792 results about "Fracturing fluid" patented technology

The invention discloses a deep learning assisted acceleration fracturing construction parameter intelligent real-time optimization method, and belongs to the field of unconventional oil and gas field development, and the method comprises the steps: constructing a structured sample database covering geological attributes, engineering parameters and fracturing effect responses, and carrying out the unified preprocessing of multi-source data; constructing a multi-modal space-time collaborative prediction model, and combining a multi-expansion time permissible convolutional network, a three-dimensional residual network and a cross attention mechanism; supervised learning training is carried out based on a database, sparse regularization and learning rate scheduling are introduced, and the model precision and generalization ability are improved; a hierarchical collaborative optimization framework of outer-layer Bayesian search-inner-layer CMA-ES refinement is provided, and reservoir transformation volume maximization and construction feasibility are achieved under complex constraints; compared with an existing method, optimization parameters of the method include the cluster distance and the section distance and further include the displacement, the sand concentration, the fracturing fluid type and other construction parameters, and real-time optimization of the fracturing construction parameters can be achieved through the machine learning agent model.

The invention discloses an ultra-low-density high-strength resin proppant capable of being carried by clear water or low-viscosity slickwater. The proppant is prepared by dispersing, polymerizing and curing a mixture comprising 15 to 50 weight percent of vinyl monomer, 5 to 10 weight percent of acrylate monomer and 50 to 70 weight percent of unsaturated resin. The preparation method comprises the following steps: controlling the resin composition in a water phase by virtue of a dispersing agent and a rotating speed to form spherical liquid drops with the particle size of 12-140 meshes and the sphericity of nearly 100%; then, the temperature ranges from 30 DEG C to 80 DEG C; the propping agent provided by the invention has ultra-low density, can be carried by clear water or low-viscosity slickwater, is suitable for low-viscosity fracturing fluid, low-displacement construction and small-scale fracturing, can realize ultra-far-end seam net support, and greatly increases the oil and gas drainage area. The breaking rate under the closing pressure of 20-90 MPa is lower than 2%, the surface is weakly lipophilic, and the oil-phase flow conductivity is higher than the water-phase flow conductivity.

The invention relates to the technical field of well site fracturing, and discloses a well site fracturing dynamic analysis method based on the Internet of Things, which comprises the following steps: S1, constructing a multi-level sensor network in a well site for acquiring fracturing equipment operation parameters, underground reservoir dynamic response data, fracturing fluid performance parameters and well site surrounding environment monitoring data in real time to form multi-source data; s2, preprocessing the collected multi-source data through an edge computing node to obtain preprocessed data, uploading the preprocessed data to a cloud analysis platform through an encryption transmission protocol, and constructing a well site fracturing digital twinborn model on the cloud analysis platform; s3, the cloud analysis platform carries out correlation calculation on the preprocessed data and the digital twinborn model through a multi-dimensional analysis model, and a comprehensive evaluation result of the fracture propagation dynamic characteristics, the reservoir flow conductivity and the fracturing equipment operation state is generated; and S4, generating a regulation and control instruction based on a comprehensive evaluation result, and dynamically adjusting the fracturing parameters.

The invention relates to the technical field of oil development, in particular to a shale oil and gas fracturing sliding sleeve capable of being opened and closed repeatedly and a using method. According to the technical scheme, a central pipe fracturing liquid inlet is formed in the upper side of a central pipe, and a reversing rail is arranged on the surface of the outer wall of the middle; a sealing cylinder sleeve and a one-way circulating valve carrier are sleeved outside the central pipe, a fracturing piston, a swivel pressing cap and a reset spring are installed in an annulus, a constant-pressure opening cavity is formed in the inner wall of the fracturing piston, a swivel is installed in the swivel pressing cap, a track pin is installed in the swivel, and the position is moved along a reversing track on the surface of the outer wall of the central pipe through the track pin. The fracturing piston moves downwards to the position of the cylinder sleeve fracturing liquid outlet under the action of pressure, the fracturing function is started, fracturing liquid is sprayed out along the cylinder sleeve fracturing liquid outlet to enter a target fracturing layer, fracturing construction of a plurality of fracturing layers can be achieved through multiple times of fracturing liquid injection and injection stopping, the fracturing sliding sleeve can be repeatedly opened and closed, and the fracturing construction efficiency is improved. And fracturing construction requirements of shale oil and gas with different layers can be met.

