Abstract: The present invention relates to the use of solutions containing glutamic acid N,N-diacetic acid or a salt thereof (GLDA) and/or methylglycine N,N-diacetic acid or a salt thereof (MGDA) in treating subterranean formations, wherein the solutions contact carbon steel-containing equipment, and to a system containing a carbon steel-containing material in contact with a solution containing glutamic acid N,N-diacetic acid or a salt thereof (GLDA) and/or methylglycine N,N-diacetic acid or a salt thereof (MGDA), at elevated temperatures and/or employing carbon steel types as usually found in subterranean formations.

Abstract: The present invention relates to a process for fracturing a subterranean formation comprising a step of fracturing the formation and a step of introducing a treatment fluid containing glutamic acid N,N-diacetic acid or a salt thereof (GLDA), methylglycine N,N-diacetic acid or a salt thereof (MGDA) and/or N-hydroxyethyl ethylenediamine N,N?,N?-triacetic acid or a salt thereof (HEDTA) into the formation, wherein the fracturing step can take place before introducing the treatment fluid into the formation, while introducing the treatment fluid into the formation or subsequent to introducing the treatment fluid into the formation.

Abstract: The present invention relates to process to reduce the corrosion of equipment containing a chromium-containing alloy in the oil and/or gas industry, comprising a step of contacting the equipment based on a chromium-containing alloy with a solution containing at least 1 wt % on total weight of the solution of glutamic acid N,N-diacetic acid or a salt thereof (GLDA) and/or methylglycine N,N-diacetic acid or a salt thereof (MGDA) having an acidic pH, the use of the above solutions in equipment containing a chromium-containing alloy to reduce corrosion, and to a system containing a piece of equipment used in the oil and/or gas industry made at least partly from chromium-containing alloy in contact with an acidic solution containing at least 1 wt % of glutamic acid N,N-di acetic acid or a salt thereof (GLDA) and/or methylglycine N,N-di acetic acid or a salt thereof (MGDA).

Abstract: Disclosed is a two-stage filter cake removal composition, and method of use thereof, for use in a wellbore for controlled removal of a filter cake present in a target production zone. The two-stage filter cake removal composition may include an enzyme present in an amount of between about 1% and 10%, and a glycolic acid in amounts of between about 1% and 10% by weight. Optionally, hydrochloric acid may be added to the glycolic acid, in an amount of about 1 and 5% by weight. The two-stage filter cake removal composition, when the enzyme is applied to the filter cake in the target production zone in a first stage and the glycolic acid is applied to the filter cake in the target production zone in a second stage, is operable to remove the filter cake in the target production zone over a predetermined extended reaction time.

Abstract: The present invention relates to a process for treating a subterranean formation wherein a fluid containing an ammonium salt of glutamic acid N, N-diacetic acid (GLDA) or methylglycine N, N-diacetic acid (MGDA) is introduced into the formation.

Abstract: The present invention relates to a process to control iron in a subterranean formation wherein a fluid containing glutamic acid N,N-diacetic acid or a salt thereof (GLDA) and/or methylglycine N,N-diacetic acid or a salt thereof (MGDA) is introduced into the formation at a temperature between 77 and 400° F. (about 2 and 204° C.). The invention also covers a process of treating a subterranean formation wherein simultaneously iron control takes place.

Abstract: The present invention relates to a process for treating a sandstone formation comprising introducing a fluid containing glutamic acid N,N-diacetic acid or a salt thereof (GLDA) and having a pH of between 1 and 14 into the formation. The invention in addition relates to a fluid and a kit of parts suitable for use in the above process containing glutamic acid N,N-diacetic acid or a salt thereof (GLDA), a corrosion inhibitor, a surfactant, and optionally a mutual solvent.

Abstract: The present invention covers a fluid and kit of parts suitable for treating carbonate formations containing glutamic acid N,N-diacetic acid or a salt thereof (GLDA) and/or methylglycine N,N-diacetic acid or a salt thereof (MGDA), a corrosion inhibitor, and a surfactant, and the use thereof.

