According to the RAE: Union, analogy or conformity with which some things are linked or correspond to each other; P. Eg, the union of the vine and the elm, the good correspondence of two or more colors, etc.
The word pairing is controversial in itself, since many see with some suspicion, the similarity between marriage and this word. Other experts, critics and amateurs prefer the terms “harmony” or “chord”.
The marriage between oil and food is the process of metaphorically marrying a food with an oil with the intention of enhancing the pleasure of eating them.
In: Dossier with recipes from the campaign “Olive oils, a whole experience”, which took place in Spain in 2015, financed with the help of the European Union and the Ministry of Agriculture, Food and Environment of Spain, Proposal of marriage with the main varieties of olives, with which we are not 100% of agreement, because it does not take into account the moment and the area of collection.
A good link where oil type typology is described, and a proposal for a pairing of Ólea.