Mechanistic Modelling of H2S Souring Treatments by Application of Nitrate or Nitrite

Abstract

The activity of sulfate-reducing bacteria (SRB) in oil field brines causes numerous problems associated with reservoir souring. Biological solutions based on stimulating nitratereducing bacteria provide novel, inexpensive, and environmentally friendly alternatives to the use of biocides and corrosion inhibitors. Experiments have been designed to understand and optimize mechanisms associated with this novel treatment and provide a sound technical basis for the application of this technology.Here, appropriate microbial growth and metabolite production kinetic models are employed in the STARS reservoir model to simulate laboratory continuous up-flow packed-bed bioreactor tests. Observed compositional changes along the length of the bioreactor are matched for various injected treatment scenarios. Sensitivity to factors affecting growth and production rates are examined.A stratified, dipping reservoir model with properties typical of North Sea conditions is then investigated as a field prototype. The complications introduced by multiphase flow effects and sweep to the basic process are indicated, and sensitivities to the amount of biodegradable carbon, assumed microbe growth/decay levels, and fractions of sessile/liquidphase bacteria on process evolution are illustrated. The simulations provide a dramatic demonstration of how this novel H 2 S souring treatment can be applied to field problem wells.

Nitrite is a more efficient inhibitor of microbial sulfate reduction in oil reservoirs compared to nitrate and perchlorate: A laboratory and field-scale simulation study

“…Moreover, there are very few studies that integrate laboratory observations to field scale predictions (Coombe et al, 2004;Haghshenas et al, 2012). Furthermore, early models of oil reservoir souring were empirical and could only account for a single microbial metabolism i.e.…”

Simulation of Bacterial Souring Control in an Alberta Heavy-Oil Reservoir

“…The bacterial modelling approach is based on earlier work comparing simulation (4) to detailed up-flow bioreactor experiments (5) conducted at the University of Calgary, but modified for the current application. First, recent experiments on field fluid samples indicate that toluene is the major electron donor and carbon source utilized (6) .…”

Simulation of Bacterial Souring Control in an Alberta Heavy-Oil Reservoir

“…The bacterial modelling approach is based on earlier work comparing simulation (4) to detailed up-flow bioreactor experiments (5) conducted at the University of Calgary, but modified for the current application as follows. First recent experiments on field fluid samples indicate that toluene is the major electron donor and carbon source utilized (6) .…”