Title: Biogenic sulfide control by nitrate and (per)chlorate – A monitoring and modeling investigation

Abstract

Biosouring is commonly encountered during secondary oil recovery when seawater or another high sulfate water source is utilized for flooding; as a result, effective souring control is of great interest to the oil industry. Here we describe a laboratory study to evaluate the relative effectiveness of souring interventions through the injection of nitrate, chlorate and perchlorate, collectively (per)chlorate, solutions and whether in-situ galvanic potential measurements can be used for convenient and quantitative tracking of sulfide dynamics. Nitrate has typically been the chemical of choice for souring treatments, while the efficacy of (per)chlorate as a new candidate inhibitor has only been explored recently. (Per)chlorate is known to inhibit oil reservoir souring via mechanisms such as toxicity, bio-competitive exclusion and sulfur redox cycling. Two sets of experiments under different matrix and inoculation conditions were conducted to evaluate treatment efficiency under variable baseline physical and biogeochemical conditions. Our data demonstrated the sensitivity of the galvanic potential signals to sulfide concentrations where the sulfide-galvanic potential correlation is similar to the theoretical predictions based on the Nernst equation, demonstrating the feasibility of using galvanic potential as a quick and economical method for quantifying in situ sulfide concentrations for tracking reservoir souring processes and subsequent interventionmore » effectiveness. Our results show that all three chemicals were effective at suppressing sulfidogenesis. A reactive transport model for perchlorate treatment was developed to simulate the reaction processes and explore the interactions between the underlying competing mechanisms of this inhibitor. A baseline simulation captured the temporal patterns of the effluent chemical species. Subsequent simulations in which individual inhibition mechanisms were systematically removed elucidated the relative role that each inhibition mechanism played at the different phases of the experiment. The simulation results complement the experimental findings. Our study supports the potential advantages of souring control with (per)chlorate treatments, and the application of galvanic signal as an economic, in-situ monitoring approach for tracking souring dynamics and treatment efficacy.« less

Authors:

Wu, Yuxin  ^[1];

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Cheng, Yiwei ^[1]; Hubbard, Christopher G. ^[2]; Hubbard, Susan ^[1]; Ajo-Franklin, Jonathan B. ^[2]

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1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Climate and Ecosystem Sciences Division
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Geosciences Division

Publication Date:

Fri Nov 17 00:00:00 EST 2017

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1476610

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Chemical Geology

Additional Journal Information:

Journal Volume: 476; Journal Issue: C; Journal ID: ISSN 0009-2541

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

02 PETROLEUM; 54 ENVIRONMENTAL SCIENCES; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Biosouring; Souring control; Galvanic potential; Reactive transport modeling