172 results about "Cement sheath" patented technology

The invention discloses a vibration-CO2 corrosion coupling effect real-time monitoring system and monitoring method for a well cementation cement sheath of an oil and gas well in a high-temperature and high-pressure environment. The system comprises a kettle system which is fixed with a base of an axial loading system, and a push rod of the axial loading system extends into the kettle system from the center of a kettle cover and is pressed on a detected body; the CT detection system is mounted below a jack supporting plate of the axial loading system; the electrolytic corrosion system is connected with the lower end of a first embedded axial pipeline on the side wall of a kettle body in the kettle system so as to apply an experimental environment; the gas pressurization system is divided into two paths, one path is led into the kettle system from the lower part, and the other path is connected with the lower end of the second embedded axial pipeline; a sleeve of the kettle system is fixed in the kettle system, the nondestructive testing system is installed in the middle of the sleeve, and the vibration system in the sleeve is installed on the lower portion of the sleeve. According to the invention, axial loading, gas pressurization and heating devices are integrated, and an underground high-temperature and high-pressure environment is simulated; and CT and ultrasonic waves cooperate to realize multi-dimensional dynamic monitoring of the corrosion process.

A wellbore staged operation method includes running, after a first well drifting operation is performed on a wellbore, a pipe string (100) in the wellbore, wherein the pipe string (100) includes, along a direction from bottom to top, a floating hoop (2), a plug seat (7), a toe-end sliding sleeve (3), and a fracturing sliding sleeve (4); performing a cementing operation, wherein cement slurry pumped into an inner chamber of the pipe string (100) enters an annulus between the pipe string and the wellbore through the plug seat (7) and the floating hoop (2) to form a cement sheath, the cement sheath isolating the toe-end sliding sleeve (3) from the fracturing sliding sleeve (4); performing a second drifting operation to ensure the toe-end sliding sleeve (3) of the pipe string (100) exposed; performing a pressure test for the pipe string; and performing staged fracturing constructions.

A numerical simulation method for the integrity of cement sheath systems in oil and gas wells under alternating temperature and pressure is characterized by the use of extended finite element method (XFEM), concrete damage plasticity model theory, Cohesive element method, and bilinear traction separation criterion, based on elastoplastic theory and plastic damage theory. This method can simulate not only the failure process of the cement sheath-casing interface under alternating temperature and pressure and characterize the mechanical behavior of interface failure, but also the failure process of the cement sheath itself and characterize its mechanical behavior. By comprehensively analyzing the failure behavior of the cement sheath system integrity in oil and gas wells, this method enables a realistic evaluation, prediction, and diagnosis of the integrity of the casing-cement sheath-casing assembly system under alternating temperature and pressure, which helps optimize cement slurry systems, improve cementing quality, and prevent cement sheath integrity failure. This invention is applicable to the field of oil and gas drilling and production engineering technology.

The invention discloses a casing centralizer with a pipe diameter adjusting function, and relates to the technical field of petroleum and natural gas drilling engineering equipment, the casing centralizer comprises two fixing rings which are symmetrically distributed left and right, the outer surface of each fixing ring is provided with a plurality of fixing seats at equal intervals in the circumferential direction, and each fixing seat is rotatably connected with a connecting plate; an elastic plate is arranged between the left connecting plate and the right connecting plate in the horizontal direction, and the two ends of each elastic plate are rotationally connected with the two adjacent connecting plates respectively. By rotating the adjusting bolt, the driving screw rod and the fixing pipe are in threaded transmission, and the distance between the two fixing rings is accurately controlled, so that the annular supporting frame formed by the connecting plate and the elastic plate generates controllable radial deformation; stepless adjustment of the supporting outer diameter is achieved, different borehole sizes are accurately matched, the problem that a centralizer with a fixed size is insufficient in supporting or difficult to descend is solved, it is ensured that a casing pipe is efficiently centered, and a foundation is laid for forming a uniform cement sheath.

