1445 results about "Well cementing" patented technology

A method may include: providing one or more inputs to a hybrid data generator, wherein one of the one or more inputs is based at least in part on a wellsite location, wherein the hybrid data generator comprises a large language model, and wherein the large language model is based at least in part on a machine learning algorithm; utilizing an information handling system to generate a cement job design based at least in part on the one or more inputs and the hybrid data generator; performing at least a portion of a cementing operation based at least in part on the cement job design; and collecting at least one measurement from at least one sensor during the cementing operation.

The invention provides a cement paste system with high strength, elasticity and toughness and application of the cement paste system in deep coal bed gas horizontal well cementation, and the cement paste system is prepared from the following raw materials in parts by mass: 40-70 parts of oil well cement, 13-40 parts of fly ash, 15-45 parts of slag, 5.0-20.0 parts of water-based organic silicon resin, 0.1-0.5 part of ultra-high performance polyethylene fiber, 3.0-8.0 parts of calcium oxide and 2.0-5.0 parts of calcium sulfate whisker. 1.0-8.0 parts of nano silicon dioxide, 1.0-6.0 parts of a fluid loss agent, 0.5-2.0 parts of a drag reducer, 0.2-1 part of a defoaming agent and 50-80 parts of water. The cement paste system disclosed by the invention has the characteristics of remarkable low-temperature quick setting and high early strength, also has the advantages of low water loss, controllable thickening, simple preparation operation and the like, and set cement is high in compressive strength, high in breaking strength and very excellent in elastic and tough mechanical properties.

The invention provides high-toughness micro-expansive cement paste suitable for high-temperature well cementation. The cement paste comprises the following raw materials in parts by weight: 60-90 parts of G-grade oil well cement, 20-40 parts of an active material, 3-12 parts of a high-performance toughening agent, 3-10 parts of nano oxide, 0.5-5 parts of an expanding agent, 3-5 parts of a chemical exciting agent, 1-3 parts of a high-temperature fluid loss agent, 0.5-3 parts of a high-temperature retarder and 0.1-1 part of a dispersing agent, and 0.2-1 part by weight of a defoaming agent. By adding the active material, the high-performance toughening agent, the nano oxide and the expanding agent, the high-temperature resistance and toughness of the cement paste, the cementation quality of a cement sheath and the like are improved; through the combined action of the four components, the high-temperature resistance, toughness and surrounding rock interface cementation performance of the cement are comprehensively improved; and the cement paste is matched with other components for use, so that the cement paste has the advantages of good stability, low water loss, good rheological property and the like, is suitable for underground gas storage well cementation, can improve the well cementation quality of a stratum sealing section, and ensures the sealing integrity of a cement sheath under frequent injection and production.

The invention relates to the technical field of self-healing agents, in particular to a well cementation cement slurry self-healing agent and a preparation method thereof. The modified polyethylene glycol terephthalate polymer comprises the following components in parts by weight: 30-50 parts of modified polyethylene glycol terephthalate polymer, 2-10 parts of metal oxide, 5-15 parts of lithium silicate, 0.5-2 parts of persulfate, 0.1-1 part of bacillus subtilis and 1-5 parts of calcium lactate. The isosorbide can react with ester bonds in polyethylene glycol terephthalate, so that more hydroxyl groups are introduced, and the hydroxyl groups can interact with cement hydration products or metal oxides and lithium silicate to promote formation of new mineral phases at cracks. The generation of the new mineral phase is beneficial to filling and repairing cracks, and the self-healing of the cement paste is realized, so that the long-term stability of a well cementation structure is improved. Tetraethyl orthosilicate can cooperate with other components such as the modified polyethylene glycol terephthalate polymer to jointly promote the self-healing process of set cement.

The invention relates to a turbine flowmeter suitable for slurry flow measurement and a method for reducing abrasion, and belongs to the technical field of well cementation grouting metrology. The turbine flowmeter comprises a flow pipe body used for feeding formula slurry, and the periphery of the flow pipe body is connected with a plurality of detachable sensor seats; the two retainers are connected to the two ends of the flow pipe body respectively. The shaft sleeve is inserted into one end, facing the flow pipe body, of the retainer; the impeller shaft is inserted into the shaft sleeve and rotates in the shaft sleeve, and the impeller shaft and the flow pipe body are coaxially arranged; the impeller is coaxially connected with the impeller shaft; the technical problems that in the prior art, when a turbine flowmeter is used for mud flow measurement, precision is low, and abrasion resistance is poor can be solved.

