Influence of Clays and Clay Fluid Interactions on Seismic Wave Allenuation in Reservoir Rocks. Milestone Report. (Seismic Wave Propagation Across Thin Clay Layers).

摘要

In order to understand the effects of clays on attenuation of seismic waves in gas reservoir rocks, shear waves were propagated across thin clay layers pressed between optically smooth silica disks. Na-montmorillonite was tested in the presence of water, ethyl alcohol and decane of various quantities. Kaolinite was also tested using water. Results included in the report showed that if the clay layer absorbed liquid in the interlamellar space between platelets, the interface was effectively decoupled so that most of the energy in the incident wave was reflected. In parallel with the laboratory measurements a theoretical model was developed. Maxwell and Kelvin rheologic models were incorporated in seismic displacement discontinuity theory resulting in two bounding theoretical models. The experimental observations were modelled, yielding excellent agreement with the Maxwell model.