Technical Paper: Successful innovative water-shutoff operations in low-permeability gas wells

Society: SPE
Paper Number: 105262
Presentation Date: 2007
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Water production from gas producing wells characterized by low productivity and low reservoir pressure zones can prematurely kill wells, leading to a considerable loss in recoverable reserves. In some cases, mechanical techniques provide a viable solution for shutting off water production, although often, such a solution will create a restriction inside the well, limiting access to deeper reservoir layers.

Even though chemical water shutoff chemicals and techniques are improving significantly, not many options are available to treat high temperature and low permeability reservoirs. It may prove difficult to squeeze cement slurries and different types of gels into such formations owing to constraints of particle sizes or fluid viscosity. It is a challenge to get a squeezable fluid into low-permeability reservoirs that will be effective in sealing the near-wellbore area and be able to withstand high differential pressure while producing. Another challenge is to determine a placement technique to prevent excess displacement of the treatment, to minimize further intervention into the well, to clean any residual treatment from the tubing, and to minimize water damage to highly sensitive producing layers.

This paper presents successful case histories of treatments that were performed to shut off water producing layers characterized by low permeability. It describes innovative techniques that were developed for this special project. The treatments were placed using coiled tubing, and only one run was required to shut off the zones in question.

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