 >99.99% 99% 100 mg/l Gluteraldehyde 0 >99.99% 0 >99.99% 200 mg/l Gluteraldehyde 0 >99.99% 0 >99.99% 50 mg/l DDAC 6 0% 6 0% 100 mg/l DDAC 6 0% 6 0% 200 mg/l DDAC 6 0% 6 0% Gluteraldehyde provides an immediate and complete reduction; Bronopol is moderately effective. DDAC not effective. 11

12 Results SRB Check Bottles BIOCIDE & DOSAGE SRB Check Bottle (log CFU/mL) 1 hr % Inhb 24 hr % Inhb Control 4 - ND - 50 mg/l Bronopol 3 90% ND mg/l Bronopol 2 99% ND mg/l Bronopol % ND - 50 mg/l Gluteraldehyde ld d % 99% ND mg/l Gluteraldehyde % ND mg/l Gluteraldehyde % ND - 50 mg/l DDAC % 9% ND mg/l DDAC % ND mg/l DDAC % ND - All biocides appear to be effective through this method. Could be due to lack of dilution biocide suppression. 12

13 Results QGA catp Measurement BIOCIDE & DOSAGE QGA catp (pg ATP/mL) 1 hr % Inhb 24 hr % Inhb Control mg/l Bronopol % 71 97% 100 mg/l Bronopol % 36 99% 200 mg/l Bronopol 39 98% 52 98% 50 mg/l Gluteraldehyde ld d % 71 97% 100 mg/l Gluteraldehyde % 59 98% 200 mg/l Gluteraldehyde % 59 98% 50 mg/l DDAC % % 100 mg/l DDAC % % 200 mg/l DDAC % % ATP results are more consistent with APB and SRB dilution bottles but require longer incubation to see substantial reduction. 13

14 Summary of Results BIOCIDE & DOSAGE % Inhibition Relative to 24h APB SRB catp 50 mg/l Bronopol 99% 0% 97% 100 mg/l Bronopol 99% 90% 99% 200 mg/l Bronopol 99% 99% 98% 50 mg/l Gluteraldehyde 99% >99.99% 97% 100 mg/l Gluteraldehyde ld d 99% >99.99% 99% 98% 200 mg/l Gluteraldehyde 99% >99.99% 98% 50 mg/l DDAC 0% 0% 19% 100mg/LDDAC 0% 0% 54% 200 mg/l DDAC 0% 0% 86% 24 hour tests show the full effect of biocide addition. APB (MPN), SRB (MPN), and ATP all show similar results. 14

15 Discussion of Results Significantly more SRB detected than APB in original (control) sample, likely a characteristic of native sample. APB and SRB Dilution Bottle methods agreed in that Gluteraldehyde achieved a complete kill, with Bronopol being effective but requiring a higher dosage and longer incubation. SRB Check Bottle method indicated that all biocides were quite effective even after 1 hour may be due to high residual biocide action during incubation period. 15

16 Discussion of Results (cont d) ATP results agreed with APB and SRB Dilution Bottle Methods. Magnitude of inhibition not as great using ATP as for dilution bottles likely because of Viable but not Culturable (VBNC) and non-apb/srb microorganisms. ATP did indicate that Bronopol was of similar or greater effectiveness as Gluteraldehyde, which was not as consistent with APB and SRB results. Different methods yield different results which helps us understand treatment effectiveness. 16

17 Comparison of Field Methods Method Dilution Bottles Check Bottles QGA catp Detected in Method 1% of total microorganisms 1% of total microorganisms Total Microorganisms Time to Obtain Results 7 (APB) to 28 (SRB) days 1 to 10 days 5 minutes What do Results Show Interferences Differentiate APB, SRB, and others SRB specifically Total biological activity TDS (if not corrected), Biocides N/A Biocides 17

18 Conclusions Given sufficient incubation time (24 hours), 2 nd Generation ATP results are similar to MPN. This can reduce the overall time to feedback (24 hours vs. 7 to 28 days). ATP provides complementary information to specific culture tests can reveal that microbiological activity exists even if other field tests do not see specific microorganisms. ATP method can be used in the field to rapidly assess hot spots or immediate treatment t t requirements (e.g. fracture fluids). It is desirable to have multiple detection tools in the field! 18

19 Acknowledgements Edward Corrin Multi-Chem Production Chemicals Stanley Leong OSP Microcheck Inc. Q U E S T I O N S? 19