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The difficulty is knowing the breakthrough saturation for a formation without lab data from samples from that formation. There are conflicting opinions about how to estimate breakthrough saturation:

The difficulty is knowing the breakthrough saturation for a formation without lab data from samples from that formation. There are conflicting opinions about how to estimate breakthrough saturation:

* Thomas et al.<ref name=ch09r62 />), Schowalter<ref name=ch09r54 />), and general industry opinions suggest oil or gas migration through plug-size samples occurs at nonwetting phase saturations of about 10% (4-17%), i.e., that the largest 10th percentile of pore throats controls breakthrough.

* Thomas et al.,<ref name=ch09r62 /> Schowalter,<ref name=ch09r54 /> and general industry opinions suggest oil or gas migration through plug-size samples occurs at nonwetting phase saturations of about 10% (4-17%), i.e., that the largest 10th percentile of pore throats controls breakthrough.

* Catalan et al.<ref name=ch09r8 />) observed breakthrough saturations of 4-20% in pack experiments. Relative permeability analysis of core plugs shows the first nonwetting phase flow occurs at approximately the same saturations for most rocks.

* Catalan et al.<ref name=ch09r8 /> observed breakthrough saturations of 4-20% in pack experiments. Relative permeability analysis of core plugs shows the first nonwetting phase flow occurs at approximately the same saturations for most rocks.

* Other workers (Alan Byrnes, personal communication, 1995) have observed breakthrough in plug samples at highly variable saturations—sometimes more than 50%.

* Other workers (Alan Byrnes, personal communication, 1995) have observed breakthrough in plug samples at highly variable saturations—sometimes more than 50%.