Browsing by Author "Reinsel, Mark A."

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Characterization of microbial souring in berea-sand porous medium with a north sea oil field inoculum
(1996-04) Chen, Ching-I; Reinsel, Mark A.
Microbial souring (H2S production) in porous medium was investigated in an anaerobic upflow porous medium reactor at 60°C using produced waters obtained from the North Sea Ninian oilfield as the inoculum. Multiple carbon sources commonly found in oil field waters (formate, acetate, propionate, iso‐ and n‐butyrates) with inorganic sulfate as the electron acceptor were used as the substrates. Stoichiometry and the rate of souring in the reactor column were calculated. A large proportion of H2S was trapped in the column as FeS and possibly as a gas phase. Concentration gradients for the substrates (organic acids and sulfate) and H2S were generated along the column. At steady state, the highest volumetric substrate consumption and H2S production were found at the front part (inlet) of the reactor column. The average volumetric sulfate reduction rate after H2S production had stabilized was calculated to be 203 ± 51 mg sulfate‐S.l‐1.d‐1. Comparison of the results with the authors’ previous work on the Alaska Kuparuk oilfield waters indicates that the two different microbial inocula (produced waters) exhibited the same experimental trends (rates and location) for souring in the experimental reactor system. This indicates that abiotic factors, as well as microbial parameters, may play an important role for microbial souring in the system.
Control of microbial souring by nitrate, nitrite or glutaraldehyde injection in a sandstone column
(1996-08) Reinsel, Mark A.; Sears, Joe; Stewart, Philip S.; McInerney, Michael J.
Microbial souring (production of hydrogen sulfide by sulfate-reducing bacteria, SRB) in crushed Berea sandstone columns with oil field-produced water consortia incubated at 60°C was inhibited by the addition of nitrate (NO3) or nitrite (NO2−). Added nitrate (as nitrogen) at a concentration of 0.71 mM resulted in the production of 0.57–0.71 mM nitrite by the native microbial population present during souring and suppressed sulfate reduction to below detection limits. Nitrate added at 0.36 mM did not inhibit active souring but was enough to maintain inhibition if the column had been previously treated with 0.71 mM or greater. Continuous addition of 0.71–0.86 mM nitrite also completely inhibited souring in the column. Pulses of nitrite were more effective than the same amount of nitrite added continuously. Nitrite was more effective at inhibiting souring than was glutaraldehyde, and SRB recovery was delayed longer with nitrite than with glutaraldehyde. It was hypothesized that glutaraldehyde killed SRB while nitrite provided a long-term inhibition without cell death. Removal of nitrate after as long as 3 months of continuous addition allowed SRB in a biofilm to return to their previous level of activity. Inhibition was achieved with much lower levels of nitrate and nitrite, and at higher temperatures, than noted by other researchers.
Kinetic investigation of microbial souring in porous media using microbial consortia from oil reservoirs
(1994-07) Chen, Ching-I; Reinsel, Mark A.; Mueller, Robert Franz
Microbial souring (H2S production) in porous media was investigated in an anaerobic upflow porous media reactor at 60°C using microbial consortia obtained from oil reservoirs. Multiple carbon sources (formate, acetate, propionate, iso- and n-butyrates) found in reservoir waters as well as sulfate as the electron acceptor was used. Kinetics and rates of souring in the reactor system were analyzed. Higher volumetric substrate consumption rates (organic acids and sulfate) and a higher volumetric H2S production rate were found at the from part of the reactor column after H2S production had stabilized. Concentration gradients for the substrates (organic acids and sulfate) and H2S were generated along the column. Biomass accumulation throughout the entire column was observed. The average specific sulfate reduction rate (H2S production rate) in the present reactor after H2S production had stabilized was calculated to be 11062 ±2.22 mg sulfate-S/day g biomass. © 1994 John Wiley & Sons, Inc.
Partition coefficients for acetic, propionic, and butyric acids in a crude oil/water system
(1994-07) Reinsel, Mark A.; Borkowski, J. J.; Sears, Joe