--> --> Abstract: Development of Mechanically Layered Haynesville-Bossier Shale-Gas Play, by Amgad I. Younes, Holly Moore, Nathan Suumeyer, Melissa Sandstrom, and Paul R. Smith; #90124 (2011)

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Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA

Development of Mechanically Layered Haynesville-Bossier Shale-Gas Play

Amgad I. Younes1; Holly Moore1; Nathan Suumeyer1; Melissa Sandstrom1; Paul R. Smith1

(1) Shell EP Company, Houston, TX.

The Haynesville shale is characterized by high TOC, good porosity, high gas saturation, low clay content and nanoDarcy permeabilities, all which makes for an exceptional shale gas reservoir. However, recent well IPs have been variable, and given the planned extensive development, it is necessary to de-risk some of the geologic variables to up-grade acreage and optimize well development plans. This was done through a two-part study covering the greater Sabine area of northwestern Louisiana, USA. The first part focused on defining the depositional environment, reservoir characteristics, and facies variation through inorganic element analysis, XRF, XRD, petrography, and biostratigraphic classification of macro and nano fossils. The second focused on interpretation of present-day stresses and characterization of the natural fracture from core, image logs, and micro-seismic data. Both parts were then integrated to assist in sweet spot definition and well planning and optimization.

Results suggest that the Haynesville’s reservoir properties (clay/calcite content, TOC, perm) are mapable showing trends that can roughly be correlate with IP rates. However, on a well-to-well basis, it is unclear what the contribution of a single property is (e.g., TOC or porosity) to productivity, and hence the predictability of future well rates or location. Similarly, fracture distribution shows mapable trends. These fractures are generally calcite cemented, and hence cannot directly contribute to well productivity unless reactivated during the stimulation. Vertically, fractures occur more extensively in the lower and upper Bossier than in the Haynesville and Mid-Bossier forming a mechanically layered system.

We show that mechanical layering combined with reservoir properties, complicates play development because the less fractured layers are richer in TOC than the highly fractured layers. Thus, while one could target a high TOC layer, the lack of fractures could hinder productivity. At the same time, the lack of natural fractures allows stimulated fracs to grow longer because the presence of natural fractures in the path of a stimulated frac dissipates its energy and produces shorter or segmented ones. A successful shale gas play development thus requires: 1) characterizing the competition between stimulated frac efficiency and value of natural fractures, or 2) realizing the balance between choosing the right reservoir properties, and reactivation of pre-existing fractures.