The invention discloses a quantitative evaluation method for complexity of shale oil and gas horizontal well reservoir reconstruction cracks, which comprises the following steps: determining a crack development strength factor representing reservoir inherent crack development potential by calculating a mineral heterogeneous coefficient based on rock sample mineral component data at each perforation cluster position in a target fracturing section; determining the optimal fracture length by combining reservoir numerical simulation, determining the total fracturing fluid amount, performing non-uniform distribution according to the heterogeneity of each cluster, and determining a fracture propagation complexity factor representing the dynamic propagation complexity of the hydraulic fracture; weighting the two factors to obtain a crack complexity index for comprehensively evaluating the reservoir transformation effect, and performing grading; according to the method, static geological evaluation and dynamic engineering evaluation are combined, quantification of inter-cluster transformation differences is achieved, the defects that a traditional method is one-sided in evaluation and low in precision are overcome, and a reliable quantitative basis is provided for optimal design of a shale oil and gas reservoir fracturing scheme and accurate evaluation of the transformation effect.

The embodiment of the invention provides a monitoring device and method for strain transmission from a crack to an optical fiber in a fracturing experiment, and belongs to the technical field of experimental physical simulation. In the device, a pressure medium injection module injects fracturing fluid into a sealed liquid injection shaft arranged on a rock sample until a fracturing crack generated by the rock sample meets the fracturing experiment purpose; the triaxial pressurization module applies confining pressure conforming to the stress condition of the experimental object to the rock sample; and the data processing module receives and processes the optical fiber strain signal acquired by the optical fiber so as to invert the transmission characteristics of the optical fiber strain in the fracturing experiment. Wherein the rock sample is provided with a plurality of penetrating holes; the optical fiber is wound around the rock sample along two or more of the plurality of through holes to acquire the optical fiber strain signal. The device can accurately position the three-dimensional expansion direction and the inclination angle of the crack in the fracturing process, so that researchers are helped to finely analyze a theoretical model of crack stress transfer.

The invention relates to the technical field of carbon dioxide geological sequestration, and discloses a coal seam mixed gas injection, displacement and sequestration integrated device and method.The coal seam mixed gas injection, displacement and sequestration integrated device comprises an injection assembly, a visual confining pressure loading assembly, a crack monitoring assembly, a permeability testing assembly and a gas output analysis assembly; the injection assembly is used for providing and injecting a gas source required by an experiment, the visual confining pressure loading assembly is used for carrying out the experiment based on the gas source injected by the injection assembly, the experiment process is converted into a visual crack image through the crack monitoring assembly, and the permeability testing assembly is used for filtering particles in fracturing fluid in the experiment process. According to the device, a transparent material is adopted, and a CT scanner is combined, so that the problem that a traditional device cannot perform real-time monitoring due to metal shielding is solved, visual monitoring of coal sample crack and pore structure evolution is realized, and the intuition and precision of crack evolution law research are improved; and reliable technical support is provided for revealing the structural response of the coal sample under the action of different stresses and fluids.

The invention discloses a shale gas well fracturing parameter optimization design method and system based on a depth Q network, and relates to the technical field of shale gas development, and the method comprises the following steps: S1, collecting geological parameters, fracturing construction parameters and productivity data of a shale gas well in advance; s2, constructing an agent model and performing environment simulation; and S3, constructing a DQN model. According to the method, a LightGBM algorithm is adopted to construct a data-driven proxy model to simulate a real fracturing environment, an optimization model is constructed based on a deep Q network (DQN), state, action, reward and epsilon-greedy strategies are defined, and technologies such as a variable step size search mechanism, experience playback and target network soft update are combined, so that the real fracturing environment is simulated. The problems that a traditional optimization method is weak in local search capability and low in convergence speed are effectively solved, multivariable synchronous optimization of the unit perforation length proppant dosage and the fracturing fluid dosage is achieved, and a global optimal parameter combination can be rapidly explored.

