Fluid flow from matrix to fractures in Early Jurassic shales

Whitby Mudstone is a clay rich rock with a low porosity. The permeability of the Whitby Mudstone is in the range of 10− 18 m2-10− 21 m2. 2D microstructures of the Whitby Mudstone show no connected pore networks, but isolated pore bodies mainly situated in the clay matrix, whereas 3D data shows that connected pore networks are present in less compacted parts of the rock. A closely spaced interconnected fracture network is often required to speed up transport of fluids from the matrix into a producing well. For fluids within the matrix the nearest natural fracture is on average at a distance of approximately 10 cm in the Whitby Mudstone. The combination of the permeability data and the porosity data with natural fracture spacing of the fractures present in outcrops along the Yorkshire coast (UK) resulted in new insights into possible fluid pathways from reservoir to well.