The pipeline isn’t the issue, it’s just a target of a tribes revenge on the government.
“The pair attacks came in retaliation of an air raid that mistakenly killed a tribal dignitary, who also served as deputy governor of Marib province, Jabir Ali al-Shabwany, along with his four bodyguards […] The targeted pipeline is located some 4 km west to the main oil production facility [Yemeni Safer Oil Company…] the tactic of today’s bombing bore al-Qaida’s characteristics”
– anonymous state official
Sources: Yemen armed tribesmen bomb another oil pipeline, Yemen tribe in new pipeline blast over airstrike, Yemen tribesmen bomb oil pipeline: provincial official.