Study of foam in model fractures: coarsening, gas trapping and gravity effects

Naturally fractured reservoirs (NFRs) gain much attention worldwide because they are often encountered in aquifer remediation, CO2 sequestration, and hydrocarbon extraction. In hydrocarbon extraction, however, oil recovery by gas injection in NFRs is usually low, because of poor sweep efficiency. During gas injection, the displacement front is...

Coarsening of foam in two model fractures with different roughness

Foam coarsening by diffusion (Ostwald ripening) has been well studied in bulk foams. However, it is less well understood in porous media. In particular, the mechanisms that may slow or stop coarsening have not been fully investigated. In this paper, we report an experimental study of foam coarsening in two 1-m-long and 15-cm-wide model fractures...

Elastic least-squares migration for quantitative reflection imaging of fracture compliances

To quantitatively image fractures with high resolution, we have developed an elastic least-squares migration (LSM) algorithm coupled with linear-slip theory, which accurately addresses seismic wave interaction with thin structures. We derive a linearized waveform inversion using the Born approximation to the boundary integral equation for...

Dual-Permeability Model Improvements for Representation of Preferential Flow in Fractured Clays

Dual-permeability models assume that the complete porous media system can be represented by two different interacting subsystems: the matrix and the fracture pore domain. For some soils like fractured clays, the fracture domain may be empty, which makes its physical behavior differ significantly from capillary flow. Our main hypothesis is...

Quantitative imaging of fractures around a borehole using linear slip theory and elastic least-squares migration

Single-well reflection imaging using sonic logging data successfully locates fine-scale structures around a borehole including fractures. In order to achieve accurate and quantitative estimation of fracture properties with high resolution, we propose to couple least-squares migration with linear slip theory. The proposed least-squares...

A parametric level-set approach for seismic full-waveform inversion

<br/>In seismic exploration, the delineation of large bodies with hard exterior contrasts but nearly constant interior properties is a challenge. Examples include salt diapirs, salt slabs, anhydrite or basalt layers. Salt geometries are of particular interest because they often have hydrocarbon reservoirs on their sides or underneath. This...

Laboratory estimation of fracture compliance of a fluid-filled fracture using AVO response of a nonwelded interface

We explore the potential of multi-angle AVO inversion of P-P and P-S reflections from a fracture to estimate fracture proper- ties. Although AVO analysis of welded interface like geologi- cal layer boundaries is common, the use of AVO variations for nonwelded boundaries like fractures is yet to be investigated. We conduct laboratory experiments...

Characterization of heterogeneous fracture compliance using multiple reflections coupled with data-driven Green's function retrieval

The spatial heterogeneity along a fracture is a key determinant for fracture-associated hydraulic properties. We propose a new method to estimate the heterogeneous compliance distribution of a fracture from the reflection response at the fracture surface. For this purpose, we formulate a data-driven approach for Green's function retrieval based...

Experimental validation of fracture aperture determination from borehole electric microresistivtiy measurements

We studied the electric response of fractures with laboratory experiments and numerical simulations for a full-bore formation microimaging tool. The laboratory setup was designed and built to perform controlled experiments with accurate measurements of all principal properties involved for electric borehole imaging. These properties are...

Nonlinear imaging condition and the effect of source illumination: Imaging fractures as nonwelded interfaces

Fluid flow through a fractured reservoir is often controlled by the large fractures. Seismically imaging these large fractures has the potential to illuminate their hydraulic properties.We derived a nonlinear imaging condition considering a medium containing nonwelded interfaces such as fractures for high-resolution fracture imaging. This was...

Non-linear imaging condition to image fractures as non-welded interfaces

Hydraulic properties of a fractured reservoir are often controlled by large fractures. In order to seismically detect and characterize them, a high-resolution imaging method is necessary. We apply a non-linear imaging condition to image fractures, considered as non-welded interfaces. We derive the imaging condition from the general correlation...

Shock-induced borehole waves in fractured formations

Natural or hydraulic fractures are of major importance for the productivity of hydrocarbon reservoirs. Besides fracture detection, also the aperture and extension of the fractures are essential for a correct reservoir productivity estimate. There are many ways to detect and measure fractures, such as borehole televiewers and electrical borehole...

Power spectral density of the heterogeneous fracture compliance from scattered elastic wavefields

Using the scattered elastic wavefield, a method to derive the power spectral density (PSD) of the heterogeneous compliance distribution, along the plane of a single fracture, is formulated. The method involves estimation of the stress field at the fracture depth from the scattered wavefield followed by least-squares optimization of the PSD of...