Since the inception of hydraulic fracturing, it has been recognized that fracture height is the dominant variable in designing or understanding hydraulic fracture growth. Later, this recognition was formalized with the development of fracture design theories by Perkins $ Kern, Gertsma deKlerk, and others. However, recognition of the importance of height is of little practical aid in the design or post analysis process for a fractured well. More recently, special production logs and open hole logs have been developed to address this problem and aid in fracture height prediction and measurement. These include, in particular, sonic log stress calculations and special spectral gamma ray logs and interpretation techniques. Also, the development of theories and models for analysis of fracturing pressures has been developed as a tool for estimating fracture height and fracture geometry. However, there is little field evidence where these various "tools" have been simultaneously utilized and compared.

This paper discusses a Rocky Mountain gas well case history where extensive testing was conducted to measure hydraulic fracturing characteristics. This included pre-frac lpg predictions of in situ stress and fracture height, in situ stress tests, pressure measurements and model calculations, and post frac temperature/gamma ray logs. The total fracture height (as well as differences in upward and downward growth) as predicted (or measured) with each technique is compared and critiqued as to its reliability and usefulness for this particular application. Of particular interest is the fracture width profile as measured with liquid RA tracer, and the changes in this with time as the fracture apparently closes. The significant differences in RA logs for liquid tracer and post-frac logs for tagged proppant are also significant. Finally, post-frac production and flow/build-up test results are compared to fracture design lengths.

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