Changes

Single-point tests are usually simple productivity tests that typically involve a measurement (or estimate) of initial or average reservoir pressure and a measurement of flow rate and flowing bottomhole pressure (which can be estimated from flowing surface pressure) at stabilized producing conditions.<ref name=pt09r1>Allen, T. O., Roberts, A. P., 1978, Production Operations, Volume 1 : Tulsa, OK, Oil and Gas Consultants International, 225 p.</ref> From these data, the productivity index, PI, can be calculated as follows:

Single-point tests are usually simple productivity tests that typically involve a measurement (or estimate) of initial or average reservoir pressure and a measurement of flow rate and flowing bottomhole pressure (which can be estimated from flowing surface pressure) at stabilized producing conditions.<ref name=pt09r1>Allen, T. O., Roberts, A. P., 1978, Production Operations, Volume 1 : Tulsa, OK, Oil and Gas Consultants International, 225 p.</ref> From these data, the productivity index, PI, can be calculated as follows:

:<math>\mbox{PI} = \frac{q}{\bar{p} - p_{\rm wf}} (\mbox{ for oil}) = \frac{q\mu B}{\bar{p}^{2} - p_{\rm wf}^{2}} (\mbox{ for gas})</math>

:<math>\mbox{PI} = \frac{q}{\bar{p} - p_{\rm wf}} \mbox{ (for oil)} = \frac{q\mu B}{\bar{p}^{2} - p_{\rm wf}^{2}} \mbox{ (for gas)}</math>

where

where