76results about How to "Good sand carrying performance" patented technology

The invention relates to an ultra-temperature organic zirconium crosslinker suitable for polymer crosslinking and prepared fracturing solutions of the ultra-temperature organic zirconium crosslinker. The organic zirconium crosslinker comprises the following raw materials in part by mass: 200 to 350 parts of water, 170 to 280 parts of organic alcohol, 40 to 100 parts of zirconium compounds, 20 to 50 parts of organic acid and 300 to 350 parts of alkanolamine. The preparation method of the organic zirconium crosslinker comprises the steps as follows: adding the organic alcohol into the water; heating the solution to 50 to 60 DEG C after uniformly mixing the organic alcohol and the water; adding the zirconium compounds into the solution for reacting for 3 to 4 hours; then adding the organic acid and the alkanolamine; and stirring at the temperature of 50 to 60 DEG C for 2 to 3 hours so as to prepare the organic zirconium crosslinker. The invention further relates to polymer fracturing solutions and a preparation method thereof, and the organic zirconium crosslinker and PAM aqueous solutions are adopted to prepare the ultra-temperature resistant fracturing solutions which can resist the temperature over 200 DEG C; and the fracturing solutions further have the characteristics of acid gluing, low damage, no residue and the like.

The invention relates to an amphoteric ionic polymer water base fracturing fluid thickening agent and a preparation method of the amphoteric ionic polymer water base fracturing fluid thickening agent, and belongs to the technical field of propping agent fracturing fluid used for oil and gas reservoir volume increase and injection increasing measures. The amphoteric ionic polymer water base fracturing fluid thickening agent is prepared through copolymerization of alkyl group acrylic amide, acrylic amide, 2-acrylic amide group-2-methyl propane sulfonic acid sodium aqueous solution, cationic monomers, vinyl monomers and polymerizable surface active agent monomers. The amphoteric ionic polymer water base fracturing fluid thickening agent and the preparation method of the amphoteric ionic polymer water base fracturing fluid thickening agent have the advantages that raw materials used for the amphoteric ionic polymer water base fracturing fluid thickening agent are all industrial products, purification treatment is not needed before a reaction, a complexing agent is added so that polymerization of the complexing agent and an initiating agent can be initiated at an appropriate temperature, and the preparation technology is simple; due to the fact that the surface active agent monomers are added, an obtained polymer has a hydrophobic association function and is higher in shearing stability, easy to dissolve, free of pollution and harm and good in sand carrying performance; and the amphoteric ionic polymer water base fracturing fluid thickening agent can be resistant to the high temperature of 180 DEG C, is suitable for fracturing of high temperature strata, has high shearing-resistant performance to meet the requirement of high-flow fracturing construction, has high sand carrying performance and no-residue performance, and causes no harm to reservoir strata.

The invention relates to long-carbon-chain amide glycine betaine clean fracturing fluid and a preparation method thereof. The glycine betaine amphiprotic surface active agent long-carbon-chain (more than 18 carbons) amide glycine betaine is used as a main agent, the carbon chain of the glycine betaine is long, the glycine betaine is dissolved in the water and is likely to form gel after being stirred, so that the fracturing fluid is good in viscosity. In addition, the clean fracturing fluid by adopting the long-carbon-chain (more than 18) amide glycine betaine as the main agent adsorbs less rock stratum, the consumption of the surface active agent is effectively reduced, the calcium resistance is strong, the gel is thorough to break, no residue exists, and the harm on the stratum is small. The prepared long-carbon-chain amide propyl glycine betaine clean fracturing fluid can be well applied to an oil field and plays an important role in increasing the yield of the oil-gas field.

The invention provides a supramolecular clean fracturing fluid, and a preparation method and application thereof. The fracturing fluid comprises the following components in percentage by weight: 0.1-5% of amphoteric surfactant, 0.1-0.8% of anionic polymer containing hydrophobic group, 0-2% of anionic surfactant, 0-4% of salt and the balance of water. The amphoteric surfactant is one or combination of an amide amphoteric surfactant with two hydrophilic groups and one hydrophobic group and an amide amphoteric surfactant with three hydrophilic groups and one hydrophobic group. The supramolecular clean fracturing fluid is applicable to oil-gas field fracturing, and can obtain higher consistency and viscoelasticity under the condition of lower concentration, thereby obtaining better rheological property and sand carrying effect.

