Usually means a sum of effective porosity and additional rock volume occupied by some minerals which are seen as porosity development by some reservoir data logs:
| \phi_t = \phi_e + \phi_{\rm {minerals}} |
For example, the neutron porosity sees shales as porosity development and can be considered as total porosity as against the effective porosity which contains hydrodynamically connected fluid volumes:
| \phi_n = \phi_e + \phi_{sh} |
Since the term does not specify the meaeument phsyics to which it relates it is not advise for the usage outside the context