Patent ID: 8636060
Filing Date: 2014-01-28
Classification: E21B

Abstract:
1. A method of monitoring downhole conditions in a borehole penetrating a subsurface formation, comprising: disposing a string of connected tubulars in the borehole, the string of tubulars forming a downhole electromagnetic network that provides an electromagnetic signal path between a plurality of sensors in the string of connected tubulars; receiving sensor data through the downhole electromagnetic network from a first sensor of the plurality of sensors; receiving sensor data through the downhole electromagnetic network from a second sensor of the plurality of sensors axially spaced apart in the string of connected tubular from the first sensor; receiving pressure data from the first and second sensors, wherein the pressure data includes pressure measurements both internal to and external of the string of tubulars; generating a pressure gradient curve using the internal and external pressure measurements; and controlling a downhole condition or a downhole parameter based on the pressure gradient curve.