The invention relates to a fracturing fluid capable of resisting high salinity water quality. The fracturing fluid is characterized by being composed of a base fluid and a cross-linking fluid which are fully mixed in proportion. The base fluid contains a chelate cosolvent and a chelate stabilizer, wherein the chelate cosolvent can restrain high salinity of water quality and promote swelling of guanidine gum. The base fluid comprises 98.2-98.65 parts of high salinity surface water, 0.1-0.15 part of the chelate cosolvent,0.3-0.4 part of thickener, 0.1-0.15 part of bactericide, 0.3-0.5 part of clay stabilizer, 0.5 part of demulsifying cleanup agent and 0.05-0.1 part of the chelate stabilizer; the cross-linking fluid comprises 50 parts of water, 50 parts of organic cross-linking agents and 0.35 part of gel breaker; and the fracturing fluid comprises 99.2-99.5 parts of the base fluid and 0.5-0.8 part of the cross-linking fluid. By aid of the fracturing fluid, water resources can be saved effectively, and the success rate for fracturing construction can be improved.

The invention provides a carbon dioxide-anti-drag water compound fracturing method which comprises the following steps of: injecting liquid carbon dioxide fracturing fluid into a stratum; after a period of time, stopping injecting the liquid carbon dioxide fracturing fluid, and then injecting anti-drag water fracturing fluid not added with a propping agent; and after a period of time, stopping injecting the anti-drag water fracturing fluid not added with the propping agent, then injecting anti-drag water compound fracturing fluid carrying the propping agent, and stopping after a period of time. According to the method, different system fracturing fluids are adopted in different injection phases, and special properties of different fracturing fluids are reasonably utilized, so that the effect of enlarging crack network scale, communicating stratum primary fractures, enhancing fracture efficiency, improving the seepage environment of the stratum and improving the reservoir yield; a carbon dioxide-anti-drag water compound fracturing process is applied to a low percolation oil and gas reservoir, so that the per-well yield can be improved, and the problem that traditional fracturing process for low percolation oil and gas reservoirs is poor in productivity improvement effect.

The invention provides a proppant-carrying acid fracturing method for a high-temperature ultra-deep carbonate reservoir. The proppant-carrying acid fracturing method for the high-temperature ultra-deep carbonate reservoir comprises the following steps that (1) fracture forming is conducted through fracturing fluid; (2) ground crosslinked acid is adopted and is made to react with rock, so that an acid-etched fracture is generated in a formed fracture, and a proppant is carried with the ground crosslinked acid for supporting the acid-etched fracture; and (3) linear glue is used for replacement, and thus acid fracturing is completed. According to the proppant-carrying acid fracturing method for the high-temperature ultra-deep carbonate reservoir, the technique is simple, operation is convenient, and the construction effect is remarkable; and the proppant-carrying acid fracturing method is suitable for transforming construction of deep well carbonatite at the high temperature of 150-170 DEG C, a supporting fracture which has deep penetration and longer flow conductivity can be formed in a stratum, the productivity is increased and the production time is prolonged after acid fracturing and well fracturing, and the length of the formed fracture is larger than 120 m.

The invention belongs to the field of chemical engineering, and particularly relates to a water-based fracturing fluid thickening agent and a synthetic method thereof. The thickening agent comprises substances in parts by weight as follows: acrylamide, methacrylamide, undecylenic acid, 2-acrylamide-2-methylpropane sulfonate, methacryloyloxyethyl trimethyl ammonium chloride, dodecafluoroheptyl methacrylate, vinyl pyrrolidone, modified corn starch, an initiator and water. The synthetic method of the thickening agent comprises steps as follows: various co-monomers and modified starch are prepared in deionized water in proportion; the PH value and the temperature of the solution are adjusted; high-purity nitrogen is fed for oxygen removal; the compound initiator is added to initiate a reaction. The thickening agent is a multifunctional high-molecular polymer which is easily soluble, free of pollution and damage, good in sand carrying property and particularly good in temperature resistance and anti-shearing sand carrying property. The thickening agent has main characteristics of wide use temperature range as well as high temperature resistance and shearing resistance, has characteristics that the thickening agent is high in sand carrying property, free of residues, causes no damage to reservoir and the like, and can be used as an excellent substitute for guanidine gum.

