  The possible existence of primordial black holes (PBHs) is an open question
in modern cosmology. Among the probes to test it, gravitational waves (GW)
coming from their mergers constitute a powerful tool. In this work, we study
how stellar mass PBH binaries could affect measurements of the clustering of
merger events in future GW surveys. We account for PBH binaries formed both in
the early and late Universe and show that the power spectrum modification they
introduce can be detected at $\sim 2\sigma-3\sigma$ (depending on some
assumptions) whenever PBH mergers make up at least $\sim 60\%$ of the overall
number of detected events. By adding cross-correlations with galaxy surveys,
this threshold is lowered to $\sim 40\%$. In the case of a poor redshift
determination of GW sources, constraints are degraded by about a factor of 2.
Assuming a theoretical model for the PBH merger rate, we can convert our
results to constraints on the fraction of dark matter in PBHs, $f_{\rm PBH}$.
Finally, we perform a Bayesian model selection forecast and confirm that the
analysis we develop could be able to detect $\sim30M_\odot$ PBHs if they
account for $f_{\rm PBH}\sim 10^{-4}-10^{-3}$, depending on the model
uncertainty considered, being thus competitive with other probes.
