Abstract
In this paper, a brief description is given to operational procedure involved in acquiring transient data using a down hole shut-in tool. Field cases (Maracaibo Lake are presented to show the advantages of this technique in active wells and for cases where reservoir pressure is below bubble point. A comparison is made between this technique and the one that is based on simultaneous measurements of tran sient flow rate and pressure. The benefits both from an economic point of view and from the reservoir evaluation side using this method are presented. A main result derived from this work is that the use of the down hole shut-in tool reduced the build-up time by a factor of 10 in some cases for tests conducted in Maracaibo Lake fields. A considerable saving in differed oil production was gained besides the benefits of having pressure transient data not strongly affected by wellbore storage and phase segregation which permits a better reservoir evaluation.
