1. n. [Formation Evaluation]

A technique for measuring formation resistivity between two or more wells. This technique measures the signal between an electromagnetic induction transmitter in one well, and a receiver array located in another well. The transmitting antenna broadcasts a continuous sinusoidal signal at programmable frequencies. Tomographic processing creates a map of resistivity of the area between the wells. Measurements acquired by this technique have a greater depth of investigation than conventional logging tools and are sensitive to fluid content. Crosswell electromagnetic induction surveys fill an intermediate role between high-resolution well logs and lower-resolution surface measurements. Asset managers utilize crosswell electromagnetic surveys for a variety of applications, such as monitoring sweep efficiency, identifying bypassed pay, planning infill drilling locations and improving the effectiveness of reservoir simulations.

See: tomography