Interactions between minerals and microbes are ubiquitous in the low permeability reservoirs.But whether or not the microbes can affect the structure and phase of the poor-Fe minerals by reducing Fe (III), and inhibiting the clay minerals swelling become a new research. Therefore, the objective of this study was to understand the interaction method of the four strains Fe (III) reducing bacteria and Ca-montmorillonite under aerobic atmosphere (Fig.1), the mainly measurements of pH, total protein content, Fe (II) concentration and Fe (III) concentration were to evaluate the extents and rates of Fe (III) reduction related to the life activity state with a regular period in the experiment. The mineralogical characterization of the ultimate microbial action of the minerals was characterized by FTIR, XRD, SEM and EDS that these methods were used to reveal the mechanism of inhibition in Ca-10 via the four strains Fe (III) reducing bacteria. In Fig.2, the reduction rates of Fe (III) in Ca-10 gradually decreased and finally stabilized. The highest Fe (III) reduction rate at 4th, 5th, 7th and 4th day were reached, the reduction rates were 47.1%, 62.9%, 67.1% and 71.1%, respectively. The results showed that the four strains bacteria were reduced efficiently of Fe (III), optimal reduction rate of 71%. Further changed in the surface morphology and the lattice structure and promoted the interlayer cations of exchanged and produced some new minerals, and inhibited efficiently the Ca-montmorillonite swelling, optimal inhibition rate of 48.9%.

Study on changes of mineral structure by Fe (III) reducing bacteria and its role in inhibiting of clay swelling in low permeability reservoirs

255th National Meeting (2018)

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