The invention provides a butane-containing fracturing fluid and a preparation method thereof. The butane-containing fracturing fluid comprises the raw materials in parts by mass: 0.5 to 2 parts of a phosphate thickening agent, 0.1 to 1 part of a crosslinking agent and 100 parts of butane. The preparation method of the butane-containing fracturing fluid comprises the following steps: gaseous butane is placed in an environment of -10 DEG C to -30 DEG C, and the gaseous butane is changed into liquid butane; at the temperature of -10 DEG C to -30 DEG C, water solutions of the phosphate thickening agent and the cross-linking agent are added to the liquid butane and are stirred evenly, and an initial product of the butane-containing fracturing fluid is obtained; at the room temperature and in a pressure-resistance air tight container, the initial product of the butane-containing fracturing fluid is magnetically stirred for 10 min, and the butane-containing fracturing fluid is obtained. The butane-containing fracturing fluid can be prepared under the normal pressure, and has relatively good temperature resistance, shear resistance and sand carrying performance.

The invention discloses a thickening agent which is provided with a branched chain structure and used for water base fracture. The thickening agent is composed of six monomers in a copolymerization mode. The six monomers comprise N, N-dimethyl acrylic amide (AAM), dimethyl diallyl ammonium chloride (DADMAC), acrylonitrile (AN), methacrylic acid (AA), 2-acrylic amide-2-methyl propane sulfonate (AMPS) and N-VINYL-2-pyrrolidone (PVN). Further disclosed is a preparation method of the thickening agent with the branched chain structure. Compared with the prior art, the thickening agent has the advantages of being low in residue, temperature resistant, prone to dissolution, anti-shearing and good in sand carrying property. The hyperbranched molecule fracturing fluid thickening agent completely solves the problems that vegetable glue fracturing fluid is high in damage and friction, general polymer fracturing liquid is not resistant to shear and incomplete in gel breaking, and the like. The thickening agent is not like vegetable glue which contains a large amount of water insoluble matters, completely dissolved in a fracturing liquid stock solution, basic zero in the water insoluble matters and free of containing solid phase composition. The obtained fracturing liquid stock solution is glittering, translucent and bright. After gel is broken, compared with a vegetable glue fracturing liquid system, contend of residue is greatly reduced. The thickening agent has the advantages of being less in residue content, low in use viscosity, good in sand carrying property, low in cost, convenient to flow back and the like.

The invention provides densifier and fracturing fluid for shale gas fracturing fluid, a preparation method and application thereof. The densifier is synthesized by viscoelastic surfactant, polyacrylamide, 2-propeneamido-methylpropanesulfonic acid, methacryloxy trimethyl ammonium chloride, N-isopropylacrylamide, pimeloyl and caustic soda flakes in a ratio of 3:(5-7):(0.4-0.6):(1-2):(1.5-2.5):(1.5-2.5):(0.8-1.2). The fracturing fluid comprises the densifier, a rheological aid mixed by surfactant and ethanol in a ratio of 1:(1.5-2.5), and a temperature stabilizing agent. The invention also provides application of the fracturing fluid in shale gas continuous sand fracturing and a shale gas continuous sand fracturing method. The fracturing fluid is clean fracturing fluid, has the characteristics of low hurt, effective thickening, temperature resistance, salt resistance, shearing resistance, low friction and the like, and is good in compatibility with other common water-borne fracturing fluid additives.

The invention discloses a dry fracturing fluid anti-drag thickening agent and a preparation method thereof. The dry fracturing fluid anti-drag thickening agent comprises, by mass, 45-65% of carbon-dioxide-philic solvent, 10-15% of oil-soluble solvent, 5-10% of hydrotropy monomer, 15-20% of tackifier monomer, 3-5% of structural monomer, 1-3% of super-carbon-oxide-philic monomer, 0.5-1% of oil-soluble chain transfer agent and 0.5-1% of oil-soluble initiator. The dry fracturing fluid anti-drag thickening agent is convenient to prepare and use, has super-fast solubility, efficient thickening performance, excellent temperature and shear resistance capacity, excellent sand carrying capacity and efficient drag reduction performance.

