How DeepLook-EM Crosswell Resistivity Works

To directly measure reservoir resistivity between two wells up to 3,280 ft [1,000 m] apart, the 32.4-ft [9.88-m] DeepLook-EM transmitter antenna in one well broadcasts a continuous sinusoidal signal at a frequency from 5 Hz to 1 kHz, selected by modeling and simulation of the borehole environment, well separation, and formation resistivity. The magnetic moment produced by the transmitter is 100,000 times stronger than the source in a conventional single-well induction logging system.

The transmitter signal induces electrical currents to flow in the formation between the wells. The currents, in turn, induce a secondary magnetic field related to the electrical resistivity of the rock. At the receiver borehole, the DeepLook-EM array of four coil receivers detects the primary magnetic field generated by the transmitter as well as the secondary magnetic field from the induced currents.

For each receiver station, the transmitter in the other well traverses the interval of interest at a logging speed of 2,000 to 5,000 ft/h [600 to 1,520 m/h]. Once a complete transmitter traverse, or profile, is collected for a receiver position, the receiver tool is repositioned, and the process is repeated.

Once all the receiver positions have been logged, the DeepLook-EM interwell resistivity distributions are exported to a field model compiled using Petrel seismic-to-simulation software. The resulting data integration and interpretation provide critical crosswell insight for fluid tracking of water and steam, detecting bypassed pay, and optimizing reservoir characterization.