The invention relates to the technical field of well site fracturing, and discloses an intelligent fracturing method and system for precise fracture forming, and the method comprises the steps: collecting underground multi-dimensional monitoring data in real time; dynamically constructing and correcting a three-dimensional crack expansion model by using the monitoring data, and outputting a prediction path containing crack geometric parameters; based on the prediction path and the real-time downhole pressure deviation, a control instruction is generated through an optimization algorithm; and the control instruction is executed, the sliding sleeve valve element is driven to move, the flow of fracturing fluid is adjusted, and accurate formation of cracks is controlled. According to the method, by fusing underground multi-dimensional monitoring data and dynamically correcting the three-dimensional crack propagation model, prediction deviation caused by single data dimension and static model solidification in a traditional method is overcome, prediction errors of the crack length and the steering angle are reduced, accurate prediction and control of the crack propagation path are achieved, and the method is suitable for large-scale popularization and application. And the geological targeting property of fracturing construction is obviously improved.

A method for controlling a fracture height in unconventional oil and gas reservoirs under multi-bedding interference is provided. The method includes: obtaining geological parameters of a target horizontal well, and determining a fracturing fluid and construction parameters based on a production capacity target of the target horizontal well; determining a hydraulic fracturing process of the target horizontal well based on a hydraulic fracturing model for processing the multi-bedding interference, and evaluating the fracture height; comparing the fracture height with an expected control height, if the fracture height is greater than the expected control height, reducing a displacement of the fracturing fluid or a total time of a hydraulic fracturing to update the construction parameters until the fracture height is less than the expected control height; and performing the hydraulic fracturing on the target horizontal well based on updated construction parameters.

The invention discloses a coal seam induced fracturing method. A hydraulic fracturing fluid comprises a basic aqueous phase system and induced functional particles dispersed in the basic aqueous phase system. The prepared hydraulic fracturing fluid is injected into a target stratum at the set displacement and pressure, and an initial main fracture is formed in a reservoir by means of the fluid pressure; in the process, the functional particles in the fracturing fluid enter the crack tip and the potential branch position along with the fluid and are uniformly distributed in a crack channel; along with migration of the fracturing fluid in the stratum, the inducible functional particles act under different triggering conditions, so that the fracture system is evolved into a multi-direction and multi-branch fracture network from a single main fracture, and the transformation volume and the reservoir permeability are increased. Expansion or reaction can be triggered in the fracture, so that stress concentration is generated locally, secondary fracture formation is induced, a complex fracture network is constructed, and reservoir permeability is improved.

The invention relates to the technical field of degradable materials, and discloses a water-soluble degradable fiber and a preparation method thereof. The water-soluble degradable fiber disclosed by the invention is prepared by taking polylactic acid as a main matrix, adding modified sodium lignin sulfonate, polyvinyl alcohol and polyethylene wax, blending, carrying out melt extrusion, and carrying out melt spinning. The fiber has water solubility, degradability, sand carrying performance and salt resistance, and has a good application prospect in a fracturing fluid used in a well drilling fracturing process based on the advantages of water solubility, degradability, sand carrying performance and salt resistance.

The invention discloses digital intelligence powder type distribution-free variable viscosity fracturing fluid skid-mounted equipment and a control method thereof, and belongs to the technical field of oil and gas field development. The equipment comprises a stirring mechanism, a feeding mechanism, a water feeding mechanism and a discharging mechanism which are centrally controlled through a control box. The feeding mechanism adopts a first screw conveyor to convey solid materials to the stirring tank body; the water supply mechanism supplies water to the tank through a water supply pump and a water outlet pipe with an electromagnetic valve, and the water quantity is monitored by a water inlet flow sensor; the discharging mechanism outputs the mixed liquid through a discharging pump, and the viscosity of the fracturing fluid is detected in real time through a viscosity sensor. The control box is connected with all the sensors and execution components, and automatic adjustment and closed-loop control of the material proportion are achieved by collecting flow and viscosity data. According to the invention, accurate and automatic preparation of the fracturing fluid is realized, the problems of inaccurate traditional manual proportioning and poor stability are effectively solved, and the fluid preparation quality and the operation efficiency are remarkably improved.

