Many different types of crude oils are extracted from Mexican reservoirs, and most of the crude oils from the northern region are heavy crude oil with API gravity between 15 and 20. Many fields in this area are mature and have been intervened as long as 50 years ago. As a consequence, the identification of the damage and selection of the right treatment is challenging for those wells. Furthermore, the type of completion used does not allow the use of production assemblies for intervention.

Traditional treatment techniques consist of reverse circulation using coiled tubing. In the first treatments, the majority used hot oil in cycles and BTEX solvents. Several of the interventions were not successful, and the logistics process was complicated. In some cases, the treatment led to asphaltenes deposition and emulsion blockages in the near-wellbore region.

Mesophase fluids based on microemulsion technology are a viable alternative remediation system for wellbore cleanup when low-producer wells experienced intervention. The fluids are carefully designed, have ultra-low interfacial tension, high oil solubilization, and good compatibility with formation fluids. They can be used to mobilize trapped fluids and solids in damaged wells, remove water blocks and in-situ emulsions, to name a few of their benefits. After many applications in Mexico and other countries, experience shows this fluids technology leads to more productive oil and gas wells because they can be remediated or protected from damage. Mesophase fluids are differentiated from conventional technologies by composition, their mechanism, and application. These novel fluids have low or no aromatics content or other solvents and easily diffuse through the formations. The application of the technology involves a carefully designed treatment train based on pills. The pills circulate from the annulus to the string assembly or reverse circulate to displace the fluids rapidly. The treatment is pumped close to the pay zone, with a radial fluid invasion of 1 to 2 feet into the formation, and then is allowed to soak overnight. More than 20 applications confirm the success of this technology in remediating heavy crude oil wells. In some cases the production increased by a 100%.

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