The invention discloses a hydraulic fracturing shaft leakage detection system and method, and the method comprises the steps: controlling an electro-hydraulic servo pressure regulating valve to inject a hydraulic medium into a confining pressure cavity, and simulating the pressure applied to the confining pressure cavity in a shaft environment; a high-pressure pump is controlled to inject high-pressure fluid into the shaft environment, and the hydraulic fracturing working condition is simulated; in the process of simulating the actual working condition, pressure data in the confining pressure cavity and strain data of any measuring point in the cement sheath are obtained, and when it is monitored that the strain data exceed a preset threshold value, pressure interlocking control is triggered: an electro-hydraulic servo pressure regulating valve is controlled to conduct graded pressure reduction treatment on the pressure in the confining pressure cavity; and fitting a crack propagation path of the cement sheath by adopting a least square method according to the monitored temperature data of the cement sheath and the pressure data after pressure interlock control. The simulation precision of the dynamic expansion path of the cement sheath crack can be improved, qualitative speculation of the crack expansion path is changed into quantitative reduction, and a reliable basis is provided for shaft sealing design.

The invention discloses a cement sheath thickness real-time calculation method, device, equipment, medium and product, and relates to the field of geophysical cased well acoustic logging, the method comprises the following steps: carrying out waveform extraction, frequency domain feature extraction and stoneley wave parameter calculation on standard array sound wave data to obtain corresponding processing data; forming a training sample set by taking the processed data as sample data and taking an open hole diameter corresponding to the standard array sound wave data as label data; training by using the training sample set to obtain a hole diameter prediction model; performing waveform extraction, frequency domain feature extraction and stoneley wave parameter calculation on the actually measured array sound wave data acquired in real time to obtain processing data corresponding to the actually measured array sound wave data, and inputting the processing data into the borehole diameter prediction model for prediction to obtain a real-time predicted borehole diameter; and calculating the thickness of the cement sheath in real time by combining the external diameter of the standard According to the invention, real-time prediction of the thickness of the cement sheath based on multi-data driving is realized.

The invention provides a monitoring system and a monitoring method for a micro annular space of an underground cement sheath. The monitoring system comprises a reaction kettle, a first injection device, a second injection device, a third injection device and a monitoring assembly, the interior of the reaction kettle is divided into a confining pressure cavity, a second annular cavity and a first annular cavity, the second annular cavity is arranged around the peripheral side of the first annular cavity, and the confining pressure cavity is arranged around the peripheral side of the second annular cavity. First liquid is injected into the first annular cavity through the first injection device to simulate the temperature and pressure in the casing pipe. Third liquid is injected into the confining pressure cavity through a third injection device, and the temperature and pressure in the stratum are simulated. And cement paste is injected into the second annular cavity through the second injection device to form a cement sheath. And the temperature information and the sound wave information of the cement sheath are monitored through the monitoring assembly, so that the expansion behavior of the micro annular space in the cement sheath in the low-temperature carbon dioxide injection process can be obtained.

The invention is suitable for the field of casing sidetrack drilling operation, and provides an elastic piece prizing type side pushing mechanism for a cement sheath knapper, the elastic piece prizing type side pushing mechanism comprises a first fixing rod, a second fixing rod, an inserting rod, an elastic piece and a movable roller shell, the elastic piece is bent to jack the movable roller shell to do lateral movement, extrusion force is applied to a casing to induce cracking of a cement sheath, and the elastic piece prizing type side pushing mechanism is suitable for the cement sheath knapper. An elastic piece prizing type lateral pushing structure is adopted, an independent driving cavity, a sealing assembly and a guiding structure do not need to be arranged, the structure of the mechanism is greatly simplified, the overall outer diameter size is reduced, miniaturization and compactness of the mechanism are achieved, the mechanism meets the tripping-in requirements of small well diameters, thin-wall sleeves and complex well conditions, meanwhile, lateral extrusion is achieved through elastic deformation of an elastic piece, and the service life of the mechanism is prolonged. Stable extrusion force is guaranteed, and the defects that an existing piston driving structure is complex and large in size are overcome.

