Ninety-eight per cent of the total cumulative production from the Cabimas Field has originated from Miocene reservoirs. The difference in density between Miocene oil and water is very small. In addition, this crude oil has a tendency to wet the surfaces of the reservoir rock. Under these conditions, a water- in-oil emulsion, and thus higher viscosities are favoured; this in turn impairs the well production capacity. Three wells were selected (R-A1, R-A2, and R-A3) for the treatment of hidden emulsions with the use of a wetting agent in an organic solvent system.

Another factor that was thought to impair the well production capacity was plugging of the Miocene slotted-liner gravel-packed completions by organic solids which are present. For considering this problem separately, two further wells (R-B1 and R-B2) were treated only with an organic solvent system.

Treatment preparation and pump operation (between 250 and 400 bbl/well) for all five wells were completed in a single week. All of these field operations were simple and were carried out with no operational or safety problems.

Thus, the use of the wetting agent proved to be a successful method for breaking hidden emulsions. Two of the wells treated in this manner, R-A2 and R-A3, respond with an increase in the fluid production rate. An exception was well R- A1; this negative result was due to the existence of a thief zone that fails to receive enough treatment fluid. Wells treated with organic solvents only did not show any change in production rate.

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