Disclosed are a recyclable clean fracturing fluid thickener, a preparation method and a recovery method thereof, and a high-temperature resistant clean fracturing fluid, which relate to the stimulation treatment of oil and gas fields. Diethanolamine and thionyl chloride are used as raw materials and reacted to obtain an intermediate, which is then reacted with an unsaturated fatty acid amidopropyl dimethylamine to produce the recyclable clean fracturing fluid thickener. The clean fracturing fluid can be used in the fracturing stimulation treatment of low and medium permeability reservoirs.

A three-poly cationic viscoelastic and a clean fracturing fluid containing the three-poly cationic viscoelastic surfactant are provided. N, N-dimethyl-1,3-propanediamine and epichlorohydrin are used to prepare an intermediate A, and then the intermediate A and a fatty acid amidopropyl dimethylamine is used to prepare the three-poly cationic viscoelastic surfactant. The preparation process is simple. The clean fracturing fluid including the three-poly cationic viscoelastic surfactant has excellent temperature and shear resistance, strong suspended sand performance, simple on-site preparation, automatic gel breaking, small damage to formation, low cost and simple preparation process. The clean fracturing fluid including the surfactant also has strong temperature resistance, and the viscosity of the product can be maintained at 42 mPa.Math.s after 80 minutes at 180 C. and 170 s.sup.1, which is higher than the viscosity requirement (>25 mPa.Math.s) of the clean fracturing fluid in on-site construction.

A three-poly cationic viscoelastic and a clean fracturing fluid containing the three-poly cationic viscoelastic surfactant are provided. N, N-dimethyl-1,3-propanediamine and epichlorohydrin are used to prepare an intermediate A, and then the intermediate A and a fatty acid amidopropyl dimethylamine is used to prepare the three-poly cationic viscoelastic surfactant. The preparation process is simple. The clean fracturing fluid including the three-poly cationic viscoelastic surfactant has excellent temperature and shear resistance, strong suspended sand performance, simple on-site preparation, automatic gel breaking, small damage to formation, low cost and simple preparation process. The clean fracturing fluid including the surfactant also has strong temperature resistance, and the viscosity of the product can be maintained at 42 mPa.Math.s after 80 minutes at 180 C. and 170 s.sup.1, which is higher than the viscosity requirement (>25 mPa.Math.s) of the clean fracturing fluid in on-site construction.

A composition of matter represented by the following formula:

##STR00001##

where R.sup.1 is an unsaturated or branched hydrocarbon chain, R.sup.2 is either a hydrogen atom or a hydrocarbon chain, and m and n are independently from 1 to 5, when used in a lubricating composition, being effective for friction and wear reduction, while providing improved protection against copper and lead corrosion in an engine.

A composition of matter represented by the following formula:

##STR00001##

where R.sup.1 is an unsaturated or branched hydrocarbon chain, R.sup.2 is either a hydrogen atom or a hydrocarbon chain, and m and n are independently from 1 to 5, when used in a lubricating composition, being effective for friction and wear reduction, while providing improved protection against copper and lead corrosion in an engine.

Disclosed are a recyclable clean fracturing fluid thickener, a preparation method and a recovery method thereof, and a high-temperature resistant clean fracturing fluid, which relate to the stimulation treatment of oil and gas fields. Diethanolamine and thionyl chloride are used as raw materials and reacted to obtain an intermediate, which is then reacted with an unsaturated fatty acid amidopropyl dimethylamine to produce the recyclable clean fracturing fluid thickener. The clean fracturing fluid can be used in the fracturing stimulation treatment of low and medium permeability reservoirs.

A method may include: placing into a wellbore penetrating a subterranean formation a foaming agent, wherein the wellbore comprises a produced fluid from the subterranean formation; and foaming the produced fluid. The foaming agent may include at least one of the following structures: ##STR00001## wherein R1 and R2 are individually selected from an alkyl group, an alkenyl group, a heteroatom substituted alkyl group, or a heteroatom substituted alkenyl group, wherein R1 comprises 5 carbon atoms to 22 carbon atoms in length, and wherein R2 comprises 1 carbon atom to 8 carbon atoms.

A method may include: placing into a wellbore penetrating a subterranean formation a foaming agent, wherein the wellbore comprises a produced fluid from the subterranean formation; and foaming the produced fluid. The foaming agent may include at least one of the following structures: ##STR00001## wherein R1 and R2 are individually selected from an alkyl group, an alkenyl group, a heteroatom substituted alkyl group, or a heteroatom substituted alkenyl group, wherein R1 comprises 5 carbon atoms to 22 carbon atoms in length, and wherein R2 comprises 1 carbon atom to 8 carbon atoms.

Disclosed is a method capable of selectively synthesizing cationic lipids by controlling the introduction rate of a fatty acid group with respect to an oligoalkyleneamine by the change of reaction conditions.

Disclosed is a method capable of selectively synthesizing cationic lipids by controlling the introduction rate of a fatty acid group with respect to an oligoalkyleneamine by the change of reaction conditions.