The invention relates to the technical field of well cementation materials and provides well cementation cement stone based on water-based benzoxazine resin as well as a preparation method and application of the well cementation cement stone. The well cementation cement stone is prepared from the following components in parts by mass: 400-600 parts of quartz sand, 4-6 parts of a retarder, 4-6 parts of a fluid loss agent, 1-2 parts of a suspension stabilizer, 1-2 parts of a dispersant, 4-6 parts of a high-temperature-resistant water-based benzoxazine monomer and 40-50 parts of water, and the high-temperature-resistant water-based benzoxazine monomer is prepared from a phenolic compound, primary amine and formaldehyde through Mannich reaction. Resin formed by the prepared benzoxazine monomer has improved mechanical properties at a high temperature of 150-200 DEG C, the mechanical properties and high temperature resistance of well cementation cement at a high temperature are significantly improved by filling pores of set cement and optimizing cement components, the benzoxazine monomer in a cement slurry system does not affect the fluidity of cement slurry, and the well cementation cement has a good application prospect. Meanwhile, the high-temperature strength of set cement can be remarkably enhanced, and the cement is suitable for well cementation of high-temperature deep wells.

The invention discloses a multi-scale performance evaluation and optimization method and device for well cementation cement stone, and relates to the technical field of oil exploitation, the well cementation cement stone is subjected to nanoindentation test and scanning electron microscope microstructure test, and a mechanical property-microstructure test result is obtained; performing electronic computer tomography and mercury injection test on the well cementation cement stone, and constructing a pore network three-dimensional model; performing triaxial mechanical property test, thermogravimetric analysis and thermal expansion test on the well cementation cement stone to obtain a thermal-mechanical coupling test result; performing X-ray diffraction and X-ray fluorescence spectrum analysis on the well cementation cement stone to obtain mineral phase information and element information of the cement stone; according to the method, a mechanical property-microstructure test result, topological parameters, a thermal-mechanical coupling test result, cement stone mineral phase information and element information are fused, an optimal design scheme for target well conditions is generated, multi-dimensional performance testing and characterization are achieved, and an accurate basis is provided for well cementation cement stone optimal design and quality control.

The invention relates to the technical field of oilfield development, in particular to a reservoir supercritical carbon dioxide fracturing soaking production simulation method and device. Well cementation is simulated; fracturing simulation: placing the core sample subjected to well cementation in a core holder, applying axial pressure and confining pressure to the core sample, simulating stratum triaxial stress at a required temperature, obtaining initial experimental data of the core sample at the moment, injecting supercritical carbon dioxide into the core sample through a shaft, and obtaining experimental data during core fracturing; soaking is simulated, and the core sample enters a soaking stage after being fractured; carrying out production simulation, enabling the core sample to enter a flowback stage under a specific return pressure condition, and recording experimental data of the core sample in the flowback stage; and performing three-dimensional imaging analysis. According to the method, the spatial distribution of the crude oil after the supercritical carbon dioxide fracturing of the unconventional reservoir can be monitored in real time, and the characteristics of the cracks formed after the fracturing and the crude oil recovery capacity are quantitatively evaluated.

The invention discloses a sliding sleeve opening and closing claw structure for oil and gas well half-way well cementation and an unlocking method, and belongs to the technical field of oil and gas exploitation, the sliding sleeve opening and closing claw structure comprises a casing string, a sliding sleeve, a slip assembly and an opening and closing claw assembly, an external groove is formed in the inner wall end of the casing string, the sliding sleeve is arranged in the external groove in a sliding mode, and the slip assembly comprises a front slip, a rear slip and a vacant groove; the front slip and the rear slip are coaxially arranged and fixedly connected, a vacant groove is formed between the front slip and the rear slip, and the switch claw assembly is movably arranged in the vacant groove and used for adjusting the position of the sliding sleeve in an external groove. The opening and closing states of the sliding sleeve in the casing string can be synchronously controlled, and when the sliding sleeve is clamped in the casing string, the built-in linkage structure can be used for automatic unlocking, so that the sliding sleeve assembly is prevented from being permanently clamped in the casing string.

