1. One consideration experts cite is that water is more corrosive than lube oils and is hence best chosen as tube side fluid . ( especially at higher temperatures due to inherent gases and air dissolved in water ) . Most often tubes can be replaced . Superior MOC for tubes like SS or admirality can be considered . Tube sheet and channels can be provided with some what liberal corrsion allowance , or they can be of cast iron or cast steel . But heat exchaner Shell material in refineries being generally carbon steel, possible shell corrosion due to use of water as shell side fluid is unwelcome .
2. Regarding Thermal considerations - experts advise is that the designer should better check the overall heat transfer coefficient in both the cases , with hot fluid on shell side and also on tube side and adopt the one that gives higher U,

3. Experts further advise is that the better choice for water is generally tube side due to its thermal conductivity.

I hope this bit of additional reading supplements the good advises of Mr Khadke and Mr Dhamelia

Best regards to all

Venugopal