1779 results about "Well cementing" patented technology

A wellhead system includes a wellhead housing and a hanger configured to support a casing within the wellhead housing. The hanger includes one or more passages formed through the hanger. The wellhead system also includes a seal assembly configured to move relative to the hanger to selectively enable a flow of fluid across the hanger via the one or more passages. The hanger, the seal assembly, and a lock ring may be run together into the wellhead housing.

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 relates to the technical field of downhole packer tools, in particular to an ultra-short radius sidetracking well flexible pipe outer packer which comprises an upper connector and a central pipe. The rotary bending device is reasonable and compact in structure and convenient to use, the upper connector and the center pipe can be rotationally bent to form a certain angle through the ball journal and the pressing cap, rigid connection between the upper connector and the center pipe in the prior art is converted into flexible connection, and the rotary bending device can smoothly pass through the inclined face and the deflecting section of the whipstock to reach the preset position; through well mouth pressing and pressure building, the packer can be reliably set on the well wall of a horizontal well section, a well hole is packed, and the purposes of half-way well cementation, staged and staged fracturing, reservoir transformation and the like are achieved; due to the fact that the center pipe can automatically rotate to adjust the angle between the center pipe and the upper connector under the action of well walls with different curvatures or inclined faces, the center pipe can better adapt to small-curvature well holes and irregular well walls, the friction force between the center pipe and the well walls is effectively reduced, and the center pipe is prevented from being clamped in a whipstock or the small-curvature well holes and damaging tools.

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 relates to the field of oil and gas well cementation, and discloses an oil well cementation cement slurry system and application thereof. The cement paste system comprises the following components in parts by weight: 100 parts of oil well cement, 20-80 parts of a high-temperature stabilizer, 15-80 parts of a high-temperature reinforcing agent, 0.5-6 parts of a retarder, 2-10 parts of a fluid loss agent, 0.1-2 parts of a defoaming agent and 35-90 parts of water, wherein the high-temperature stabilizer is a mixture containing quartz sand, silica fume and nano-silica which are different in average particle size; the high-temperature reinforcing agent is selected from at least one of pyrophyllite, epidote, actinolite, aluminum stone, sillimanite and boehmite. The cement paste system is mixed by adopting a conventional method, the density and the thickening time are adjustable, the flowing property is good, the water loss is small, the strength of formed cement stone is high, the cement stone does not decline for a long time at the high temperature of 150-240 DEG C, and the technical requirements of deep and ultra-deep high-temperature and high-pressure well cementation construction are completely met.

The invention relates to the technical field of numerical simulation, in particular to a grid model generation method for the fluid displacement process of well cementation engineering. The method comprises the following steps: acquiring geological data of a well cementation project area, and constructing an initial geological model; well cementation engineering design data are obtained, well cementation engineering topological structure modeling is carried out, and a well cementation engineering topological structure model is obtained; according to the initial geologic model and the well cementation engineering topological structure model, fluid dynamic simulation is carried out, and a fluid characteristic matrix is obtained; performing fluid displacement process simulation according to the fluid characteristic matrix to obtain fluid displacement process data; performing fluid displacement process optimization on the well cementation engineering design data based on the fluid displacement process data to obtain optimized fluid displacement process data, and performing resource allocation redistribution on the well cementation engineering design data according to the optimized fluid displacement process data to obtain optimized well cementation engineering design data. According to the invention, the accuracy of fluid displacement simulation can be improved.

The invention relates to the technical field of petroleum well cementation, in particular to a drilling-free graded cementing device and a using method.The drilling-free graded cementing device comprises a cementing device body, a plurality of limiting pieces, connecting rings, an opening seat, a sliding plug and a pressing plug, a plurality of liquid outlet holes are formed in one sides of a plurality of connecting grooves correspondingly, and baffle rings are arranged on one sides of the connecting grooves; the multiple limiting pieces are arranged in the connecting grooves correspondingly, each limiting piece comprises a sliding block and a limiting block, the sliding blocks are arranged on one side of the baffle ring in a sliding mode, the limiting blocks are fixedly connected with the sliding blocks, the connecting ring is fixed to the bottom of the cementing device body, the opening seat is arranged at the bottom of the connecting ring in a sliding mode, and multiple communicating holes are formed in the sliding plug. The sliding plug is arranged in the opening seat, the longitudinal sliding position of the sliding plug is limited through the limiting block, and the pressing plug is arranged at the top of the sliding plug and used for pushing the sliding block to relieve limitation of the limiting block to the sliding plug. Graded cement injection can be carried out more conveniently, drilling is not needed after cement injection is completed, and the construction efficiency is improved.