The invention discloses a well cementation cement sheath seepage corrosion and mechanical property evaluation device and method, and belongs to the field of oil and gas well cementation material corrosion evaluation. The device comprises an acidic corrosive gas injection system, a formation water injection system, a high-pressure oil injection system, a control system and a corrosion and test system, the corrosion and test system comprises a main body, an upper cover and a base, and the main body sequentially comprises a metal cylinder, a simulated formation, a simulated sleeve and a center rod from outside to inside; a cement sheath maintenance-corrosion space is formed between the simulated stratum and the simulated casing, a temperature control device is arranged in an annulus formed between the simulated casing and the center rod, and the center rod is provided with a plurality of displacement meters at different positions and angles to measure deformation displacement of a simulated casing-cement sheath combination. The method for evaluating seepage corrosion and mechanical properties of the well cementation cement sheath by using the device is simple and convenient to operate, realizes three functions of cement sheath maintenance, acid medium corrosion and cement sheath mechanical integrity evaluation at high temperature and high pressure, and has a wide application prospect.

The invention discloses a concentric tube geothermal well structure capable of improving heat exchange efficiency. The concentric tube geothermal well structure comprises a first well opening section and a second well opening section. The first well opening section comprises a first casing pipe, and first well cementation cement is arranged between the inner wall of the first well opening section and the first casing pipe; the second well opening section is provided with a second casing pipe, second well cementation cement and a central casing pipe; a distance is arranged between the second casing pipe and the well wall of the second well opening section, second well cementation cement is arranged between the center casing pipe and the second casing pipe, a water stopping device is arranged at the upper end of the second well cementation cement and is of a reducing structure with the diameter sequentially increased from top to bottom, and the inner wall of the top end of the water stopping device is connected with the center casing pipe. The bottom end of the water stop device is connected with the second sleeve; a packing structure is arranged at the bottom end of the second well cementation cement, and a permeable section is arranged at the lower end of the packing structure. The invention further provides a construction method of the geothermal well structure. The structure is reliable, the heat exchange efficiency is improved, and the industrial long-term operation requirement is met.

The invention relates to the field of rock salt mine well drilling water solution mining, in particular to a device for enhancing the strength of a well cementation cement sheath, which comprises a connecting pipe arranged at the bottom of a production casing; a woven spring is arranged in the spring box, and the spring box is fixed at the bottom of the connecting pipe; the spring laying mechanism comprises a first elastic piece, a second elastic piece, an anchor rod and a trigger device, wherein the first elastic piece and the second elastic piece are fixed to the outer side of the connecting pipe. The first elastic piece is connected with the triggering device, the triggering device can be started according to the diameter change of well cementation, the second elastic piece is released after the triggering device is started, and the second elastic piece pushes the anchor rod and fixes the anchor rod to the inner wall of a drilling well; when well cementation is conducted through the device, the thickness of the outer ring space of the production casing of the ore-bearing section can be increased, a cement sheath with the high overall structural strength can be formed after springs are automatically arranged and cement is automatically poured in the hole expanding section, and the production casing of the ore-bearing section is prevented from being damaged. And the service life of the production sleeve is further prolonged.

The invention relates to the technical field of well cementation operation, in particular to an automatic well cementation multi-channel integrated control device which comprises a main valve body, a rotary valve element, a gland and a driving device, the main valve body is provided with a mounting cavity with an upward opening, the rotary valve element with the upper end located above the mounting cavity is arranged in the mounting cavity, and the rotary valve element is rotationally connected with the main valve body; the rotary valve element is provided with a communicating cavity with a downward opening, a gland fixedly installed together with the outer side of the upper end of the main valve body is arranged on the outer side of the upper portion of the rotary valve element, the rotary valve body is rotationally connected with the gland, and a driving device capable of driving the rotary valve element to rotate is arranged at the upper end of the rotary valve element. The quick switching valve is reasonable and compact in structure and convenient to use, through holes in different positions communicate with the communicating cavity by rotating the rotary valve element, and therefore quick switching of different working solutions is achieved; the forward blades and the reverse blades are arranged, so that two paths of cement paste are fully and uniformly mixed; and by arranging the station display device, the current working state is visually displayed, and the device has the characteristics of stability, reliability and high efficiency.

