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Priority claimed from US06/687,715external-prioritypatent/US4622854A/en
Priority claimed from US06/687,716external-prioritypatent/US4622855A/en
Application filed by Schlumberger LtdfiledCriticalSchlumberger Ltd
Priority claimed from EP85402446Aexternal-prioritypatent/EP0192903B1/en
Application grantedgrantedCritical
Publication of ATE66297T1publicationCriticalpatent/ATE66297T1/en