Joint inversion of transient‐pressure and dc resistivity measurements acquired with in‐situ permanent sensors: A numerical study

Abstract

We develop a quantitative methodology to interpret jointly in-situ transient pressure and dc resistivity measurements acquired in a hypothetical water injection experiment, with the goal of displacing oil in a hydrocarbon-bearing formation. The assumed measurement acquisition system consists of enforcing timevariable flow rates while injecting water into the surrounding rock formations, thereby producing a sequence of repeated transient pressure pulses. In-situ dc resistivity measurements are acquired at the end of every flowrate pulsing sequence. The objective of the experiment is to estimate the spatial distributions of absolute fluid permeability and electrical resistivity. Geophysical inverse theory is used to account for the presence of noisy measurements.Synthetic data with noise are inverted to assess the relative benefits of different types of sensor geometries in axisymmetric models of permeability and electrical resistivity. Results strongly suggest that cooperative inversion of in-situ transient pressure and dc resistivity measurements reduces nonuniqueness in the estimation of resistivity and absolute permeability governed by dynamic fluid-flow phenomena. This leads to a more accurate estimate of permeability and resistivity compared to separate inversion of each data type.

4-D inversion of DC resistivity monitoring data acquired over a dynamically changing earth model

“…In particular, direct current (DC) resistivity monitoring has been actively used to obtain hydrogeological properties, since the resistivity of subsurface material is easily affected by conductive or resistive fluid injection (Daily and Ramirez, 1995a,b;Daily and Ramirez, 2000;Slater et al, 2000;Alpak et al, 2004;Vargemezis et al, 2007). An approach commonly used for interpreting monitoring data is to independently invert the measured data acquired at each monitoring phase and to reconstruct time-lapse images.…”

Structure‐coupled multiphysics imaging in geophysical sciences

“…In many cases, detecting and monitoring the presence or movement of fluids within such systems from multimodal signal sensing and imaging are a primary objective for several reasons, and require accurate knowledge of the structure holding or confining the fluids. In the Earth sciences for instance, accurate characterization of material heterogeneity and its influence on fluid flow or storage in subterranean reservoirs is of crucial importance in a wide range of contemporary issues including the use of groundwater resources, volcano and earthquake monitoring, methane storage in wetlands, carbon dioxide sequestration and efficient extraction of fossil fuels and landfill methane [e.g., Beckwith and Baird , 2001; Hertrich and Yaramanci , 2002; Binley et al , 2002; Gedney et al , 2004; Roecker et al , 2004; Comas et al , 2005; Chen et al , 2006; Alpak et al , 2004, 2008; Bedrosian et al , 2007]. (A glossary of some common geophysical terms is included and their first appearance is in italics).…”

Characterization of Reservoir Heterogeneity Through Fluid Movement Monitoring With Deep Electromagnetic and Pressure Measurements

“…Marlinverno and Torres-Verdin (2000), Charara et al (2002), and Manin et al (2002) also used synthetic time-lapse resistivity data from a permanent array cemented outside of the casing with or without transient pressure measurements to monitor the water-injection fronts, while Alpak et al (2004c) applied the same synthetic data to estimate absolute permeability in different layers. Compared with previous studies, the study being reported has the following distinct features:…”