The invention discloses a multistage self-locking type ball catching circulating short section for half-way well cementation and a control method, and relates to the technical field of oil well cementation operation, the multistage self-locking type ball catching circulating short section comprises a short section assembly, the short section assembly comprises an outer shell, a discharge port is formed in the top of the outer shell, a displacement assembly is arranged in the outer shell, and the short section assembly comprises a sliding sleeve connected into the outer shell in a sliding mode; a containing groove is formed in the outer ring of the sliding sleeve, a first ball is slidably connected into the containing groove, an upper connector is fixed to one end of the outer shell, and a lower connector is fixed to the other end of the outer shell. The non-return structure has the beneficial effects that through the arrangement of the short section assembly and the limiting assembly, after the second ball body is put in, the displacement assembly can be driven to slide and displace in cooperation with continuously-fed media and pumping pressure, non-return locking operation is completed, the second ball body is prevented from being disengaged at will, the bypass requirement is well met, and compared with a traditional spring and rubber part non-return structure, the non-return structure is simple in structure and convenient to use. The stability is better, and the well cementation operation is well carried out.

The present disclosure relates to the technical field of petroleum extraction, and disclosed are a forward and reverse circulation combined cementing tool and method, aiming to solve the problem of poor adaptability when using forward or reverse circulation cementing alone. The forward and reverse circulation combined cementing tool comprises a cross-circulation sub (2) and a reverse circulation cementing choke float shoe (3) which are arranged from top to bottom; the reverse circulation cementing choke float shoe (3) comprises a choke assembly (33) and a one-way valve (32), and the choke assembly (33) comprises a control module (332) and a choke module (333). The forward and reverse circulation combined cementing tool and method make full use of the advantages of forward and reverse circulation cementing processes, achieving pressure balance and cement slurry delivery, solving the problems of ultra-long cementing sections and complex formation cementing, greatly improving cementing quality and construction efficiency, and the cementing tool and method are suitable for cementing operations in oil and gas wells under complex geological conditions.

The utility model discloses a float collar and a well cementation casing system. The float collar comprises a shell, an inner plug bush and a check valve core, wherein the inner plug bush and the check valve core are arranged in the shell; the check valve element is arranged below the inner inserting sleeve, and oil well cement is filled between the inner wall of the shell and the outer wall of the inner inserting sleeve and between the inner wall of the shell and the check valve element. The inner plug bush comprises a first hole section and a second hole section, and the aperture of the first hole section is larger than that of the second hole section; the first hole section is used for being matched with an inner pipe cementing plug, the second hole section is used for being matched with a drill rod rubber plug, and the second hole section is provided with a clamping spring groove so as to be matched with a clamping spring of the drill rod rubber plug to limit the drill rod rubber plug. The problems of easy plug reserving, empty replacement and the like of inner pipe method well cementation can be solved, and the well cementation construction risk is reduced.

The invention provides a self-repairing microcapsule as well as a preparation method and application thereof, and belongs to the technical field of self-repairing of well cementation cement-based materials in oil and gas well engineering. The preparation method of the self-repairing microcapsule comprises the following steps: uniformly mixing gamma dicalcium silicate powder with nano calcium carbonate powder to obtain a capsule core material; the preparation method comprises the following steps: by taking a mixed solution of ethanol and water as a solvent, sequentially adding a silicon source, a capsule core material and a dispersing agent, uniformly dispersing to form sol, adjusting the pH value to 9-11, and carrying out hydrolytic polycondensation to obtain the silica-coated gamma-type dicalcium silicate and nano calcium carbonate microcapsule; adding the silica-coated gamma dicalcium silicate and nano calcium carbonate microcapsule into an EVA (Ethylene Vinyl Acetate) hot melt adhesive solution, and carrying out spray drying to obtain the self-repairing microcapsule. By the adoption of the technical scheme, the microcracks of the cement stone of the CO2 geological storage well can be effectively and efficiently repaired, and the long-term integrity of the cement stone of the deep well and safe and permanent storage of CO2 can be guaranteed.

The invention discloses low-temperature coagulation-accelerating anion styrene-butadiene latex for oil field well cementation and a preparation method of the low-temperature coagulation-accelerating anion styrene-butadiene latex. The low-temperature coagulation-accelerating anion styrene-butadiene latex comprises the following components in parts by mass: 100 parts of anion styrene-butadiene latex raw stock; 4 to 10 parts of a nonionic surfactant I; 2 to 4 parts of a nonionic surfactant II; 10 to 20 parts of water glass; 0.5 to 1 part of a defoaming agent; and 15-20 parts of deionized water. The low-temperature coagulation-accelerating anionic styrene-butadiene latex prepared by the invention is used in cement paste, has short thickening time at low temperature, can resist sodium chloride brine to reach semi-saturation, and can effectively control the water loss of the cement paste, improve the anti-channeling performance of a cement paste system, reduce the elastic modulus of set cement, increase the density of the set cement and improve the stability of the set cement. Therefore, formation gas is effectively prevented from invading cement stone, and well cementation quality is guaranteed.

