Numerical Modeling of Periodic Pumping Tests in Wells Penetrating a Heterogeneous Aquifer

Abstract

This study investigated how to utilize multiple frequency components of pressure data from periodic pulse tests to estimate the intra-well permeability and compressibility distribution and also the presence of heterogeneities in a real field case. Periodic well testing is a technique in which injection or production pulses of a fluid are applied to a well in a periodic fashion. One of its main advantages is that ongoing operations do not have to be interrupted during the test as the superposed harmonic components can be identified using Fourier analysis. Further, modeling calculations are much faster than calculations in the time domain as no time-stepping is required and only the frequencies observed in the test need to be evaluated. We applied an earlier developed numerical code in the frequency domain to evaluate periodic-test results in a shallow aquifer and obtained a good match between data and calculations. The interpreted formation heterogeneity is in line with the local geology. Joints of various orientations constitute the main hydraulic conduits of the tested subsurface but they do not directly connect the wells. Thus communication between the wells has to be established through low-permeability features. The interwell periodic testing has corroborated the geological understanding of the aquifer and helped understanding the fluid flow pattern.

What’s Conventional and what’s Special in a Reservoir Study for Underground Gas Storage

“…The need to acquire this information, which would call for expensive traditional testing campaigns, can be better satisfied by alternative well testing procedures, such as harmonic pulse testing [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] and injection testing [39,40]. A harmonic test is characterized by a periodic sequence of alternating production or injection rates that can be imposed after a long shut in of the tested well, similar to conventional well testing, or can be superposed to ongoing production, minimizing or avoiding economic losses.…”

Joint inversion of hydraulic head and self‐potential data associated with harmonic pumping tests

“…Fokker et al . [] successfully performed multifrequency harmonic pressure stimulations in the frequency domain to estimate the simplified permeability of a heterogeneous aquifer. The use of a frequency domain model gave them the possibility to significantly reduce the computational time required for solving the forward problem.…”

Analytical and Semi‐Analytical Tools for the Design of Oscillatory Pumping Tests

“…At the GEMS site in Kansas, USA, McElwee et al () used an approximate model of oscillatory pressure travel time to tomographically analyze periodic pumping test data. Most recently, Fokker et al () re‐analyzed data from the periodic tests of Renner and Messar () using a numerical modeling approach to estimate parameters of geometrically constrained geologic bodies.…”