Notice of RetractionStudy on seepage model of coalbed methane based on threshold pressure gradient

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

The presenting author of this paper has the option to appeal this decision by contacting TPII@ieee.org.

Disadvantages of the coal seams in China are low permeability, low reservoir pressure and low gas saturation, which mean that the classical seepage model can´t adapt the gas reservoir completely because of variability of the fluid seepage. The threshold pressure gradient exists during the gas flowing in low permeability media based on the experiment using the RMT-150B Rock Mechanics Testing and the coal samples from Sijiazhuang coal mine. For seepage model decrypting the characteristics of the fluid migration accurately in the low permeability seam to guide production practices, based on the migration law of the coalbed methane (CBM), continuity equation of fluid and Darcy´s law, a three-dimensional, two phase flow seepage model considering threshold pressure gradient is presented to describe the characteristics of the fluid flow in low permeability seam. Finally the paper decrypts finite difference method to the model, which lays foundation for numerical simulation of CBM reservoir.