This chapter discusses chemical methods to control water and gas production. Some of these techniques can be used to shut off either water or gas.

As oilfields mature, they produce increasing quantities of water. Handling such large volumes of water is an expensive business and can even cause bottlenecking at the surface-processing facilities. One report published in 2007 illustrated the cost using a typical North Sea field of 50 wells, with each well producing 5,000 bbl of water per day. If the cost of treating each barrel is $0.50, the daily water-handling cost for the oilfield would equate to $125,000, ($45.6 million per annum).1 Water production costs are not just associated with handling the water. Water production can cause scale formation, fines migration, sandface failure, corrosion of tubulars, and even kill wells by hydrostatic loading. Thus, it pays to defer water production for as long as possible.2-3

The most common techniques for shutting off water-producing zones are mechanical isolation, cement squeezing, and polymer gel treatments, which require zonal isolation. Disproportionate permeability reducer (DPR) or relative permeability modifier (RPM) treatments can be bullheaded, and so they are an alternative to zonal isolation treatments.