Section 27-535 - Status and powers of unit; liability and expenses; lienA. The obligation or liability of the lessees or other owners of the oil and gas rights in the several separately owned tracts for the payment of unit expense shall at all times be several and not joint or collective and in no event shall a lessee or other owner of the oil and gas rights in the separately owned tract be chargeable with, obligated or liable, directly or indirectly, for more than the amount apportioned, assessed or otherwise charged to his interest in such separately owned tract pursuant to the plan of unitization and then only to the extent of the lien provided for in this article.B. Subject to such reasonable limitations as may be set out in the plan of unitization, the unit shall have a first and prior lien upon the leasehold estate and all other oil and gas rights (exclusive of one-eighth landowners' royalty interest) in and to each separately owned tract, the interest of the owners thereof in and to the unit production and all equipment in the possession of the unit, to secure the payment of the amount of the unit expense charged to and assessed against such separately owned tract. The interest of the lessee or other persons who by lease, contract or otherwise are obligated or responsible for the cost and expense of developing and operating a separately owned tract for oil and gas in the absence of unitization shall, however, be primarily responsible for and charged with any assessment for unit expense made against such tract and resort may be had to overriding royalties, oil and gas payments, royalty interests in excess of one-eighth of the production, or other interests which otherwise are not chargeable with such costs, only in the event the owner of the interest primarily responsible fails to pay such assessment or the production to the credit thereof, is insufficient for that purpose. In the event the owner of any royalty interest, overriding royalty, oil or gas payment, or any other interest which under the plan of unitization is not primarily responsible therefor pays in whole or in part the amount of an assessment for unit expense for the purpose of protecting such interest or the amount of the assessment in whole or in part is deducted from the unit production to the credit of such interest, the owner thereof shall to the extent of such payment or deduction be subrogated to all the rights of the unit with respect to the interest or interests primarily responsible for such assessment. A one-eighth part of the unit production allocated to each separately owned tract shall in all events be regarded as royalty to be distributed to and among, or the proceeds thereof paid to, the royalty owners free and clear of all unit expense and free of any lien therefor.