Oil and gas leases may be for an initial term of from five up to ten years and shall be extended for so long thereafter as lessee shall produce oil, gas or associated substances in paying quantities from the leased lands or is prosecuting development on the leased land with due diligence of a prudent operator upon encountering oil, gas or associated substances; or shall be engaged in drilling, deepening, repairing, or redrilling any well thereon; or shall be participating in a unit plan in accordance with RCW 79.14.020; or shall be prosecuting operations with due diligence of a prudent operator in accordance with RCW 79.14.050.