Compositions are disclosed for dewatering mixtures of petroleum and water. The compositions comprise one or more of the following: an unreacted polysaccharide component; and one or both of a polysaccharide component reacted with a hydrophilic component and a polysaccharide component reacted with a hydrophobic component. The compositions may also include viscosifying agents or stabilizers to stabilize the compositions against separation, for example, prior to use. In particularly preferred embodiments the invention is drawn to compositions for breaking an emulsion; such compositions comprising a carbohydrate component containing a cationic starch joined to a hydrophobic moiety, providing the carbohydrate component oil solubility. The composition may optionally comprise one or more additional demulsifier selected from, without limitation, salts (such as a polyaluminum chloride, an aluminum chlorohydrate, an alum, etc.), metal salts (such as iron and zinc salts), dithiocarbamate, tannin, and organic demulsifiers such as poly-DADMAC and similar compounds.

A crude oil desalter unit includes a settler, an inlet manifold fluidly coupled to the settler, and one or more inlet distributors extending from the inlet manifold to discharge a water-in-oil emulsion into the settler. Each inlet distributor includes a riser having a first end, a second end, and an inner flowpath extending between the first and second ends, wherein the riser is coupled to the inlet manifold at the first end, one or more outlet nozzles provided at the second end and in fluid communication with the inner flowpath, and a static mixer positioned within the inner flowpath and defining one or more helical pathways operable to induce rotational flow to a fluid flowing within the inner flowpath.

Adding a cationic starch and/or an anionic starch to a conventional demulsifier or water clarifier reduces activity of the resulting product without losing demulsifier or water clarifier performance.

The present disclosure describes a method including: receiving input data from a gas and oil separation plant (GOSP), wherein: one or more demulsifiers is being injected into an emulsion to achieve a separation, a plurality of flow rates of water and the one or more demulsifiers are being measured inside the GOSP, the input data comprises the plurality of flow rates as well as temperatures corresponding to the plurality of flow rates, and determining, for each of the one or more demulsifiers, efficiencies of the separation based on the flow rates measured at corresponding temperatures; grouping respective efficiencies of separation according to a set of temperature ranges; and generating, for at least one temperature range, a histogram for the at least one temperature range; ranking the one or more demulsifiers according to the histogram; and providing a feedback to indicate a ranked order of the one or more demulsifiers.

A demulsifier composition comprises an oxyalkylated polybenzoxazine having repeating units of Formula (I):

##STR00001##

wherein R.sub.1 is hydrogen, a C.sub.1-30 alkyl, a C.sub.3-30 cycloalkyl, a C.sub.6-30 aryl, a C.sub.7-30 alkylarylene, a C.sub.7-30 arylalkyl, a C.sub.5-30 heteroaryl, or a C.sub.3-30 heterocycloalkyl; R.sub.2 is a C.sub.1-30 alkyl, a C.sub.3-30 cycloalkyl, a C.sub.6-30 aryl, a C.sub.7-30 alkylarylene, a C.sub.7-30 arylalkyl, a C.sub.5-30 heteroaryl, or a C.sub.3-30 heterocycloalkyl; R.sub.3 is hydrogen or a C.sub.1-10 alkyl; each occurrence of R.sub.4 is independently hydrogen or a C.sub.1-5 alkyl; and p is at least 1.

Treatment fluids and associated methods and systems for demulsifying an emulsified well fluid. An example method includes contacting the emulsified well fluid with a treatment fluid comprising: an aqueous base fluid; an alcohol; a resin alkoxylated oligomer; a polyol; and a polyamine polyether. The emulsified well fluid is separated into an aqueous phase and an oleaginous phase after contact with the treatment fluid.

A single-phase microemulsion additive may be introduced to a stream containing mixtures of or emulsions of oil and water in an effective amount to separate oil from the water in the stream and/or separating water from the oil in the stream. The single-phase microemulsion additive is formed by combining at least one demulsifier, at least one water clarifier, at least one surfactant, and optionally at least one solvent.

A method and composition for isolating a paraffinic hydrocarbon layer from a sludge comprising a mixture of paraffinic hydrocarbons, water, and solids are provided. The method comprises providing a paraffinic hydrocarbon isolation composition comprising isopropylamine dodecylbenzene sulfonate, a surfactant, and a solvent; contacting the sludge with the paraffinic hydrocarbon isolation composition; and allowing the paraffinic hydrocarbon isolation composition to separate the sludge into a three phase separation comprising a paraffinic hydrocarbon layer, a water layer, and a layer of settled solids.

Described is a method for concentration and extraction of gas field chemicals. The method includes collecting produced water from a gas oil separation plant, treating the produced water to remove oil, and receiving a feed solution containing a gas field chemical and water. The treated produced water is used as a draw solution to concentrate and absorb water from the feed solution using a forward osmosis chamber. A concentrated feed solution containing the gas field chemical and a diluted draw solution is produced. The concentrated feed solution is extracted and stored for injection into gas wells.

Disclosed herein is a novel class of multiple charged cationic or anionic compounds that are derived from an aza-Michael Addition reaction between a polyamine (Michael donor) and an activated olefin (Michael acceptor), methods of making the same, and use thereof. Also disclosed herein are the methods of using multiple charged cationic or anionic compounds disclosed herein in a reverse emulsion breaker composition to break reverse emulsion commonly found in a produced fluid in oil and gas operations. The disclosed REB methods or compositions are found to be more effective than those methods or compositions including commonly used for oil/solid and water separation.