Cal. Pub. Resources Code § 3016
For purposes of this chapter, abandoned underground personal property, including a well, of an operator shall become the property of the mineral interest owner when the operator loses the right to remove the personal property under common law or under a lease or any other agreement that initially gave the operator the right to drill, operate, maintain, or control the well. In that case, in accordance with paragraph (3) of subdivision (c) of Section 3237, the mineral interest owner shall be held jointly liable for the well if, in the lease or other conveyance, the mineral interest owner retained a right to control the well operations that exceeds the scope of an interest customarily reserved in a lease or other conveyance in the event of default.
Ca. Pub. Res. Code § 3016