Reservoir stress path and induced seismic anisotropy: Results from linking coupled fluid-flow/geomechanical simulation with seismic modelling

We present a workflow linking coupled fluid-flow and geomechanical simulation with seismic modelling to predict seismic anisotropy induced by nonhydrostatic stress changes. We generate seismic models from coupled simulations to examine the relationship between reservoir geometry, stress path and seismic anisotropy. The results indicate that geometry influences the evolution of stress, which leads to stress-induced seismic anisotropy. Although stress anisotropy is high for the small reservoir, the effect of stress arching and the ability of the side-burden to support the excess load limit the overall change in effective stress and hence seismic anisotropy. For the extensive reservoir, stress anisotropy and induced seismic anisotropy are high. The extensive and elongate reservoirs experience significant compaction, where the inefficiency of the developed stress arching in the side-burden cannot support the excess load. The elongate reservoir displays significant stress asymmetry, with seismic anisotropy developing predominantly along the long-edge of the reservoir. We show that the link between stress path parameters and seismic anisotropy is complex, where the anisotropic symmetry is controlled not only by model geometry but also the nonlinear rock physics model used. Nevertheless, a workflow has been developed to model seismic anisotropy induced by non-hydrostatic stress changes, allowing field observations of anisotropy to be linked with geomechanical models

Using RAPD markers for genetic analysis in Three Species of Datura in Iraq

The study amis to develop the evidence genetic of active substances for several kinds of the Datura plant (Datura sp.), So it was procedure steps to isolated the Genomic DNA from leaf of Datura specis    it is (Datura metel, Datura innoxia and Datura stramonium).(&#x0D;  Has been used 51 primers in the experiments of the RAPD markers, but did not show 17 primers including any amplified band while showed in genomic in Datura plants, and 34 primers show results Differentiated locations where all the primers gave a differentiated binds Polymorphic band These results have been invested to study genetic variability among the species involved in study.&#x0D;  &#x0D; http://dx.doi.org/10.25130/tjps.23.2018.165</jats:p

Combining the modified discrete element method with the virtual element method for fracturing of porous media

Simulation of fracturing processes in porous rocks can be divided into two main branches: (i) modeling the rock as a continuum enhanced with special features to account for fractures or (ii) modeling the rock by a discrete (or discontinuous) approach that describes the material directly as a collection of separate blocks or particles, e.g., as in the discrete element method (DEM). In the modified discrete element (MDEM) method, the effective forces between virtual particles are modified so that they reproduce the discretization of a first-order finite element method (FEM) for linear elasticity. This provides an expression of the virtual forces in terms of general Hook’s macro-parameters. Previously, MDEM has been formulated through an analogy with linear elements for FEM. We show the connection between MDEM and the virtual element method (VEM), which is a generalization of FEM to polyhedral grids. Unlike standard FEM, which computes strain-states in a reference space, MDEM and VEM compute stress-states directly in real space. This connection leads us to a new derivation of the MDEM method. Moreover, it enables a direct coupling between (M)DEM and domains modeled by a grid made of polyhedral cells. Thus, this approach makes it possible to combine fine-scale (M)DEM behavior near the fracturing region with linear elasticity on complex reservoir grids in the far-field region without regridding. To demonstrate the simulation of hydraulic fracturing, the coupled (M)DEM-VEM method is implemented using the Matlab Reservoir Simulation Toolbox (MRST) and linked to an industry-standard reservoir simulator. Similar approaches have been presented previously using standard FEM, but due to the similarities in the approaches of VEM and MDEM, our work provides a more uniform approach and extends these previous works to general polyhedral grids for the non-fracturing domain.acceptedVersio

Distance-Independent Contactless Interrogation of Quartz Resonator Sensor with Printed-on-Crystal Coil

A novel quartz crystal resonator sensor, which embeds a conductive printed planar coil that enables electromagnetic contactless interrogation techniques is presented. An aerosol-jet process is used to precisely and accurately deposit electronic inks onto a 330 µm-thick bare piezoelectric quartz crystal to print the planar coil and the electrodes. The proposed interrogation technique enables distance-independent operation, and is based on the measurement of the reflected impedance of the quartz resonator sensor through the planar primary coil of the coupled inductors. The resonant frequency, measured without contact using the primary coil connected to an impedance analyzer, results 4.790260 MHz. Contactless operation distances up to 12.2 mm have been obtained. The experimental results have a maximum deviation of about 50 Hz, i.e. 10.5 ppm, with respect to reference measurements taken via contact probes

Distance-Independent Contactless Interrogation of Quartz Resonator Sensor with Printed-on-Crystal Coil

A novel quartz crystal resonator sensor, which embeds a conductive printed planar coil that enables electromagnetic contactless interrogation techniques is presented. An aerosol-jet process is used to precisely and accurately deposit electronic inks onto a 330 µm-thick bare piezoelectric quartz crystal to print the planar coil and the electrodes. The proposed interrogation technique enables distance-independent operation, and is based on the measurement of the reflected impedance of the quartz resonator sensor through the planar primary coil of the coupled inductors. The resonant frequency, measured without contact using the primary coil connected to an impedance analyzer, results 4.790260 MHz. Contactless operation distances up to 12.2 mm have been obtained. The experimental results have a maximum deviation of about 50 Hz, i.e. 10.5 ppm, with respect to reference measurements taken via contact probes