The invention discloses a rock unconventional reservoir carbon dioxide fracturing temperature field simulation method and system, and belongs to the technical field of oil and gas exploitation. Rock unconventional reservoir parameters and wellbore parameters are obtained, fluid physical property parameters of carbon dioxide fracturing fluid flowing in a wellbore are determined, and a multi-dimensional physical partition model is constructed; the unconventional reservoir is divided into a plurality of physical areas including a fluid flowing area, a static fluid area, a solid area and a porous medium area; thermal boundary conditions of all physical areas are coupled through an energy conservation equation, stratum elasticity modulus and Poisson's ratio are added to the thermal boundary conditions, a thermal-force coupling equation is constructed, carbon dioxide fracturing construction parameters obtained in real time are estimated, temperature field distribution nephograms of carbon dioxide fracturing fluid at different moments in the shaft flowing process are obtained, and the temperature field distribution nephograms of the carbon dioxide fracturing fluid at different moments are calculated. According to the method, the temperature distribution rule of different fracturing stages in the shaft-crack direction can be truly reflected.

The invention discloses a fracturing imbibition system for refracturing a low-permeability tight oil reservoir and a preparation method of the fracturing imbibition system, and belongs to the technical field of fracturing fluids, the fracturing imbibition system comprises: an acid liquid base fluid: hydrochloric acid, hydrofluoric acid, EDTMPS and deionized water; an amphoteric betaine viscoelastic surfactant; biologically modifying the nanoparticles; a Gemini cationic surface active agent; a corrosion inhibitor; and an organic silicon defoaming agent and a fluorocarbon discharge aiding agent. According to the fracturing imbibition system, through the integrated design of the multifunctional surfactant, the problems that a traditional acid fracturing fluid is insufficient in silicate mineral dissolving capacity, high-temperature viscosity is attenuated, and corrosion inhibitor dependence is caused are solved.

The invention provides a high-temperature-resistant degradable temporary plugging agent and fracturing fluid synergistic system and an application method thereof, and the synergistic system maintains a weak acid environment in a construction stage, protects the core strength of the temporary plugging agent to be slowly attenuated, and ensures stable pressure bearing of a plugging layer; in the flow-back stage, a coating layer of the temporary plugging agent is rapidly damaged by injecting a strong acid activating solution, the specific surface area of the temporary plugging agent is rapidly increased, and rapid hydrolysis of an inner core polymer chain is commonly catalyzed by cooperating with high temperature, so that rapid and thorough degradation of the temporary plugging agent is realized. By means of the design, the temporary plugging agent perfectly balances the contradiction between tough plugging in the construction period and rapid plugging removal after construction is completed, the application window of the temporary plugging fracturing technology in a complex high-temperature reservoir is greatly widened, the reservoir damage risk caused by temporary plugging agent residues is effectively reduced, and the fracturing transformation efficiency and the oil and gas well flowback rate are improved.

The application relates to a dry powder drag reducer for fracturing fluid and a preparation method thereof, and belongs to the technical field of drag reducers; the dry powder drag reducer is copolymerized and modified by preparing a polymerizable modifier, aromatic rings and sulfonic acid ion structures are introduced into the dry powder drag reducer, the high-temperature resistance and salt resistance of the dry powder drag reducer are effectively improved, in addition, the modified dry powder drag reducer structure also has a catechol structure, can form a stable five-membered ring borate with a boron crosslinking agent, and the dry powder drag reducer can be mixed with a guar gum drag reducer when the boron drag reducer is used, so that the problem of poor sand carrying capacity of the dry powder drag reducer is effectively solved.

