Lecture3 aquifer influx models Pot aquifer Schilthuis steadystate

Lecture-3 aquifer influx models Pot aquifer Schilthuis’ steady-state Hurst’s modified steady-state The van Everdingen-Hurst unsteady-state § Edge-water drive § Bottom-water drive § Linear-water drive The Carter-Tracy unsteady-state Fetkovich’s method § Radial aquifer § Linear aquifer

The van Everdingen-Hurst unsteady-state

Water does not encroach on all sides of the reservoir, or the reservoir is not circular in nature.

Example- Van Everdingen and Hurst

Previous Solution Δp=constant

Multiple pressure drop Ø 1 st period Ø 2 nd period

Multiple pressure drop Ø 3 rd period Ø In general

Calculation of Δp 1, 2, 3, 4, . . Ø Δp 1 Ø Δp 2 Ø simplified Ø Δp 3 Ø Δp 4

Bottom Water Drive

Example Bottom Drive

The Carter-Tracy Water Influx Model The technique assumes constant water influx rates over each finite time interval. The cumulative water influx at any time, tn can be calculatd directly from the previous obtained tn-1

Example 10 -9 T. Ahmed

Solution

Solution

Carter Tracy method overestimates the water influx 250 200 We, [Mbbl] 150 Carter-Tracy Van-Everdingen 100 50 0 0 182, 5 365 547, 5 Time Period 730 912, 5

250 200 We, [Mbbl] 150 Carter-Tracy Van-Everdingen modified Carter-Tracy 100 50 0 0 182, 5 365 547, 5 Time Period 730 912, 5

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