Wells are unlocked after completing the quest "The gambler". There are two wells, a gold well and blood crystal well. These wells are server specific, meaning only people on the same server as you can enter their gold into your well.
The gold well is where you can gamble gold. You tap on the well and type in the amount of gold you wish to enter.
The number at the top of the screen (to right) is the server total of coins in the well. This is the jackpot, if you win, you get all that gold. The number below it is the amount of time left till someone wins. Once someone wins, the well is emptied, and given to that player. The next number (Under the well, once you put in an amount of gold) is how much gold you put in. The more gold you put in, the higher chance of you winning. The number under that is the chance you have of winning.
There is a 5% tax on the gold well
Blood Crystal Well Edit
The blood crystal well allows you put throw away blood crystals in the well. It functions the same as
the gold well.
Minimum amount: 50*
Maxium amount: Ranges from 50 to 100,000
*If the max is at 50, you can put blood crystals into the well.
This bug has been resolved, it is no longer canon.
If the blood well is at max of 50, no one can put blood crystals in the well, as the min for the well is 100. (This has been checked, since the well was at 50 max on March 20th, 2019 at 7:40 am.)