Almost forgot to mention that if you are expecting problems with water cut measurements, for example you have strong emulsion and its hard to measure water cut in field conditions. You can use during flow-after-flow test pressure recorder with resistivity tool. It must be calibrated in water content units, so during the test you will see stepwise water content rise with encrease of pressure drawdown for water conning.
For chanelling or fingering it would be oscillating around some constant value.