The invention discloses a crosslinking agent for a sea water-based fracturing fluid as well as a preparation method and an application of the crosslinking agent, and belongs to the technical field of oilfield chemistry. The crosslinking agent is prepared from components by weight as follows: 50-60 parts of water, 10-20 parts of polyols, 10-15 parts of organic acid, 1-5 parts of inorganic acid and 3-8 parts of inorganic zirconium salt. The preparation method comprises steps as follows: mixing and heating the water and the polyols to completely dissolve the polyols, adding the organic acid, the inorganic acid and the inorganic zirconium salt to a polyol solution under the stirring condition, and increasing the temperature to 55-70 DEG C for a reaction for 4 to 6 hours to obtain the crosslinking agent. The crosslinking agent prepared with the method can be crosslinked with a thickening agent base solution prepared directly from seawater, and sea water-based fracturing fluid jelly is formed; the jelly has good shear resistance at 150 DEG C, meets demands of the offshore reservoir fracturing transformation technology at the high temperature of 150 DEG C, improves the offshore fracturing efficiency and reduces the operating cost.

The invention discloses an organic aluminum-zirconium crosslinking agent and a preparation method thereof, and a low-molecular polymer fracturing fluid. The crosslinking agent is prepared by reacting the following raw materials in parts by weight: 15-25 parts of zirconium salt, 15-25 parts of aluminum salt, 150-250 parts of polyalcohol, 75-85 parts of organic acid, 15-25 parts of gluconate and 55-65 parts of water. The organic aluminum-zirconium crosslinking agent has excellent high temperature resistance, and has favorable crosslinking effect under the conditions of high temperature and high salinity. The organic aluminum-zirconium crosslinking agent is stable under the condition of low pH value, can implement acid crosslinking, and ensures the normal proceeding of the acid fracturing. The organic aluminum-zirconium crosslinking agent has favorable compatibility with polymers and high crosslinking capacity; and the fracturing fluid formed by compounding the organic aluminum-zirconium crosslinking agent with polymers has the advantages of stable gel, excellent solid carrying capacity, excellent viscosity breaking performance and excellent shearing resistance under high-temperature conditions. The organic aluminum-zirconium crosslinking agent has the characteristics of high solubility, no pollution and low damage degree to the reservoir, and has wide application prospects.

The invention provides water base guanidine gum fracturing fluid, and belongs to the field of oil field fracturing technologies. The water base guanidine gum fracturing fluid comprises the following ingredients: guanidine gum derivative, cross-linking agents, gel breakers, thickening agents, PH value adjusting agents and water. The invention further provides a water base guanidine gum fracturing fluid preparation method. The method includes the following steps of (1) dissolving gelatinizing agents in the water, evenly mixing, and obtaining thickened water; (2) dissolving the cross-linking agents in the water, evenly mixing and obtaining cross-linking agent water solution; (3) adjusting the PH value of the thickened water to 9-10, then slowly adding the cross-linking agent water solution into the thickened water to obtain jelly solution; (4) and adding the thickening agents into the jelly solution, and finally adding the gel breakers to obtain the water base guanidine gum fracturing fluid. The water base guanidine gum fracturing fluid is low in sludge content after gel breaking, and meanwhile the cost of the water base guanidine gum fracturing fluid is greatly reduced.

The invention provides clean self-thermogenesis pressurization reservoir reconstruction liquid and a preparation method thereof. The mass of the clean self-thermogenesis pressurization reservoir reconstruction liquid sums up to 100%, and the clean self-thermogenesis pressurization reservoir reconstruction liquid is prepared from, by mass, 0.5 wt%-0.8 wt% of thickening agents, 0.1 wt%-0.5 wt% of discharge aiding agents, 0.1 wt%-0.3 wt% of deforming agents, 3 wt%-10wt% of thermogenesis pressurization agents FC, 4wt%-15wt% of thermogenesis pressurization agents FD, 0.5wt%-6wt% of thermogenesis catalysts, 0.3wt%-1.0wt% of cross-linking agents, 0.02wt%-0.5wt% of gel breaking agents and the balance water. The invention further provides the preparation method of the clean self-thermogenesis pressurization reservoir reconstruction liquid. The clean self-thermogenesis pressurization reservoir reconstruction liquid is clean, free of residues, low in damage to a reservoir, simple in production method and low in cost.

