Monitoring directional fluid flow in shale gas hydraulic fracturing through electrically energized steel well casings

Yang, Dikun; Li, Yinchu

doi:10.1190/gem2019-012.1

Cited by 6 publications

(1 citation statement)

References 7 publications

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“…The presence of steel-cased wells can help us detect targets at depth using electrical and EM methods, and in fact, additional steel infrastructure, such as multiple wells, can further amplify signals of interest (e.g. Yang and Li (2019)). The story is more complicated though if a current source is connected to a multilateral well where current is then distributed along multiple different wells (Weiss, 2017).…”

Section: Discussionmentioning

confidence: 99%

Electrical and electromagnetic responses over steel-cased wells

Heagy,

Oldenburg

2021

Preprint

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Electrical and electromagnetic (EM) methods can be diagnostic geophysical imaging tools for monitoring applications, such as carbon capture and storage or hydraulic fracturing. In these settings, it is common that steel-cased wells and other steel infrastructure are present. In this paper, we revisit and examine some of the fundamental physics of grounded-source electrical and EM surveys in settings with steel-cased wells.We highlight examples where steel casing can help targets at depth be detected and illustrate how EM methods can improve detectability. We also discuss some of the challenges that require further research for us to work with these data in practice, including numerical modelling and the implications of magnetic permeability.

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Section: Discussionmentioning

confidence: 99%

Electrical and electromagnetic responses over steel-cased wells

Heagy,

Oldenburg

2021

Preprint

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3D borehole-to-surface and surface electromagnetic modeling and inversion in the presence of steel infrastructure

Kim

Wilt

2020

GEOPHYSICS

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The borehole-to-surface electromagnetic (EM) method is a viable imaging and monitoring tool for energy reservoirs, geologic storage, geothermal exploration, fault zones, and other subsurface targets. Data interpretation typically requires considering steel-casing effects, but it is difficult and impractical to directly discretize arbitrarily oriented hollow steel-cased wells in a 3D reservoir-scale earth model because of their extremely high electrical conductivity and long hollow geometry. We have considered a borehole-to-surface EM configuration in which an electric dipole source is placed below the bottom of a steel-cased well. To practically simulate the casing effects on EM measurements, we develop a novel 3D finite-element EM algorithm using an unstructured tetrahedral mesh. To avoid excessive use of fine grids for modeling a steel-cased well, the well is replaced with the combination of a short solid conductive prism and a long linewise perfect electric conductor. We find that this combined structure can approximate casing effects at a small fraction of the computational cost required for modeling a complete hollow casing because the linewise structure is volumeless and does not require an excessive number of small elements. We also find that steel-cased wells distant from sources and receivers can be modeled as simple linewise perfect electric conductors, further improving the computational efficiency. Using this approximation, the 3D EM algorithm presented here is well-suited to modeling many arbitrarily oriented steel-cased wells. After verifying the accuracy and efficiency of this approach using various examples, we performed a 3D borehole-to-surface/surface-to-borehole and surface EM inversion and determine that the inversion can image a deep localized target in the presence of steel infrastructure.

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The effects of well damage and completion designs on geoelectrical responses in mature wellbore environments

Beskardes

Weiss

et al. 2021

GEOPHYSICS

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Well integrity is one of the major concerns in long-term geologic storage sites due to its potential risk for well leakage and groundwater contamination. Evaluating changes in electrical responses due to energized steel-cased wells has the potential to quantify and predict possible wellbore failures as any kind of breakage or corrosion along highly-conductive well casings will have an impact on the distribution of subsurface electrical potential. However, realistic wellbore-geoelectrical models that can fully capture fine scale details of well completion design and state of well damage at the field scale require extensive computational effort or can even be intractable to simulate. To overcome this computational burden while still keeping the model realistic, we utilize the Hierarchical Finite Element Method which represents electrical conductivity at each dimensional component (1-D edges, 2-D planes and 3-D cells) of a tetrahedra mesh. This allows us to consider well completion designs with real-life geometric scales and well systems with realistic, detailed, progressive corrosion and damage in our models. Here, we present a comparison of possible discretization approaches of a multi-casing completion design in the finite element model. The impacts of the surface casing length and the coupling between concentric well casings, as well as the effects of the degree and the location of well damage on the electrical responses are also examined. Finally, we analyze real surface electric field data to detect the wellbore integrity failure associated with damage.

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Monitoring directional fluid flow in shale gas hydraulic fracturing through electrically energized steel well casings

Cited by 6 publications

References 7 publications

Electrical and electromagnetic responses over steel-cased wells

Electrical and electromagnetic responses over steel-cased wells

3D borehole-to-surface and surface electromagnetic modeling and inversion in the presence of steel infrastructure

The effects of well damage and completion designs on geoelectrical responses in mature wellbore environments

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