【单选题】A large valve,usually installed above the ram preventers,that forms a seal in the annular space between the pipe and wellbore or,if no pipe is present,on the wellbore itself is called the().
【简答题】Following shut-in at the suce, fluid continues to flow from the reservoir into the wellbore, compressing the gas and liquid already in the wellbore and storing more fluid. This continued production...