Abstract
It has been observed over the years that shale gas production modeled with conventional simulators/models is much lower than the actually observed field data. Generally reservoir and/or stimulated reservoir volume (SRV) parameters are modified (without much physical support) to match the production data. Instead of modifying the reservoir parameters without physical support, we aim to investigate the shale closely and see if we are missing some vital part in the flow physics.
Shale is a complex unconventional reservoir with a significant organic fraction. Traditionally, it is perceived that the gas is stored in pore space and adsorbed on pore surfaces. In this work, we postulate that significant amount of gas is also stored in the bulk of organic matter or kerogen. We show a conceptual model of one shale pore and model the flow behavior taking into account the free gas (stored in natural fractures and nanopores), adsorbed gas, and gas dissolved in kerogen. Therafter, we upscale the model to a laboratory scale sample. We propose a numerical model for the complex "quad" porosity system while also accounting for non Darcy flow in shale nanopores. We then calibrate the model against a laboratory experimental data. This laboratory scale model can be upscaled suitably for field scale simulation of shale reservoirs.