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 gas / oil well mouth sealing equipment, in particular to an inner inserting pipe type well cementation well mouth sealing device structure which comprises a drill rod radish head, a first annular protrusion I, a second annular protrusion II, a sealing ring, a sealing ring, a sealing ring and an inner inserting pipe sealing ring, the outer cylindrical face of the drill rod radish head is provided with a first annular protrusion I, and the lower end face of the first annular protrusion I is a conical slope b; a second annular bulge II is arranged on the inner wall of the upper section part of the sleeve joint, and the upper end surface of the second annular bulge II is a conical inclined surface c; a central hole is formed in the pressing cap; the drill rod radish head seat is placed in the sleeve joint, the conical inclined surface b is adaptively propped against the conical inclined surface c, and a sealing ring is arranged between the conical inclined surface b and the conical inclined surface c; a pressing cap is arranged on the radish head of the drill rod from top to bottom in a sleeving mode, abuts against the conical slope a and is connected with the sleeve joint in a threaded fit mode; cement paste is injected into a well through the drill rod, and the cement paste directly enters a gap between the stratum well wall and the casing pipe from the lower end of the drill rod, so that well cementation is achieved. The sealing device has the beneficial effects that the sealing effect is excellent, and the situation of sealing failure is not prone to occurring; the structure is simple and cost is low.

The invention discloses a high-temperature and high-pressure well cementation interface shear cementing strength measuring device and method, and belongs to the field of oil and gas well cementation. The device comprises a kettle body, an oil storage tank, a hydraulic pump, an electric control system, a display, a supporting frame and a base, wherein the kettle body comprises a top cover, an upper kettle, a lower kettle, a bottom cover, a simulation sleeve, a simulation stratum, a positioning steel cylinder, a piston cylinder body, an inner piston, an outer piston and a floating bearing plate. The method comprises the following steps: pouring cement paste into an annular space between a simulation casing and a simulation stratum; curing the cement paste at constant temperature and constant pressure; slowly increasing the pressure of the inner cavity of the piston, and enabling the inner piston to move downwards until the simulation sleeve is separated from the cement sheath; the pressure of the inner cavity of the piston is continuously increased, and the outer piston moves downwards under the pushing action of the inner piston until the cement sheath is separated from the simulated stratum. The test process is controllable, the test result conforms to the underground environment, and an important technical means is provided for optimizing the cement slurry performance and well cementation process parameters and further improving the well cementation quality of an oil and gas well.

The invention relates to the technical field of well cementation, in particular to construction of oil wells and / or gas wells or geothermal energy. More specifically, the subject matter of the present invention is a cementitious composition and an improved well cementation method by introducing a polymeric microgel into the cement as an anti-gas migration agent.

Rotating a casing during a cementing operation to ensure efficient displacement of cement slurry. More specifically, embodiments are directed towards a sub and rotating tool that are positioned above a first cement operation, wherein the rotating tool is positioned in a kickoff point or build section of a horizontal well.

The invention relates to the technical field of well cementation engineering tools, and discloses an anti-falling float collar float shoe which comprises a float collar, a sleeve and a float shoe, the float collar, the sleeve and the float shoe are sequentially arranged from top to bottom, the float collar comprises a first pipe body, a first anti-falling connecting piece and a first one-way flow guide piece, the first one-way flow guide piece is arranged in the first pipe body, and the first anti-falling connecting piece is connected with the first one-way flow guide piece. The first pipe body is arranged at the upper end and the lower end of the first pipe body and used for preventing cement paste from flowing back into the casing pipe, and the first anti-disengaging connecting pieces are arranged at the upper end and the lower end of the first pipe body correspondingly. The design of the first one-way flow guiding piece and the second one-way flow guiding piece ensures that the cement paste can flow forwards into an annular space between the casing pipe and the well wall in the well cementation process; and cement paste is effectively prevented from flowing back to the interior of the casing pipe, so that the stability and the sealing performance of the casing pipe can be kept, and the casing pipe has the advantages of being high in practicability and firmness.

