well congratulations if you have secured such rank . You will be having option to choose from all the CS branches and core branches .
i am skeptical about the petroleum branches as at our time of councelling , we had them filled up . (i had a rank little higher than you ) . Yet , i am hopeful because i heard from juniors that petroleum was available to them till 4k . If that is true then you will be able to put a waitlist to the branch .
you will be shown the live statuses of the filling up of branches . and will be asked to eitheir give a confirmed branch or waitlist a branch and confirm one . So be hopeful about everything the college offers in UG courses .
for the review of college and courses , see my answers on my profile .
happy to help .
all the best .