modified isochronal test
A type of deliverability test conducted in gas wells to generate a stabilized gas deliverability curve (IPR). This test overcomes the limitation of the isochronal test, which requires long shut-in times to reach the average reservoir pressure.In the modified isochronal test, the shut-in periods are of equal duration, as are the flowing periods. The final shut-in pressure before the beginning
Detailed Explanation
of the new flow is used as an approximation of the average reservoir pressure. The same procedure is typically repeated four times. A stabilized point (pseudosteady state) is usually obtained at the end of the test.Modified isochronal tests are commonly used in gas wells, because they require less time and money to produce results comparable to the isochronal test.