The invention discloses a clean fracturing fluid thickening agent and a preparation method thereof. The thickening agent is prepared by mixing methacrylamide, 2-acrylamide-2-methyl-1-moropholino ethanesulfonic acid salt, styrene, acryloyloxyethyl trimethyl ammonium chloride, sodium p-styrenesulfonate and N-vinyl-pyrrolidone in solvent water, adjusting the pH value of mixed reaction liquid to be 8-9, adding an initiator for initiating a free radical under the protection of nitrogen and then performing polymerization according to a microwave method. The clean fracturing fluid thickening agent has the advantages of high shearing resistance, high viscosity, high carrying property and the like; furthermore, the clean fracturing fluid thickening agent is short in liquid mixing time, high in dispersion property and high in swelling speed, and can realize simultaneously liquid mixing and construction.

The invention provides a guar gum grafted copolymer nanocomposite gel fracturing fluid and a preparation method thereof. The fracturing fluid comprises the following components in percentage by mass:0.4-1.2% of a guar gum grafted copolymer thickening agent, 0.05-0.5% of a nanomaterial and 0.2-1% of a cross-linking agent, with the balance being water. According to the invention, guar gum or a derivative thereof and acrylamide monomers are used as raw materials to synthesize a guar gum graft copolymer, the guar gum graft copolymer is used as the thickening agent, a nanomaterial dispersion liquid is added, and the nanocomposite gel fracturing fluid is prepared under the action of the cross-linking agent. Hydrophilic flexible polymer branched chains are introduced to semi-rigid macromolecularchains of guar gum, so mutual entanglement and adsorption between the guar gum and the nanomaterial are facilitated, the compatibility of the guar gum and the nanomaterial can be greatly improved, and interaction between the nanomaterial and a polymer matrix is further improved; and the prepared nanocomposite gel fracturing fluid has better temperature resistance, shearing resistance, sand carrying property and filtrate loss reduction property.

The invention provides a preparation method for alcohol ether modified guar and a fracturing liquid. The preparation method comprises the following steps: by adopting a strong alkali solution, implementing alkalization treatment on alcohol ether to facilitate the reaction of the alcohol ether and paratoluensulfonyl chloride, and dropping a paratoluensulfonyl chloride organic solution into the alcohol ether alkali; further dropping sulfonated alcohol ether into a raw material, namely an alkalized solution of guar, implementing grafting so as to obtain alcohol ether modified guar, enriching oxygen atoms and hydroxyl in the structure of the guar, forming a three-dimensional stable structure with a cross-linking agent, furthermore performing sufficient hydration swelling under a low-temperature condition, releasing viscosity, and putting the guar into the fracturing liquid in a relatively low concentration, thereby ensuring the sand carrying effect of the fracturing liquid. Results of embodiments show that after alcohol ether modified guar prepared by using the preparation method is put into the fracturing liquid in the concentration of 0.1-0.3%, an excellent sand carrying effect can be still ensured, and no sedimentation is resulted within 24 hours.

The invention belongs to the technical field of petrochemical engineering, and particularly relates to an anhydrous fracturing fluid suitable for shale gas and a preparation method of the anhydrous fracturing fluid. The anhydrous fracturing fluid suitable for shale gas is prepared from the following raw materials in percentage by mass: 0.5-2% of a crosslinking agent, 2-6% of a complex iron activator and the balance of a low carbon hydrocarbon; in a pressure vessel with a pressure of 0.8-3.0 MPa, the crosslinking agent is added into the low carbon hydrocarbon to be uniformly mixed, the complex iron activator is added to be stirred for 2-5 min, so that the anhydrous fracturing fluid suitable for shale gas is obtained; and the low carbon hydrocarbon is one or a mixture of more of propane, butane, n-hexane, n-heptane and kerosene. The anhydrous fracturing fluid suitable for shale gas easily flows back, has a good sand-carrying property, does not harm reservoirs, and can satisfy the needs of fracturing reconstruction of shale oil and gas and strong water-sensitive compact oil and gas reservoirs. A synthetic method is simple, and the content of an effective component dialkyl phosphate in a product is high, thereby facilitating the industrialization production of the anhydrous fracturing fluid.

