The overall objective of this project is to develop and demonstrate a new technology for large-volume, targeted comminution of rock in low permeability formations to enhance recovery of unconventional oil and natural and gas (UOG) resources.

Oklahoma State University (OSU), Stillwater, OK 74078

Collaborators
The University of Tulsa, OK 74104
 

This project develops and demonstrates a new technology for large-volume and targeted comminution of rock in low permeability formations to enhance recovery from UOG resources. The technology is based on a strategically designed interaction of multiple induced seismic pulses that assist the hydraulic fracturing process to enhance shear and multi-planar crack formation.  To develop and demonstrate the proposed technology, this project investigates two aspects of multi-source excitation.  This increased stimulated rock volume stimulation is expected to result in significant increases in permeability leading to increased recovery factors for sub-surface fluids. The proposed technology is especially applicable for enhanced recovery in emerging UOG plays, such as ductile shales that are resistant to opening-mode fracturing by conventional hydraulic fracturing processes.

Increased recovery factors directly reduce the environmental impact of UOG resource development. To achieve higher recovery factors requires a fundamental understanding of the basic processes that govern interaction between well completion and stimulation activity, and reservoir dynamics. This challenge is addressed by developing a new technology that utilizes dynamic failure phenomena for large-scale stimulation of rock to yield increased resource recovery.

• Quantitative composition analysis using XRD/XRF
• Non-destructive micro-CT analysis of shale shows internal cracks
• Macropore and mesopore analysis of shales with Mercury Intrusion Porosimetry (MIP)
• Dynamic compression tests have been conducted to collect data on damage progression. This data is being evaluated as an input into the numerical models. Specimens have been machined and fabricated for the 2D stress wave–crack interaction experiments.
• Two manuscripts and one patent disclosure are currently under preparation. This work was presented at the annual Society of Experimental Mechanics conference for 2021 titled “Dynamic Damage Evolution in Shale in the Presence of Pre-existing Microcracks.”
• Centrally crack weakened plane polycarbonate specimens were tested and shown to have a dependence on the angle of the weakened plane. The central crack would be the primary cause for failure while the weakened plane influenced crack propagation path to fracture along the weakened plane. In summary, the results indicated that the wave propagation and crack interactions are affected by the introduction of centrally cracked weakened planes.
• Two manuscripts and one patent disclosure are currently under preparation. This work was presented at the annual Society of Experimental Mechanics conference for 2022 titled “Experimental Investigation of Non-local Dynamic Damage Mechanism in Shale”, ”Use of Full-field Strain Measurements to Determine Mechanical Properties of Shale Under Repeated Cyclic Loading” and, ”Mixed-mode Fracture Interaction Along Centrally Cracked Weakened Planes.”
   

A true triaxial apparatus is being built in-house to investigate the superposition of three-dimensional shear and planar waves generated using plasma arc electrohydraulic discharge (PAED) with fluid loaded cracks under triaxial conditions to simulate hydraulically fractured multi-borehole rock reservoirs. The focus of the current efforts will be on the following, and continue as planned:

1. Use dynamic damage data from experiments as inputs in the numerical models.
2. Two-dimensional experiments will be continued and analyzed to study the interactions of stress waves with pre-existing cracks for both a model material and shale.
3. Analysis of shale and synthetic substitutes using micro-CT for non-destructive pore and crack identification will continue.
    

$1,500,000

$375,000

NETL — Anthony Zammerilli (anthony.zammerilli@netl.doe.gov or 304-285-4641)
OSU — Raman Singh (raman.singh@okstate.edu or 918-594-8155)