In this field, a polysaccharide polymer is often used to either fracture the rock or form a filter cake. After
US 5,253,711 claims the addition of calcium or magnesium peroxide
as a component of a fracturing fluid. The products are then activated
by heat. Magnesium peroxide achieves a delayed break at high temperatures
whereas lower temperatures activate calcium peroxide.
US 200,309,251 and US 6,488,091 claim the use of calcium or magnesium peroxide in fracturing fluids of different compositions and processes.
US 5,624,886 claims the use of alkaline earth metal peroxides for fracturing of subterranean formation. The products are granulated into a pellet or prill.
US 5,238,065 claims the destruction of filter cakes using solutions
containing calcium or magnesium peroxide together with an acid. The
acid activates the peroxide at the desired time.
US 5,697,905 and US 6,494,263 claim the incorporation of magnesium peroxide as a breaker in different filter cake compositions. At the appropriate time, an activator solution is used to release hydrogen peroxide from magnesium peroxide.
US 6,138,760 claims the incorporation of magnesium peroxide in a pretreatment fluid which is introduced prior to the polymer containing fluid. This enhances degradation of the polymer in the filter cake from the reservoir side of the filter cake during flow back of the treatment fluid.
WO 03,054,109 claims the encapsulation of an inorganic peroxide in order to improve its stability while embedded in the filter cake and reduce premature degradation of the polymer. At the appropriate time, pH is decreased in order to activate the inorganic peroxide.