The production cumulative index (bbl/psi) or CPI, is the relation of the cumulative production versus the decline in the reservoir static pressure. This recorded index shows that the reservoir produces more bbl/psi static pressure as the reservoir static pressure decreases. The increase in the CPI can also be seen in a DST during the build up period. The increase in the CPI is explained by a better use of the reservoir energy when the production is lifted for shorter distances above the perforation. To increase the CPI it is necessary to produce the well by a compensated pump. This is a pump which is not driven by the intake fluid. Producing the well by a compensated pump increases the well efficiency in rate and cumulative production by about 200-250%.

Keywords:
drillstem/well testing, static pressure decline, Perforation Depth, cumulative production, Efficiency, dynamic liquid level, Upstream Oil & Gas, static pressure, pressure decline, reservoir
Subjects:
Artificial Lift Systems, Well & Reservoir Surveillance and Monitoring, Formation Evaluation & Management, Drillstem/well testing
Copyright 2007, Society of Petroleum Engineers
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