The invention discloses a device for testing the sealing performance of a full-size sleeve-cement sheath-stratum combination of a hydrogen storage bank. Relates to the technical field of petroleum and natural gas drilling and production engineering, and is characterized in that the device comprises a sleeve-cement sheath-simulated stratum maintenance device for preparing the simulated stratum, an alternating load applying device and a sealing performance testing device; the method comprises the following steps: preparing a full-size simulated stratum through a maintenance device, constructing a'sleeve-cement sheath-simulated stratum 'integrated assembly by taking the full-size simulated stratum as a carrier, completing maintenance, and detecting the sealing integrity of the cement sheath after simulating the actual underground working condition; the simulation stratum capable of being used for testing the sealing performance of the cement sheath is prepared, the full-size simulation stratum serves as a core testing carrier, and quantitative evaluation of the sealing performance of the full-size cement sheath is achieved.

The invention belongs to the technical field of oil well windowing, and discloses a double-layer casing windowing sidetrack drilling test device and test method. The double-layer casing windowing sidetrack drilling test device comprises an inner-layer casing, an outer-layer casing, a filler, a guide piece and a drilling piece, the outer-layer casing is arranged outside the inner-layer casing in a sleeving mode, and an oil well with the double-layer casing can be simulated; the filling space between the inner-layer sleeve and the outer-layer sleeve can be filled with the filling material, and the filling material is used for simulating a cement sheath in actual construction; the guide piece fixed in the inner hole of the inner-layer sleeve is used for simulating a whipstock; a drilling part used for simulating a milling cone can move to be in contact with the guiding inclined face of the guiding part and move to be in contact with an inner-layer sleeve, a filling material or an outer-layer sleeve under the guiding of the guiding inclined face, the drilling part can mill the inner-layer sleeve, the filling material or the outer-layer sleeve through rotation so as to open windows and drill holes in the inner-layer sleeve, the filling material and the outer-layer sleeve, and the inner-layer sleeve, the filling material and the outer-layer sleeve can be driven by the drilling part to rotate. Double-layer casing windowing sidetrack drilling is simulated on the ground, and the success rate of actual windowing sidetrack drilling is increased.

The application provides a cement sheath anti-casing deformation capacity evaluation method and system for oil and gas well cementing, and the evaluation method specifically comprises the following steps: filling the annulus of a mold with cement slurry for cementing after preparation to obtain a sample; applying non-uniform extrusion or shear load to the sample by using a shear test device to simulate the displacement amount of a formation; determining the relative displacement ΔS and the radial size change amount ΔD of the inner cylinder of the mold; determining the deformation amount ΔL of the sample based on the relative displacement ΔS and the radial size change amount ΔD; and judging whether the deformation amount ΔL of the sample is greater than 25 mm, if yes, it is considered that the cement slurry belongs to a large strain cement slurry, and the cement sheath formed has the ability to inhibit casing deformation, otherwise, it is considered that the cement sheath formed by the cement slurry does not have the ability to inhibit casing deformation. The application can quantitatively evaluate the contribution of the cement slurry to reducing the degree of casing deformation, and provides technical support for selecting a cement slurry to reduce casing deformation caused by formation sliding.

The invention relates to the field of oil and gas well drilling and production, and discloses experimental equipment for simulating erosion corrosion of an oil and gas well at high temperature and high pressure and a use method thereof. The experimental equipment comprises an erosion corrosion fluid module, a corrosion fluid module, a reaction kettle and a damage analysis module. The erosion corrosion fluid module is used for manufacturing an erosion corrosion fluid material; the corrosive fluid module is used for manufacturing corrosive fluid materials. The reaction kettle is provided with a reaction chamber for mounting an experimental object, and the experimental object is a combined body comprising an oil pipe, a sleeve and a cement sheath; the experimental object and the reaction chamber act together to form a first chamber in the oil pipe and communicated with the erosion corrosion fluid module, a second chamber located between the oil pipe and the casing pipe and communicated with the erosion corrosion fluid module, and a third chamber located between the casing pipe and the cement sheath and communicated with the erosion corrosion fluid module. And the damage analysis module is used for analyzing the experimental object and obtaining an erosion-corrosion analysis result of the experimental object, so that the erosion-corrosion resistance test experiment of the material under the complex underground working condition is completed.

