Pore-Scale Investigation of CH₄ Hydrate Kinetics in Clayey-Silty Sediments by Low-Field NMR

Clayey-silty sandy media have been widely discovered in naturally occurring hydrate-bearing sediments in the South China Sea. However, the phase change behavior of CH4 hydrate (MH) and the resulting pore structure change and the migration of fluid in clayey-silty sediments remain less known and warrant investigation. In this study, we examine the pore-scale behavior of MH formation and dissociation in clayey-silty sediments and the associated fluid migration by low-field nuclear magnetic resonance (NMR). Based on T2 spectra measurement, MH starts to grow in small pores (pore size <1 μm) first and in large pores (pore size >10 μm) subsequently. The presence of clay, i.e., Na-MMT, practically retards the overall growth kinetics of MH evidenced by the low H2O conversion (<10%) to MH in clay-associated small pores. During depressurization, MH starts to dissociate in sand-associated large pores first. Free water migrates to clay-associated small pores and partially converts to clay-bound water. MRI visualization depicts the heterogeneous spatial distribution of both MH and the residual water in the process. The experimental results provide possible explanations on the spatial heterogeneity of MH in clay-silty sediments in nature and on the multiphase fluid migration during energy recovery from MH reservoirs

Protective effect of glucagon-like peptide-1 agents on reperfusion injury for acute myocardial infarction: a meta-analysis of randomized controlled trials

<p><b>Background:</b> The cardioprotective properties of glucagon-like peptide-1 (GLP-1) receptor agonists in acute myocardial infarction (AMI) patients against reperfusion injury remain unclear. We performed a meta-analysis to assess their role in the acute phase of AMI.</p> <p><b>Methods and results:</b> Randomized controlled trials (RCTs) comparing GLP-1 agents with placebo in AMI patients undergoing percutaneous coronary intervention were identified by searching PubMed, Embase and Cochrane libraries. Six RCTs with 800 patients were included in the meta-analysis. Compared with placebo, GLP-1 agents improved left ventricular ejection fraction (LVEF) by 2.46 [95% confidence interval (CI): 0.23–4.70%] and reduced the infarct size in grams as well as in percentage of the area at risk [weighted mean difference (WMD) − 5.29, 95% CI: −10.39 to −0.19; WMD −0.08, 95% CI: −0.12 to −0.04, respectively]. The incidence of cardiovascular events appeared to be lower with GLP-1 therapy, but the statistical significance was not reached [relative risk (RR): 0.78; 95% CI: 0.58–1.06]. In terms of safety evaluation, GLP-1 treatment increased the risk of gastrointestinal adverse events (RR: 5.50, 95% CI: 2.85–10.60).</p> <p><b>Conclusions:</b> Our analysis shows that in patients with AMI undergoing PCI, GLP-1 treatment is associated with improved LVEF and reduced infarct size.</p

Characterization of Hydrate Formation and Flow Influenced by Hydrophilic–Hydrophobic Components within a Fully Visual Rocking Cell

The intricate interplay of crude oil composition and additives critically affects hydrate formation and flow behavior, which is significant for flow assurance particularly in deepwater. To investigate, we varied the hydrophilic and hydrophobic properties by proportioning two nonionic surfactants (Span 80 and Tween 80) and conducting hydrate formation experiments in a visual rocking cell. The results show that the increasing hydrophilic–lipophilic balance (HLB) value shifted emulsions from water-in-oil to multiple and oil-in-water phases and significantly affected the hydrate formation among different emulsion types, with a marked increase in the hydrate formation rate in the HLB range of 9 to 11. Slurries maintained flowability due to low hydrate conversion, yet higher HLB (>11) led to slight agglomeration and deposition. In addition, the impacts of water conversion were investigated by multiple pressurization, showing that the hydrate formation amount affected slurry flowability but was primarily dependent on the hydrophilicity and hydrophobicity of the surfactants. When the HLB was below 11, the final water conversion was about 80%, but the formed hydrate still exhibited good dispersion and flowability. In contrast, HLB exceeding 13 resulted in extensive adhesion and deposition on the cell walls. When the water conversion reached about 40%, flowability was completely lost and hydrate blockage occurred

Characterization of Hydrate Formation and Flow Influenced by Hydrophilic–Hydrophobic Components within a Fully Visual Rocking Cell

The intricate interplay of crude oil composition and additives critically affects hydrate formation and flow behavior, which is significant for flow assurance particularly in deepwater. To investigate, we varied the hydrophilic and hydrophobic properties by proportioning two nonionic surfactants (Span 80 and Tween 80) and conducting hydrate formation experiments in a visual rocking cell. The results show that the increasing hydrophilic–lipophilic balance (HLB) value shifted emulsions from water-in-oil to multiple and oil-in-water phases and significantly affected the hydrate formation among different emulsion types, with a marked increase in the hydrate formation rate in the HLB range of 9 to 11. Slurries maintained flowability due to low hydrate conversion, yet higher HLB (>11) led to slight agglomeration and deposition. In addition, the impacts of water conversion were investigated by multiple pressurization, showing that the hydrate formation amount affected slurry flowability but was primarily dependent on the hydrophilicity and hydrophobicity of the surfactants. When the HLB was below 11, the final water conversion was about 80%, but the formed hydrate still exhibited good dispersion and flowability. In contrast, HLB exceeding 13 resulted in extensive adhesion and deposition on the cell walls. When the water conversion reached about 40%, flowability was completely lost and hydrate blockage occurred

