I am a student of petroleum engineering. Recently I have been working on a reserve estimation and a well test interpretation project. I have been given the data of a FAF test conducted in 2007. The test was supposed to test a perforation interval at a depth range of 9652-9722 ft from the surface. The report stated that the pressure gauge was hung at a depth of 9300 ftWzl.
I don't understand the term 'Wzl' with ft. The average reservoir pressure was estimated to be 3500 psia at 9300 ftWzl. My question is can I use this pressure value as the static reservoir pressure or I have to interpolate? Also the flowing pressure & shut-in pressure was measured at 9300 ft. Can these pressure data can be used to properly interpret the average reservoir (or drainage area) pressure?