Disclosed are surface-modified nanoparticles and surfactants used in compositions and methods for enhancing hydro-carbon recovery from subterranean formations.

Described herein are methods of treating fluid comprising hydrocarbons, water, and polymer being produced from a hydrocarbon-bearing formation are provided. The method can include adding a concentration of a viscosity reducer to the fluid to degrade the polymer present in the fluid and adding a concentration of a neutralizer to the fluid to neutralize the viscosity reducer in the fluid. The viscosity reducer is buffered at a pH of 7 or less (e.g., at a pH of from 2 to 7, such as at a pH of from 3.5 to 7, or at a pH of from 5 to 7). The addition of the concentration of the viscosity reducer is in a sufficient quantity to allow for complete chemical degradation of the polymer prior to the addition of the concentration of the neutralizer in the fluid such that excess viscosity reducer is present in the fluid. The addition of the concentration of the neutralizer is sufficiently upstream of any surface fluid processing equipment to allow for complete neutralization of the excess viscosity reducer such that excess neutralizer is present in the fluid prior to the fluid reaching any of the surface fluid processing equipment.

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.

A method of treating a well comprising introducing a well treatment fluid into the well, and a well treatment fluid, are provided. The well treatment fluid comprises an aqueous base fluid, sepiolite clay, and a polymer component selected from the group of an acryloylmorpholine polymer, a polyvinylpyrrolidone polymer, and mixtures thereof. In one embodiment, for example, the method is a method of drilling a well. In this embodiment, the well treatment fluid is a drilling fluid.

The present invention relates to substituted saccharides or glycosides and their use in drilling fluid compositions. The substituted saccharide or glycoside bears a substituent A, a substituent B and a substituent C, wherein the substituent A comprises in its structure a group ##STR00001##
the substituent B comprises in its structure a group ##STR00002##
and the substituent C comprises in its structure a unit —NH—R.sub.7—. The definition of each group is described in the description. The drilling fluid composition can show good temperature resistance, filtration loss reducing reduction property, pollution resistance, inhibition property, lubricating property or reservoir protection property, and has no biotoxicity.

A method of removing calcium-containing water-based filter cake from a wellbore involving contacting the calcium-containing filter cake with a biodegradable acid solution of water, hydrochloric acid, formic acid, citric acid, and a surfactant. The method is performed at a pressure of 200 to 400 psi and a temperature of 50 to 125° C. The method removes calcium-containing filter cake made of water, calcium carbonate, a polymer or starch and a clay. The method meets industry standard steel corrosion rates of less than 0.049 lb/ft.sup.2 per day. Also disclosed is a biodegradable acid solution of water, hydrochloric acid, formic acid, citric acid, and a surfactant that meets OECD 301B thresholds for ready biodegradability.

Disclosed herein are optical swell meters and methods for using them to measure fine-scale variations in the swelling behavior of shale specimens. In an embodiment, the optical swell meters can include: a glass imbibition chamber containing a specimen, where an imbibition fluid is located within the glass inhibition chamber and at least partially covering the specimen; a digital camera set a distance away from the chamber and facing the chamber; and a light source, where the light source illuminates the specimen. The method of using the optical swell meter can provide a swelling strain profile of the shale specimens during its interaction with the imbibition fluid.

Disclosed herein are optical swell meters and methods for using them to measure fine-scale variations in the swelling behavior of shale specimens. In an embodiment, the optical swell meters can include: a glass imbibition chamber containing a specimen, where an imbibition fluid is located within the glass inhibition chamber and at least partially covering the specimen; a digital camera set a distance away from the chamber and facing the chamber; and a light source, where the light source illuminates the specimen. The method of using the optical swell meter can provide a swelling strain profile of the shale specimens during its interaction with the imbibition fluid.

Multiple charged cationic compounds, which are derived from polyamines through an aza-Michael addition with an α, β-unsaturated carbonyl compound, in a clay treatment composition to reduces clay swelling, clay migration, and sludge formation in a subterranean formation in oil and gas operations are provided. The disclosed methods or compositions are found to be more effective than those methods or compositions commonly used for reducing clay swelling, clay migration, and sludge formation.

A chemical gel system having a polymer and a silicon oxide Janus nanosheets crosslinker for treating thief zones in carbonate formations. The polymer and silicon oxide Janus nanosheets crosslinker may form a crosslinked polymer gel to reduce or prevent water production via thief zones during hydrocarbon production. The silicon oxide Janus nanosheets crosslinker includes a first side having negatively charged functional groups and a second side having amines. The negatively charged functional groups may include negatively charged oxygen groups and hydroxyl groups. Methods of reducing water production in a thief zone using the silicon oxide Janus nanosheets crosslinker and methods of manufacturing the silicon oxide Janus nanosheets crosslinker are also provided.