Unconventional Reservoirs - Solutions
Challenge

Development of unconventional resource plays is primarily driven by engineering and environmental concerns related to the placement of lateral boreholes and the execution of an effective frac program. Geophysical data and methodologies can be an important component of this process. Challenges faced by reservoir engineers that geophysics can play an important role in resolving include:

  • Identification of silica-rich or calcite-rich “sweetspots” (zones with greater porosity, permeability and brittleness) which are desirable to target for lateral well paths and fracking.
  • Identification of ductile zones. These areas can be prolific hydrocarbon source kitchens but are avoided for well completions because fractures artificially-generated in these zones will collapse around the proppant without generating any additional permeability corridors.
  • Identification of seismic and sub-seismic faults and fractures, including the density of occurrence and whether open or sealed. Open natural faults may penetrate through the reservoir formation into adjacent formations, and thus cause the loss of fracking fluids or the contamination of production with saline formation water. Conversely, fracture swarms may be natural permeability conduits into the reservoir formation and greatly enhance production.
  • Determination of the actual stimulated volume of rock due to hydraulic fracturing and the delineation of artificially-created fractures. This determines the effectiveness of the frack program and can determine whether more or less effort (i.e. expense) needs be put into certain zones. It also has a direct bearing on the spacing of laterals from a single surface location.
RSI Solutions

We offer a range of technology to integrate rock physics, seismic inversion, cross-well tomography and microseismic analysis:

  • Effective Medium Modeling of wells within the prospect to calculate a rock model that can be used to predict reservoir properties (iMOSS). This may include crack modeling to assess the contribution of cracks to the porosity and permeability framework of the reservoir.
  • Calibration of rock properties at well control data points (iMOSS). This includes tying surface seismic data, pre-stack and post-stack, to well log synthetics.
  • AVATAR pre-stack and post-stack seismic data conditioning to increase the fidelity, resolution, and accuracy of gathers and stacks, including angle stacks.
  • Azimuthal seismic inversion to calculate magnitude of anisotropy (a proxy for the intensity of fracturing in fracture swarms) and azimuth of fracture orientation. The inversion results are also used to predict static reservoir attributes of porosity, lithology and pore fluids and geomechanical reservoir attributes such as Young’s modulus, Shear modulus and Poisson’s ratio.
  • iMOSS to calibrate inverted acoustic and elastic attributes to well data.
  • Coherence and Automatic Fault Extraction (AFE) to map seismic and sub-seismic faults and fractures.
  • ATTRIB3D to calculate fracture-sensitive attributes and LITHANN to input these attributes into a Kohonen self-organizing neural network. The result is facies classifications that are correlated to fracture intensity.
  • Integration of AFE fault planes with microseismic events and production data. This allows a comprehensive assessment of natural and artificially-induced fracture locations and whether the naturally-occurring fractures are open or closed, or have been re-opened by the frac program.
  • Multi-attribute geological and seismic stratigraphic interpretation of reservoir heterogeneities and rock properties. This may include geomechanical assessment of in-situ fracture and stress orientation.