Characterization of Hydrate Formation and Flow Influenced by Hydrophilic–Hydrophobic Components within a Fully Visual Rocking Cell

The intricate interplay of crude oil composition and additives critically affects hydrate formation and flow behavior, which is significant for flow assurance particularly in deepwater. To investigate, we varied the hydrophilic and hydrophobic properties by proportioning two nonionic surfactants (Span 80 and Tween 80) and conducting hydrate formation experiments in a visual rocking cell. The results show that the increasing hydrophilic–lipophilic balance (HLB) value shifted emulsions from water-in-oil to multiple and oil-in-water phases and significantly affected the hydrate formation among different emulsion types, with a marked increase in the hydrate formation rate in the HLB range of 9 to 11. Slurries maintained flowability due to low hydrate conversion, yet higher HLB (>11) led to slight agglomeration and deposition. In addition, the impacts of water conversion were investigated by multiple pressurization, showing that the hydrate formation amount affected slurry flowability but was primarily dependent on the hydrophilicity and hydrophobicity of the surfactants. When the HLB was below 11, the final water conversion was about 80%, but the formed hydrate still exhibited good dispersion and flowability. In contrast, HLB exceeding 13 resulted in extensive adhesion and deposition on the cell walls. When the water conversion reached about 40%, flowability was completely lost and hydrate blockage occurred

Characterization of Hydrate Formation and Flow Influenced by Hydrophilic–Hydrophobic Components within a Fully Visual Rocking Cell

The intricate interplay of crude oil composition and additives critically affects hydrate formation and flow behavior, which is significant for flow assurance particularly in deepwater. To investigate, we varied the hydrophilic and hydrophobic properties by proportioning two nonionic surfactants (Span 80 and Tween 80) and conducting hydrate formation experiments in a visual rocking cell. The results show that the increasing hydrophilic–lipophilic balance (HLB) value shifted emulsions from water-in-oil to multiple and oil-in-water phases and significantly affected the hydrate formation among different emulsion types, with a marked increase in the hydrate formation rate in the HLB range of 9 to 11. Slurries maintained flowability due to low hydrate conversion, yet higher HLB (>11) led to slight agglomeration and deposition. In addition, the impacts of water conversion were investigated by multiple pressurization, showing that the hydrate formation amount affected slurry flowability but was primarily dependent on the hydrophilicity and hydrophobicity of the surfactants. When the HLB was below 11, the final water conversion was about 80%, but the formed hydrate still exhibited good dispersion and flowability. In contrast, HLB exceeding 13 resulted in extensive adhesion and deposition on the cell walls. When the water conversion reached about 40%, flowability was completely lost and hydrate blockage occurred

Characterization of Hydrate Formation and Flow Influenced by Hydrophilic–Hydrophobic Components within a Fully Visual Rocking Cell

The intricate interplay of crude oil composition and additives critically affects hydrate formation and flow behavior, which is significant for flow assurance particularly in deepwater. To investigate, we varied the hydrophilic and hydrophobic properties by proportioning two nonionic surfactants (Span 80 and Tween 80) and conducting hydrate formation experiments in a visual rocking cell. The results show that the increasing hydrophilic–lipophilic balance (HLB) value shifted emulsions from water-in-oil to multiple and oil-in-water phases and significantly affected the hydrate formation among different emulsion types, with a marked increase in the hydrate formation rate in the HLB range of 9 to 11. Slurries maintained flowability due to low hydrate conversion, yet higher HLB (>11) led to slight agglomeration and deposition. In addition, the impacts of water conversion were investigated by multiple pressurization, showing that the hydrate formation amount affected slurry flowability but was primarily dependent on the hydrophilicity and hydrophobicity of the surfactants. When the HLB was below 11, the final water conversion was about 80%, but the formed hydrate still exhibited good dispersion and flowability. In contrast, HLB exceeding 13 resulted in extensive adhesion and deposition on the cell walls. When the water conversion reached about 40%, flowability was completely lost and hydrate blockage occurred

Characterization of Hydrate Formation and Flow Influenced by Hydrophilic–Hydrophobic Components within a Fully Visual Rocking Cell

The intricate interplay of crude oil composition and additives critically affects hydrate formation and flow behavior, which is significant for flow assurance particularly in deepwater. To investigate, we varied the hydrophilic and hydrophobic properties by proportioning two nonionic surfactants (Span 80 and Tween 80) and conducting hydrate formation experiments in a visual rocking cell. The results show that the increasing hydrophilic–lipophilic balance (HLB) value shifted emulsions from water-in-oil to multiple and oil-in-water phases and significantly affected the hydrate formation among different emulsion types, with a marked increase in the hydrate formation rate in the HLB range of 9 to 11. Slurries maintained flowability due to low hydrate conversion, yet higher HLB (>11) led to slight agglomeration and deposition. In addition, the impacts of water conversion were investigated by multiple pressurization, showing that the hydrate formation amount affected slurry flowability but was primarily dependent on the hydrophilicity and hydrophobicity of the surfactants. When the HLB was below 11, the final water conversion was about 80%, but the formed hydrate still exhibited good dispersion and flowability. In contrast, HLB exceeding 13 resulted in extensive adhesion and deposition on the cell walls. When the water conversion reached about 40%, flowability was completely lost and hydrate blockage occurred