Water blockage is a common phenomenon that significantly deteriorates well deliverability. It is caused by introduction of external water in critical matrix which changes parent saturations thus damaging relative permeability to oil or gas. This paper discusses the case of a gas well that suffered complete loss of production due to water blockage which, however, was later successfully treated and revived using alcohol based recipe.

The well K-1 was drilled By UEP in Sindh, Pakistan and encountered hydrocarbon hearing BS-1 and BS-2 Sands. The well was put on commingle production from BS-1 & BS-2. After few months of production, water breakthrough was observed from BS-2 and was subsequently isolated, based on production logging results, using mechanical plug. However, well behavior indicated integrity issue of mechanical plug with well ceased to flow from BS-1. Attempts to revive the well proved futile as K-1 did not revive. Detailed investigations identified that well loaded up due to cross flow of BS-2 water into BS-1 resulting in water blockage.

In order to treat water blockage, alcohol based system was used. It is a volatile non-aqueous solvent which basically lowers the surface tension of acid and thereby achieves deeper penetration into rock matrix. Alcohol based recipe proved successful in curing water blockage and reviving the well's production.

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