The invention discloses a fracturing technology for improving effective support of a shale fracturing complex fracture network. The fracturing technology comprises the following steps that (1) well cleanup is conducted; (2) perforation is conducted; (3) fracturing treatment is conducted, specifically, a suspension fluid formed by mixing a prepad fluid with 140-300 mesh quartz sand is pumped at thedisplacement of 10-12 m<3> / min firstly, then a sand-carrying fluid is pumped at the displacement of 10-12 m<3> / min, 70-140 mesh quartz sand is adopted as an early-period proppant of the sand-carryingfluid, 40-70 mesh ceramsite is adopted as a later-period proppant of the sand-carrying fluid, finally, a displacing fluid is pumped for displacement, and pumping is stopped after displacement; (4) segment treatment is conducted; and (5) the steps (2) and (3) are repeated, and next segment of fracturing operation is completed. According to the fracturing technology, a microfracture and a secondaryfracture network can be effectively supported, meanwhile, a fracturing major fracture and a branched fracture are also supported advantageously, finally, effective support of the shale complex fracture network is improved overall, the yield of shale gas is increased, and the successive decreasing speed of a shale gas well is decreased.

The invention provides oil and gas field fracturing fluid, an oil and gas field well cementation agent and an oil and gas field fracturing temporary plugging agent, which contain PVA (Polyvinyl Alcohol) fibers. The PVA fibers are papered from polyvinyl alcohol with the polymerization degree of 1000 to 3000 and the alcoholysis degree of 80 mole percent to 99.5 mole percent through spinning; the hydroformylation degree eta of the PVA fibers is 25 percent to 35 percent and Rp is 120 DEG C to 180 DEG C. The PVA fibers have the monofilament density of 1.0dtex to 1.8dtex at normal temperature and have the elongation at break of 10 percent to 25 percent; the slenderness ratio of the fibers is 200 to 600 and the real density of the fibers is 0.8g / cm<3> to 1.4g / cm<3>. The yield increasing range of the oil and gas field can reach 30 percent to 50 percent; the strength and toughness of the well cementation agent are remarkably improved and the well cementation agent can also have an anti-leakage effect; when being used in the fractured oil and gas field, the oil and gas field fracturing temporary plugging agent aims at plugging old cracks and breaking new cracks; when the fracturing temporary plugging agent is used, the pressure is raised by 6MPA or above and the yield of the oil and gas field is improved by two times or above.

The invention relates to oil well shaft test devices, in particular to a fluid sand carrying experimental device. The technical scheme is that the fluid sand carrying experimental device is mainly composed of a water tank, a centrifugal pump, a test tube, a sand feeding pipeline, a sand feeding hopper and a pipeline. The water tank is connected with the centrifugal pump and the test tube through the pipeline, the test tube is connected with the sand feeding pipeline, the sand feeding pipeline is connected with the sand feeding hopper, and the connection position of the test tube and the sand feeding pipeline is connected with the water tank through the pipeline. The fluid sand carrying experimental device has the advantages that a statistic relation of sand grain settling speed and well liquid average speed is built on the basis of a well shaft flow simulation experiment, and the optimum sand carrying effect can be achieved.

The invention provides a nano-composite fracturing fluid as well as a preparation method and an application thereof. The nano-composite fracturing fluid is prepared from components in parts by weight as follows: 0.1-3.0 parts of a nano-composite thickening agent, 0.1-0.5 parts of a structure regulator, 0.1-1.0 part of a clay stabilizer, 0.1-1.0 part of a cleanup additive, 0.1-1.0 part of a foaming agent, 0.1-2.0 parts of an organic crosslinking agent, 0.01-0.5 parts of a gel breaker and 90.0-99.39 parts of water. Due to interaction between the structure regulator and the nano-composite thickening agent, the nano-composite fracturing fluid has extremely excellent sand carrying performance, good high-temperature resistance and anti-shearing performance, can effectively break gel in situ under a formation condition, can form multiscale nano-composite micelle through separate nano-dispersion and nucleation processes, is applicable to oil and gas exploitation in various stratum environments and improves the oil and gas injection and exploitation efficiency.

