|Content Type||Conference Paper|
|Title||A New High Performance Quaternary Phosphonium Biocide for Microbiological Control in Oilfield Water Systems|
|Authors||Jeffrey F. Kramer, Frank O?Brien and Steven F. Strba, BWA Water Additives|
|Source||CORROSION 2008, March 16 - 20, 2008 , New Orleans LA|
|Copyright||2008. NACE International|
|Keywords||biocide, quaternary phosphonium compound, tributyl tetradecyl phosphonium chloride, TTPC, surface activity, compatibility, biofouling, souring, microbiologically influenced corrosion, MIC, water injection, produced water, storage tanks, pipelines|
Microorganisms can cause severe problems in oilfield water systems. This paper describes a new quaternary phosphonium biocide based on tributyl tetradecyl phosphonium chloride (TTPC). Laboratory and field data has shown that TTPC is effective at low concentrations, is fast acting and is effective against both acid producing and sulfate reducing bacteria. It has out performed both glutaraldehyde and THPS in comparative biocidal tests giving complete kill of aerobic and anaerobic sulfate-reducing bacteria in one hour at 5 and 50 ppm active, respectively. Glutaraldehyde required >40 and 150 ppm active and THPS required 40 and >200 active to match the performance of TTPC versus aerobic and anaerobic sulfate-reducing bacteria, respectively. TTPC is compatible with oxidizing biocides, hydrogen sulfide and oxygen scavengers and has excellent thermal stability which makes it broadly applicable to oilfield water systems.
Microbial growth in oilfield water systems can cause severe problems including energy losses due to increased fluid frictional resistances, formation plugging, souring of oil and gas and microbiologically influenced corrosion (MIC).1-6 The most common method of controlling microbial growth in oilfield water systems has been through the application of biocides. While a wide variety of biocides are available for use in oilfield water systems, improved methods are required to address efficacy, economic and environmental concerns. Biocides commonly used in oilfield water systems can be divided into two types; cationic or non-ionic. Cationic biocides include quaternary ammonium and quaternary phosphonium biocides. The quaternary ammonium biocides commonly used in oilfield water systems are of the alkyl dimethyl benzyl ammonium chloride (ADBAC) and dialkyl dimethyl ammonium chloride (DDAC) variety while the common quaternary phosphonium biocide is based on tetrakishydroxymethyl phosphonium sulfate (THPS). Unlike traditional quaternary biocides, which have at least one long alkyl chain (hydrophobe), THPS is a small, symmetrical molecule. The general structures of ADBAC, DDAC and THPS are shown in Figure 1. Non-ionic biocides commonly used in oilfield water systems include acolein, cocodiamine, formaldehyde and glutaraldehyde (glute). Recently, a second quaternary phosphonium biocide, tributyl tetradecyl phosphonium chloride (TTPC), has been registered with the US EPA for use in oilfield applications. TTPC is unique in that it combines a quaternary phosphonium group with the long alkyl chain of the quaternary ammonium biocides in the same molecule (see Figure 1). This unique structure makes TTPC particularly effective at controlling problem causing organisms and biofilms. In one study using laboratory recirculating water systems inoculated with Pseudomonas fluorescens, weekly treatments of 12.5 ppm active TTPC maintained biofilm levels at 5.0 x 105 bacteria/coupon compared to 2.7 x 1010 bacteria/coupon in the untreated control.7 In addition to outstanding biocidal activity, TTPC also has excellent thermal stability. A one percent solution of TTPC showed no loss of active ingredient when refluxed at 214 ? 216°F (101 - 102 °C) for six hours and differential scanning calorimetry showed that no significant thermal degradation occurred at temperatures up to 572°F (300°C). TTPC has been used in Europe, Asia and Latin America for several years where it has shown excellent activity versus algal and bacterial biofilms. In this study, the performance of TTPC is compared to other cationic and non-ionic biocides commonly use in oilfield water systems.
|File Size||417 KB||14|