The present disclosure relates to biocide compositions, formulations and methods for using formulations. In particular the present disclosure relates to biocide compositions and their use in effecting biocidal activity in subterranean oil and gas wells being drilled, completed, worked over or produced.

A method for the fracking or stimulation of a hydrocarbon-bearing formation, said method comprising the steps of: providing a wellbore in need of stimulation; inserting a plug in the wellbore at a predetermined location; inserting a perforating tool and a spearhead or breakdown acid into the wellbore; positioning the tool at said predetermined location; perforating the wellbore with the tool thereby creating a perforated area; allowing the spearhead acid to come into contact with the perforated area for a predetermined period of time sufficient to prepare the formation for fracking or stimulation; removing the tool from the wellbore; and initiating the fracking of the perforated area using a fracking fluid. Also disclosed is a corrosion inhibiting composition for use with the acid composition.

The invention is directed to hydrophilic and hydrophobic superparamagnetic nanoparticles and their use as contrast agents for NMR including agents that distinguish oil and water in NMR logging of geological formations containing oil or water. Methods of making these SPIONs are also described.

A drilling fluid comprises one or more deep eutectic solvents in an amount greater than or equal to 70 wt. % based on the total weight of the drilling fluid. Each deep eutectic solvent comprises at least one hydrogen bond acceptor compound and at least one hydrogen bond donor compound. A molar ratio of the total moles of the hydrogen bond donor compounds to the total moles of the hydrogen bond acceptor compounds in each deep eutectic solvent is from 0.1 to 1.0. The drilling fluid has a density greater than or equal to 200 kg/m3. The drilling fluid has a viscosity greater than or equal to 0.5 Pa.Math.s when measured at 25° C. Methods for drilling wells in subterranean formations using the drilling fluid are also disclosed.

The invention is directed to hydrophilic and hydrophobic superparamagnetic nanoparticles and their use as contrast agents for NMR including agents that distinguish oil and water in NMR logging of geological formations containing oil or water. Methods of making these SPIONs are also described.

A modified drilling mud includes a drilling mud selected from a group consisting of water-based mud (WBM), oil-based mud (OBM) and synthetic-based mud (SBM), and a liquid treatment composition including water and collectively 35-55 weight percent of one or more hydroxide compounds, wherein a ratio of the liquid treatment composition to the drilling mud in the modified drilling mud is in a range of 10 gallons of the liquid treatment composition per 42,000 gallons of drilling mud to 100 gallons of the liquid treatment composition per 42,000 gallons of drilling mud.

Methods for the fracking or stimulation of a hydrocarbon-bearing formation are provided in multiple embodiments. According to one method, it comprises the steps of: providing a wellbore having a casing; inserting a plug in the wellbore at a predetermined location; inserting a perforating tool and an acidic composition into the wellbore; wherein the acidic composition includes a corrosion inhibiting composition comprising at least two compounds selected from: Group A-I, and wherein at least two compounds are selected from different groups of the Groups A-I.

The invention includes methods for stimulating a hydrocarbon-bearing formation by perforating a wellbore and introducing an acidic composition in the wellbore. A preferred embodiment includes inserting an isolation plug in the wellbore at a predetermined location followed by inserting a perforating tool and a breakdown acid into the wellbore. The wellbore is perforated by the tool to create a perforated area. The breakdown acid is allowed to come into contact with the perforated area for a predetermined period of time sufficient to prepare the formation for stimulation. The tool is then removed from the wellbore wherein stimulation of the perforated area is thereby initiated. Also disclosed is a corrosion inhibiting composition for use with the acidic composition.

A composition of matter includes a core-shell quantum dot particle having an inorganic core and an organic shell and drilling fluid. A method includes introducing a core-shell quantum dot particle having an inorganic core and a polymer shell into a drilling fluid, circulating the drilling fluid through a well during a drilling operation that creates formation cuttings such that the core-shell quantum dot particle interacts with the formation cuttings, creating tagged cuttings, collecting returned cuttings from the circulating drilling fluid at a surface of the well, detecting the presence of the core-shell quantum dot particle on the returned cuttings to identify the tagged cuttings, and correlating the tagged cuttings with a drill depth in the well at a time during the drilling operation.

Polyacrylamide (PAM)-coated nanosand that may be a relative permeability modifier (RPM) and that is applied to treat a wellbore in a subterranean formation. The treatment may be for excess water production. The PAM-coated nanosand is PAM-hydrogel-coated nanosand. The PAM-coated nanosand os nanosand coated with PAM hydrogel. The PAM hydrogel includes crosslinked PAM in water. Application of the PAM-coated nanosand may reduce water production from the subterranean formation into the wellbore. The PAM hydrogel of the PAM-coated nanosand may expand in a water zone of the subterranean formation to restrict water flow into the wellbore. The PAM hydrogel of the PAM-coated nanosand may contract in an oil zone of the subterranean formation so not to significantly restrict crude oil flow into the wellbore.