Exhibit 23.4 PETROLEUM CONSULTANT'S CONSENT We consent to incorporation by reference in the Registration Statement on Form S-8 of Devon Energy Corporation, the reference to our appraisal report for Devon Energy Corporation as of December 31, 1999, which appears in the December 31, 1999 annual report on Form 10-K of Devon Energy Corporation. LAROCHE PETROLEUM CONSULTANTS, LTD. WILLIAM M. KAZMANN William M. Kazmann, Partner