The invention provides a thickening agent for an oil field fracturing fluid, a preparation method of the thickening agent and the fracturing fluid, and belongs to the technical field of fracturing fluids. Comprising a polymer, a synergist, a salt-resistant component, a structure regulator, a suspending agent and an emulsifier. The polymer prepared by the invention contains abundant anions and cations, including quaternary ammonium salt cation structures, sulfonate anions and the like, and molecular winding can be realized through mutual attraction of the anions and cations, so that the elasticity modulus is increased, the sand-carrying performance is improved, and the sand-carrying and thickening performance of the thickening agent is improved; the fracturing fluid has good temperature resistance, salt resistance, shearing resistance, water solubility and thickening property, integrates the functions of drag reduction, sand carrying, fracture forming, swelling prevention, discharge aiding, low damage and the like, and has wide application prospects.

The invention discloses an ultrahigh-temperature and high-salinity water-based guanidine gum fracturing fluid and a preparation method thereof. The guanidine gum fracturing fluid is prepared from a base fluid, a buffering agent, a cage-shaped molecule composite cross-linking agent and a gel breaker according to the mass ratio of 100: (0.1 to 0.6): (0.2 to 0.8): (0.01 to 0.08), the base solution is prepared from the following components in percentage by weight: 0.55 to 0.6 percent of a cyclodextrin modified thickening agent, 0.1 to 0.6 percent of a composite antioxidant, 0.4 to 0.8 percent of a multi-effect auxiliary agent, 0.1 to 0.2 percent of a sterilizing agent and the balance of hypersalinity water. According to the ultrahigh-temperature hypersalinity water-based guanidine gum fracturing fluid, through chemical modification of the guanidine gum thickening agent and synergistic interaction of various additives, the ultrahigh-temperature hypersalinity water-based guanidine gum fracturing fluid can resist the temperature of 200 DEG C, can be directly prepared by using hypersalinity water, realizes good fracture forming, sand carrying, temperature resistance and shearing resistance, and is low in filtration loss and damage; and the requirements of fracturing construction of ultra-deep ultra-high-temperature low-permeability reservoirs of offshore and onshore oil fields are met.

The invention relates to the field of fracturing fluids, in particular to a modified polyacrylamide polymer fracturing fluid and a preparation method thereof, which are used for solving the problems that the existing polyacrylamide polymer fracturing fluid is poor in temperature resistance and salt resistance and is difficult to adapt to fracturing operation requirements in high-temperature and high-salt environments. According to the fracturing fluid, the modified polyacrylamide dry powder thickening agent is adopted as a core component, so that the performance of the fracturing fluid in a high-temperature and high-salinity environment is improved, the thermal stability of the fracturing fluid at a high temperature and the chemical stability of the fracturing fluid at a high salt concentration are remarkably enhanced, and relatively high viscosity and shear stability can be kept in the high-temperature and high-salinity environment; therefore, effective sand carrying, collapse prevention and crack expansion in fracturing operation are guaranteed, the oil well fracturing effect and efficiency are remarkably improved, effective development of oil and gas resources is achieved, and the method can be widely applied to oil and gas exploitation of deep and complex geological structures, the exploitation efficiency is improved, and economic benefits are obtained.

The embodiment of the invention relates to the technical field of oil and gas field development, in particular to a fracturing simulation device and method.The fracturing simulation device comprises a pump injection system, a reconstruction system, a flowback system and a monitoring system; the pump injection system is used for injecting sand-carrying fracturing fluid into the horizontal shaft; the reconstruction system is used for performing multi-cluster fracturing on the rock sample based on the sand-carrying fracturing fluid injected into the horizontal shaft; inverting rock sample multi-cluster fracturing to obtain fracture form data of the rock sample; the flow-back system is used for enabling sand-carrying fracturing fluid to flow back to the horizontal shaft from rock sample cracks after rock sample multi-cluster fracturing is finished; the monitoring system is used for acquiring migration data of the sand-carrying fracturing fluid corresponding to the fracture form data so as to determine a fracturing scheme according to the migration data, and the migration data at least comprises first migration state data of the sand-carrying fracturing fluid in the process of flowing back to the horizontal shaft.

