Abstract: Fluid producing or injecting wells may be treated with a water-in-oil emulsion for the removal or inhibition of unwanted particulates, including pipe dope, asphaltenes and paraffins. In addition, such emulsions are effective in the displacement of oil base drilling muds and/or residues from such muds from wells. The emulsion may also be used to break the interfacial and/or rheological properties of oil base mud and synthetic oil base mud filter cakes, and act as a demulsifier to break the water-in-oil emulsion present in such oil base and synthetic oil base muds. The water-in-oil emulsions may optionally contain a dispersing agent as well as a surfactant.

Abstract: A biodegradable water-in-synthetic oil base emulsion, effective in the removal of filter cakes, consists of an external phase of a surfactant emulsified in a paraffinic base oil. The emulsion is particularly effective in breaking-down the interfacial rheological properties of oil base mud and synthetic oil base mud filter cakes and acts as a demulsifier to break the water-in-oil emulsions present in such oil base and synthetic oil base muds.

Abstract: A method of reclaiming a well completion brine solution by using an organic chelant that is capable of discriminating between (i) iron and non-zinc heavy metals; and (ii) calcium and zinc. The chelant contains a functional group selected from the group —CO2H or —PO(OH)R20 or a salt or ester thereof, —C(O)—, —OE, —SE, —N?C(R2)R3, EO—N?C(R2)R3, —N(R2)R3, and —N(C(O)R1)R2 group optionally substituted with a —COOH or —PO(OH)R20 or a salt or ester thereof, —SE or —OE group, wherein R2 and R3 are independently selected from E or forms, with nitrogen, phosphorous, oxygen or sulfur, a heterocyclic ring; E is R1 or —H; R1 is a C1-C30 alkyl or aralkyl group or a derivative thereof and R20 is —OH or R1.

Abstract: A method of treating a well consists of introducing into the wellbore a biodegradable fluid system containing a blend of lactic acid ester, such as ethyl lactate, and a fatty acid ester, such as methyl soyate. The fluid system may be further in the form of a microemulsion that is formed by combining a blend with one or more emulsifiers, an alcohol, and water. The fluid system may be used in displacement, well remediation and stimulation as well as additional, alternative applications such as the cleaning of surface and/or downhole equipment.

Abstract: A method of treating a well consists of introducing into the wellbore a biodegradable fluid system containing a fatty acid ester, such as methyl soyate. The fluid system may further contain a lactic acid ester, such as ethyl lactate, and/or a nonionic surfactant. The fluid system may be used in displacement, well remediation and stimulation as well as additional, alternative applications such as the cleaning of surface and/or downhole equipment.

Abstract: A method of reclaiming a well completion brine solution by using an organic chelant that is capable of discriminating between (i) iron and non-zinc heavy metals; and (ii) calcium and zinc. The chelant contains a functional group selected from the group —CO2H or —PO(OH)R20 or a salt or ester thereof, —C(O)—, —OE, —SE, —N?C(R2)R3, EO—N?C(R2)R3, —N(R2)R3, and —N(C(O)R1)R2 group optionally substituted with a —COOH or —PO(OH)R20 or a salt or ester thereof, —SE or —OE group, wherein R2 and R3 are independently selected from E or forms, with nitrogen, phosphorous, oxygen or sulfur, a heterocyclic ring; E is R1 or —H; R1 is a C1-C30 alkyl or aralkyl group or a derivative thereof and R20 is —OH or R1.