Fluid data collected while drilling a wellbore in a drilling operation that includes a first well trajectory is received. A first productivity metric for a next section of the wellbore on a continued trajectory of the first well section trajectory is determined, based at least in part on the fluid data. A second well section trajectory for the next section of the wellbore different from the continued trajectory of the first well section trajectory is determined. A second productivity metric for the second well trajectory is determined. The drilling operation is adjusted if the first productivity index differs from the second productivity index by more than a threshold amount.