The invention discloses a soft coal seam nanofluid fracturing propping material and a preparation method thereof.The soft coal seam nanofluid fracturing propping material is prepared from, by weight, 80-90% of a base material, 1-5% of a super-hydrophobic coating, 5-10% of a catalytic active component and 5-15% of a rheological enhancer, the base material is a compound of high-purity silicon dioxide nanoparticles and graphene nanosheets GNP, the particle size of the high-purity silicon dioxide nanoparticles is 50-200 nm, the super-hydrophobic coating is a fluorosilane modified layer, the thickness of the super-hydrophobic coating is 5-20 nm, and the invention relates to the technical field of coal bed gas exploitation. According to the soft coal seam nanofluid fracturing propping material and the preparation method thereof, the surface of the material is provided with a super-hydrophobic coating, friction force with a coal matrix is reduced, high embedding resistance is achieved, the flow conductivity is specifically enhanced, an extra flow channel is provided through a porous nanostructure, the fracturing fluid permeability is improved, and meanwhile gas desorption can be cooperated; catalytic active sites are introduced to the surface of the material to promote adsorption and diffusion of methane molecules.

The application discloses a kind of corrosion and scale integrated fracturing fluid, and relates to fracturing fluid technical field.The fracturing fluid includes thickening agent, crosslinking agent, composite corrosion and scale inhibitor and water;The composite corrosion and scale inhibitor includes the first component and the second component with mass ratio of 3:0.5~1, wherein the first component is prepared by the reaction of polyethyleneimine, long-chain acrylate monomer, acrylic acid monomer and hydroxyethyl acrylate monomer, and the second component is prepared by imidazole compound containing a primary amine and glyoxylic acid.The corrosion and scale integrated fracturing fluid of the application has good compatibility between components, and at the same time, it has good corrosion and scale inhibition and anti-sloughing performance.

A high-pressure hydraulic fracturing pump. The pump is in-line in orientation, with a static section having a high-pressure discharge chamber and a dynamic section having a dynamic internal bore threaded to the static section. A fluid routing plug is disposed within a bore which includes the dynamic internal bore. The pump is designed for ease of access and for reducing wear. Large, external threads on the dynamic section pair with internal threads on the static section to reduce wear associated with repeated pressurization of hydraulic fracturing fluid found within the pump. Seals and wear rings are found at a nose of the dynamic section to further prevent wear and damage.

A pump includes a power end and a fluid end coupled to the power end. The power end includes a plunger, and the fluid end includes a crossbore in selective fluid communication with inlet and outlet bores. A suction valve controls fluid communication between the inlet bore and the crossbore, and a discharge valve controls fluid communication between the outlet bore and the crossbore. An actuation device is used to move the discharge valve between an open position and a closed position. A position sensor measures a position of the plunger. A pressure sensor measures a pressure of the crossbore, the inlet bore, or the outlet bore. A controller operates the discharge valve based on data from at least one of the position sensor or the pressure sensor.

The invention discloses a polymer dry powder fracturing fluid and a preparation method thereof, and belongs to the technical field of oil and gas field yield increase. The preparation method comprises the following steps: adding polymer dry powder, modified fluorocarbon, polyvinylpyrrolidone and beta-cyclodextrin into a mixer, stirring and mixing for 20-40 minutes, then sieving with a 120-180-mesh sieve, and packaging to obtain the polymer dry powder fracturing fluid. Nano silicon dioxide is modified and then subjected to a copolymerization reaction with acrylic acid, acrylamide and 2-acrylamido-2-methylpropanesulfonic acid, and nano particles with rigidity and extremely high thermal stability are chemically bonded to a polymer molecular chain, so that thermal oxidative degradation and shear fracture of the molecular chain at high temperature can be effectively inhibited; the shear resistance and the high temperature resistance of the fracturing fluid are improved; the fluorocarbon chain segment in the modified fluorocarbon can significantly reduce the interfacial tension between the fracturing fluid and the inner wall of the pipeline and the formation fluid, and the drag reduction capability of the fracturing fluid is enhanced in cooperation with the uniform and stable viscosity characteristic of the polymer system.

