isochronal test — Oil & Gas Glossary
A type of deliverability test conducted in gas wells. This test is used to generate a stabilized gas deliverability curve (IPR) without actually flowing the well for the time required to achieve stabilized conditions (pseudosteady state). This type of test is especially useful for low-permeability reservoirs.In an isochronal test, the well flows at a constant rate and then is shut
Detailed Explanation
in, allowing the pressure to build up to the average reservoir pressure. The same procedure typically is repeated four times. It is called isochronal because the flow periods are of the same length. A stabilized point (pseudosteady state) is usually obtained at the end of the test.