ESTIMATING BRITTLENESS USING SEISMIC DATA IN AN UNCONVENTIONAL SHALE RESERVOIR, FORT WORTH BASIN, NORTH CENTRAL TEXAS
Abstract
Brittleness within unconventional shale plays is a major component in reservoir
stimulation. Mineralogy measured in nearby wells estimates brittleness and can be
correlated to elastic parameters measured in well logs and surface seismic data. Brittle
zones are dominated by high quartz and TOC while ductile zones are dominated by clay
and calcite with lower TOC. λρ and µρ calculated from prestack inversion seismic data
predictes brittle and ductile zones, which is validated using microseismic data. Near the
heel of the well, many microseismic events propagated into the more ductile Forestburg
limestone. Using a borehole image log, it appears that open and partially open fractures
allow perforation energy to travel into the overlying more ductile formations. Near the
toe of the well events occur in the more brittle areas of the target Barnett Shale formation.
Correlating fracture type with curvature, low (near zero) values of most positive curvature
are highly fractured and contains the most microseismic activity. Creating a brittleness
volume, microseismic events occur in brittle and less brittle zones with the exception of
the events that occur in the ductile Forestburg limestone due to an increase in open and
partially open fractures towards the heel of the well.
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- OU - Theses [2091]