This invention discloses a method for reliability analysis of cement sheath quality in coiled tubing drilling, relating to the field of construction technology. The steps of this invention are as follows: S1: Identify the damage forms and characteristics of the cement sheath; S2: Test the impact of cement sheath loss on the external load of the casing; S3: Test the casing performance using different parameters; S4: Calculate the external load and strength data of the casing; S5: Calculate reliability data, test the failure morphology of the cement sheath after fracturing under high-pressure formation fluid and fracturing conditions, test the sealing integrity of the perforated section under fracturing operation conditions, and observe the cement sheath crack propagation morphology and microcrack propagation characteristics around the perforation channel using CT scanning. This invention, through method improvements, facilitates the visual observation of cement sheath failure morphology; evaluates the cement sheath sealing performance under different operating conditions; and analyzes the impact of different cement sheath damage degrees on the casing stress state.

This invention discloses a core-shell structure oil absorbent for cementing under oil-based drilling fluid conditions and its preparation method. The oil absorbent comprises the following components in parts by weight: 20-25 parts ester monomers, 3-7 parts modified composite materials, 1-5 parts dispersant, 20-25 parts pore-forming agent, 0.5-0.8 parts crosslinking agent, 1.3-1.5 parts initiator, and 50-70 parts water. The oil absorbent of this invention expands after absorbing oil and possesses a certain rigidity, compensating for defects without causing a decrease in the mechanical properties of the cement stone. Furthermore, the addition of this oil absorbent allows the cement stone to meet the low elasticity requirements under multi-stage fracturing conditions, enhancing the elasticity of the cement stone and improving the long-term sealing performance of the cement sheath.

The present invention discloses a device and method for evaluating the seepage corrosion and mechanical properties of cement rings in well cementing, which belongs to the field of corrosion evaluation of cementing materials in oil and gas wells. The device includes an acidic corrosive gas injection system, a formation water injection system, a high-pressure oil injection system, a control system, and a corrosion and testing system. The corrosion and testing system comprises a main body, an upper cover, and a base. The main body comprises, from the outside to the inside, a metal cylinder, a simulated formation, a simulated casing, and a center rod. A cement ring maintenance-corrosion space is formed between the simulated formation and the simulated casing. A temperature control device is provided in the annulus formed between the simulated casing and the center rod. Multiple displacement gauges are provided at different positions and angles on the center rod to measure the deformation displacement of the simulated casing-cement ring assembly. The method for evaluating the seepage corrosion and mechanical properties of cement rings using this device is simple to operate and simultaneously realizes three functions: cement ring maintenance under high temperature and high pressure, acidic medium corrosion, and cement ring mechanical integrity evaluation. It has broad application prospects.

The application relates to a device and a method for testing the bonding strength between a casing and well cement by using rotary torque, and belongs to the technical field of drilling material detection. The device comprises a test sample, a slip, a joint and a load applying device. Power is generated by a power device of a rotary dynamic torque tester to form rotary output, which drives a wellbore simulation casing to rotate. The wellbore simulation casing and a cement sheath fixed on a cementing cylinder are relatively displaced to form rotary torque. A torsion meter reads and records the torsion value when the cementing interface is damaged in real time, and the maximum value of the torsion value is taken as an index for representing the cementing strength. The device disclosed by the application is simple and convenient to operate, simple in structure, low in cost and reusable, and can be widely applied to the measurement and evaluation of the cementing performance of casings and well cement of different wellbore sizes.

The application discloses a temperature calculation method for a multilayer casing cement sheath structure, which comprises the following steps: discretizing a radial heat conduction differential equation in a cylindrical coordinate by using a difference method to calculate the temperature of non-boundary points and non-interface points of a wellbore; calculating the temperature of boundary points and interface points based on the boundary conditions and the temperature and heat flux density continuous conditions of any structure interface; and calculating the radial temperature from the center of the wellbore to the outer boundary of a stratum by using a linear equation group obtained by discretizing the heat conduction differential equation in the cylindrical coordinate and the boundary conditions of the radial temperature of the multilayer structure of the wellbore. According to the structural parameters of the wellbore, the thermal physical property parameters of materials and the boundary temperature parameters, the application can accurately calculate the temperature of the multilayer casing cement sheath structure, solves the radial temperature transmission problem under different structures according to the thermal continuous boundary conditions of different structure contact surfaces, and provides a theoretical basis for the temperature transmission problem of the multilayer structure since the calculation method is accurate and efficient.

