Myrna, my daughter has low low low porosity hair and we had no luck sealing with oil ( grape seed oil works somewhat on low dew days), her hair just does not absorb it and leaves a greasy oily sheen.
We have dews in the high 60's lately and her hair was a big poof ball, with no clue what else to try used EverSleek Humidity Defying Leave-In Creme by loreal and the transformation was awesome. She has waist length hair when wet and she put 3 pumps in soaking wet hair and followed up with a spray gel which left her with frizz free well defined curls for 2 days ( she usually washes every day because she is a very active 13 year old ).
My high porosity hair loves this stuff too, but I would never have thought it would work so well on low porosity hair.
2c/3a cg 01/10/13

Hair Properties: low( first 4 inches) / high porosity, medium density, fine/medium texture Climate : hot humid summer, coastal GA

Co-wash: Suave Naturals Coconut / Everlasting Sunshine, V05
Rinse out :Tresemme Naturals Nourishing Moisture, VO5 ocean refresh
Gel: La Looks sport, Volumax mega gel,Biosilk Rock Hard gel my HG

Love ACV , pedaheh's gelatin treatment
My hair hates everything Deva curl and Curl Keeper,