Well EM-0014 is one of the six pilot wells where GreenZyme® was tested between 2013 and 2014 in the Neuquen Basin. El Mogotito field is located in the southern section of the basin. It was discovered in 1966. A total of 10 wells have been drilled to date, 6 have been abandoned, 3 are shut in due to resulting uneconomic and only 1 is on production (EM-0014).
Well EM-0014 was drilled and completed to the Lotena Formation, where the reservoirs are composed of a series of poorly selected conglomerates with inter bedded fine to coarse sandstone. Porosity ranges between 10 and 15%. Drive mechanism is mainly a strong aquifer. Reservoir fluid characteristics: gravity 26 °API oil; wax content 34%; asphaltene content 3.3%. The well was put on production in April 2007 with an IP of 185 bopd and a 50% water cut.
There was historical evidence that paraffin build-up in the wellbore had caused production blockage. This well has a record of a hot-oil clean up job performed on the well as well as another one done on the line leading to the battery. At the beginning of 2014, a steep and sudden decline of oil production was evidenced. The oil production dropped close to 60% in four months, from 16 bopd to 6 bopd. The well was selected as a GreenZyme® candidate a few months earlier, so it proved to be an excellently timed situation.
Well EM-0014 was treated with a GreenZyme® solution in early May 2014 under YPF/Apache management transition. The well was kept shut-in for four days to allow soaking and diffusivity of the enzyme solution. Oil production returned slowly to its normal rate. A couple of months later it surpassed the normal rate by 12%.
An interesting fact is that the SRP system was working with a timer before the treatment. When the well was brought back online, the timer was no longer needed due to the improvement in the dynamic fluid level, clear indication of the ability of the enzyme molecule to allow for movement of all reservoir fluids by detaching oil that was promoting a restrictive flow environment.
The GreenZyme® treatment on this well proved to be a success. If the well had not been treated, it would have turned uneconomic in under 7 months (see production graph). The GreenZyme® treatment not only normalized production by removing the paraffin blockage, but it also extended the life of the well. Cumulative incremental oil production as of 31/1/18, 44 months after treatment with GreenZyme®, amounts to 18,905 barrels of oil.