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maximum horizontal stress field over the Haynesville area, there are lateral variations in the local stresses. Te understanding of this variability is crucial for optimal completions. Potentially brittle zones have been identified and their associated DHSR, fracture initiation pressure and closure stress have been estimated. Calibration and validation are critical. Tese seismically derived predictions were calibrated with existing production and well core and test measurements to determine optimal zones for drilling and completion. Te azimuthal signature needs to be adequately recorded, processed and measured In order to estimate the stress field distribution. After gather conditioning a dataset should have maximised signal-to- noise ratios, flattened reflector events and preserved amplitude variations. Te key steps in compliant amplitude-


versus-offset and amplitude-versus-azimuth seismic data conditioning are random noise attenuation, angle muting to remove spurious energy beyond a threshold angle of incidence, high-resolution de-aliased radon transform de-multiple and high-density velocity analyses for both anisotropic and azimuthal velocity derivation. Ray bending for offset angle gather conversion and reservoir-oriented


gather conditioning for prestack inversion are also critical. Multi-attribute analysis of the Tri-Parish data suggests that better development locations are found here in areas that have a combination of certain key rock properties, for example, better porosity development, high siliceous mineralogical content, and high values of TOC. Detailed rock property analyses showed that properties such as Poisson’s ratio and Lambda-Rho (incompressibility) are useful for identifying these areas in this field. Low Poisson’s ratio areas indicate the more siliceous, low- carbonate content, normally associated with better porosity development. Bulk volume of gas can be estimated by combining these properties via multi-attribute analysis.


Stress-related attributes In general, we found that no single attribute provided enough information to correlate seismic data to production, but multiple elastic- and stress-related attributes can be correlated to average production and horizontal well length at well locations with 95 per cent correlation. Te predicted production shows several undrilled areas with potentially high productivity. For validation, we compared the predicted


local stress fields to tri-axial measurements from core samples at two locations. Te full strain tensor and the principal stress directions were measured from these core samples, which then served as baseline values for correlating seismic predictions. We found that the direction of maximum horizontal stress, predicted from seismic observations, matched the corresponding core stress measurements to within 5 per cent. Although a statistical method of exploitation, where several wells are drilled near a productive well and areas around failed wells are abandoned, has proved successful so far in the relatively homogeneous Haynesville Shale, there are opportunities to increase production by targeting predicted sweet spots. Tis is what CGGVeritas can provide through the analysis and calibration of the stress and related attribute volumes derived from this seismic shale gas workflow. Tis analysis and workflow have the potential to predict fracture behaviour and reservoir drainage geometry, enabling optimal well placement and completion designs including stage zoning in hydraulic fracture stimulation. Significantly, this will also mitigate the risks associated with drilling hazards and hydraulic stimulation. Meanwhile, since launching BroadSeis


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