Low rate after Nitrogen underbalance

23 July 2013 Hi,

I have the following situation during testing a new exploration well: - the well is drilled to 5000m - during drilling we had good gas shows on several intervals on gas chromatograph - formation is sandstone and estimated pressure around 650bar - the well has been perforated by TCP with Connex type gun and the hole underbalanced (the string filled with water) - after perforation the well was flowing with a rate of 10 liters/minute (the water from tubing) - after string displacement with Nitrogen down to 2500m the rate decreased dramaticaly to less than 2 liters /minute This was happened on4 DST's performed on different intervals. I cannot find any explanation for this behaviour.

Any sugestions will be very appreciated

4 Answer(s)

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