After the discovery of oil, gas or other hydrocarbons in paying quantities, lessee shall proceed to develop the oil, gas or other hydrocarbons in the lands covered thereby through the drilling of such wells as will efficiently extract the oil, gas or other hydrocarbons therefrom and such development shall take into account the productiveness of the producing horizon, the depth at which it occurs, the average cost of wells, the market requirements obtaining at any given time, and the maintenance of proper oil and gas ratios.