Process for the removal of deposits from an oil or gas well, and/or from the surface structures, and/or from the equipment connected therewith, and/or from hydrocarbon bearing formations

A process for removing deposits, the process comprising:

• injecting at least one oil-in-water nanoemulsion into at least one space selected from the group consisting of an oil well, a gas well, a surface structure, and a hydrocarbon bearing formation;
• and
• leaving the at least one nanoemulsion in the space for from 1 hour to 10 days,
• wherein said oil-in-water nanoemulsion has a dispersed phase consisting essentially of an oil and a dispersing phase consisting essentially of water and at least one surfactant, and
• wherein said oil-in-water nanoemulsion is prepared according to a process comprising diluting a homogeneous water/oil mixture (1) in a dispersing phase consisting of water to which at least one surfactant (2) has been added,
• wherein:
• the homogeneous water/oil mixture (1) comprises water, in an amount ranging from 65% by weight to 99.9% by weight with respect to a total weight of the mixture (1), and at least two surfactants (1) having a different hydrophilic-lipophilic balance from one another, in amounts such that the mixture (1) is homogenous;
• an interface tension of the homogeneous water/oil mixture (1) is lower than or equal to 1 mN/m;
• the surfactants (1) and (2) are selected from the group consisting of a non-ionic surfactant, an anionic surfactant and a polymeric surfactant;
• and
• amounts of said dispersing phase and of said surfactant (2) are such that the oil-in-water nanoemulsion has a hydrophilic-lipophilic balance higher than that of the homogeneous water/oil mixture (1).