The invention relates to an assembling method of a standard ring pipe piece for a sunken vertical shaft and a related equipment structure thereof. The method mainly comprises the steps of construction preparation, standard ring pipe piece hoisting, continuous hoisting and adjusting, fixing and stabilizing, installation and overall finishing, well cementation, construction completion and the like. Through the specially-made lifting appliance for lifting the duct pieces, accurate lifting and positioning of the duct pieces are achieved, and the stability of connection of the duct pieces and the strength of the whole structure are ensured by combining the shear steel and the U-shaped bolt assembly. The invention further describes the structural design of the standard ring pipe piece and the lifting appliance in detail, so that the construction efficiency is improved, the construction quality is guaranteed, and solid technical support and safety guarantee are provided for construction of the sunken vertical shaft. By means of the splicing method, efficient and accurate splicing of the standard ring pipe pieces can be achieved, and then the overall quality and efficiency of vertical shaft construction are improved.

A method of cementing a geothermal wellbore includes pumping a first volume of cement slurry down a wellbore. The first volume of cement slurry has a first water to cement ratio. A second volume of cement slurry is pumped down the wellbore. The second volume of cement slurry has a second water to cement ratio that is less than the first water to cement ratio. The first volume of cement slurry hardens at a vertical portion of the wellbore, and the second volume of cement slurry hardens at a horizontal portion of the wellbore.

The invention is applicable to the technical field of ash sample sampling, and provides a well cementation ash sample sampler, which comprises a connecting pipe, a sampling part arranged on the side wall of the connecting pipe, a sampling cavity horizontally arranged in the connecting pipe, and a sampling part arranged on the side wall of the sampling part, one end of the sampling cavity is communicated with the connecting pipe; a sampling opening is formed in the bottom of the sampling cavity and is in threaded connection with a sampling barrel, and a first piston plate is slidably connected into the sampling barrel in the length direction of the sampling barrel; a plugging piston is slidably connected in the sampling cavity in the length direction of the sampling cavity, two first sealing rings are arranged on the side wall of the plugging piston, and a first soft scraping ring is installed at the end, close to the connecting pipe, of the plugging piston. By means of the detachable sampling barrel and the mode that the sampling opening is opened and closed to block the piston, dust cannot be raised in the air when a dust sample is taken; and the plugging piston is matched with the soft scraping ring I to push redundant ash in the sampling cavity into the connecting pipe again.

The invention discloses deep coal bed gas well cementation cement paste and a preparation method thereof, and the deep coal bed gas well cementation cement paste is prepared from the following raw materials in parts by weight: 100 parts of G-grade oil well cement, 5-15 parts of water-borne epoxy resin, 1.5-3 parts of a nano silicon dioxide solution, 0.5-1.8 parts of calcium sulfate whiskers, 0.2-0.6 part of composite coating fibers, 1.2-1.8 parts of a fluid loss agent and 0.5-1.8 parts of a retarder. 0.3 to 0.5 part of a drag reducer, 0.2 to 0.5 part of a defoaming agent and 38 to 42 parts of water; wherein the composite coating fiber is hydrophilic epoxy resin modified polyethylene fiber. The cement paste can improve the well cementation cementing packing quality of a coal seam, and has good filtration property.

The invention relates to the technical field of oil and gas field development, in particular to well cementation self-healing cement paste and a preparation method thereof. The concrete is prepared from the following components in parts by weight: 4 to 6 parts of repairing agent, 41 to 53 parts of cement, 18 to 22 parts of silica fume, 0.1 to 0.5 part of basalt fiber, 1 to 5 parts of expanding agent, 0.3 to 0.9 part of fluid loss agent, 0.2 to 0.4 part of bentonite, 1.7 to 2.3 parts of naphthalene sulfonate formaldehyde condensate, 0.1 to 0.2 part of simethicone and 1 to 3 parts of retarder, wherein the repairing agent is formed by modifying ethyl cyanoacrylate, candelilla wax and 3-isocyanate propyl trimethoxy silane according to the mass ratio of 1: (1-2): (0.1-0.3). According to the invention, ethyl cyanoacrylate is used for repairing micro cracks of cement, candelilla wax and nano silicon dioxide are used for carrying out microencapsulation to protect ethyl cyanoacrylate, and methoxy groups of 3-isocyanate propyl trimethoxy silane enhance the interface bonding force between microcapsules and a cement slurry system, so that the service life of a cement structure is effectively prolonged.