The invention relates to a novel high-temperature-resistant nano-composite zirconium cross-linking agent as well as a preparation method and application thereof, and belongs to the technical field of oilfield chemistry. The cross-linking agent is prepared from the following raw materials in parts by weight: 45-50 parts of ethylene glycol, 7-10 parts of inorganic zirconium salt, 15-18 parts of polyhydric alcohol, 23-26 parts of organic acid, 0.1-0.2 part of a nano-particle material and 10-20 parts of a dispersing agent. The preparation method comprises the following two steps: firstly, an organic zirconium cross-linking agent is synthesized, and then the molecular surface of the organic zirconium cross-linking agent is modified by adopting a nano-particle material to prepare the nano-composite zirconium cross-linking agent. When the nano-composite zirconium cross-linking agent is applied to the acidic cross-linking fracturing fluid, good gel can be formed under high-temperature and acidic conditions, even gel can be formed under the condition that the concentration of the acidic cross-linking fracturing fluid is relatively low, the nano-composite zirconium cross-linking agent is high in shear resistance, good in temperature resistance and high in sand carrying capacity, the preparation method is simple, convenient to popularize and apply and suitable for industrial production, and good application prospects are realized.

The invention discloses clean CO2 / N2 foam fracturing fluid and a preparation method thereof. The clean CO2 / N2 foam fracturing fluid is an anhydrous fracturing fluid and comprises liquid carbon dioxide, nitrogen and a foaming agent; and the preparation method comprises the following steps: mixing the liquid carbon dioxide with the foaming agent uniformly under conditions of temperature greater thanor equal to 2 DEG C and pressure greater than or equal to 3.4 MPa, and feeding nitrogen to obtain the CO2 / N2 foam fracturing fluid. The clean CO2 / N2 foam fracturing fluid provided by the applicationhas advantages of relatively high viscosity, strong carrying capacity, no damage to formation, easy recovery and simple preparation method.

The invention discloses a rectorite saturated brine drilling fluid for drilling under a rock salt deep stratum and belongs to the technical field of drilling and oil exploitation. The drilling fluid is prepared from an auxiliary agent, NaCl and water according to a certain proportion, wherein the auxiliary agent at least comprises 1 to 8 percent of sodium base rectorite, 0.2 to 14 percent of main fluid loss agent, 0.1 to 5 percent of auxiliary fluid loss agent, 0.1 to 1 percent of coating agent, 1 to 5 percent of wall protective agent, 1 to 5 percent of lubricant, 0.1 to 0.5 percent of antifoaming agent and 0.1 to 0.5 percent of NaOH, wherein the NaCl is in a saturated state in the drilling fluid. The drilling fluid of the invention can still keep good rheological property, prop-carrying capacity and filtration property resistance at the highest temperature of 200 DEG C, can quickly and safely drill in a salt layer, guarantees the smooth drilling operation under the deep stratum salt layer and is particularly suitable for drilling under the rock salt deep stratum and extracting rock cores.

The invention provides an erucic acid-based alkyl quaternary ammonium surfactant and a preparation method thereof. The invention aims to solve the problems of reducing sand-carrying capability and reducing performance caused by quick reducing colloidal viscosity under high temperature and high shearing rate of the present quaternary ammonium surfactant used as a main agent of a clean fracturing fluid. The structural formula (I) of the erucic acid-based alkyl quaternary ammonium surfactant is as shown in the specification. The preparation method for the erucic acid-based alkyl quaternary ammonium surfactant comprises the steps of compounding erucyl amide and compounding the erucic acid-based alkyl quaternary ammonium surfactant in turn. The invention can solve the problems of reducing sand-carrying capacity and reducing performance caused by quick reducing colloidal viscosity under high temperature and high shearing rate of the present quaternary ammonium surfactant used as the main agent of the clean fracturing fluid.

The invention relates to a fracturing fluid capable of resisting high salinity water quality. The fracturing fluid is characterized by being composed of a base fluid and a cross-linking fluid which are fully mixed in proportion. The base fluid contains a chelate cosolvent and a chelate stabilizer, wherein the chelate cosolvent can restrain high salinity of water quality and promote swelling of guanidine gum. The base fluid comprises 98.2-98.65 parts of high salinity surface water, 0.1-0.15 part of the chelate cosolvent,0.3-0.4 part of thickener, 0.1-0.15 part of bactericide, 0.3-0.5 part of clay stabilizer, 0.5 part of demulsifying cleanup agent and 0.05-0.1 part of the chelate stabilizer; the cross-linking fluid comprises 50 parts of water, 50 parts of organic cross-linking agents and 0.35 part of gel breaker; and the fracturing fluid comprises 99.2-99.5 parts of the base fluid and 0.5-0.8 part of the cross-linking fluid. By aid of the fracturing fluid, water resources can be saved effectively, and the success rate for fracturing construction can be improved.