There is a large number of various pressure diffusion models.

The popular classifications are summarized below:

Number of phases	Number of wells	Solver type	Spatial dimension
Single-phase	Single-well	Analytical Linear	0D
Multi-phase	Multi-well	Analytical Pseudo-Linear	1D
		Numerical Linear	2D
		Numerical Non-Linear	3D

In many practical cases a pressure diffusion process is honouring some PDE with constant coefficients availing a number of very efficient computational and diagnostic techniques:

Time Convolution	Spatial Superposition
Pressure convolution model	Pressure superposition model
Pressure deconvolution model	Pressure decomposition model

In some cases a pressure diffusion process can be fairly approximated by a hybrid model based on PDE with constant coefficients and PseudoPressure and PseudoTime.

There is a number of specific pressure diffusion models which represent the key practical scenarios of pressure diffusion and play important academical and practical role:

	Transient flow	Steady-State (SS) flow	Pseudo-Steady State (PSS) flow
Radial flow	Radial Flow Pressure Diffusion @model	Steady State Radial Flow Pressure Diffusion @model	Pseudo-Steady State Radial Flow Pressure Diffusion @model
Linear flow	Linear Flow Pressure Diffusion @model	Steady State Linear Pressure Diffusion @model	Pseudo-Steady State Linear Pressure Diffusion @model

See also