I think it would be too soon to give outlook for 2018 . The block chain market is very volatile and unpredictable. The upcoming events of 2018 is not known to any of us . So this will be very soon to assumpt . If we look at the ongoing trends and the graphs it is very easy to say that bitcoin may outgrow and cross the mark of $10000 by the end of even mid of 2018 but any major event can lead to a drastic fall as well .
Some of the major players of the market are speculating that bitcoin might fall again by march . So all the events will decide the fate of bitcoin in 2018 . I can conclude by saying that bitcoin might not go below $5000 for a long time to come.