The embodiment of the invention provides a test system for horizontal well fracturing simulation, and belongs to the field of oil and gas field reservoir fracturing. The testing system comprises a shaft comprising an opening in the side wall of the shaft; the fracturing fluid injection device is used for injecting fracturing fluid from the inlet of the shaft, so that the fracturing fluid flows out of the open hole; the signal monitoring device comprises an optical fiber fixed on the outer surface of the shaft, and the optical fiber is used for acquiring the vibration signal and converting the vibration signal into a photoelectric signal; the fracturing fluid circulating device comprises a first connecting pipeline located between the open hole and the fracturing fluid injection device. According to the invention, a distributed optical fiber monitoring system is adopted to record acoustic vibration signals caused under the stable flow condition of the system, and DAS signals under various working conditions can be collected and subjected to data analysis. Meanwhile, the test system can further provide data support for subsequent construction of a machine learning association model.

The invention provides a polymer thickening agent, a preparation method thereof and fracturing fluid prepared from the polymer thickening agent, and belongs to the technical field of fracturing fluid. The invention relates to a water-soluble polymer, which is prepared from a polymer monomer, acrylamide, methacryloyloxyethyl trimethyl ammonium chloride and 1-vinyl-2-pyrrolidone according to a mass ratio of (111-218): (21-36): (16-23): (41-52). The polymer thickening agent prepared by the invention has better tackifying performance, shearing resistance, salt resistance, excellent temperature resistance, good sand-carrying performance and better acid resistance, reduces the acid rock reaction rate, improves the penetration depth of acid etching cracks, is non-toxic, safe and environment-friendly, is safer in gel breaking and lower in damage, and has a wide application prospect.

The invention provides a shale primary formation water ion composition evaluation method and device. The method comprises the following steps: acquiring ion composition and tritium content of flow-back fluid in at least one time after hydraulic fracturing of a target well section of a target shale gas well; the ion composition and the tritium content of fracturing fluid used for hydraulic fracturing of the target well section of the target shale gas well are obtained; on the basis of the obtained tritium content of the flow-back fluid at each time and the tritium content of fracturing fluid used for hydraulic fracturing of the target well section of the target shale gas well, the mixing proportion of formation water in the flow-back fluid at each time is determined; and determining the ion composition of the formation water of the target well section of the target shale gas well by combining the determined mixing proportion of the formation water in the flow-back fluid at each time based on the obtained ion composition of the flow-back fluid at each time and the obtained ion composition of the fracturing fluid at each time. According to the method, the water ion composition of the primary formation of the shale reservoir can be accurately determined by utilizing the fracturing flow-back fluid ion content and tritium nuclide characteristics.

The invention provides a fracturing fluid base fluid, a water-based fracturing fluid and a preparation method of the water-based fracturing fluid, and relates to the technical field of oil fields. The fracturing fluid base fluid is prepared from the following components in percentage by mass: 97.3 percent to 98.1 percent of produced water, 0.5 percent to 0.55 percent of hydroxypropyl guar gum, 0.004 percent to 0.005 percent of sodium hypochlorite, 0.015 percent to 0.03 percent of citric acid, 0.1 percent to 0.18 percent of dodecyl dimethyl benzyl ammonium bromide, 0.2 percent to 0.3 percent of ethylenediamine tetraacetic acid disodium salt, 0.3 percent to 0.5 percent of a temperature stabilizer, 0.6 percent to 0.8 percent of a pH value regulator and 0.2 percent to 0.3 percent of a cleanup additive; the pH value of the fracturing fluid base fluid is 7.5. The fracturing fluid base fluid prepared from the produced water has the advantages of rapid adhesion, no precipitation, no weak crosslinking and no floccule phenomenon, so that the guar gum fracturing fluid prepared from the fracturing fluid base fluid has the characteristics of self-adaption to a reservoir, ultralow damage and high performance.