Enhanced Reservoir Characterization Using Hydraulic Fracture Microseismicity

Abstract

Microseismic measurements were integrated with seismic reservoir characterization and injection data to investigate variability in the hydraulic fracture response between three horizontal wells in the Montney shale in NE British Columbia, Canada. When wells were close enough, hydraulic fractures were found to interact with pre-existing faults, which acted as a barrier to fracture growth, and resulted in relatively large-magnitude microseismicity. Pre-existing faults were identified by edge detection/ant tracking algorithms applied to seismic reflection data, as well as from advanced analysis of the microseismicity, including microseismic deformation levels, magnitude-frequency characteristics and composite failure mechanism analysis. In cases where the wells were far from pre-existing faults simple, planar hydraulic fractures were observed, although there was a tendency to grow towards regions of low Poisson's ratio based on amplitude versus offset inversion of the seismic reflection data. The tendency for the hydraulic fractures to be asymmetric and grow preferentially towards the low Poisson's ratio region is attributed to material property changes and associated lower stresses in these regions. Insight from the enhanced reservoir characterization with integrated microseismic and treatment data is being used for better well placement, improved completion designs and increased production.

Induced seismicity and hydraulic fracturing for the recovery of hydrocarbons

“…The fault is approximately 200 m from the injection well. 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 Mapping hydraulic fractures in the Montney Formation, Canada, using seismicity, shows that hydraulic fractures can terminate at faults which have been mapped using 3D seismic reflection data (Maxwell et al, 2011) (Fig. 7).…”

Hydraulic Fracture Orientation and Stress Field Revealed by Surface Based Microseismic Monitoring

“…Shawn Maxwell et al concluded that typically hydraulic fractures are considered to be single tensile fractures created orthogonal to the direction of minimum principal stress [5,6] . However, the injected fluid will follow a path of least resistance and depending on the stress conditions, may intersect pre-existing planes of weakness associated with either healed or open fractures.…”

Understanding Hydraulic Fracture Variability through Integrating Microseismicity and Seismic Reservoir Characterization

“…The surface treating pressure for wells A, B and C was discussed in Maxwell et al, 2011. Due to the close proximity of the wellbores similar treatment responses would be expected in wells A, B and C. However, it is clear from the surface treating pressure data that not only did the wells respond differently from wellbore to wellbore, but that there were also notably different responses from stage to stage in the same wellbore.…”

“…Finally, composite focal mechanisms were computed for the two clusters defined by the different b-values (Maxwell et al, 2011). Composite focal mechanism plots fit the observed seismic radiation patterns from groups of events to theoretical mechanisms to estimate the average failure mechanism (Rutledge et al, 2004).…”

“…Norton et al (2010) described integrating the locations of the microseismicity with reservoir conditions identified from seismic reflection data. Maxwell et al (2011) describe further integration of microseismic source attributes and injection data to better understand the impact of reservoir conditions on the hydraulic fracturing. Here we extend this investigation, by examining other aspects of the microseismicity and reservoir characterization to better understand how the hydraulic fractures grow in heterogeneous reservoir conditions.…”