Abstract: The present invention relates to a process for treating a sandstone formation comprising introducing a fluid containing glutamic acid N,N-diacetic acid or a salt thereof (GLDA) and/or methylglycine N,N-diacetic acid or a salt thereof (MGDA) and having a pH of between 1 and 14 into the formation. The invention in addition relates to a fluid suitable for use in the above process containing 5-30 wt % of glutamic acid N,N-diacetic acid or a salt thereof (GLDA) and/or methylglycine N,N-diacetic acid or a salt thereof (MGDA), a corrosion inhibitor, a surfactant, and a mutual solvent.

Abstract: The present invention includes processes to create wormholes in carbonate reservoirs by contacting a formation with a solution comprising glutamic acid N,N-diacetic acid (GLDA) and/or a salt thereof, methylglycine-N,N-diacetic acid (MGDA) and/or a salt thereof, or a combination thereof. The present invention also includes processes to remove wellbore damage in a carbonate reservoir by contacting a damaged zone of the carbonate reservoir with a solution comprising GLDA and/or a salt thereof, methylglycine-N,N-diacetic acid (MGDA) and/or a salt thereof, or a combination thereof. The present invention further includes solutions comprising a salt and further comprising GLDA and/or a salt thereof, methylglycine-N,N-diacetic acid (MGDA) and/or a salt thereof, or a combination thereof.

Abstract: A method and composition for protecting cement surfaces in a well bore treatment zone from the destructive effects of acid mud and other acidization processes commonly used to stimulate hydrocarbon production from the formation, includes contacting the cement with an aqueous acid mixture of HAc and HF in a mutual solvent for a sufficient period of time to form a protective deposit or precipitate layer that is resistant to the acidization composition. In a preferred embodiment, the aqueous acid mixture includes corrosion inhibitors and inhibitor aids, and a preflush with an ammonium chloride solution in a mutual solvent is used to prepare the cement surfaces in the treatment zone.

Abstract: A method and composition for protecting cement surfaces in a well bore treatment zone from the destructive effects of acid mud and other acidization processes commonly used to stimulate hydrocarbon production from the formation, includes contacting the cement with an aqueous acid mixture of HAc and HF in a mutual solvent for a sufficient period of time to form a protective deposit or precipitate layer that is resistant to the acidization composition. In a preferred embodiment, the aqueous acid mixture includes corrosion inhibitors and inhibitor aids, and a preflush with an ammonium chloride solution in a mutual solvent is used to prepare the cement surfaces in the treatment zone.

Abstract: A method and composition for protecting cement surfaces in a well bore treatment zone from the destructive effects of acid mud and other acidization processes commonly used to stimulate hydrocarbon production from the formation, includes contacting the cement with an aqueous acid mixture of HAc and HF in a mutual solvent for a sufficient period of time to form a protective deposit or precipitate layer that is resistant to the acidization composition. In a preferred embodiment, the aqueous acid mixture includes corrosion inhibitors and inhibitor aids, and a preflush with an ammonium chloride solution in a mutual solvent is used to prepare the cement surfaces in the treatment zone.

Abstract: A method and composition for protecting cement surfaces in a well bore treatment zone from the destructive effects of acid mud and other acidization processes commonly used to stimulate hydrocarbon production from the formation, includes contacting the cement with an aqueous acid mixture of HAc and HF in a mutual solvent for a sufficient period of time to form a protective deposit or precipitate layer that is resistant to the acidization composition. In a preferred embodiment, the aqueous acid mixture includes corrosion inhibitors and inhibitor aids, and a preflush with an ammonium chloride solution in a mutual solvent is used to prepare the cement surfaces in the treatment zone.

Abstract: Sealing a zone in a subterranean well-formation is effected with an aqueous silicate solution containing an alkali metal silicate, at least one activator and a mixture of a chelating agent and a phosphonate. This composition greatly increases the divalent ion tolerance of the silicate gelling system.