The use of naturally occurring selectively isolated bacteria for inhibiting paraffin deposition

One of the most severe problems at any oil fields producing paraffinic oils is that of paraffin depositions. Romania which has a long experience in oi l production is also faced with this problem in many oil fields. The microb ial treatment, based on the activity of naturally occurring, selectively is olated bacteria, is already proved as an effective alternative to conventio nal methods to prevent and remove paraffin damage. Using such kind of bacte rial products, exciting results for inhibiting paraffin depositions have be en obtained. In this paper results concerning the naturally occurring bacte ria selectively isolated from hydrocarbon polluted sites as well as from pa raffinic oils, semi-solid and solid paraffin depositions are presented. Aft er a laboratory screening, 15 bacterial strains (BS 1-15), three bacterial consortia(BC 1-3) and a Special Bacterial Consortium (SBC1) were selected. For the selection of bacterial consortia, the classical enrichment culture method has been used. The Special Bacterial Consortium resulted from a mixt ure of BS 1-15 and BC 1-3 following the steps of the classical enrichment c ulture method. The BS 1-15, BC 1-3 and SBC1 have been tested for their perf ormances in producing biosurfactants and biosolvents as well as for hydroca rbon utilisation. The SBC1 has been tested for its ability in degradation o f hydrocarbons contained in several types of paraffinic or non-paraffinic o ils, and then for inhibiting paraffin deposition on a 'flow equipment' usin g two types of paraffinic oils. The SBC1 has been also tested for degradati on of hydrocarbons contained in semi-solid and solid paraffin depositions. The results obtained could support further applications to prevent and cont rol paraffin depositions. (C) 1999 Elsevier Science B.V. All rights reserve d.