Applications of sonic waves in the estimation of petrophysical, geophysical and geomechanical properties of subsurface rocks

摘要

Sonic waves play an important role in estimating rock properties that are crucial in an efficient and safe production of oil and gas wells. An acoustic source in a fluid-filled borehole can generate both nondispersive headwaves as well as relatively stronger borehole guided modes. Processing of waveforms recorded with adequate spatial sampling yields sonic velocities in the surrounding formation over the receiver aperture. These velocities are then transformed into elastic moduli of the propagating medium. Elastic moduli of the formation provide many useful petrophysical, geophysical and geomechanical attributes of porous rocks that constitute hydrocarbon bearing formations. Petrophysical attributes of hydrocarbon bearing formations include porosity, pore pressure, and fluid mobility. Geophysical attributes of the formation deal with anisotropy characterization of formations on a seismic scale. Geomechanical properties of rock consists of estimating in-situ formation stresses and strengths as a function of radial position away from the borehole surface.