An apparatus for constructing a target core to enable testing at simulated wellbore conditions. The apparatus includes a support core having a target core receiving region. A flexible jacket is operable to receive the support core and apply a confining stress to the support core. A quantity of unconsolidated sand is disposed within the target core receiving region of the support core. The support core is operable to transmit at least a portion of the confining stress to the unconsolidated sand, thereby forming the target core. The apparatus simulates downhole conditions such that flow tests may be performed on the target core before and after perforating the target core.