Mechanistic Modelling of H2S SouringTreatments by Application of Nitrate or Nitrite

摘要

The activity of sulfate-reducing bacteria (SRB)in oil fieldbrines causes numerous problems associated with reservoirsouring. Biological solutions based on stimulating nitrate-reducing bacteria provide novel, inexpensive, andenvironmentally friendly alternatives to the use of biocides andcorrosion inhibitors. Experiments have been designed tounderstand and optimize mechanisms associated with thisnovel treatment and provide a sound technical basis for theapplication of this technology. Here, appropriate microbial growth and metaboliteproduction kinetic models are employed in the STARS reservoirmodel to simulate laboratory continuous up-flow packed-bedbioreactor tests. Observed compositional changes along thelength of the bioreactor are matched for various injectedtreatment scenarios. Sensitivity to factors affecting growth andproduction rates are examined. A stratified, dipping reservoir model with propertiestypical of North Sea conditions is then investigated as a fieldprototype. The complications introduced by multiphase floweffects and sweep to the basic process are indicated, andsensitivities to the amount of biodegradable carbon, assumedmicrobe growth/decay levels, and fractions of sessile/liquid-phase bacteria on process evolution are illustrated. Thesimulations provide a dramatic demonstration of how this novel H2S souring treatment can be applied to field problemwells.