Gels are used worldwide to control water co-production in gas and oil wells (WSO treatments) but the criticality of a correct placement in the Italian scenario had strongly limited their use in this Country. For instance, in gravel packed wells or in wells where the "ID casing/ID tubing" ratio is over 2.5, inflatable packers cannot be efficiently used for gel diversion; moreover, dual injection has to be usually applied with these tools, making a treatment very often too expensive and, as a result, unacceptable.

A review of water problems and displacement data collected during past matrix treatments performed in Italian gas fields led to the study of possible alternatives for treatments to be performed using standard crosslinked polymer and unusual displacement techniques. Relative Permeability Modifier (RPM) polymers were also considered and lab tested for WSO in shaly sands because the use of gels is still considered too risky. In fact, most of the treatments performed in Italy have to be performed bullheading in order to reduce the cost of the operations, making WSO treatments more attractive.

In this paper a brief summary of laboratory activities for a correct selection of polymers and gels, suitable for shaly, low permeability sands are reported as well as field treatments data and results.

Bullheading technique seems to be the only cost-effective and field proven placement method for rigless WSO treatments to produce marginal gas reserves from shaly, depleted, low temperature, multilayered reservoirs.

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