Microbial-induced carbonate precipitation applicability with the methane hydrate-bearing layer microbe

Abstract

Production of methane gas from the methane-hydrate-bearing layer below the deep-ocean floor is expected to be crucial in the future of energy resources worldwide. During the methane gasproduction phase from the methane hydrate with the depressurisation method, the depressurising zone around the production well will lose strength, causing a potential geohazard. In this study, a biomediated treatment to reinforce the methane hydrate layers is proposed. A urease-producing bacterium, Sporosarcina newyorkensis, was isolated for the first time from a pressure core sampled from the Nankai Trough seabed methane-hydrate-bearing layer in Japan. This newly isolated species can survive deep-seabed environments and also enhance the population under nutrient-rich conditions. In addition, it is uniquely characterised with higher urease activities under low-temperature conditions in comparison to the well-known bacterium S. pasteurii. The results of triaxial tests suggest that this bacterium can catalyse the precipitation of calcium carbonate through urea hydrolysis, which enhances the soil strength below of the ocean floor and hence reinforces the production well. This will not only make methane gas extraction safer but may also reduce sand production in the well, making extraction operations more efficient and cost effective.

Comparison of the Vertical Gas-Hydrate Production Profile with the Simulation Results Obtained Using Geophysical Log-Based Reservoir Characteristics and Reasons for Their Discrepancies in the Nankai Trough

“…The selection of reservoir and well locations and techniques for a wide range of water control is essential for stable gas production. In this study, we focused on the implication of microbiologically induced calcite precipitation and water glass (sodium silicate) for water control because their treatment media are fluid and do not contain solids that prohibit dispersion into the broad domain of the formation. Detection techniques for the water-bearing zone are another important topic, and some seismic attributes can be useful to find low gas-hydrate saturation water-bearing streaks …”

Bio‐mediated soil improvement: An introspection into processes, materials, characterization and applications

“…The reduced injectivity, reduced pressure fall‐off and increased solids showed a successful sealing effect of MICP. Hata et al (2020) evaluated the feasibility of MICP for ground improvement in the deep ocean using native bacteria. The urease‐producing bacteria (i.e.…”

Numerical History-Matching of Modeling and Actual Gas Production Behavior and Causes of the Discrepancy of the Nankai Trough Gas-Hydrate Production Test Cases

“…Survey techniques for reservoir heterogeneity are key R&D issues. These techniques include identification of low S h and water-bearing regions, water shut-off technologies using chemical or biological measures, , selection of suitable sand-control devices to prevent sand intrusion and clogging by fine particles, drilling techniques for unconsolidated soft sediment to prevent sloughing and hole enlargement, and well stimulation to mitigate “skin” problem. Another possible missing link can be geomechanical effects such as reservoir compaction, creation of fluid pathway, and migration of fines, and those were not considered in the study.…”