During ODP Leg 155, color reflectance was routinely measured downhole at all but one site to determine light-reflectance levels in the wavelength band of visible light (400 to 700 nm) of the sediments recovered. Reflectance measurements taken on previous ODP legs have demonstrated that lithologic changes in carbonate-rich (>20%) pelagic and hemipelagic sediments can be characterized using these...

Wellbore instability in oil and gas drilling is resulted from both mechanical and chemical factors. Hydration is produced in shale formation owing to the influence of the chemical property of drilling fluid. A new experimental method to measure diffusion coefficient of shale hydration is given, and the calculation method of experimental results is introduced. The diffusion coefficient of shale ...

seismic refraction and downhole survey were employed to study dynamic characteristics of subsurface materials in bam city, southeast of iran. the data acquisition was performed at 160 p and s-wave refraction stations and 15 boreholes in the city. to derive velocity depth sections along these profiles as well as to perform downhole diagrams, seisimager software was used. based on the obtained va...

A downhole electric tubular resistive heater is proposed for the oil-shale in situ resorting. After flowing through a set of heating tubes, outlet temperature and flow rate injected gas can be conveniently adjusted to match requirement pyrolysis oil shale. The calculation demonstrates effects inner diameter, length tube, inlet on heat transfer performance heater. It was found that, compared wit...

Within the crust, the weathered layer has been shown to contain some of the greatest values of shear wave velocity anisotropy. There are two main causes of this shear wave velocity anisotropy. In all rock types, anisotropy results from structural weaknesses commonly manifest as aligned open fractures. In sedimentary rocks, additional anisotropy can result from mineral or grain particle alignmen...