METHODS AND APPARATUS FOR MEASURING STREAMING POTENTIALS AND DETERMINING UNDERGROUND FORMATION CHARACTERISTICS Russian patent published in 2013 - IPC G01V3/26 

FIELD: physics.

SUBSTANCE: underground formation characteristics are determined using a group of electrodes which can be used to measure streaming potentials in the formation. The electrodes are mounted on a wireline cable, a logging while drilling tool or at fixed points near the completed wellbore. The measured streaming potentials are generated by drilling with overbearing pressure, cutting the mud cake in the wellbore, injecting acid or using any other method which causes fluid movement. The obtained data are interpreted in order to locate fractures. The transient process of variation of voltage which corresponds to the streaming potential having a profile with a double peak indicates fractures in the formation.

EFFECT: high accuracy of locating fractures.

18 cl, 23 dwg