The invention provides an oil field well casing residual strength evaluation method and system based on numerical simulation, and relates to the technical field of oil field development casing safety evaluation. Based on the casing damage evaluation basic data of the target oil field block, establishing a block scale fluid-solid coupling numerical model reflecting an injection-production dynamic and formation mechanical response coupling relationship, and obtaining redistributed crustal stress field data around a shaft; redistributed crustal stress field data are used as boundary conditions, a three-dimensional coupling mechanical model containing a stratum, a cement sheath and a casing pipe is established in combination with the casing pipe structure and material parameters, and the stress distribution and the maximum equivalent stress of the casing pipe under the injection-production load effect are obtained through numerical simulation; and based on the maximum equivalent stress and the yield strength of the casing material, performing residual strength evaluation and damage risk grading on the casing according to the strength utilization rate and the residual strength coefficient. Therefore, the accuracy and the dynamic prediction capability of the residual strength evaluation of the oil field casing are improved, and a scientific decision basis is provided for casing damage treatment.

The invention relates to the technical field of petroleum and natural gas, and discloses a method and system for testing the failure time of the self-healing capacity of a well cementation cement sheath. The well cementation cement sheath performance simulation experiment device is used for executing the following steps that self-healing performance testing is conducted on a well cementation cement sheath multiple times till the gas measurement flow does not change, and multiple self-healing capacity values corresponding to multiple times are obtained; performing polynomial fitting according to the plurality of times and the corresponding plurality of pieces of self-healing capability data to obtain a relation model of the time and the self-healing capability; and obtaining the time corresponding to zero of the self-healing capability value by using the relation model, and obtaining the failure time of the self-healing capability of the well cementation cement sheath. According to the invention, the technical problem that how long the self-healing capability of the well cementation cement sheath fails under the conditions of high temperature and high pressure cannot be determined can be solved, and the failure time of the radial self-healing capability of the well cementation cement sheath can be accurately tested by measuring and utilizing numerical fitting.

The invention relates to the technical field of corrosion resistance of CCUS well cementation cement sheaths, in particular to a tertiary amine modified CCUS corrosion-resistant admixture as well as a preparation method and application thereof. And uniformly mixing the epoxy resin emulsion with the tertiary amine modified curing agent for reaction to obtain the tertiary amine modified CCUS corrosion-resistant admixture. The tertiary amine modified CCUS corrosion-resistant cement admixture system is prepared from the tertiary amine modified CCUS corrosion-resistant admixture, a fluid loss agent, a coagulation accelerator and a defoaming agent. The CCUS corrosion resistance of a cement matrix is improved by adding a tertiary amine modified CCUS corrosion-resistant cement admixture system into oil well cement. The tertiary amine modified CCUS corrosion-resistant cement system provided by the invention has excellent corrosion resistance, a composite corrosion-resistant structure is constructed through cooperation of a polymer film structure and tertiary amine group carbon adsorption, and the corrosion resistance of a cement matrix is remarkably improved.

A comprehensive safety evaluation method, system, equipment, and storage medium for gas storage injection and production wells includes the following steps: S1, calculating the effective internal and external pressures, remaining internal pressure resistance, and external extrusion resistance of the gas storage injection and production well casing to evaluate the remaining strength of the casing; S2, calculating the failure probability of the gas storage injection and production well casing and cement sheath, generating curves showing the variation of casing failure probability with service life and cement sheath failure probability with formation pressure to measure the reliability of the gas storage injection and production wells; S3, predicting the failure probability of gas storage injection and production wells by reading and learning failure probability prediction sample data; S4, calculating and generating curves showing the variation of corrosion rate of gas storage injection and production wells with service life to predict the remaining life of the gas storage injection and production wells, using the prediction results to control the service life of the gas storage injection and production well casing, and providing a decision-making basis for whether to seal or modify the gas storage well.

