Wettability

Logic provides a value for n in non-strongly water wet reservoirs

A value for mixed wettability n: Many oil reservoirs have mixed wettabilities. These will have Sw’s below those implied from conventionally cleaned, strongly water wet, capillary pressure Sw-Ht data. If we reverse calculate n from these high capillary pressure Sw’s using log data, n will be high: we shall be assuming a higher Sw for the logged resistivity. Conversely, the conventionally cleaned and hence strongly water wet special core analysis electrical n values on these same plugs will be low: water wet systems have low n’s, n will be low. These two observations provide a means to constrain n and largely overcome your worries in mixed wet reservoirs. This information is probably sitting quietly behind you on your shelf, right now.  Can you hear it?