Anisotropic stress model delivers fracture success
Schlumberger used TerraTek services to perform an evaluation of this
Barnett Shale reservoir. Analysis gave the operator a detailed evaluation of
this formation and a completion methodology designed for success. The
completion methodology, designed for perforation placement avoiding laminated
intervals, focused on more siliceous layers with low-closure stress. To avoid
fracturing down into the water zone below the shale, analysis suggested
perforating in intervals to promote upward growth.
With the analysis providing a full understanding of the reservoir, the
operator incorporated a tapered proppant mesh throughout the course of the
hydraulic fracture treatments. Key components of the evaluation methodology
included the use of ECS elemental capture spectroscopy sonde, FMI fullbore
formation microimager, ELANPlus software, Sonic Scanner acoustic scanning
platform, Platform Express wireline logging tool, and TerraTek core analysis to
provide a complete characterization of the reservoir and its potential.
Processing mechanical properties with an anisotropic stress model is
critical to predicting and mitigating proppant entry issues, as well as
predicting fracture geometry. A thorough knowledge of the stress gradient and
contrasts is vital to determining the optimum way to hydraulically fracture the
reservoir. Detailed fluid sensitivity tests lead to the selection of the best
Complete analysis leads to solid completions
Combining all of these analyses with a perforation strategy helped the
client avoid completion failures common in this reservoir, like fracture growth
out of the zone, potentially into a water zone. The 3D anisotropic processing
revealed that apparent fracture barriers in carbonate and high-clay intervals
did not exist. Surface-passive microseismic monitoring of the hydraulic
fracture treatment later confirmed this. The relevance of processing
geomechanical data with an anisotropic stress model proved invaluable to the
development of the reservoir.
Analysis of core data resulted in better placement for perforation
clusters, optimized well trajectory for horizontal laterals, and enhanced
production. This well, completed using TerraTek analysis, showed an average
production increase of 500 Mcf/d.