Palm | Kelapa Sawit

I've got a coursework to hand in and i think I'll get a better grade if I say how finding out the viscosity of oil help solve problems. There is a definite link. Can someone help?Why is calculating viscosity important in the oil industry?
Just knowing what I know about oil and gas law, the viscosity of oil is important because we have to use machines to drill and extract the oil from the ground. The thicker or more viscous the oil, the more friction is caused along the extraction pipes. This requires more power (read: $) to extract it.