Michigan Compiled Laws, Chapter 565. Conveyances of Real Property § 565.83

Sec. 3. The assignment shall become and be and remain effective and a good and valid assignment as against all persons, including the mortgagor or those claiming under or through him, from and after the date of execution and delivery thereof, subject however, as in the case of conveyances of an interest in real estate, to the provisions of chapter 65 of the Revised Statutes of 1846, as amended, being sections 565.1 to 565.49, inclusive, of the Compiled Laws of 1948. The assignment shall not be effective as to pipe line companies or other purchasers taking delivery of oil and gas produced from the mortgaged oil and gas properties at the time of execution and delivery of the assignment, until an executed or certified copy thereof shall have been served personally or by registered mail on the pipe line company or other purchaser.