Joint inversion of aquifer test, MRS, and TEM data. Issue 5 (20th May 2014)

• Record Type: Journal Article
• Authors: Vilhelmsen, Troels N.; Behroozmand, Ahmad A.; Christensen, Steen; Nielsen, Toke H.
• Is Part Of: Water resources research. Volume 50:Issue 5(2014:May)
• Page Start: 3956
• Page End: 3975
• Publication Date: 2014-05-20
• Subjects: Hydrology -- Periodicals; 333.91
• DOI: 10.1002/2013WR014679
• Languages: English
• ISSNs: 0043-1397

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>This paper presents two methods for joint inversion of aquifer test data, magnetic resonance sounding (MRS) data, and transient electromagnetic data acquired from a multilayer hydrogeological system. The link between the MRS model and the groundwater model is created by tying hydraulic conductivities (<italic>k</italic>) derived from MRS parameters to those of the groundwater model. Method 1 applies <italic>k</italic> estimated from MRS directly in the groundwater model, during the inversion. Method 2 on the other hand uses the petrophysical relation as a regularization constraint that only enforces <italic>k</italic> estimated for the groundwater model to be equal to MRS derived <italic>k</italic> to the extent that data can be fitted. Both methodologies can jointly calibrate parameters pertaining to the individual models as well as a parameter pertaining to the petrophysical relation. This allows the petrophysical relation to adapt to the local conditions during the inversion. The methods are tested using a synthetic data set as well as a field data set. In combination, the two case studies show that the joint methods can constrain the inversion to achieve estimates of <italic>k</italic>, decay times, and water contents for a leaky confined aquifer system. We show that the geophysical data can assist in determining otherwise insensitive <italic>k</italic>, and vice versa. Based on our experiments and results, we mainly advocate the future application of method 2 since this seems to produce the most reliable results, has a faster inversion runtime, and is applicable also for linking <italic>k</italic> of 3‐D groundwater flow models to multiple MRS soundings.</p> </abstract>