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 discloses a low-temperature early-strength cement slurry system based on a cellulose-based composite phase change material, and belongs to the field of oil and gas field well cementation. The preparation method of the composite phase change material comprises the following steps: adding pretreated waste paper fibers, a cross-linking agent and a heat conduction material into an alkali / urea solution, and putting the mixture into an ultrasonic cleaning instrument to obtain a mixture A; transferring to a dialysis bag, and soaking in deionized water to obtain a mixture B; and performing in-situ mixing on the mixture C and organic phase change material molecules to obtain a mixture C, and performing vacuum freeze drying. The low-temperature early-strength cement slurry system is prepared from the following components in parts by weight: 100 parts of cement, 0.3-1 part of a composite phase change material, 5-25 parts of a density reducing material, 0.1-0.8 part of an early strength agent, 0.2-1 part of a dispersing agent, 0.2-2 parts of a fluid loss agent, 0.01-0.5 part of a defoaming agent and 44-58 parts of water. While cement hydration heat release is regulated and controlled, the early compressive strength of the cement can be improved, and the operation time efficiency and the construction safety are improved.

The invention relates to the technical field of oil and gas well cementing cement paste, and discloses an anti-corrosion material for cement paste, carbon dioxide corrosion resistant cement paste and a preparation method and application of the carbon dioxide corrosion resistant cement paste. The anti-corrosion material comprises a mixture A and a mixture B, wherein the mixture A comprises activated carbon, nano silicon dioxide and nano aluminum oxide; the mixture B comprises a component C and a component D; the component C is selected from diatomite and / or fly ash; the component D is selected from one or more of metakaolin, pumice and coal gangue. The anti-carbon dioxide corrosion cement paste prepared from the anti-corrosion material has good anti-corrosion capability in a CO2 corrosion environment, the compressive strength of set cement before corrosion is higher, the structure is compact, the compressive strength of the set cement after corrosion is not obviously reduced, the permeability is small, the mechanical property is good, the sedimentation stability is good, the rheological property is good, and the like. And the well cementation quality of the CCUS well is guaranteed, and efficient storage of CO2 is achieved.

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.

An improved method and apparatus for dropping a ball, plug or dart during oil and gas well operations (e.g., cementing operations) employs a specially configured valving member with curved and flat portions that alternatively direct fluid flow through a bore or opening in the valving member via an inner channel or around the periphery of the valving member in an outer channel. In one embodiment, the ball(s), dart(s) or plug(s) are contained in a sliding sleeve that shifts position responsive to valve rotation. An optional indicator indicates to a user or operator that a ball or plug has passed a selected one of the valving members.

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 invention discloses a water-non-dispersible cement paste system for well cementation. The water-non-dispersible cement paste system comprises the following components in parts by weight: 100 parts of oil well cement, 2-3 parts of an expanding agent, 1-5 parts of an anti-dispersing agent, 0.5-2 parts of a drag reducer, 0-0.1 part of a defoaming agent and 40-45 parts of water, the anti-dispersing agent is formed by copolymerizing the following components in percentage by mass: 15 to 60 weight percent of acrylic acid, 0 to 15 weight percent of N, N-dimethyl acrylamide, 30 to 85 weight percent of acrylamide, 0 to 10 weight percent of N-vinyl pyrrolidone and 0 to 1.5 weight percent of ethylene diamine tetraacetic acid disodium salt; the drag reducer is obtained by graft polymerization of a polyacrylic acid monomer and fatty acid vinyl ester in a molar ratio of (8-36): 1; the polyacrylic acid monomer is formed by copolymerizing 2-acrylamido-2-methylpropanesulfonic acid, acrylic acid, sodium p-styrenesulfonate and acrylamide according to a molar ratio of (0.08 to 0.6): 1: (0.05 to 0.3): (0.1 to 1); the water non-dispersible cement paste system for well cementation has good dispersion resistance and flowing property, and the water invasion resistance of the cement paste is effectively improved.

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.