Hydraulic Fracture Properties

Shale gas reservoir materials naturally have very low permeabilities, and therefore require stimulation by hydraulically-induced fractures. It is poorly understood how induced hydraulic fractures will interact with pre-existing faults/fractures and how stimulation through hydraulic fracture can maximise productivity of gas from shale.

For illustration, wax was injected under pressure into a pre-formed notch in an unconfined perspex cylinder and fluid-driven fractures propagated through the material. For fluid injection tests on shales, acoustic emission (AE) events are recorded through 8-channels.

In addition to carrying out hydraulic fracture tests in standard 'triaxial' testing equipment, we are developing novel apparatus for 4D in-situ imaging of fracture initiation and propagation in shale materials using the Diamond-Manchester X-ray Imaging Beamline (DMB) at the Diamond synchrotron. Fracture growth is imaged using X-ray tomography coupled with acoustic emission mapping.

The aim is to determine how hydraulic fractures initiate, how they propagate into the anisotropic rock volume, the initiation complexity of shear mode fracture growth, and how resistance to fracture initiation and growth depends on rock elasticity and ductility.

Acoustic emsiiion imaging is also coupled to permeability and mechanical testing in the Rock Deformation Laboratory at Manchester to investigate the behaviour of samples over a wider range of pressure/temperature conditions than possible at the DMB, followed by static X-ray imaging of fractured samples. Methods for determination of fracture toughness and measurement of slow crack growth are also employed.

Recent Publications
  • Chandler, M., P. Meredith, N. Brantut, B. Crawford. Evolution of Fracture Properties and Anisotropy in the Mancos Shale with Elevated Temperatures and Confining Pressures. TSG: 2015: -. eScholarID:264986
  • Chandler, M., P. Meredith, N. Brantut, B. Crawford. Implications of fracture-toughness anisotropy for crack-growth geometry in the Mancos shale. 2014: -. eScholarID:264985

Academic Staff: Prof Ernest Rutter, Dr Julian Mecklenburgh, Prof Peter Lee (Diamond Light Source) | Research Staff: Dr Mike Chandler

 

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