No common pipeline carrier may discriminate between or against shippers in regard to facilities furnished, services rendered, or rates charged under the same or similar circumstances in the transportation of crude petroleum, coal, gas, or carbon dioxide, nor may there be any discrimination in the transportation of crude petroleum, coal, gas, or carbon dioxide produced or purchased by itself directly or indirectly. In this connection the pipeline must be considered as a shipper of the crude petroleum, coal, gas, or carbon dioxide produced or purchased by itself directly or indirectly and handled through its facilities. No such carrier in such operation, directly or indirectly, may charge, demand, collect, or receive from anyone a greater or lesser compensation for any service rendered than from another for a like contemporaneous service. This does not limit the right of the commission to prescribe rates and regulations from or to some places different from other rates or regulations for transportation from or to other places as it may determine, nor is any carrier guilty of discrimination when obeying any order of the commission. Where there is offered for transportation more crude petroleum, coal, or carbon dioxide than can be transported immediately, the same must be apportioned equitably. Gas must be taken on a pro rata basis or on such basis as may be established by the industrial commission pursuant to section 38-08-06.