Identification method of gas hydrate morphologies based on analysis of logging while drilling resistivity
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.
electromagnetic wave resistivityring resistivityfracture-filling gas hydratepore-filling gas hydratecrossplot
万方数据
维普
