The Haynesville Shale is an unconventional gas reservoir located in east Texas and northwest Louisiana. High gas prices and the success of other shale gas plays have led operators to invest highly in this unconventional reservoir. It has great potential for development by applying all the new technology that is available in the oil and gas industry today.

Petrophysical evaluation of reservoirs has long been used for exploration and reserve estimates. New logging tools and analysis techniques have been developed to provide more precise data about target zones and bounding layers that are important when considering hydraulic fracturing for unconventional reservoirs.

A processed log interpretation calibrated for the Haynesville Shale is computed using a typical triple-combo suite of logs. Other log data, such as borehole imaging, magnetic resonance, dipole sonic, and spectral gamma ray, will improve and verify the interpretation. Core analysis provides accessory data on mineralogy, total organic carbon (TOC), and rock mechanical properties to calibrate this processed log computation and improve the accuracy of the total shale interpretation.

Identification of the following reservoir characteristics provides the starting point for completion-and hydraulic-fracture stimulation design:

  • Identification of free-gas zones

  • Identification of rock types and mineralogy

  • Total organic content

  • Quantification of effective shale porosity

  • Estimates of shale permeability

  • Mechanical stress measurement for hydraulic-fracturing design

  • Identification, classification, and orientation of marginal-class, open-conductive, and drilling-induced fractures

A number of Haynesville Shale examples are presented to highlight all interpretation techniques and variations in the shale itself within its proven productive area. This interpretation can be critical for the hydraulic-fracture design approach for the Haynesville Shale.

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