BuildCraft version: 7.99.21
Forge version: 14.23.5.2768
Link to crash report or log: Crash report
Singleplayer or multiplayer: SSP
Steps to reproduce:

1. In Buildcraft config (Mods > Buildcraft > Config > World Generation > oil > spouts) set same values for small_max_height and small_min_height (or large_max_height and large_min_height) params
2. Restart game
3. Create new world and explore it a bit

Additional information: