Method for generating a flow profile of a wellbore using resistivity logs

Abstract

A method for generating a flow profile of a wellbore whereby a resistivity tool is run through the wellbore, while the wellbore is being drilled, to sequentially measure and record, at each of a sequence of selected points along the wellbore, a sequential series of resistivities measured while drilling (MWD). Fluid from the wellbore is then allowed to permeate into the formation. The resistivity tool is then run through the wellbore, after the drilling mud has permeated into the formation, to sequentially measure and record, at substantially the same points at which the MWD resistivity measurements were made, a sequential series of resistivities measured after drilling (MAD). For each point, the arithmetic difference between the MWD resistivity and the corresponding MAD resistivity recorded for the respective point is calculated. For each respective point in the sequence of points, the sum of the arithmetic differences for the respective point and each point which follows the respective point in the sequence of points is recorded. A flow profile of the wellbore is generated by plotting the value of the sums calculated for each point of the sequence of points, wherein the magnitude of the permeability of a zone in the formation and, hence, of the potential productive flow from that point in the wellbore, is substantially proportional to the magnitude of the slope of the profile corresponding to that point.