The utility model relates to the technical field of float collars and float shoes, and discloses a float collar and float shoe for well cementation of a deep well, which comprises a pipe body, G-grade cement is fixedly connected in the pipe body, a valve body is fixedly connected at the bottom of the G-grade cement, a spring is arranged in the valve body, a ball seat is slidably connected in the valve body, a ball body is fixedly connected at the top of the ball seat, and the top of the ball seat is fixedly connected with the spring. A twisted rod is fixedly connected to the bottom of the ball seat, a cross seat is rotatably connected to the periphery of the twisted rod, and a plurality of brushes are fixedly connected to the top of the cross seat. By arranging the pipe body, the G-grade cement, the valve body, the spring, the ball seat, the ball body, the twisted rod, the cross seat, the brush and the like, silt attached to the periphery of the spring can be cleaned, and the situation that due to the fact that too much silt is deposited in cement paste in the valve body, the too much silt attached to the periphery of the spring hinders stretching and retracting of the spring is prevented; the using effect of the valve body becomes poor, and the cement paste conveying efficiency is reduced.

The invention belongs to the field of well cementation devices, and discloses a well cementation grouting centralizer, a casing pipe and a packer, a positioning cylinder is connected with the casing pipe or the packer, a centralizing cylinder is connected with the positioning cylinder through a connecting rod, and after centralizing wings of the centralizing cylinder are blocked by broken stones when descending a well, the resistance of the broken stones can drive a pressed rotating mechanism to rotate, so that the well cementation grouting centralizer is used for well cementation grouting. At the moment, the centralizing cylinder drives the connecting rod and the limiting ring to rotate relative to the positioning cylinder, so that the centralizing wings rotate to stagger the broken stones on the well wall, after avoiding, the centralizing cylinder rotates through reset driving of the reset assembly, the next avoiding work can be normally carried out, and the broken stones can be accurately avoided in the mode that the centralizing cylinder is pressed to rotate to avoid the broken stones. The centralizing cylinder can independently rotate relative to the positioning cylinder, so that the positioning cylinder can independently rotate after being mounted on a packer or a sleeve, and rotation of the sleeve and rotation of the packer are not affected.

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.

The invention belongs to the technical field of geothermal energy development and utilization, and particularly relates to efficient extraction equipment for a deep geothermal exploitation well, which comprises a plurality of water pumping devices, the plurality of water pumping devices are sequentially communicated in series through a plurality of extension pipe fittings, and the water pumping device close to a wellhead is fixedly connected with a steel wire rope on hoisting equipment; the water pumping device comprises a water pumping mechanism, a well cementation assembly and a guide mechanism, the outer wall of the water pumping mechanism is sleeved with the well cementation assembly, the well cementation assembly is used for making friction contact with the well wall so as to keep the working position of the water pumping mechanism in a well, and the guide mechanism is arranged at the bottom end of the water pumping mechanism and used for guiding the water pumping mechanism to work. And the guide mechanism is used for smoothly lowering the water pumping mechanism into the well and keeping the water pumping mechanism coaxial with the well body. It is guaranteed that the water pumping mechanism is stably fixed in a well, smoothly lowered to the bottom of the well and always coaxially positioned with the well body, and the stability of extraction operation is improved.

The invention discloses a CO2-heavy salt water collaborative sealing device and sealing method, and relates to the technical field of crossing of unconventional oil and gas reservoir development and carbon sealing technology, a drilling structure extends to a fluid sealing storage layer from the earth surface in the vertical direction, and the part, located on the fluid sealing storage layer, of the drilling structure gradually inclines in the horizontal direction from top to bottom; the bottom end of the base extends in the horizontal direction; the casing pipe structure is arranged in the well drilling structure and extends synchronously with the well drilling structure, and a well cementation structure is arranged between the part, located above the fluid seal storage layer, of the casing pipe structure and the well drilling structure; the sleeve structure is located in the fluid sealing storage layer, and a liquid outlet is formed in the horizontally-extending part of the sleeve structure. The inner pipe structure is located in the sleeve structure, a gap is formed between the inner pipe structure and the sleeve structure, the bottom end of the inner pipe structure is located in the horizontally-extending part of the sleeve structure and provided with a gas outlet, and the problem that in the prior art, the absorption efficiency is low in the gas-liquid fluid mixing process, and consequently efficient fluid mixing cannot be achieved is solved.

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.