Shell conducted two steam-foam pilots in the Kern River field, one on the Mecca lease (1980-85) and the other on the Bishop fee (1982-86). The pilots consisted of four contiguous inverted five-spots covering 12 and 14 acres [4.8 and 5.7 ha], respectively. The Mecca pilot began after 9 years of steam soaks and 10 years of unconfined steam-drive; the Bishop pilot was preceded by 19 years of steam soaks and 1 year of steam-drive. Steam foam in both pilots was generated by continuous injection of 250 B/D [39.7 m3/d] per pattern [coldwater equivalent (CWE)] of 50% quality steam, with 4 wt% NaCl and 0.5 wt%AOS-1618 surfactant in the aqueous phase and 0.06 mol% N2 in the vapor.