Mich. Comp. Laws § 570.263

Sec. 13. For the purpose of this act the terms "owner, part owner or lessee" shall be construed to include all the interests, legal or equitable, which any person, firm, corporation, association, syndicate, trustee, co-partnership or joint adventurer may have in the leasehold, oil or gas runs, oil well, gas well, oil pipe line, gas pipe line, oil or gas derrick, oil tank, machinery, materials, tools, supplies, buildings and appurtenances upon which the improvements contemplated by this act are made.