Pipelines are usually buried under the ground. Pumping statins could be protected by short range SAM systems. An undegraund pipeline can be destroyed by a heavy glide bomd (not an option for Iran) but should be relatively safe from shahed drones. Iran's ballistic rockets are not precise enough to hit a pipeline wihtout spending multiple rockets (in which case it would be cheaper to repair the pipeline than to produce all these rockets).

sure, as the oil wells and the pumping stations and everything not underground, but right now there's not even an option to try. (also loss of a pipe section compared to the loss of a tanker is much better economically, easy to replace, not to mention that there's no loss of life, so ultimately it can bear more risk even if there's an active conflict.)