A cement sheath sealing performance simulation method includes: establishing a three-dimensional deformable solid model of the borehole, dividing the model from inside to outside into a casing, cement sheath, a filter cake and a formation, performing mesh division, assigning material parameters to the casing, cement sheath and formation; establishing an element set for defining the filter cake material, assigning the element set to the meshes of the filter cake, obtaining material parameters of the filter cake based on Python code by considering the filter cake's heterogeneity, setting a boundary condition, simultaneously applying a load to the casing, inserting cohesive units for the interfaces between the casing and cement sheath, the cement sheath and the filter cake, and the filter cake and the formation respectively, performing linear damage evolution based on Maxs damage, and obtaining the equivalent plastic strain of the cement sheath and the micro-annulus size during the load application.

The present application belongs to the field of oilfield drilling fluid, and discloses a multifunctional polymer drilling fluid mud cake modifier, a preparation method and application thereof, wherein the mud cake modifier comprises, by mass fraction, 5-95% of acicular wollastonite powder, 1-20% of sodium gluconate and 1-10% of instant sodium carbonate; the mud cake modifier is directly added into drilling fluid during use, and the addition amount is 0.5-1.5% by mass fraction. The mud cake modifier can improve the hardness, compactness and toughness of the mud cake, and improve the properties of the mud cake on the well wall; the mud cake modifier can form a thin, hard, tough and compact mud cake on the well wall, reduce the filtration loss of the drilling fluid, improve the rheological property of the drilling fluid, has no obvious influence on the density and viscosity of the drilling fluid, and has the dual functions of enhancing the affinity between the cement sheath and the mud cake and stabilizing the well wall.

The invention discloses a marine natural gas hydrate multi-gas commingling production drilling shaft temperature field calculation method which comprises the following steps: S1, establishing a marine natural gas hydrate multi-gas commingling production drilling shaft temperature model according to the law of conservation of energy; s2, on the basis of the marine natural gas hydrate multi-gas commingling well drilling shaft temperature model, an energy conservation equation of an infinitesimal body of each area in a shaft is analyzed by utilizing the energy conservation law, the heat transfer theory basic theory and the fluid mechanics basic theory, and a marine natural gas hydrate multi-gas commingling well drilling shaft temperature field calculation method is obtained; the infinitesimal body includes one or more of a drill string internal fluid, a drill string, an annulus internal fluid, a casing, a cement sheath, and a wellbore surrounding formation. The temperature distribution mathematical model in the shaft circulation period is established, and the temperature of the marine natural gas hydrate multi-gas commingling well drilling shaft can be accurately calculated.

The invention provides a cement sheath thickness measurement method, device and equipment and a storage medium, and belongs to the field of applied geophysics and oil-gas exploration, and the measurement method comprises the steps: obtaining full-wave waveform data of a Lamb wave received at different orientations at a certain depth point in a target depth interval; performing waveform processing on the full-wave waveform data of the Lamb wave received at different orientations of the depth point, and determining corresponding group delays of the depth point at different orientations; based on the group delays corresponding to the depth point in different orientations, circumferential cement sheath thicknesses corresponding to the depth point in different orientations are determined; and repeatedly executing the steps until the circumferential cement sheath thickness corresponding to each depth point of the target depth interval in different directions is obtained. Through the method provided by the invention, accurate calculation of the thickness of the cement sheath between the casing and the stratum can be simply and quickly realized, and the well cementation quality can be accurately evaluated.

The invention provides an ultrahigh-strength well cementation cement system as well as a preparation method and application thereof. The cement system comprises the following raw materials in parts by weight: 0.5-1.5 parts of a water reducing agent, 100 parts of a solid reactant, 1-10 parts of a toughening material, 0-5 parts of a dispersing agent, 0.02-0.06 part of a suspension stabilizer diquat, 0.5-5 parts of a defoaming agent and 20-35 parts of water, the solid reactant is a combination of micro-silicon and cement; the toughening material is calcium sulfate whiskers or composite fibers. The cement strength is improved mainly by reducing the water cement ratio, the viscosity of the cement paste is reduced through the ball effect of the micro-silicon, the polymer water reducing agent and the dispersing agent, and the suspension stability of the cement paste is controlled by using the diquat glue. The cement system disclosed by the invention has better flowability, well cementation cement stone with high strength and excellent suspension stability can be obtained by curing under the condition of 50 DEG C for a short time, and the integrity of a cement sheath after bearing perforation and fracturing operation is favorably improved.

