Multidisciplinary approach in determining the best zone to land a Haynesville horizontal well

Abstract

The Upper Jurassic Haynesville Shale Formation in the East Texas Basin, North America, is a black, organic-rich, calcareous mudstone that lies below the Bossier Shale and above the Cotton Valley Limestone. The reservoir quality was controlled by primary depositional process and secondary diagenesis. The best lithology type in terms of drilling, completion, and production is the organic-rich, silty calcareous mudstone with low clay content. The studied well traversed the entire Haynesville Formation with the objective to assess the production potential of this formation. We acquired open-hole, triple-combo logging while drilling (LWD) logs, two types of production logs, and regional microseismic data. Postdrill log modeling confirmed that the horizontal well stayed on the planned trajectory, based on the log correlation between the horizontal and offset wells. Log modeling demonstrated that the LWD resistivity logs in horizontal wells are subject to resistivity anisotropy and polarization horn effects. We integrated the production log results with the open-hole, log formation evaluation and mineralogy-based brittleness index, to understand the static reservoir properties and dynamic inflow performance. The open-hole and cased-hole logs consistently showed that the “rabbit ears” interval at the base of the Upper Haynesville and the top interval of the Upper Haynesville were excellent lateral well-landing zones for best production. We combined microseismic data with production log data and found that the effective stimulated rock volume by hydraulic fracturing was mostly concentrated in the top interval of the Upper Haynesville and the “rabbit ears” interval at the base of the Upper Haynesville. The study demonstrated that a multidisciplinary approach was necessary in determining the best zone to land Haynesville horizontal wells.