There are five requirements for surfactants to successfully disperse oil: 
*Dispersant must be on the oil's surface in the proper concentration
*Dispersant must penetrate (mix with) the oil
* Surfactant molecules must orient at the oil-water interface (hydrophobic in oil and hydrophilic in water)
* Oil-water interfacial tension must be lowered (so the oil can be broken up).
* Energy must be applied to the mix (for example, by waves)