The application discloses a horizontal well section interval optimization method based on cement ring integrity dynamic constraint, and belongs to the technical field of unconventional oil and gas development engineering. The method constructs a non-uniform cementing mechanics model based on a casing eccentricity to lock a stress target, activates a transient fluid-solid coupling mechanism to solve an expansion load, and extracts a spatial stress disturbance scalar. Nonlinear fatigue evolution under alternating load is tracked, and a double-mode safety tolerance limit that locks the body damage and interface anti-channeling is constructed. Finally, the optimal section interval is output by taking the rigid constraint as the driving force for multi-objective optimization. The application optimizes the yield target and wellbore integrity, accurately avoids hidden engineering risks such as annular pressure from the source, and maximizes the comprehensive development benefit of a single well.

The application provides a cementing slurry and a preparation method and application thereof, the cementing slurry comprises oil well cement, active material, hollow glass microspheres, corrosion-resistant material, tough material, suspending agent, dispersing agent, fluid loss additive, retarder, defoaming agent and water; the density of the cementing slurry is 1.2-1.6 g / cm 3 . The preparation method comprises the following steps: (1) mixing oil well cement, active material, hollow glass microspheres, corrosion-resistant material, tough material, suspending agent, dispersing agent and fluid loss additive to obtain dry mixture; (2) mixing retarder, defoaming agent and water to obtain wet mixed agent water; and (3) mixing the dry mixture and the wet mixed agent water to obtain the cementing slurry. The cementing slurry provided by the application realizes high-quality and rapid well building, guarantees long-term sealing integrity of the cement sheath, and provides strong technical support for large-scale exploration and development of high-sulfur natural gas wells and CCUS wells and reduction of wellhead gas channeling and annular pressure bearing risk.

The invention discloses an interface fluid channeling simulation test device and method considering perforation initial damage, and belongs to the technical field of oil and gas exploitation, and the interface fluid channeling simulation test device considering perforation initial damage comprises an inner cylinder assembly, an outer cylinder assembly, a cement sheath body, a container assembly and a perforating gun. The simulation casing pipe and the simulation rock which are matched with the casing pipe component and the rock component in size are designed to form the inner cylinder assembly and the outer cylinder assembly so as to achieve simulation of the shaft structure, and the cement sheath body and the perforating gun are arranged in the filling interval between the inner cylinder assembly and the outer cylinder assembly so as to achieve simulation of the shaft structure. Construction of the test device in an initial damage environment can be achieved, simulation of shaft hydraulic pressure can be achieved by simulating injection of liquid in a first injection interval in a casing pipe based on the constructed test device, and fluid is injected into a first interface, a second interface and a second injection interval through a container assembly. Therefore, the interface fluid channeling simulation test considering the initial damage of the perforation is completed.

The invention discloses a multifunctional high-temperature-resistant strength recession agent for oil well cement and a preparation method thereof, and the recession agent comprises the following components in parts by mass: 75-85 parts of a high-temperature reinforcing agent A, 8-12 parts of a nano anti-permeability preservative B and 8-12 parts of a high-temperature expanding agent C. The high-temperature reinforcing agent A comprises silicon powder compounds with different granularities, the nano anti-permeability preservative B is white carbon black, and the high-temperature expanding agent C comprises 20-25 parts of dihydrate gypsum, 20-25 parts of bauxite and 50-60 parts of magnesium oxide. The invention solves the problems of high permeability and poor corrosion resistance of set cement when only single-mesh silicon powder is used as an anti-recession agent in the prior art. The multifunctional high-temperature-resistant strength declining agent for oil well cement prepared by the invention can simultaneously meet the requirements of high corrosion resistance and low permeability of set cement, prevention of shrinkage of a cement sheath, micro-expansion function and long service life, and overcomes the defects of an oil and gas well cementing technology in related fields.