Simulated drawdown is interpreted using the Cooper–Jacob method. This is achieved with the help of simulations in 3 homogeneous one-layered confined and isotropic aquifer models using MODFLOW. The study illustrates and discusses the effect of using the Cooper and Jacob method to interpret multi-well aquifer-pumping tests. Despite the wide use of the method, the effects of using the Cooper and Jacob method to interpret multi-well aquifer-pumping test data are hardly discussed. For observation wells (piezometers), the method said to be valid when u < 0.01 when drawdown observations are made in the near vicinity of the pumping well after a sufficiently long time of pumping. The method can be used to interpret both pumping and observation well drawdown. Cooper, Jacob, Trans Am Geophys Union 27:526534, 1946) method is widely used to interpret data from both single- and multi-well aquifer-pumping tests in a porous homogenous and isotropic confined aquifer system. Examples describing how one can use the model to better design well tests i n commingled formations are also included.The Cooper and Jacob (Trans Am Geophys Union 27:526–534. The degree to which crossflow affects pressure response can also be measured. This feature enables the engineer to simulate the actual flow rate coming from each layer and the resultant reservoir response as measured downhole from a pressure recording tool. Reservoir and wellbore equations are solved simultaneously using the fully implicit Newton method.Īpplications for this model include determining the dynamic wellbore pressure drop versus time for both single phase oil or gas, and multiphase production and shut-in in vertical and deviated wells, and the resultant change in production rates at the wellbore sandface with time.
WELL DRAWDOWN TEST EASTERN WASHINGTON SKIN
The wellbore flow is handled by use of the Bernoulli equation including friction and kinetic contributions to pressure drop.Īnother feature of this model is the use of the full rate equation for gas flow in the reservoir, including the inertial-turbulent (forcheimer) term, in order to handle the rate-dependent skin in addition to mechanical skin at the wells. This coupling allows the user to assign production, injection, and shut-in of wells at the surface point, where the valves are physically located, instead of downhole for conventional reservoir simulators.
This paper describes new applications of a recently developed integrated single well model (ISWM) that couples equations describing dynamic wellbore flow with ones describing transient reservoir flow.
A complicating factor comes in if the layers are communicating, which may significantly reduce the accuracy of available analytical methods. depth in addition to downhole pressure is required so as to ascertain how much rate is coming from each layer in order to analyze the response of each layer separately. Often, measurements of both downhole rates vs. The problem of designing and analyzing well tests for wells producing from multiple zones through the same production string is often complicated by the interaction between the different layers.
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