An aqueous suspension of polymer bodies is made by coalescing polymer from a flowing aqueous solution. These suspended bodies may be fibrous in appearance. However, the coalescence of the polymer bodies may be controlled to produce shapes. The coalesced polymer bodies are used for treating a downhole location within or accessed by a borehole. The bodies may be formed by coalescence at the surface and then pumped downhole or may be formed by coalescence downhole. Coalescence of polymer may result from crosslinking, complexing with material of opposite charge, or change in the polymer solution temperature, pH, solute concentration or solvent. The coalesced polymer bodies are maintained in aqueous solution after coalescence, and are not removed from solution for strengthening.

The present disclosure provides a drilling fluid lubricant and a preparation method and use thereof. The preparation method includes steps of: 1) mixing styrene and water, then adding a nano-inorganic intermediate, a crosslinking agent and an emulsifier and stirring to obtain a first mixture; 2) under an inert atmosphere, stirring the first mixture to obtain an intermediate emulsion; then heating the intermediate emulsion to 70-85° C., then adding an initiator, keeping temperature and stirring for 7-10 hours to obtain an emulsion of polystyrene nanocomposite with a particle size of 40-90 nm; the emulsion of polystyrene nanocomposite being sequentially subjected to a granulating treatment to obtain polystyrene nanocomposite particles; 3) mixing industrial base oil, polystyrene nanocomposite particles and industrial oleic acid, and stirring evenly at room temperature to obtain the drilling fluid lubricant.

One or more embodiments presently described are directed to drilling fluid compositions that include lubricants, methods for making the drilling fluids, and methods for drilling subterranean wells utilizing the drilling fluids. According to one embodiment, a drilling fluid composition may include a base fluid including water, a weighting agent in an amount of from 0.1 weight percent (wt. %) to 75 wt. % relative to the total weight of the water-based drilling fluid, and a lubricant in an amount of from 1 wt. % to 10 wt. % relative to the total weight of the water-based drilling fluid. The lubricant may include one or more alkyl esters and a fatty acid blend including one or more medium-chain fatty acids. The one or more medium-chain fatty acids may be at least 50 wt. % of the fatty acid blend.

In accordance with one or more embodiments of the present disclosure, a drilling fluid may include a base fluid and one or more formaldehyde-based resins. The drilling fluid may further comprise one or more water-soluble acid catalyst precursors or the reaction products of such water-soluble acid catalyst precursors. The base fluid may include an aqueous or non-aqueous solution. The present disclosure also describes sealed subterranean petroleum formations that include such drilling fluids and methods for sealing subterranean wellbores by utilizing such drilling fluids.

In accordance with one or more embodiments of the present disclosure, a drilling fluid may include a base fluid and one or more formaldehyde-based resins. The drilling fluid may further comprise one or more water-soluble acid catalyst precursors or the reaction products of such water-soluble acid catalyst precursors. The base fluid may include an aqueous or non-aqueous solution. The present disclosure also describes sealed subterranean petroleum formations that include such drilling fluids and methods for sealing subterranean wellbores by utilizing such drilling fluids.

Waste water is remanufactured with ozone in a series of mixing vessels. The ozone is dispersed to both a top and a bottom portion of each mixing vessel, but in different amounts. This creates an electrical potential difference across the height of each mixing vessel which significantly improves the oxidation of organic carbon-based impurities and eliminates H.sub.2S and bacteria. Sludge and solids floating to the top of each mixing vessels are removed, as well as sludge and solids settling to the bottom of the mixing vessels. When oil and gas well waste water is treated in this manner, the resulting treated water is purified and has a high salt content suitable for oil or gas well injection.

Waste water is remanufactured with ozone in a series of mixing vessels. The ozone is dispersed to both a top and a bottom portion of each mixing vessel, but in different amounts. This creates an electrical potential difference across the height of each mixing vessel which significantly improves the oxidation of organic carbon-based impurities and eliminates H.sub.2S and bacteria. Sludge and solids floating to the top of each mixing vessels are removed, as well as sludge and solids settling to the bottom of the mixing vessels. When oil and gas well waste water is treated in this manner, the resulting treated water is purified and has a high salt content suitable for oil or gas well injection.

A method of improving rheological properties of a divalent brine based downhole treatment fluid at an elevated temperature comprises adding to the divalent brine based downhole treatment fluid a rheological modifier, which comprises a carboxylic acid ester, or a phosphate ester blended with an ethoxylated glycol, or a combination comprising at least one of the foregoing in an amount effective to improve the rheological properties of the divalent brine based downhole treatment fluid at a temperature of greater than about 200° F. The divalent brine based downhole treatment fluid comprises calcium bromide, calcium chloride, zinc bromide, zinc chloride, or a combination comprising at least one of the foregoing.

A method of improving rheological properties of a divalent brine based downhole treatment fluid at an elevated temperature comprises adding to the divalent brine based downhole treatment fluid a rheological modifier, which comprises a carboxylic acid ester, or a phosphate ester blended with an ethoxylated glycol, or a combination comprising at least one of the foregoing in an amount effective to improve the rheological properties of the divalent brine based downhole treatment fluid at a temperature of greater than about 200° F. The divalent brine based downhole treatment fluid comprises calcium bromide, calcium chloride, zinc bromide, zinc chloride, or a combination comprising at least one of the foregoing.

A composition including a fluorescent polymer tag and an aqueous-based drilling fluid is provided. Also provided is a method of determining drill depth of recovered drill cuttings. The method includes introducing a fluorescent polymer tag into a drilling fluid, the fluorescent polymer tag includes the composition having the fluorescent compound linked to the polymer. The method then includes circulating the drilling fluid through a well during a drilling operation that creates formation cuttings such that the fluorescent polymer interacts with the formation cuttings, creating tagged cuttings. The returned cuttings are collected from the circulating drilling fluid at a surface of the well. The method then includes detecting the presence of the fluorescent polymer tag on the returned cuttings to identify the tagged cuttings, and correlating the tagged cuttings with the drill depth in the well at a time during the drilling operation.