Well drawdown test eastern washington8/26/2023 ![]() To derive the hydraulic properties of the aquifer, such as transmissivity and the storage coefficient, or to reveal the presence of any hydraulic boundaries.How much drawdown does it take to yield a certain amount of water? To assess the hydraulic performance of a borehole, usually in terms of its yield-drawdown characteristics.To determine the reliable long-term yield (or ‘safe’ yield) of a borehole, and therefore whether or not the borehole can be regarded as a ‘success,’ and how many people it will be able to supply.Pumping tests can be undertaken for a wide variety of reasons, including the following: The way in which the water levels respond to the pumping is then analyzed to derive information about the performance characteristics of the borehole and the hydraulic properties of the aquifer. Examples describing how one can use the model to better design well tests i n commingled formations are also included.Pumping tests or aquifer performance tests is a field experiment in which a well is pumped at a controlled rate and water-level response (drawdown) is measured in one or more surrounding observation wells and optionally in the pumped well (control well) itself. 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. 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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