Marine natural gas hydrates exhibit diverse morphologies,making accurate identification crucial for evaluating reservoir properties and resources.While integrating logging-while-drilling(LWD)with coring data offers quantitative assessment,coring operation sare complex and expensive,often resulting in partial or no data at most drilling sites.Combining ring resistivity and velocity logging can identify gas hydrate-bearing sediments but cannot distinguish between fracture-filling and pore-filling hydrates due to similar high values in both parameters.Our analysis of electromagnetic wave resistivities at various source-receiver spacings and crossplots of multiple resistivity parameters reveals distinct anomaliesin fracture-filling gas hydrate formations,particularly in high-frequency phase resistivity.Conversely,pore-filling hydrate formations exhibit consistent electromagnetic wave resistivities.Comparing electromagnetic wave resistivity and ring resistivity reveals a key difference:electromagnetic wave resistivity shows obvious high-value anomalies in fracture-filling hydrate formations,while ring resistivity exhibits similar anomalies in pore-filling hydrate formations.We propose that the electromagnetic wave resistivity is sensitive to high-angle fractures and effectively discriminates between different gas hydrate morphologies.This sensitivity is highly valuable for exploring and evaluating gas hydrate reservoirs.
关键词
电磁波电阻率/环形电阻率/裂隙充填型水合物/孔隙充填型水合物/交会分析
Key words
electromagnetic wave resistivity/ring resistivity/fracture-filling gas hydrate/pore-filling gas hydrate/crossplot
维普
万方数据