This is a feature i did for my custom story to help the player continue.
Create the following function in your script file:
Then, add this line inside your OnStart() function
<code php> AddTimer ( "", 5, "OilRecovery" );
When the map starts, it triggers a timer that every 5 seconds recovers 0.25 oil if the player is not using his lantern. Increase the number if you think 0.25 is too low.
Amn.-