Interpretation of a pumping test with interference from a neighboring well

In confined aquifers, the impact of nearby active wells is frequently overlooked during pumping test interpretation. This oversight may lead to inaccurate assessments of aquifer properties. Prior research has shown that ignoring such interference can skew estimates of transmissivity and storativity. Established methods typically assume a single pumping well and a uniform aquifer. However, real-world conditions often involve multiple wells operating simultaneously. This gap motivated the development of new techniques that account for interference. No prior work had resolved how to interpret data when an interfering well starts pumping before the test. This paper contributes by introducing methods that improve estimation accuracy. The study addresses a specific challenge in aquifer testing, where multiple wells affect the results. It builds on existing Theis and Cooper-Jacob models but adapts them to handle interference.

The aim of this study is to improve the interpretation of pumping tests in confined aquifers affected by nearby wells. The specific problem is the misinterpretation of transmissivity and storativity due to unaccounted interference. The motivation comes from the limitations of existing methods, which assume a single pumping well and ignore nearby influences. The study seeks to develop a new approach that accounts for interference from neighboring wells. It also aims to distinguish between interference and other deviations, such as impermeable boundaries. The goal is to provide more accurate estimates of aquifer properties. The approach focuses on data where an interfering well starts pumping before the test. The ultimate purpose is to enhance the reliability of aquifer testing in complex field conditions.

The study introduces new analytical methods for interpreting pumping test data in the presence of interference from a neighboring well. These methods are based on the Theis solution for confined aquifers but modified to account for an additional pumping source. The key innovation is the ability to estimate transmissivity and storativity without knowing the aquifer's initial natural level. This is important because the interfering well may have started pumping before the test. The methods use the pumping rate of the interfering well and the time since pumping began in both wells. The researchers applied these methods to data from a numerical model to test their effectiveness. The approach avoids assumptions about the aquifer's pre-test state, which is often unknown. The methods also help differentiate interference effects from other deviations like boundary influences. The results were validated by comparing them to known model parameters.

The new methods provided more accurate estimates of transmissivity and storativity compared to traditional approaches that ignore interference. The improvement was particularly significant for storativity values. The methods successfully distinguished interference effects from other deviations like impermeable boundaries. When applied to numerical model data, the results closely matched the known aquifer properties. The study demonstrated that the new methods do not require the aquifer's initial natural level, which is a key advantage. This eliminates a major limitation of previous techniques. The methods also showed robustness when the interfering well started pumping before the test. The results suggest that neglecting interference can lead to substantial errors in aquifer characterization. The new approach was validated through a controlled numerical experiment, confirming its reliability.

The authors propose that the new methods improve the accuracy of transmissivity and storativity estimates in confined aquifers affected by neighboring wells. They emphasize that ignoring interference can lead to erroneous interpretations. The methods do not require the aquifer's initial natural level, which is often unknown. This makes the approach more practical for field applications. The study also shows that the methods can distinguish interference from other deviations like boundaries. The results suggest that the new methods are more reliable than traditional ones in complex scenarios. The authors conclude that their approach enhances the interpretation of pumping tests in multi-well environments. They recommend using these methods when interference is suspected to avoid misestimating aquifer properties.