Core Lab Issued Revised Guidance Late Friday, Citing Delays In International Revenues; Sees Q2 EPS $0.57-$0.59 vs $0.65 Est., Sales $174M-$175M vs $178.12M Est.; Sees Q3 EPS $0.64-$0.66 vs $0.74 Est., Sales $177M-$179M vs $187.04M Est.