Abstract: A treatment fluid and process for enhancing hydrocarbon production from a shale formation using a treatment fluid comprising a water soluble delayed release carbonate-dissolving agent and introducing the treatment fluid into the shale formation after or as part of a hydraulic fracturing process.

Abstract: The invention relates to in-situ acidizing processes that involve the dissolution of an acid-soluble material. Treatment fluids have been identified that can effectively dissolve acid-soluble materials at low temperatures, such as temperatures of 30° C. or lower. In some embodiments, the processes may also be usefully employed at higher temperatures. The processes and treatment fluids of the invention can advantageously be used to dissolve acid-soluble materials, including filter cakes, in underground formations.

Abstract: The present invention relates to a process for treating formation damage in an underground formation, including damage in the form of an oil-based drill-in fluid filter cake. The process makes use of a treatment fluid that contains a cyclodextrin or a starch and an enzyme capable of generating a cyclodextrin from the starch.

Abstract: The present invention relates to processes for consolidating an underground formation with a consolidating mineral. The consolidating material is a carbonate and is produced from an alkaline treatment fluid containing, in at least some embodiments, environmentally friendly and inexpensive components. In one embodiment, the process can be applied to consolidation of an underground formation during or following drilling. The present invention also provides a treatment fluid suitable for use in such processes.

Abstract: The present invention relates to processes for consolidating an underground formation with a consolidating mineral. The consolidating material is a carbonate and is produced from an alkaline treatment fluid containing, in at least some embodiments, environmentally friendly and inexpensive components. In one embodiment, the process can be applied to consolidation of an underground formation during or following drilling. The present invention also provides a treatment fluid suitable for use in such processes.

Abstract: A process for disrupting filter cake in an underground formation, which process comprises: (i) incorporating into a treatment fluid a solid polymer capable of being converted by hydrolysis into one or more organic acids; (ii) introducing the treatment fluid into the underground formation; and (iii) allowing the solid polymer to hydrolyse in the presence of water to produce organic acid such that acid soluble material within the filter cake or adjacent formation is dissolved.

Abstract: An underground formation is consolidated by (a) incorporating into a treatment fluid (i) at least one chemical substance which is capable of undergoing a chemical change that alters the physico-chemical environment of the treatment fluid and which is a bicarbonate or a compound that generates a phosphate, phosphoric acid, sulphate, sulphuric acid, hydrogen sulphide, S2?, carbon dioxide, bicarbonate, base or acid; and, optionally, (ii) at least one additional chemical substance selected from salts and complexes of metals having a valency of 2 or higher; introducing the treatment fluid into the formation; and allowing the chemical substance (i), alone or in combination with the optional chemical substance (ii), to undergo a chemical change that alters the physico-chemical environment of the treatment fluid such that a consolidating mineral is deposited in the underground formation.

Abstract: A process is disclosed for treating an underground formation, which process comprises: (a) introducing into the underground formation a micellar dispersion comprising water, one or more organic acid precursors, one or more surfactants and, optionally, one or more salts, co-surfactants and/or organic liquids that are not organic acid precursors; and (b) allowing (i) the micellar dispersion to solubilize hydrocarbons, emulsions or water blocks present in the underground formation, and (ii) at least a portion of the organic acid precursor to hydrolyze in-situ to produce sufficient organic acid to substantively dissolve acid soluble material present in or adjacent to filter cakes or other damage in the underground formation.

Abstract: A process for producing a self-disrupting filter cake in an underground formation, which process comprises: (a) incorporating into a drilling fluid a solid polymer capable of being converted by hydrolysis into one or more organic acids; (b) using the drilling fluid to drill a wellbore into the underground formation such that the solid polymer in the drilling fluid contributes to the formation of a filter cake; and (c) allowing the solid polymer to hydrolyse in the presence of water and to disrupt the integrity of the filter cake. A drilling fluid which contains as a bridging agent one or more solid polymers capable of being converted by hydrolysis into one or more organic acids is also provided.

Abstract: A process for forming a gel, which process comprises mixing an alkaline silicate solution with a polymer in solid form, the polymer being capable of being converted by hydrolysis into one or more organic acids; and allowing the polymer to release sufficient acid to cause formation of a silicate gel.

Abstract: A process is disclosed for treating an underground formation, which process comprises: (a) introducing into the underground formation a micellar dispersion comprising water, one or more organic acid precursors, one or more surfactants and, optionally, one or more salts, co-surfactants and/or organic liquids that are not organic acid precursors; and (b) allowing (i) the micellar dispersion to solubilise hydrocarbons, emulsions or water blocks present in the underground formation, and (ii) at least a portion of the organic acid precursor to hydrolyse in-situ to produce sufficient organic acid to substantively dissolve acid soluble material present in or adjacent to filter cakes or other damage in the underground formation.

Abstract: A process for disrupting filter cake in an underground formation, which includes (i) incorporating into a treatment fluid a solid polymer capable of being converted by hydrolysis into one or more organic acids; (ii) introducing the treatment fluid into the underground formation; and (iii) allowing the solid polymer to hydrolyze in the presence of water to produce organic acid such that acid soluble material within the filter cake or adjacent formation is dissolved.

Abstract: A method for treating an underground reservoir, which method comprises introducing into the reservoir a treatment fluid comprising, dissolved or dispersed in water, an ester and a polymer breaker, such that the ester hydrolyses to produce an organic acid to dissolve acid soluble material present within the reservoir and the polymer breaker degrades polymeric material present within the reservoir.

Abstract: A method for treating an underground reservoir, which method comprises introducing into the reservoir a treatment fluid comprising, dissolved or dispersed in water, an ester and a non-enzyme catalyst capable of increasing the rate of hydrolysis of the ester, such that the ester hydrolyses to produce an organic acid to dissolve acid soluble material present within the reservoir.

Abstract: A method of precipitating or depositing material within an underground reservoir which comprises introducing into the reservoir in aqueous solution (i) an isolated enzyme and (ii) a substrate for the enzyme, such that the action of the enzyme on the substrate leads to the precipitation or deposition of material within the underground reservoir.

Abstract: A crosslinked water-based gel, for example a gel plug in an underground rock formation or a pipeline, is broken by an enzyme and a substrate which is capable of being converted by the enzyme into an organic acid which breaks down the gel. The enzyme is allowed to catalyze the conversion of the substrate into the acid to cause the breakdown of the gel.

Abstract: A method of acidising an underground reservoir comprisesa) injecting into the reservoir (i) a substrate for an enzyme, which substrate is capable of being converted into an organic acid by the enzyme, and (ii) the enzyme; andb) allowing the enzyme to catalyse the conversion of the substrate into the acid.