Abstract: Certain sugars, when exposed to high temperatures, undergo oxidation to produce acidic species. Certain sugar alcohols are also acid precursors. The acidification process is a function of temperature, salinity, pH, and/or the presence of an agent, such as an accelerator or a retarder. The rate of acidification may be controlled within a filter cake breaker fluid in order to achieve a predetermined fluid pH after a selectable period of time. The time controllable nature of the acidification allows the development of filter cake breaker fluids with an engineered activity delay.

Abstract: Certain sugars, when exposed to high temperatures, undergo oxidation to produce acidic species. Certain sugar alcohols are also acid precursors. The acidification process is a function of temperature, salinity, pH, and/or the presence of an agent, such as an accelerator or a retarder. The rate of acidification may be controlled within a filter cake breaker fluid in order to achieve a predetermined fluid pH after a selectable period of time. The time controllable nature of the acidification allows the development of filter cake breaker fluids with an engineered activity delay.

Abstract: A method of treating a wellbore comprises injecting into the wellbore a high density brine comprising water; an inorganic salt; and a polyol having at least four hydroxyl groups per molecule, the polyol being present in an amount effective to cause the high density brine to have a density of about 14.2 pounds per gallon to about 22 pounds per gallon; and to suppress the true crystallization point of the brine to about ?70° F. to about 70° F. at a pressure of about 0 to about 20000 psi determined according to API 13J.

Abstract: High density brine compositions may be formulated including water and at least one rare earth nitrate salt, where the at least one rare earth salt is present in an amount effective for the high density brine composition to have a density in the range of about 8.5 to about 21 pounds per gallon (about 1020 to about 2500 kg/m3). Suitable rare earth nitrate salts include, but are not necessarily limited to, lanthanum nitrate (La(NO3)3), cerium nitrate (Ce(NO3)3), scandium nitrate, and/or yttrium nitrate. Alkaline earth metal salts such as, but not limited to, calcium bromide (CaBr2), and alkali metal salts and metal salts may also be used with the rare earth nitrate salt(s). In one non-limiting embodiment the high density brines have an absence of zinc and cesium salts. These high density brine compositions may be suitably used for completion fluids in hydrocarbon recovery operations.