ExpressConnect for Oracle 15.7.1 SP100 is installed with Replication Server 15.7.1 SP100. ExpressConnect for Oracle is not installed as a standalone product.
ExpressConnect for Oracle (ECO) does not include the Oracle client libraries, which are required to run ECO. You must download and install these libraries separately. See the General Information and Technical Notes section of the ECO cover letter for information on correct version and platform of Oracle client libraries, and installation instructions. If the cover letter is not available, see Installing Oracle Instant Client Libraries in the ExpressConnect for Oracle Configuration Guide.