At the top of the page ther eis a search bar.
Type "tank cleaning" into this and click on the results - this has been discussed many times.
Please define "heavy cycle oil" - do mean asphalt? please be a bit more precise
Why would you need to cut it?
Please also provide some more background information otherwise all you will get is general responses, so things like:
Product ( be as precise as possible)
Is the tank fixed roof or floating?
Can you get entry into using manholes - if so how many and size
What is size of tank?
Is there a clean out door or specificed area to cut
Is the tank lined?
Are the contents dangerous to health or could create an explosive atmosphere?
Where in the world are you?
What have you done before to clean it?
Are you the owner, operator, supervisr or contractors?
How long has it been in service?
Why clean it now?
All helps us to help you...
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.